Signs of Winter 11: The Great Backyard Bird Count

Photo by rhaij, Pixabay

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Starting tomorrow (February 16th) and running until Monday (February 19) the Cornell Laboratory of Ornithology, Birds Studies Canada and the National Audubon Society are sponsoring their annual “citizen’s science” project called “The Great Backyard Bird Count” (GBBC). This world wide count of birds began in 1998 and has grown in scope and participation with each passing year. Participants are asked to spend fifteen minutes either stationary at some observation point or walking through a habitat counting and identifying the birds they see. On-line checklists developed by eBird facilitate the reporting of these observations, and the compilation of the data from the observers seems to be nearly instantaneous!

If you are interested in participating in the count click here for more information!

Some highlights of last year’s count (found on the GBBC web site) include the total number of checklists submitted (181,643) and the total number of people submitting one or more checklist (210,000). A total of 6,261 species of birds were identified and 29,604,680 birds were counted! This was, indeed, a very robust survey of birds!

Photo by D. Sillman

There was a distinct North America bias to last year’s count as 62% of the checklists came from the United States. The ten most frequently mentioned species on the lists were also all very common North American species (led by the northern cardinal and the American crow), and all of the top ten most numerous birds in the count were also North American species that are found in large flocks (the 4,793, 261 snow geese topped this list!). There is, though, a growing international participation in the count with birders from 140 countries participating! Pennsylvania, by the way, was second only to California in total number of checklists submitted, and looking down the list of names of participants who filled out check lists from Pennsylvania counties, I found a number of regular readers of this blog! Let’s try to get even more of us out there this year!

Photo by E. Denes, Wikipedia Commons

Some observations from the 2017 GBBC include the continuing southerly drift of a number arctic and northern forest dwelling bird species. The pink-footed goose, for example, a Greenland species that a few decades ago was almost never seen in North America now is regularly observed by GBBC participants in Nova Scotia, Connecticut, New York and New Jersey! The great grey owl, a species of the northern, boreal forest of Canada and Alaska (and the northern mountains of U.S. Rockies and Cascades) was observed in northern Minnesota and New York. The great grey owl is the largest North American owl and has a voracious need for food in the winter (each owl must

Photo by A. List, Wikimedia Commons

eat seven, vole-sized mammals each day to sustain themselves). Limited food supply in their Canadian ranges is thought to be the ecological force pushing them southward into the Lower Forty-eight Sates.

Also, the Bohemian waxwing, a slightly larger version of the relatively common cedar waxwing, is like the grey owl a bird of the northern boreal forest and muskeg. Like the cedar waxwing, the Bohemian waxwing forms large, foraging and migrating flocks that may wander over vast areas that includes parts of the western Lower Forty-eight States. In 2017, though, GBBC observers reported 200 Bohemian waxwings in New Hampshire, including a flock of 40 feasting on crabapples!

The relatively mild winter weather last year had two interesting impacts: 1. It may have been responsible for the reduction in overall numbers of birds reported from bird feeder stations across the country (it is hypothesized that many birds in the warmer than average conditions relied more on natural foods rather than human-provided seeds and suet), and 2. A number of migrating species arrived in their spring and summer ranges many weeks before historical averages. These included common grackles and red-winged blackbirds in the Eastern United States and Canada (they were widely spread in both areas in late February), killdeer and American woodcock in New England and around the Great Lakes (they also arrived there in mid to late February), and tree swallows setting historically early spring arrivals in Illinois, Quebec and Massachusetts.

Photo by D. Wicks

Greater sandhill cranes ( a species I have discussed in posts from New Mexico and from Wyoming) are also found here in the Eastern United States. Most of these eastern sandhill cranes migrate to Florida in the winter and to areas around the Great Lakes (especially Wisconsin and Michigan) in the summer (although there is a small sub-population of Florida cranes that stay in Florida year round and do not migrate). To the left is a picture of a yard-full of sandhill cranes in Florida that a friend (Don Wicks) just sent me (probably to taunt me with their “cold” 63 degree weather!). Observations by GBBC participants on these cranes indicate that some of them are overwintering further north than ever before (in Alabama’s Wheeler National Wildlife Refuge, for example) and are migrating north and especially to the northeast earlier and in greater numbers than ever before and breeding in places where they have not bred before. Breeding pairs of sandhill cranes, in fact, have been reported in Pennsylvania, New York and throughout New England!

The species that I counted for my all of my Great Backyard Bird Count lists were as common as could be. All of my birds were in the top ten of the “most frequently listed” species. My birding experiences don’t range into wild, exotic discoveries. My birds were cardinals, juncos, blue jays, titmice, chickadees, and crows, and I was very pleased to see them!

Some years ago I was giving a talk at a conference about Deborah’s and my Virtual Nature Trail and the actual, physical nature trail on our campus that was the inspiration for it. At the end of my presentation I was asked a question, “what was special, or unique about this nature trail?” I sensed an undertone to the question of “why would anyone want to go see this trail?” Usually you come up with answers to questions like this much later, but somehow I found the answer right away: There is nothing particularly unique or “special” about this trail, and this is what makes it so important. It is the beauty in the ordinary, as Bill Bryson once put it “the low level ecstasy” of the common species and common terrain that make this site so wonderful. Sitting back and seeing what is around you in nature always elevates and inspires you!

And, to me, this is what makes the Great Backyard Bird Count and the sight of all of those ordinary birds that every day gobble down my sunflower seeds, corn, peanuts and thistle, so amazing. They are common but each individual is a work of wonder and beauty!

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Signs of Winter 10: Parasites and Pathogens

Dog tape worm. Photo by CDC. Wikimedia Commons

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Parasites and pathogens often have very obvious effects on the their hosts. Some parasites (like tapeworms, for example) basically steal a percentage of their host organism’s food and, thus, reduce the energy available to the host for growth, movement, or reproduction. In mildly competitive environments a parasitized individual may function quite well, while in more intensely competitive (and stressful) environments, the parasitized individual may perish. It is in the parasite’s great short-term interest to preserve the host in which it resides: parasites don’t “want” to kill their hosts right out. They “want” to use them as a  habitat and an energy source for as long as possible unless, of course, the continued existence of the host presents a barrier to the parasite’s reproduction or dispersal. Pathogens, on the other hand, seem less concerned with the preservation of their hosts possibly because of their already extremely well developed (and very efficient) mechanisms of dispersal.

Parasites and pathogens (and the variations of reactions to them by individuals in a host species’ population) can be very powerful forces for population control and also for evolution. In a population under assault by a particular parasite or pathogen any individual that even has a slight resistance to infection or disability would logically be more likely to survive and reproduce and pass along those resistance traits to their offspring.  So, exposure of a population to a parasite or pathogen over evolutionary time would be expected to result in that population becoming less and less vulnerable to these maladies.

“British” red squirrel. Photo by P. Trimming. Wikipedia Commons

This evolutionary logic sets up some very interesting interactions when a species enters a new environment. For example, some invasive species carry parasites or pathogens to which they have evolved significant resistance. Native species that are similar to these invasive organisms, though, may have very weak resistances to the invader’s parasites or pathogens. The North American gray squirrel, for example carries, with few health consequences, a parapoxvirus. When the gray squirrel was introduced into Great Britain it encountered the British red squirrel which occupied a very similar ecological niche. The red squirrel, though, had no evolutionary history of exposure and adaptation to the parapoxvirus, and , as a consequence, was weakened by infection and then decimated by subsequent competition with the healthy, vigorous gray squirrel.

Similar “parasite/pathogen” aided species invasions have been seen in Asian cyprinid fish that oust native fish from streams in Europe, in garlic mustard plants deploying their toxic mycorrhizal fungi against potential competing plants throughout North America, and in invasive American bullfrogs spreading their self-tolerated fungus (Batrachochytrium) to almost all other native (and highly vulnerable) amphibian species. Introduced pheasants in the United Kingdom also carried a fungus (Heterakis gallinarum) to which they were evolutionarily adapted but to which the U.K. native partridges, much to their great detriment, were not.

Photo by J. Clardy. Wikimedia Commons

Sometimes an invasive species does not bring the parasite or pathogen with them, though. Sometimes the invader is just naturally more resistant to a native parasite or pathogen than the native species are. The possible mechanism for this may involve prior evolutionary exposure of the invader to similar pathogens, but it may just be a consequence of chance. For example, vineyards in California are being overwhelmed by invasive, grapevine-damaging leaf hoppers that are resistant to the native parasites and parasitoids that keep native leaf hopper populations under control. The native leaf hoppers, then, are being extirpated from their habitats, and the grape crops are being severely damaged as a consequence of this ecological imbalance.

In another example, invasive, often intentionally introduced, European brown trout aggressively push native fish species into warmer, lower current flow sections of their streams. This exposes the native species to higher levels of parasite exposures and higher levels of debilitation and mortality. Similar patterns are seen in the invasion of South African mussel beds by trematode resistant Mediterranean mussels, and in the red introduced fire ants in the American South that are unaffected by the parasitoid wasps that greatly reduce the activity of many native ant species. Numerous invasive grasses and weeds are also able to flourish in their new environments because of their innate (and maybe serendipitous) resistance to some controlling virus or fungus that regulates populations of native plants.

Photo by A. Wild, Wikimedia Commons

There are some examples of the opposite, regulatory serendipity, too. Some invading species turn out to be more sensitive to controlling parasites or pathogens than native species. Red invasive fire ants, for example, may be unaffected by native parasitoid wasps but they are much more sensitive to an exotic parasitoid than are native ants. This observation suggests a possible program of biological control for the southern U. S. through the introduction of these exotic parasitoids. In another example, the North American eastern white pine has turned out to be exquisitely sensitive to the European endemic blister rust fungus. Introduction of the eastern white pine into Europe, then, has not been possible nor has there been any invasion of European forests by the eastern pine occurred because of this sensitivity.

Parasites and pathogens may also alter host organisms’ behaviors often to allow the parasite or pathogen to continue on its life cycle. There are some anecdotal accounts of humans that are infected with viral pathogens tending to be more social and more likely to be clustered together with other (possibly un-infected) humans. This tendency is ascribed to the “need” of the virus to escape its infected host and find a fresh human environment in which it can proliferate. Happy flu season, everyone!

Photo by h.hach, Pixabay

There are also some scientifically rigorous studies that have shown that rodents infected with Toxoplasma gondii (a protozoan parasite) are less vigilant around predators (like cats) and are even, in fact, drawn to cats (and the scent of cat urine). These reactions suggest a level of control by the parasitic T. gondii (that “wants” to get into the body of the cat so that it can carry out its reproductive life cycle) over the T. gondii carrying rodent host (that presumably does not really “want” to get eaten!).

This idea that a parasite can control the behavior of its host even to the detriment and death of the host itself expresses itself in many other parasite-host systems. For example, hairworms (Nematomorpha) cause infected crickets to seek bodies of water into which they can plunge themselves and drown. The hairworm is then able to leave the dead cricket’s body, find a mate in the body of water, reproduce and start a new life cycle. Bad for the cricket but very good for the hairworm.

“Zombie ant.” Photo by D. Hughes (Penn State). Flickr.

Another example of parasite control over a host was recently published in the Proceedings of the National Academy of Science by a group of Penn State researchers. They looked at the interaction of a fungal parasite (Ophiocordyceps unilateris) with a carpenter ant (either Camponotus castaneus or Camponotus americanus). The infected ants are referred to as “zombie ants” due to their predilection to stagger up onto vegetation overhanging their colony, clamp their mandibles on the underside of a leaf or twig and then hang there until they die. Then, out of their dead bodies a fungal stalk arises from which spores are released. The spores rain down on the ant colony below and infect new individuals. Using some very elegant imaging techniques the Penn State team found that the fungus forms a dense network of cells throughout the ant’s body. These fungal cells especially wrap themselves around the ant’s muscles and take over their control (“like a puppeteer controlling a marionette,” as one researcher put it). The ant had little control over its activities by the time the fungal cellular system was fully developed. The ants were “a fungus in ant’s clothing,” according to another one of the researchers.

Parasitism is an incredibly common strategy of life! There are theories that our reflexive revulsion to parasites is, in fact, an evolutionary adaptation by which we, as potential hosts, avoid them! So wash your hands and cook your food! That’s about the best that you can do!

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Signs of Winter 9: House Cat Day Year 6!

Photo by D. Sillman

Five years ago I wrote about Groundhog Day and suggested that we change this early February day-of-prediction to focus not on an animal that is sound asleep in his grass-lined burrow dreaming of gardens to ravage, but rather on an animal with whom we could more naturally base an ecologically or culturally significant day of hope for the coming spring.

I went through the cases for using a number of different species for our new holiday. Robins, for example, are the classical spring arrival species. Also, many robin flocks spend the winter locally in close by refuges. On mild, sunny days throughout the winter flocks of robins drop into my yard and check out the leaf piles, but then they depart especially if it starts snowing on them! With their sudden appearances and departures, robins might not be a reliable enough species on which to base our new holiday.

I also suggested that bumblebees might be an excellent indicator species in recognition of the early emergence of the hibernating queens and their remarkable ability to generate body heat and survive (usually) that initial cold flight of early spring. If we force the queen bumblebees out on early February flights, though, they probably would all freeze to death. Not a very happy thought for a day of celebration!

Photo by D. Sillman

I also thought about scarlet tanagers as a species representing the long distance migrators that return to our northern habitats after a winter respite in South America. The scarlet tanagers, though, will not be around until April (much too late to get any publicity about the coming spring).

Taking all of this into consideration, I settled on what was, to me anyway, the most logical and most reliable and most available indicator species among us. That species, of course, is the house cat (Felis catus).

Cats are the most popular house pet in the United States (the Humane Society estimates that there 74 to 86 million house cats in the U.S. (as compared to “only” 70 to 78 million dogs)). As I wrote in my November 24, 2016 blog (“Our Other Best Friend”) cats have a complex relationship with humans and may be the only animal species that has chosen us as a co-evolutionary partner rather than vice-versa (hence the hypothesis that cats are not really domesticated at all but are wild animals exploiting our habitats and resources!). The resemblance of domesticated cats to their closely related wild species, the focus of many cats on places rather than people, and their perceived aloofness and self-absorption are factors that cause people to have intense feelings (both positive and negative) about cats.

Photo by D. Sillman

A cat’s inherent love of sunshine and warmth, though, make them a perfect biological agent to help us predict the nearness of the coming warm seasons! And, since they are living in our houses year round, they are available for predictive experimentation!

Five years ago on February 2, 2013 I took one of my cats, Mazie (pictured to the left), out into the snow-covered front yard (I tried to take both of my cats, but Taz sensed that something was up and disappeared into one of her magical hiding places somewhere in the house). I put Mazie down in the yard (on a nice dry towel!), and left the front porch door open. If Mazie ran for the porch, then we would have six more weeks of winter. If she stayed on her towel or started walking around in the yard thus avoiding a dash back into the house, then spring was just around the corner.

I was amazed how fast she ran back into the house! But, that year the weather suddenly turned warm. March temperatures set record breaking highs (I even remember a day when it nearly got up to ninety degrees!).  Maybe our predictive model was not articulated correctly.

Photo by D. Sillman

In 2014 and 2016 I followed the same experimental procedure, and Mazie, as I reported on this blog, responded with equal speed and agility and got back into the house almost before Deborah could take the lens cap off of her camera. In both of these years winter hung on grimly well into March. Mazie’s predictions, then, fit the observed phenomenon.

In 2016, though, Mazie’s response to the front yard was entirely different. She stepped off her towel and explored the front flowerbed, jumped at some little Pardosa spiders that were running around in the grass and seemed to enjoy herself very much, and the early onset of spring that this behavior predicted came about! We had a mild, pleasant March and April and eased our way into a warm, early summer.

Last year (2017)  Mazie not only ran back into the porch but she headed straight for the basement and hid in a box in the furnace room! Her reaction, though, did not match the resulting weather as both February and March had average monthly highs of 66 and 67 degrees! Definitely an early (and sustained) Spring!

So Mazie has been correct about the onset of Spring three out of five times! We’ll see how it goes this year!

Photo by M. Hamilton (Binx and Mora)

By the way, my daughter who has been living in Albuquerque (recently moving to an apartment in Denver, which may inhibit her House Cat Day observations) put her cats (Mora and Bella) out on House Cat Day. The predictive model is slightly altered down there in warm, sunny New Mexico, though. When her cats go outside into the southwestern sunshine they do not come back into the house until it is time for dinner. In early February, the New Mexico spring has already started! In order to make House Cat Day a worldwide event, we may need to adjust the timing model in order to compensate for variations in latitude.

Send on your own experiences and observations!

Happy Winter, everyone! (But, it’s almost time to start thinking about Spring!)

(Housecat Day 2018 is once again dedicated to Taz and Binx. They will be greatly missed forever!)


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Signs of Winter 8: Winter Deer

Public Domain

On our two acres just outside of Apollo (Armstrong County, PA) we have a group of deer that Deborah and I enjoy watching very much. Now these deer do a number of things that are annoying (they eat anything we try to grow in our garden, they mow down most of the volunteer and also any carefully planted tree seedlings, and they gobble down any black oil sunflower seeds that are left overnight in our bird feeders). But, they have also given us a great deal of pleasure over the years: I remember the newly born fawn one early  June morning that walked up to our front porch on its still wobbly legs, I remember the twin fawns eating sour apples from the ground in our orchard in August, and many people remember the dioramas in our front yard in December of a group of deer (eating sunflower seeds, of course!) colorfully lit by our outside Christmas lights, causing a mini-traffic jam on our quiet street as people stopped their cars to look at the “reindeer.”

We shamelessly anthropomorphize our deer but recognize that they are wild animals interfacing with and trying to survive in a human dominated and in many cases human generated ecosystem.

I spend as much time as I can at my writing desk in the back room of our house. My desk faces a large window that looks out on our very sheltered back yard, and I have included in this blog many of the observations I have made from my “sit spot” by this window. The deer regularly pass through the back yard and have on occasion even come up to the window to get a closer look either at me working at my desk or at one of my cats who had taken over either the desk or the inside window ledge. As long as we don’t make any sudden moves, the deer are very content to stand and stare for many minutes on end.

Photo by ForestWander, Wikimedia Commons

One very interesting deer behavior that I have observed concerns the relatively large (7 to 8 individuals) winter group that crisscrosses through the yard and field throughout the winter. The group is made up of three older does and their now well grown fawns. In the afternoon or early evening the largest doe (who I assume to be the eldress of the group) leads the other deer in single file around the yard and field sampling a great variety of plants. The lead doe browses on the vegetation (the low hanging apple tree branches, the bushy crabapple tree twigs, the arbor vitae, the oak saplings, the hemlocks, the honeysuckle bushes, and so on) and one by one the members of the group walk up to the same spot after she has moved on, feed for a few minutes, and then move on to the next vacated feeding station. The orderliness of the process is amazing.  It has occurred to me that the lead doe possesses the “group knowledge” of what browse is best to take or possibly what order of browse is most digestible. She may also have some knowledge about what intensity of browsing is suitable for the long-term, sustainable productivity of the habitat (but, probably, that is hoping for too much!).  Possibly these feeding behaviors have been habituated in the lead doe by example and repetition in her youth, and, hopefully, they are being drilled into the younger deer. The winter diet of this group (significantly augmented by the sunflower seeds from my birdfeeders, of course) has maintained a good number of generations of these animals very well over the twenty-eight winters that I have observed them!

At the upper edge of our field we have a small orchard with apple, pear, and cherry trees. The trees are old and not well tended, so the fruit is usually small and frequently riddled with insects (the pears, though, from the Bartlett pear tree are some of the sweetest I have ever eaten!). I let the birds (especially the cardinals and the waxwings) have the cherries, and I leave the apples and most of the pears for the deer. Deborah made a great video of those fawns I mentioned earlier eating the green (and very sour!) apples. Their facial contortions and foot stompings as they bit into the sour fruit were remarkably human!

Photo from Pixabay

Since these deer are used to apples (they regularly dig frozen fruit out of the leaf litter under the snow), I feel comfortable putting out some apples through the winter for them. Many fruit stands and orchards advertise “deer apples” just for this purpose. You have to be careful, though, not to put out apples (or any other high calorie or exotic food) for the deer in the winter if those foods are not something that the animals have been regularly eating. A deer’s digestive system gets patterned to digest browse and those other “consistent” foods they find in its environment. A sudden exposure to corn, or apples, or rich hay could upset their digestive systems and possibly even lead to fatal consequences!  Deer are very sensitive to changes in their diet!

Mostly, deer rely on their fat deposits for their metabolic energy in the winter. At the start of the winter a deer in prime condition may have as much as 30% of its body weight in fat! The fat is subcutaneous (which also adds to body insulation) and is also found extensively around the internal organs of their bodies. This is their “fuel tank” carefully filled through the spring, summer, and fall. In normal years these fat deposits represent enough calories to carry the individuals through to the next, bountiful spring.

Preferred winter browse for deer include cedar (like arbor vitae!), sassafras, apple, most types of maples, basswood, and flowering dogwood. Secondary browse includes hemlock, honey suckle, mountain ash, willow, white oak, and many other deciduous trees. Last resort choices for browse (sometimes referred to as “starvation food” because if you see these trees being browsed by deer you know that the herd is in trouble!) include pines, mountain laurel, beech, aspens, poplars, black locust and birches. (This browse data is from the New York State Department of Environmental Conservation).

You can tell if a tree or shrub has been browsed by deer because of the way deer feed. They use their lower jaw incisor teeth to crush a stem or branch against their upper jaw’s hard pad of cartilage. This feeding method results in torn (shredded) stems and branches rather than cleanly nipped off edges.

Public Domain

The cellulose-rich food material is then passed through the deer’s four-part stomach and digested (at least somewhat) by the bacteria and protozoa that reside there. The low calorie nature of even these preferred winter browse species almost makes you think that the browse food is designed to make the deer feel like they have food in their stomachs even though they must be primarily living on their stored fat.

The deer are well insulated (and well camouflaged) by their winter coats. The gray-brown outer hairs cover a dense, wool-like undercoat and are very protective against cold, wet, wind, and snow. The hair shafts are also connected to tiny muscles in the skin that can lift and rearrange the angles and packing of the hairs to alter the degrees of insulation.

Deer behaviors also contribute to their winter survival. Small family groups typically form larger herds, and these larger herds confine themselves to the most sheltered and protected sub-sections of their broader, summer ranges. Our winter group is probably two or three family units, and their selected protected spaces are the woodlots, fields, and yards right around our Rose Street house!


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Signs of Winter 7: Observations

Photo by D. Sillman

It was very cold a few nights ago. Deborah’s phone app registered -8 when we got up a bit after 7 am. I took Izzy out for her morning “business” and to fill the bird feeders and add water to the bird bath. Deborah made coffee (it was hot and wonderful!). Sunrise was coming soon (7:42 am that morning) but there was already a lot of light in the sky. Daylight periods are lengthening by almost a minute a day. That day we had ten more minutes of light than we did on the Winter Solstice two weeks before.

It was the last day of that intense cold spell. I am sure that all of my bird feeder birds and bird feeder mammals were as glad of that as Deborah and I were. Interestingly, Izzy doesn’t seem to notice the cold. She races around in her usual exuberance until one of her paws freezes up, and then she limps back to the front porch door. I have only had to carry her home once this year. When we got Izzy from South Carolina the rescue group sent her to us with a warm, winter doggie coat (complete with a furry hood!). We never put it on her, though. The rescue people greatly underestimated Izzie’s hardiness and terrier metabolism!

Photo by D. Sillman

This past fall I kept to my plan of raking fallen leaves into piles scattered about the yard. I have been doing this for the past six or seven years and have noticed, among other things, an increase in tree frogs in the spring and summer possibly due to the formation of high quality hibernation spots in the thickening piles of leaves. I also have more slimy salamanders in my driveway drain that I did before letting the leaves pile up.

Right now the tops of the leaf piles are poking up through a scattered snow cover. Juncos, cardinals, blue jays, Carolina wrens, and white-throated sparrows spend most of the day digging down into the piles looking for food.  The wrens sometimes bury themselves in the leaves and then pop up through the snow cover with some tidbits in their long, pointy beaks. The gray squirrels rip around at leaf pile surfaces, too, probably looking for the acorns, chestnuts, and shelled corn from my bird feeders that they have stashed there.

Photo by D. Sillman

The gray squirrels have been very interesting this winter. I remember reading many years ago an article by Chuck Fergus. Chuck talked about gray squirrels tending to stay in their winter nests when temperatures fell below freezing. The squirrels would rely on stored and stashed food stuffs in their nests until the weather eased off. You can picture an energy-return graph for these squirrels: at very cold temperatures it would be too metabolically costly for them to be out foraging for food that was scattered across a natural landscape. So, it made sense for them to hunker down and wait for less stressful conditions. The equation gets shifted quite a bit, though, when the abundance and predictability of food is increased. Gray squirrels that have bird feeders to rely on stay active even in subzero temperatures. In fact, my gray squirrels only stayed in their winter nests when wind chills hit the negative teens. The combination of wind and cold was too much for them (prompting my cousin’s wife, Charlene, to call my squirrels “wimps” (her squirrels were still raiding her bird feeders up in Rochester, N.Y. when temperatures were well below zero!)). This morning, though, there were two gray squirrels waiting for their peanuts out at the bird feeders when I was out with Izzy at 7:30 am (and -8 degrees). I gave them an extra-large pile!

We drove to the grocery store yesterday and saw two flocks of Canada geese flying in extended V’s over North Apollo. They seemed to be cruising up and down the Kiski River looking for open water. The length of the Kiski between the Apollo and Vandergrif Bridges was frozen solid. The geese may have to land on the ice. I hope that they are finding food.

Late Friday night I was lying in bed listening for the furnace to click on when I heard a great horned owl hooting outside. Thus is the time of year when the great horned owls call each other and set up mating pairs, but it seemed far too cold to even think about that! The calling only lasted a few minutes (mating calls sometimes go on for hours!), so whomever it was must have realized the futility of his (or hers) efforts.

Photo by D. Sillman

We went several weeks without seeing the three wild turkeys that have been regular visitors to our yard since July.  Two of them showed up a few mornings ago to feed on the shelled corn under the bird feeders and then, very unexpectedly, a flock of seven or eight showed up and paraded around on the neighbor’s lawn across the street. This morning one turkey came into the back yard and headed directly to the front feeders to get his fill of corn. He looked extremely healthy and fit (and spent almost 30 minutes feeding in the yard!).

I found an old barometer when I was straightening up some of my bookshelves here in my home office this Fall. I set it and

Photo by Daderot, Wikimedia Commons

have been watching the air pressure slide up and down the scale as the weather fronts poured over us. The lowest barometric pressure I observed (which was also, according to the Weather Underground, the lowest pressure of our local weather year) was 29.14 inches of mercury (on November 19, 2017). The highest pressure I observed (which was also, according again to the Weather Underground, our highest pressure of 2017) was 30.72 inches of mercury (on December 28, 2017).

There are many diverging opinions about the impacts of barometric pressure on our health. There are a few studies that categorically state that changing barometric pressure does not affect joint pain or the incidence of migraines or any other possible human health metric. There are, though, even more studies that back up the “common sense” or “folklore” ideas that you can, indeed, feel storms and weather changes coming “in your bones and joints.”

For example, there seems to be a widespread consensus that people are most comfortable at air pressures around 30 inches of mercury. “High” air pressures (those that exceed 30.3 inches of mercury) are associated with blood vessel constriction and an increased resistance of the circulatory system (which puts stress on the heart). “Low” air pressures (those that are less than 29.7 inches of mercury) allow blood vessels to expand which can also make it more difficult for the heart to pump efficiently. Both of these events, then, stress the heart and can lead to an increased incidence of heart attacks. “Low” barometric pressures can also increase sinus pain and exacerbate joint pain especially for those with joints already inflamed with arthritis. “Low” pressures can also trigger migraine and other types of vascular headaches via dilation of the blood vessels going into cranium.

I do have days when my knees ache more than usually. I will try to match up the barometer readings to my daily need for ibuprofen!

Spring is on the way! Stay warm!



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Signs of Winter 6: Fire Ants

Photo by A. Wild, Wikimedia Commons

(Many thanks to Chris Urik, one of  my old students, for keeping my interest in fire ants alive!)

There aren’t any fire ants in Western Pennsylvania, and even if there were they would not be active in the winter. If fact, it is our winter that keeps fire ants from invading our yards and fields (Tennessee is farthest north the fire ants can go before the prolonged and intense cold of the winter kills the colonies. Who knows what will happen with on-going global warming, though?).

Anyway, I am just using this winter period to reminisce about my interactions with fire ants and think about some of the newest research concerning them.

I first encountered fire ants in southeastern Texas in 1970. I was camping near Lake Corpus Christi and since the night was warm and humid I was sleeping out on tarp near the lake shore. A breeze kept the mosquitoes down, and I had just fallen asleep when all of sudden my arm and leg were set upon by a stinging swarm of tiny attackers. I had spread out my tarp near a fire ant nest and the foragers were coming out to look for food and to deal with intruders. I jumped into the lake not caring about the water moccasins I had seen earlier in the day and washed the ants off. There were no alligators in Lake Corpus Christi then (there are some now thanks to the on-going, Texas recovery of the species!) but I would not have cared about them either. I can still vividly remember the pain of those stings and the fight-or-flight panic they triggered!

Fire ant colony. Photo by M. LaBar, Flickr

Red imported fire ants (“RIFA,” or Solenopsis invicta) were first identified in Alabama in the 1930’s. They undoubtedly entered the United States via the seaport in Mobile. Recent analysis of their DNA indicates that these ants are from a northern province of Argentina. Natural dispersal mechanisms (seasonally generated, winged alates) and human-assisted dispersal mechanisms (including the transport of plants with infested root balls, shipments of grass sod and soil, and the long distance movement of many other types of agricultural products) facilitated their rapid spread across the continent. They are now found in fourteen states stretching from Georgia all the way to California.

For the most part control and eradication methods have been ineffective against RIFA’s. The pesticide Mirex was specifically used against them from 1962 to 1975 but with little impact. The toxicity of the Mirex and its high rate of accumulation in biological tissues turned out to be an even more severe environmental problem than the fire ants themselves! Mirex manufacturing and use was banned in 1978. One of the reasons that neither chemical control nor physical control (fire or flooding) are effective against RIFA’s is that each colony contains multiple queens. The survival of even one of these queens enables the ants to quickly re-establish a colony in nearby locations.

Fire ants are very aggressive and will kill not only the native ant species they encounter but also many other insect species. They can make a pasture unusable by grazing animals and can even make the use of agricultural machinery impossible in heavily infested fields.

Photo by M. Klassen, Pixabay

Fifteen years ago RIFA invaded Hong Kong, and they have since spread throughout the province’s urban and rural habitats (see November 1, 2017 article in The Scientist). These ants have established themselves in the extensive parkland of Hong Kong and also have made colonies under concrete sidewalks and streets and even inside of electrical equipment. Pesticides have been used on specific colonies of these ants, but authorities recognize that they will not be able to eradicate them but only control their eventual distribution. Taiwan also has an extensive, established population of invasive fire ants, and they have also been reported at several seaport sites in Japan. So far, though, no colonies have been established in Japan.

Fire ants are extremely adaptive and resilient. A single queen arriving in stored cargo is enough to establish a massive ant invasion. It is thought that the multiple queening seen in the fire ant colonies in the United States is an adaptation to attempts at population control using pesticides. Also, the Argentinian province from which they originate is prone to flooding, so fire ants have evolved the ability to form large, interconnected floating masses of individuals by which they ride out the flood. These fire ant masses were seen in the Houston area this summer following the flooding from Hurricane Harvey. Also, fire ants can merge small colonies into larger and larger “super” colonies, and, thus, more easily overwhelm their competitors and not waste their energies competing with each other.

Photo by Bentleypkt, Wikimedia Commons

Another invasive ant species from Argentina, though, is beginning to interfere with the dominance of fire ants in the Gulf Coast region of the United States (Science (February 28, 2014)). This new ant (the “tawny crazy ant” (Nylanderia fulva) (the name “crazy” comes from the erratic patterns of movement exhibited by individuals of this species) is able to coat itself with its own formic acid-rich secretions and, thus, denature many of the proteins in the fire ant’s venom. The functional loss of these proteins makes the venom less effective and enables the tawny crazy ant to out-compete and even destroy the previously nearly invincible RIFA. The tawny crazy ant is from the same Argentinian province as the RIFA and it is thought that its secretory and behavioral specializations came about after a long evolutionary history of RIFA encounters.

The venom of the fire ant contains a group of chemicals called “solenopsins” (a term derived from the genus name of the RIFA). Medical research into the therapeutic uses of these solenopsins have revealed several interesting potential applications. Researchers at Emory University and Case Western Reserve in a paper published in Scientific Reports (September 11, 2017)  reported that solenopsins help to reduce skin thickening and inflammation in mouse models of psoriasis. They can also inhibit the formation of new blood vessels and may thus be useful as anti-cancer medications. There might be some considerable human health benefits, then, from these destructive, invasive ants!

I am very glad that we don’t have fire ants here in Western Pennsylvania! We have to deal with brown, marmorated stink bugs, gypsy moths, emerald ash borers, spotted lantern flies, wooly adelgids, and many more invasive insects. None of them, though, would make me jump into a lake full of water moccasins!




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Signs of Winter 5: Snowshoe Hares and Road Salt

Winter morph. Photo by D.G.E. Robertson. Wikipedia Commons

The North American distribution of the snowshoe hare (Lepus americanus) covers an extensive swath over the upper half of the continent. Most of Alaska and most of the provinces of Canada all the way east to Newfoundland and Nova Scotia are included in the snowshoe hare’s range. It is a species of the North! There are also, though, three finger-shaped, southerly extensions of the snowshoe hares’ range that follow the high altitudes of mountain ranges into remarkably low latitudes. In the far west, one extension runs down the Cascades and Sierras, and in the near west another follows the Rockies. The third extension, in the east, follows the scattered clusters of mountains that make up the Appalachians. The eastern subspecies of the snowshoe hare (L. americanus virginianus) is found in this Appalachian portion of its range, and these are the snowshoe hares we find in Pennsylvania.

Snowshoe hares live a wide variety of habitats, but they are especially abundant in forests that have a well developed shrub and underbrush layers. These hares are nocturnal or sometimes crepuscular and spend the daylight hours in shallow excavations under the cover of shrubs, ferns, downed trees or piles of branches. These daylight hideouts are called “forms.”

Snowshoe hares are well adapted to winter activity. They have very large back feet (from which their common name is derived) that enable them to move about easily over a snow cover, and they seasonally shed their fur to generate a white, winter camouflaging coat. They eat a wide variety of plant materials and seasonally consume whatever food stuffs are available. They are even known to eat dead mice and other small animals (and even meat from baited traps) to add protein to their relatively poor quality diet. Green, leafy vegetation is their predominant food in spring and summer, while bark, buds, twigs and evergreen needles are their primary foods in the winter. These hares are in turn eaten by a wide variety of avian and mammalian predators.

Summer morph. Photo by W. Sigmund, Wikipedia Commons

The southerly distribution of the snowshoe hare in Pennsylvania coupled with their very specific adaptations to cold, snowy habitats make them very interesting organisms for studying the early impacts of climate change and global warming. Researchers at Penn State have been monitoring Pennsylvania snowshoe hares for the past several years and have seen some interesting trends in their morphology, behavior and physiology.

For example, Pennsylvania snowshoe hares are now larger than snowshoe hares living in the Canadian Yukon, and their fur is shorter and less dense. A shorter, food-limiting winter season in Pennsylvania could explain the size differences and the reduced coat might reflect less extreme winter temperatures. A less well insulated animal would function more optimally in a warmer winter. Further, Pennsylvania snowshoe hares are exhibiting a much less obvious winter color change. Fewer of the PA hares are turning completely white, and a number are retaining their summer-brown coats throughout the winter. The reduction in snowfall throughout Pennsylvania may be setting up a classic natural selection system in which the white rabbits stand out more clearly against the predominantly brown landscape and are, thus, being preferentially taken by predators.

Pennsylvania snowshoe hares also produce less metabolic heat in the winter compared to their Yukon counterparts and select their winter resting spots for their potential cover and protection from predators rather than for their optimal thermal advantages. Subtle, yet very logical and very adaptive changes, then, are being observed in this winter-focused species!

Photo by T. Brueckner, Flickr

Far away from the mountain habitats of the snowshoe hares humans are mining and spreading rock salt (halite) so that their roads and sidewalks are useable throughout the icy winter. Most of the rock salt spread on roadways in Pennsylvania comes from deep mines in nearby Ohio where massive deposits of halite were laid down by the evaporation of a shallow, tropical ocean some 400 million years ago. The United States spreads between 17 and 20 million tons of rock salt on its roads each winter. This salt unquestionably makes driving (and walking!) safer, but it also causes considerable damage to cars, concrete, asphalt, plants and lawns. Salt spread on roadways and sidewalks also moves out into the surrounding ecosystems and may lead to some very distant and very unexpected problems.  Two of Barry Commoner’s Four Laws of Ecology apply here: “Everything is connected to everything else,” and “Everything must go somewhere.”

Photo by K. Emigh, Penn State Sites

Penn State Erie (The Behrend College) is an excellent place to look at ice and snow (and salt). Typically Erie, Pennsylvania gets 113 inches (almost 10 feet!) of snow a year, and last month (December 2017), Erie set a record with a monthly total of 63 inches of snow! Penn State Erie spreads more than 500 tons of rock salt on its sidewalks and parking lots each winter and PennDOT (the Pennsylvania Department of Transportation) adds another 27,500 tons of salt to the streets and highways of the surrounding Erie County. Dr. Pam Silver, a distinguished professor of biology at Penn State Erie, applied Commoner’s two laws and wanted to find out where all of this spread salt ends up. So, several years ago, she and some of her students began to test the snow around campus and the waters of the nearby wetlands and streams to see if they could monitor the movement and ,possibly, the impact of all of this salt.

Some constructed wetlands near a road built on one side of the campus offered an excellent experimental design for part of this study. The water in these wetlands was new and unexposed when they were established three years ago. One of these wetlands, though, directly received flow from the new road (which was salted in the winter) while the other was isolated from the road runoff. Yearly monitoring of these wetlands showed clearly that the roadside wetland had significantly elevated salt concentrations and that the invertebrates in its sediment were greatly reduced. These invertebrates serve as part of the base of the food web of the entire aquatic ecosystem that extends on into nearby Lake Erie. Salt induced declines in these invertebrates may foreshadow subsequent declines in the fish and amphibians that rely on these invertebrates for food.

At several sampling points around the campus salt concentrations were detected that exceeded safe salt levels for human drinking water. The potential impact of this salt as it inevitably moves into Lake Erie (from which drinking water is obtained) must be considered in terms of human health consequences and also in terms of the cost for effective water treatment.

Everything is connected to everything else. Everything must go somewhere. Snowshoe hares in Pennsylvania are changing because atmospheric carbon dioxide levels are increasing. Rock salt spread on Pennsylvania sidewalks and roadways may be killing off fish in our streams and lakes! Everything is connected! What an important lesson for us all.




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Signs of Winter 4: More on Bees

Bumblebee. Photo by Trounce, Wikimedia Commons

Bees are the giant pandas of the insect world. They are charismatic and almost universally admired by the lumbering humans around them. We recognize that they pollinate not only our food plants but also a significant percentage of the plants that form the structure and substance of the ecosystems around us. I like to think of them as “gateway insects” that can be used to draw people into appreciating the millions of other insects that collectively make life on Earth possible.

Our perspective on bees, though, needs a closer look. What are we thinking about when we say “bee?”

We probably have in mind the larger members of the seven families and 20,000 species that are classified as “bees.” Honey bees and bumblebees are the usual species that people recognize as “bees,” but they represent a very small number of the “bees” that are around us and upon which our natural ecosystems depend.

There are four thousand native species of bees in North America. Most of these bees are tiny and most go about their ecological and reproductive tasks with very little human notice. In fact, the honey bees that so many us are familiar with are actually alien species brought to North America by European settlers. Fortunately, we don’t append the second adjective “invasive” to the honey bee because they seem to carry out their life functions without greatly impinging upon the ecological niches of the native bee species. As important as the honey bees are especially for pollinating the large number of plant species that European settlers brought with them to North America (i.e. a great deal of the plant community of our agricultural ecosystems!), they are not able to pollinate many of the plants that are native to North America. The often small, solitary, native bee species are needed for that.

Sweat bees. Photo by Benjamint444, Wikimedia Commons

The NPR show “Science Friday” had an interview on November 10, 2017 with a University of Texas researcher who studies many of these tiny, native bee species. She talked about the almost unbelievably small size of several of the species (the size of grain of rice!) and the vigor with which these very small bees pollinate their plants. One rice-sized species that she studied flew over a mile to find their proper plants. She related this “bee distance” to a human equivalent of traveling from Chicago to Los Angeles! These tiny bees include the “sweat bees” that drink the perspiration and tears of many vertebrates and tiny carpenter bees that tunnel their way into stems and twigs to make their brood chambers. Most of these tiny bees are solitary, but they all make a substance called “bee bread” (a semi-solid mix of honey, pollen, bee saliva and associated fungi and bacteria) upon which they lay their eggs and on which their developing larvae feed.

These tiny bees do not have the ability to overwinter in our cold climates. Unlike honey bees who are able to generate enough collective metabolic heat in their hives to maintain warm (90 degrees F!) inter-hive conditions through even the coldest winter (as long as their food supply lasts!), these solitary bees only live for part of the warm, plant flowering season and then leave their eggs and larvae resting on their stored reserves of bee bread to over-winter and continue the species in the next growing season.

(Great thanks, by the way, to Jennifer Wood who passed along the link to the recording of the Science Friday show on tiny bees! Click here and check it out!)

Photo by Buhl, Wikimedia Commons

Paul Glaum is a PhD student in ecology at the University of Michigan. Glaum and a group of fellow students became interested in how urbanization affects populations of bees. They examined research published in the scientific literature and found that some studies indicated that the more urbanized a site is the fewer bees it has, but that other studies showed that urbanization did not affect bee populations at all. Further, there were even some studies that indicated that intermediate levels of urbanization actually increased numbers and species diversity of bees. Glaum wondered if the lack of agreement in these studies might be arising from different ways previous research teams defined and described the “bees” they were studying. Could the great diversity of species referred to as “bees” (remember, there are 4000 native species of bees in North America alone!) along with their wide ranges of ecological and life history adaptations be obscuring real trends in these vital pollinators’ adaptations to urbanized environments? To try to correct for this potential source of error, Glaum decided to look at just one type of wild bee, the bumblebee (Bombus) and explore how it responds to varying degrees of urban development.

Five urban sites in southeastern Michigan were selected. These cities ranged from small, very recently incorporated cities to the largest city in Michigan, Detroit. The team found that four of these five cities had very clear relationships of their bumblebee populations to the area of impervious surfaces (concrete and asphalt roads, sidewalks, parking lots etc.) per square kilometer: the higher the percentage of concrete, the lower the numbers of bumblebees. This was very logical considering that bumblebees dig their resting and brood burrows into the ground and, thus, require penetrable soil in order to survive. The one urban site that did not display this relationship, though, was Detroit. Detroit had a high percentage of impenetrable surfaces per unit area but still had high numbers of bumblebees.

Former apartment building site in Detroit. Photo by A. Jameson, Wikimedia Commons

Glaum and his team explained this divergence in their observation by describing the unique landscape configuration of Detroit. The impact of decades of financial decline and human depopulation has left great areas of Detroit vacant. These unoccupied areas generate a patchwork of greenspaces in the cityscape that can be utilized by bumblebees for their ground burrows. Sustaining a population of bumblebee pollinators in an urban environment, then, can be accomplished by designing patterns of open spaces in which burrows can dug and reproduction carried out.

One last observation made by Glaum and his team had to do with the impact of urbanization on sex ratios in bumblebee populations. It turns out that male bumblebees are almost completely unaffected by degrees of urbanization, but that females are significantly diminished in numbers in sites that are more urbanized. This alteration of gender ratios could significantly affected rates of growth and the sustainability of a population of bumblebees. The reason for this differential gender impact is very obvious: only the females dig burrows (in which they subsequently rest at night and into which they lay their eggs). The males remain above ground and actually sleep at night sheltered in  the petals the very flowers they gather nectar from during the day. Questions about which types of flowers are preferentially utilized by male bumblebees for shelter should be answered in subsequent studies.



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Signs of Winter 3: Acrylamides and You!

Acrylamide model by B. Mills, Wikimedia Commons

Acrylamide is an industrial chemical used in the manufacturing of many types of polymers. These polymers can then be used in water treatment systems (and wastewater treatment, too) and in the synthesis of various grouts, cements, cosmetics, plastics, pesticides and paper (and more). The United States used over 250 million pounds of acrylamide in industrial processes in 2007. Acrylamide is also used in molecular biology laboratories as a reagent in the synthesis of electrophoretic gels .

Twenty years ago construction workers on a tunnel site in Sweden began complaining of nausea, dizziness and numbness in their fingers. In areas around the tunnel project, cows were found paralyzed and ponds were full of dead fish. Researchers found that acrylamide, a component of the grout that the workers were using to seal the tunnel wall, was poisoning the workers (it is rapidly absorbed through exposed skin) and was also leaking out into the surrounding pastures and ponds. Acrylamide, even back in the 1990’s, was known to have neurotoxic and carcinogenic properties. What surprised researchers, though, as they tried to determine the magnitude of the construction workers’ acrylamide exposure, was that everyone whose blood they tested, even people who had not been exposed to the acrylamide grout of the tunnel project, had acrylamide in their blood.

Where was this acrylamide coming from?

Maillard reaction. Public Domain

It turns out that acrylamide is formed when carbohydrate-rich foods are heated (or cooked) at very high temperatures (above 120 degrees C (or, 248 degrees F). It is a by-product of the Maillard reaction in which amino acids in a food react with reducing sugars (like glucose or fructose) to form the browned (and extremely flavorful)  surface layer of the food. Toasting bread, grilling steaks, frying potatoes, or roasting coffee beans are all ways to generate a Maillard reaction. One of the twenty, naturally occurring amino acids (asparagine) is thought to be essential in the specific Maillard reaction that forms acrylamide as a by-product. Raw foods or foods that have been boiled do not contain acrylamides.

These observations led to a number of investigations that explored the possible connection between dietary acrylamide and cancers. Large studies conducted primarily in the early 2000’s found some evidence that certain cancers (like ovarian and endometrial cancers) might have a correlation with dietary intake of acrylamide, but these connections were not confirmed in later studies. Researchers stress that one of the problems in these studies is accurately quantifying an individual’s dietary intake of acrylamide since it is not just certain foods that contain it but the method of cooking those foods that causes it to be synthesized. Measured serum levels of acrylamide did not, however, correlate with the increased incidence of either of these cancers.

This is a very good time to go from this qualitative discussion of acrylamide to one that is more quantitative in nature. Numbers really do matter here, and the numbers I use in the following discussion come from The World Health Organization (WHO).

For example, it is very clear at what level acrylamide will cause neurological symptoms. This value is based on a daily accumulation of acrylamide per kg of body mass. Anyone who takes in 0.5 mg of acrylamide per each kg of their body mass per day will develop neuropathies. This means that an 80 kg (176 pounds) person must absorb 40 mg or acrylamide a day to generate these types of symptoms (the tunnel workers, mentioned above, for example, reached and probably exceeded these levels of exposure). Acrylamide can also cause infertility, and this response occurs when an individual is exposed to about four times the level that would cause neuropathies. So, our 80 kg test subject would have to be exposed to 160 mg of acrylamide per day. The connection of acrylamide to cancer, though, is still not clear and, therefore, has not been quantified. Logically, though, if acrylamide is carcinogenic the potential impact level exposure would be chronic and could be substantially less than 0.5 mg exposure per kg body weight per day that causes neurological symptoms.

Photo by Crisco 1492, Wikipedia Commons

The average amount of acrylamide absorbed from dietary sources is 1.0 microgram per kg body weight per day. A microgram is one thousandths of a milligram (1000 micrograms = 1 milligram). This means that our 80 kg person will absorb 80 micrograms (or 0.08 mg) of acrylamide every day from their consumption of French fries, burned toast, coffee, etc. This value is 0.2 % of the acrylamide needed to generate neurological symptoms.  It is still an unresolved question, though, as to whether this value approaches a chronic exposure level that could have potential carcinogenicity, but most studies feel that these levels of dietary acrylamide intake are not inherently harmful.

There is another source of acrylamide, though, that can elevate serum acrylamide levels significantly: cigarette smoke. The processing of tobacco causes the synthesis of acrylamides and the subsequent burning of the tobacco generates even more. Smoking cigarettes, according to a study published in the Annals of Agricultural and Environmental Medicine in 2016, exposes the average adult smoker to 0.17 micrograms of acrylamide per kg body weight per day. For our 80 kg example subject, this would be almost 14 more micrograms of acrylamide absorbed per day.

An article in The Scientist (April 1, 2017) presented a concise overview of the history and current status of the medical research concerning acrylamide. Most scientists feel that other areas of chemical exposure control would generate more significant cancer reductions than regulation of dietary acrylamides. It is logical, though, that foods that are deep fried or excessively browned are, in fact, potential sources of this toxin, and that they should be eaten in moderation. It is also logical, as if we needed more evidence about this, that avoiding cigarettes and cigarette smoke is an excellent way to maintain better health.



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Signs of Winter 2: Circadian Rythms

Photo by jonathunder, Wikimedia Commons

This year’s Nobel Prize in Physiology or Medicine went to three scientists who have explored the fundamental genetics and physiology of living organisms’ biological clocks. Over the past three decades these researchers have put together an incredibly compelling picture that explains how each and every cell inside an organism is able to “know” what time it is!

A gene in fruit flies was the start of it all. This gene was found to encode for a protein that is synthesized in a cell during the night and then broken down in that same cell during the day. The concentrations of this protein, then, is an exquisitely sensitive index of the time of day. There was, though, much more to this. Three genes (and three proteins) were found to interact in ways that allowed an organism to not only modify their own day/night cycle but also stretch or shrink their cycle to fit patterns greater than or less than the typical 24 hour day period. Further, these “clock proteins” are intertwined with the other signaling and controlling proteins of a cell and, thus, have great influences on the activities of almost all aspects of a cell’s metabolism.

The science of Circadian Biology has grown out of the groundbreaking work of these new Nobel Laureates. Circadian Biology studies the physiological consequences of the changing “clock proteins” on the metabolic processes of an organism.

Figure by Yassim Mrabet, Wikimedia Commons

For example, in a 24-hour period there are times when your conscious neurons are working most efficiently (increased alertness, faster reaction times). This period of time is related to circadian regulation. Also, there are times when your immune system is operating more efficiently, when your blood pressure is typically on the rise, when your heart is under its maximum daily stress, when your muscles are controlled in the most coordinated way they can be, when you generate a maximum daily body heat and when you generate your minimum amount of daily body heat. There is also a time when you readily make melatonin (and are, thus, able to naturally fall asleep) and other times when a variety of hormones are being synthesized.

A practical application of Circadian Biology is “chronotherapy.” Chronotherapy explores the body’s response to different stresses or treatments at different times of day. For example, a study in England demonstrated that individuals who received their flu shots in the morning (the time when immune responses are most robust) made more anti-flu antibodies than those individuals who received their flu shots in the afternoon. Also, short-term control of serum cholesterol can be achieved via drugs that slow down the critical rate controlling liver enzyme for cholesterol’s synthesis. It turns out that that enzyme is maximally functional at night, and if the inhibitory medication is also taken at night (say right before bed) it is much more effective in reducing cholesterol levels.

Chemotherapies timed to the circadian biology of the tumor cells are not only more effective but also have fewer side effects. Anti-histamines and inhaled corticosteroids designed to control allergies and asthma are also more effective when they are taken at night when the circadian rhythms of the affected cells are at their maximum states of activity.

A common set of drugs designed to reduce arterial blood pressure are angiotensin-2 receptor blockers. Blocking these receptors causes an overall vasodilation (volume increase) in the body’s arteries which reduces the overall pressure of the system. These angiotensin receptors, though, operate cyclically under circadian control. They are most active at night! Taking the angiotensin-2 receptor blockers at night, then, is the most effective way to use this medication to achieve blood pressure control.

Photo by Ion Chibzii, Wikimedia Commons

An October 26, 2017 article in the British medical journal The Lancet described data from almost six hundred open heart surgeries conducted at Lille University Hospital (Lille, France). These data showed greatly improved patient outcomes when the surgeries were conducted in the afternoon rather than in the morning. There was, according to this study, a 50% lower risk of heart failure or other cardiac event in the afternoon surgeries! The heart muscle itself was more resilient and quicker to regain its ability to contract after these afternoon surgeries, and there were 287 circadian rhythm genes operating at different levels between the morning surgery and the afternoon surgery heart muscle samples.

Back in 2015 (Signs of fall 12: Seasonal Jet Lag (Nov. 12, 2015)) I wrote about the impacts of the time change from Daylight Savings to Standard Time. People do get a little off: accidents go up, hospitalizations go up, productivity at work goes down. The chances, though, that our “human society time” means anything at all to the plants and animals around us are pretty small. We have recently seen the effects of the shortening day length on the leaf biology of our senescing deciduous trees and on the behaviors of many of our birds who were compelled to fatten up and fly south. They really don’t care if sunrise is at 6:55 am (Standard time) or 7:55 am (Daylight time): they just care that there are 10 hours and 17 minutes (and falling!) of daylight in the 24 hour period! We will get down, by the way, to 9 hours and 16 minutes of daylight on December 21 (5 hours and 47 minutes less daylight than back on the June Solstice), and then we will start it all over again!

Photo by D. Sillman

Any animals that are tied in to human activity patterns, though, are sure to notice that something has changed when Standard Time returns. My front yard crows have come to expect their morning pile of peanuts to be out there when they arrive a little after dawn. My wild turkeys have timed their appearance in the front yard bird feeder area to coincide with no human presence (I walk Izzy between 6:30 and 7:30 am, and Deborah leaves for work around 8. The turkeys usually roll in around 8:30, which on Day #1 of this Fall’s Standard Time, was 7:30 (right when I was out with Izzy). They were pretty startled by our presence! I hope that they come back!). Izzy, herself, is not sure what to think about the un-naturalness of this time change either. She is used to having her supper at 4:30 pm. Her “biological” supper time is an hour out of phase with this new Standard Supper Time. She is staring at me right now: 3:35 pm. I hope her circadian rhythms adjust soon!

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