Signs of Summer 2: Our Yard Ecosystems (part 2)

Photo by D. Silman

(Click to access an audio version of this blog)

Last week we talked about the plant components of our home-ecosystems. Listed in that post were estimates of $30 billion dollars spent each year by Americans on lawns and $14 billion dollars spent on flowers. These figures need to be augmented by a guess at how much is then spent on home-ecosystem trees (purchasing, planting, trimming, removing etc.). I tried to find this data but, unfortunately, only could reliably find how much we Americans spend on Christmas trees each year ($1.32 billion)). So, just to keep the narrative going, I am going to estimate $20 billion for the tree component for our home-ecosystems. I think that it is a good guess and is probably an underestimate.

So, putting all these figures together, we Americans spend about $64 billion dollars each year creating and maintaining the plant components of our home-ecosystems! To put this figure in perspective, $64 billion is greater than the GDP of 138 countries on Earth according to a publication by the United Nations Statistic Division (2016). It is, then, a lot of money.

Photo by D. Sillman

Once you have built this exotic, invasive species laden, botanical paradise, though, it fills up with animals at relatively little cost! As they (sort of) said in the movie “Field of Dreams,” “if you build it, they will come!” You can, if you choose, and 65 million Americans do choose to do this, put out a variety of seeds and feeding stations to attract birds and a constellation of other wildlife, but even if you don’t do that, a considerable number of animal species will migrate into and establish themselves in your home-ecosystem. Americans, by the way, spend $3 billion a year on bird seed! That’s a pretty large amount of money, but a pretty small percentage of the overall home-ecosystem cost.  I talked about the motivation for providing food for wildlife and its possible consequences in a previous blog (Signs of Winter 11, Feb 11, 2016).

So what kinds of animals inhabit our home-ecosystems?

Here in Western Pennsylvania all sorts of furry, feathered, and scaly guys show up when any type of cover or edible vegetation is established. Plant-nibbling critters (like white-tailed deer, woodchucks, cottontail rabbits, meadow voles, etc.), an array of seed and fruit eaters (like gray squirrels, red squirrels, fox squirrels, white-footed mice and chipmunks) and some predators and omnivores (including voles, skunks, racoons, opossums, toads, garter snakes, black snakes and maybe even red foxes and coyotes) are all likely to become part of the home-ecosystem.  If you add your own domesticated animals (dogs and cats) to the mix, you have a pretty diverse animal community, and if you are lucky, you might even have a black bear come and visit your house! Bats may also use parts of the home-ecosystem for their roosts, although, sadly, their numbers are dwindling in our area.

Photo by D. Sillman

White-tailed deer are actually becoming more abundant around human habitations than they are out in more rural habitats. Fewer predators and little or no hunting pressure have contributed to this “city-deer” transformation. There is also some speculation in the scientific literature that the exotic plants of a suburban landscape may be more calorie rich and nutritionally fitting for deer than their usual fare out in the surrounding countryside (see Signs of Spring 1, March 1, 2018).

Many of these animals will do considerable damage to the plant community of your home-ecosystem. Wildlife damages incurred by metropolitan residents in the U.S. have been estimated at $3.8 billion annually (PA Game Commission, 2014). The Game Commission estimates that about 10% of this damage is caused by white-tailed deer.

Photo by D. Sillman

Looking over my notebooks, I count 18 species of mammals as regular or occasional components of my home-ecosystem, along with 8 species of reptiles and amphibians and 55 species of birds. I put out bird seed (black oil sunflower seed, peanuts and shelled corn) every day, and I maintain a year round source of water (heated bird bath in the winter). I also plant a garden each year and much of that production, unfortunately, goes to sustain some of the plant-feeding wildlife species.

As I pointed out in Signs of Spring 8 (April 6, 2017) humans underwent significant evolutionary changes as a result of the foods and processes of agriculture and as a consequence of living in the crowded, stressful conditions of cities. The overall diversity of the human genome decreased. Genes to digest complex carbohydrates and milk sugars were selected for and any flaws in immune system function were brutally selected against by the array of epidemic diseases that arose from contact with agricultural livestock. The ability to tolerate contaminated drinking water or efficiently metabolize the alcohols that were developed to replace simple water supplies for hydration were also positively selected for.

It is not surprising, then, that the animals that are coming into our home-ecosystems are also undergoing evolution! Isolated white-footed mice populations in the parks of New York City are showing genetic changes that enable them to live in habitats enriched with formerly toxic levels of heavy metals like lead and cadmium. Cliff swallows living near busy highways are developing shorter wings that enable them to more easily evade collisions with passing cars. The beaks of house finches and great tits are becoming larger and more robust so that they can more easily eat the often hard-to-crack seeds found in bird feeders. In cities a new species of mosquito has evolved that is able to breed in the waters of underground sewers and subways instead of the above-ground puddles preferred by its progenitors. Crested anole lizards in Puerto Rico are developing longer legs and stickier toes to enable them to better climb the side of buildings. (See M. Johnson and J. Mushi-South, Science,  03 Nov 2017).

So, the fauna of our home-ecosystems are quite diverse and rich. One friend has told me that he has spotted 21 different mammals in his less than one acre, suburban yard, and reports that he still hasn’t seen a red fox, a flying squirrel or a coyote! Some other friends have had a mink drop in to their garden pond and eat their fish and a black bear guzzle down the sugar water in their hummingbird feeders!

Keep your eyes open!!

Happy Summer, everyone!





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Signs of Summer 1: Our Yard Ecosystems (part 1)

Photo by M.O.Stevens, Wikimedia Commons

(Click to access an audio version of this blog)

Each of us who owns a house manages the ecosystem that surrounds it. We make choices about what plants we want to grow in our home-ecosystems, and we make choices about how controlled we want those ecosystems to be.

The most prominent feature of a yard-ecosystem is usually the lawn. On average, 75 to 80% of a house lot area is set aside for grass. Most lawns are closely trimmed and densely vegetated with tightly packed grass plants. Fescue and bluegrass are the dominant grasses. Most lawns are extremely controlled monocultures: no clover, no dandelions, no ground ivy, and no “weeds” of any kind. A monoculture, be it lawn or cornfield, is an unstable ecosystem. Successional forces and waves of opportunistic, invading plant species (the “weeds”) exert immense pressures on the system. These forces would very quickly change a lawn- grass system into a system dominated by annual weeds. A great deal of energy has to be

Photo by D. Sillman

employed to keep these successional forces at bay.

The grass manager (i.e. the home owner) has to set up a regime in which the grass plants are vigorously stimulated to grow (by the addition of water, fertilizer, lime etc.), and in which less desirable plants (the “weeds”) are selected against by the frequent plant tissue destruction caused by mowing (and the more you “feed” and water a lawn the more you have to mow it!), by the very occasional direct removal of “weeds,” and by the very frequent, broad application of herbicides designed to kill non-grass plants. These steps are the only ways to insure that a lawn remains a singular grass ecosystem.

The cost of this control is astounding. Here are some numbers for lawns in the United States (derived primarily from EPA, Audubon Society, and The Garden Club of America publications and web sites):

  1. 54 million people mow their lawns each summer weekend, 800 million gallons of gasoline are used in gas lawn mowers each year,
  2. 17 million of these gallons of gasoline are spilled during refueling mishaps,
  3. mower exhaust and the volatile organic chemicals from the gas spills contribute to lower atmospheric ozone production (“smog”) all summer and also generate about 5 % of the nation’s total air pollution,
  4. 78 million pounds of herbicides/pesticides/fungicides are used on lawns each year (with almost no oversight or control),
  5. 3 million tons of fertilizers are applied to lawns each year (again, with almost no oversight or control),
  6. 50 to 70% of the total residential water volume is used for landscaping (mostly to water lawns),
  7. a total of $30 billion is spent annually on lawns (installation, care, and maintenance).
  8. lawns in the United States cover approximately 50,000 square miles. This area represents the largest single, irrigated “crop” grown in the United States.

The growing economic and environmental cost of maintaining lawns, especially in regions of low rainfall, have begun to raise serious questions about the sustainability of this phenomenon. Added to these concerns are the realizations that the grass plants themselves that have assumed such a dominating presence in our urban, suburban, and rural landscapes are, in fact, non-native, and, frequently, invasive plant species. Even “Kentucky” bluegrass is a plant native to Europe, Asia, and northern Africa! These plants are invading and upending our natural floral ecosystems!

Norway maple, J. Billinger, Wikimedia Commons

The most common trees in the yards of my neighborhood are Norway maples, blue spruces, Norway spruces, and silver and sugar maples. The spruces are often of substantial sizes (more than a foot in diameter and 40 to 50 feet tall) with broad growth forms with little branch shading or limb pruning. Only in a very few cases are any of the trees in branch contact with each other. For the most part, the trees are widely separated and quite isolated. There are also some yellow and European white birch, yellow poplar, cherry, and crab apple trees growing in these home-ecosystems along with a variety of shrubs including rhododendron, azalea, burning bush, yew, privet, Rose of Sharon, forsythia, lilac, and a variety of forms of arbor vitae.

Now without getting too preachy or picky about the subject, it is important to consider the idea of “native” vs. “non-native” plants with regard to these tree and shrub species. The three most abundant trees are introduced, exotic species. The Norway maple is native to eastern and central Europe and has been, primarily because of its tolerance of a wide range of site conditions, extensively planted throughout the eastern United States.  The Norway maple, though, because of its prodigious production of seed and its tendency to form dense thicket masses in untended ecosystems, is classified by the National Park Service as an alien, invasive plant that should be avoided. The escape of this species into the wild has done a great deal of damage to native plants throughout the eastern United States.

Norway spruce, Photo by D. Sillman

The Norway spruce (which is native to northern Europe) and the blue spruce (which is native to western North America) have also both been widely planted as ornamental trees throughout the United States. Their respective reproductive and growth patterns do not generate invasive or destructive responses in unmanaged ecosystems, although both have “escaped” extensively from their landscape systems into surrounding forests and both have, undoubtedly, had some negative impacts on competing, native tree species.

Rhododendron, arbor vitae, and some (but not all) of the azalea types are native plants in our region. Burning bush (from northeast Asia), privet (there is a European form, a Japanese form, and a Chinese form), Rose of Sharon (from southeast Europe and southwest Asia), lilac (from Europe and Asia), forsythia (from eastern Asia), and yew (from England) are all exotic, introduced shrubs. Of these plants only the lilac and the English yew are classified as “non-invasive,” although both are recognized as having frequently “escaped” into surrounding ecosystems.  The other species (burning bush, privet, Rose of Sharon, and forsythia) have not only widely escaped but also have caused, according to the U. S. Forest Service, via their dense and destructive growth patterns, widespread declines in many native plant species.

Photo by K. Andrew, Flickr

Flower beds often border the home-ecosystem swath of lawn. Some typical home-ecosystem flowers include roses (a very old domesticated flower which probably originated in the Middle East thousands of years ago), crocuses, daffodils, and tulips (which are from southern Europe, North Africa, and Asia).  The “top ten flowers” planted in the United States (as listed by include lilies, sunflowers, tulips, roses, pansies, sweet peas, nigellas, marigolds, California poppies and Dianthus varieties (the “pinks,” sweet William and carnations). Of these only sunflowers and California poppies are native to the United States (there are some native lilies, but most garden varieties are from Asia). For potted plants the USDA indicates that chrysanthemums (Asia), orchids (mostly tropical species), geraniums (eastern Mediterranean), and poinsettias (Mexico) are the dominant plants sold in the United States. These flower represent (according to about 46% of the $31.3 billion generated each year by floral products industry!

So, from our grasses to our trees to our flowers, we have made and sustain (and pay steeply for!!) an ecological node of invasive plants all around our houses.

(next week: some animals of our home-ecosystems!)

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Signs of Spring 12: Yellow-Bellied Marmots and an Update on Bats!

Photo by Inklein, Wikimedia Commons

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Yellow-bellied marmots (Marmota flaviventris) are one of the largest members of the “squirrel” family of rodents. They can be two feet long and weigh up to eleven pounds and can live singly or in colonies of up to twenty individuals. They are abundant in the high meadows and rocky slopes of the mountains of the western United States and southwestern Canada.

Some years back, when we were hiking in Rocky Mountain National Park, we saw yellow-bellied marmots at almost every turn of the trail. In fact, they converged on us whenever we stopped for a water or snack break. I remember one of the marmots being fascinated with some dangling threads on the cuffs of Deborah’s jeans (the marmot did her best to chew the treads free) and others who tried to climb into our packs to get at our crackers and bags of peanuts and M and M’s. They were numerous and persistent!

The marmots we encountered apparently lived in colonial groups along the well-used trails of the park. They were obviously very accustomed to augmenting their plant based diet with anything they could glean from passing hikers. Such an optimal habitat could support a large number of marmots, and we never saw any marmot-on-marmot antagonistic behaviors even their frenzy for the occasionally dropped M and M.

Photo by A. Vernon, Wikimedia Commons

Yellow-bellied marmots have built-in behavior patterns that help them to keep their population densities from exceeding the quality of their resource bases. Yearlings (right after their long (often eight months!) hibernation) leave the protection of their birth colony and set off to establish themselves in some unoccupied habitats. All male yearlings are dispersed in this way and about half of the females. The quality and quantity of food resources plays a role in exactly how many females are permitted to stay close to the birth burrow. The mortality figures for these young marmots are extreme: only half of the original birth cohort survived to one year of age, and the consequence of this yearling dispersal is a very high rate of predation (primarily by coyotes, black bears, badgers, American martens and golden eagles). Being a young marmot is not for the weak of heart!

At reproductive maturity (2 years of age) males will establish and protect a burrow with up to four females. There can be up to twenty marmots living in very closely connected home burrows in an optimal habitat. These marmots display varying degrees of amicable social behaviors (social grooming, play, greeting behaviors) and, occasionally some aggressive, agonistic behaviors (dominance grooming, mounting, and even fighting).

Yellow-bellied marmots, then, have a very facultative approach to living in social groups.

There are a lot of advantages to living in a group. There are more eyes available to watch for predators, and each individual spends less of their own time on guard and more time on feeding or resting. Food resources can be more efficiently located and care of the young can be shared among the group. For many social animals, the loss of these group benefits can be devastating. Humans, baboons, macaques, dolphins and sheep all show terrible individual wear and tear when individuals live without a supportive society around them (for humans, living without social contacts is as serious a negative health factor as smoking a pack of cigarettes a day!). It is surprising, then, to find that yellow-bellied marmots actually live longer when they live solitary, less social lives.

Photo by C. Hernandez, NPS

In a paper published earlier this year (January 17, 2018) in Proceedings of the Royal Society B, Daniel Blumstein of UCLA and a group of associates determined that social interactions were not beneficial to yellow-bellied marmots. Blumstein’s paper indicated that yellow-bellied marmots with active social lives tend to live two years less than marmots that live a more solitary existence. In a species with an average life expectancy of fifteen years, this loss of two

years is a very significant reduction!

Blumstein speculates that close social interactions may facilitate the spread of disease or may distract the marmots from their watchfulness for predators. The long hibernation period of these marmots is also a time of high mortality and group hibernation may lead to inappropriate wakefulness and, thus, an increased risk of starvation during the long mountain winters.

We are planning to go back to Rocky Mountain National Park this summer. I intend to keep a close eye on the yellow-bellied marmots (not only to make sure they stay away from my M and M’s!).

Little brown bat on tree. Photo by M. Graham, NPS

Quick bat update:

Deborah and I saw our first bat of the spring the other night. Where we once had dozens of bats circling over our house and field, this year we have only seen this one individual. The impact of white-nose syndrome has been devastating on the bat species in our area. Populations of our four major bat species have declined by 75% due to this infection! White-nose syndrome is caused by a fungus (Pseudogymnoscus destructans) that was introduced from Europe in 2006. Infected individuals wake up inappropriately during hibernation and end up starving because of excessive body energy expenditures.

The bad news is that the fungus that causes white-nose syndrome has just been found in bat caves in northern Texas. Texas has a rich and diverse bat fauna. Thirty-two species of bats are found in the state! The spread of white-nose into this region could be devastating. To add to the sadness and futility of this situation, it is thought that people by ignoring warnings and by not taking precautions against the contact with and transmission of this fungus, are responsible for the spread of the fungus into these western states.

I’ll have more updates about our bats as the summer goes on!


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Signs of Spring 11: Bold and Shy Elk

Bull elk. Photo by Skeeze, Pixabay

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When Europeans began exploring North America in the Sixteenth Century they encountered great herds of large, reddish-brown deer. Because of this animal’s great size and because of the impressive, spreading antlers on the males, they called this deer an “elk.” Now “elk” was already the European name for another huge member of the deer family, the moose, and moose are found not only in North America but also all across northern Europe and Asia. I don’t know why the European name

“Moose.” Photo by P. Owen, NPS

for “moose” was appended to an obviously different animal, and I am not sure what these Europeans did when they subsequently encountered a real moose here in the New World. Maybe that’s when they invented the word “moose.” Anyway, today we have a very unfortunate point of name confusion in which both the large New World deer and the Eurasian “moose” are called “elk.” This is a wonderful example of common name confusion and a very strong argument for the use of scientific names if you are really trying to be specific in your communications!

American “elk,” by the way, are most precisely called Cervus canadensis, and “moose” in America, Europe and Asia are most precisely called Alces alces.

To add possibly a bit more confusion to this whole elk/moose naming run-about, some well-meaning, I am sure, large mammal folks also refer to the American elk by their Shawnee and Cree name, “wapiti,” and “wapiti” has, in particular, been specifically applied to Asian species of “elk” (like the Altai wapiti and the Manchurian wapiti, etc.) to avoid confusion with the historical name of the Eurasian moose.

Confused? Me, too.

Elk were found almost everywhere across North America prior to the arrival of Europeans, but their numbers declined and their ranges diminished drastically as Europeans spread across the continent. According to the Pennsylvania Department of Conservation and Natural Resources, the last wild eastern elk was shot in Pennsylvania on September 1, 1877, and the eastern elk subspecies was declared extinct three years later. Today, elk are primarily found in the northern and central Rocky Mountains and in the Pacific Northwest with small islands of isolated herds scattered across Canada and in the Southwest and southern Midwest of the United States.

Elk, though, have returned to Pennsylvania! Between 1913 and 1926 the Pennsylvania Game Commission imported and released 177  elk (50 of them from Yellowstone National Park!) into several counties in the north-central part of the state. Today a herd of around 800 elk roam across an 800 square mile Pennsylvanian range and form the foundation of an active, local tourist industry.

Elk at Mammoth Hot Springs, B. Inaglory, Wikimedia Commons

When we were out in Wyoming last summer we saw a lot of elk. In particular, driving through Yellowstone, herds of elk were a regular and very popular roadside attraction. One evening, as we drove through the town of Mammoth, a small (population 263) town with scattered buildings that house a visitor’s center, a chapel, the Yellowstone Park Headquarters, a ranger station and some barracks and houses, we were struck by the abundance of lounging elk on almost every street corner and on almost every lawn. I have been told that these “city elk” are a herd descended from an old bull elk who figured out that being in the proximity of Mammoth’s buildings offered significant protection from predators (and maybe even some extra food sources?).

This “city elk” phenomenon is not restricted to Mammoth, though.

Elk in Yellowstone,. Photo by D. Fulmer, Wikimedia Commons

Dr. Robert Found of the University of Alberta studies the elk of Western Canada. He has applied a system that characterizes individual elk in a herd as either “bold” or “shy.” This classification system was developed by a group of researchers from the University of Alberta and the University of Calgary and published in the Proceedings of the Royal Society B (S. Ciuti et al., September 5, 2012).  Some characteristics of bold elk include short flight initiation distances (FID’s)(i.e. they allow people to approach them relatively closely), they also seem unconcerned about possible predators (and spend little time watching for potential dangers), they readily fight with other elk in the herd, they tend to remain on the periphery of the herd rather than in the safer areas of the herd’s center while grazing, and they willingly approach unfamiliar objects (like old tires or other human cast-off materials). Shy elk exhibit opposite characteristics (long FID’s, very high predator vigilance, avoidance of intra-herd fighting, central herd grazing positions, avoidance of unfamiliar objects).

Most interestingly, Dr. Found determined that the bold elk are more likely to move into human developed areas (towns and cities) especially in the winter. They avoid their historically long migrations down from their high altitude summer ranges into lower, more sheltered winter ranges by their selection of these urban sites. Shy elk, on the other hand, are more likely to carry out their traditional, seasonal migration. The possible energy savings by the non-migrating, increasingly human dependent, bold elk may have significant ecological and, possibly, evolutionary impacts! Dr. Found’s study is described in his 2016 paper in Animal Behavior.

There have been, though, other studies of behavioral and ecological differences between shy and bold elk. Bold elk, for example, are more likely to be taken by hunters and other predators because of the unidimensional nature of their response to danger (run away quickly). Shy elk, on the other hand, have more complex and more subtle strategies that act to avoid the development of potential hunter/predator confrontations, and they are, thus, much more likely to survive a hunting/predation interaction.

Photo by O. Daniels, Wikimedia Commons

Also, shy elk are more likely than bold elk to form symbiotic relationships with other species. A recently published study by Dr. Found (Biology Letters, November 29, 2017) looked at the interactions of elk and magpies. He noticed that some resting elk in a herd had magpies that landed on their backs (and heads!) and pecked away at insects and ticks that resided in the elk’s thick coat. Using the “bold/shy” elk profile, Dr. Found determined that the shy elk were much more likely to allow the magpies to land and feed on them!

This behavioral difference between bold and shy elk may have even more significance than their differences in winter migration. Ticks are becoming an increasingly serious problem especially in the warmer, shorter winters of our climate-altered world. In Maine for example, moose (our original “elk”) are dying in the winter because of massive tick infestations (see this AccuWeather article!). Pale colored “ghost moose” are the consequence of a tick riddled moose scratching its dark, insulating outer coat off in an attempt to rid itself of these maddeningly, itchy ectoparasites. These ghost moose are dying from loss of insulation and loss of blood. Some 70% of moose calves die each winter because of their huge loads of ticks.

It will be interesting to watch the relative proportions of shy and bold elk in the wild elk herds over the coming years. Will the segregation of the individuals into “city” and “rural” herds separate gene pools and possibly lead to speciation? Will the increasing presence of wolves in these regions select for more shy (i.e. predator vigilant) elk? Or will the increasing populations of ticks driven by global warming and climate change favor those elk who can open themselves up to the mutualistic symbiosis with magpies?

We’ll find out in a couple of centuries! Stay tuned!




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Signs of Spring 10: Fungi

Fungal mycelia. Photo by R, Hile. Wikimedia Commons

(If you would prefer to listen to an audio version of this blog, please click on this link!)

In order to really appreciate fungi we need to understand at least an overview of their general structure. Most fungi are complex, multicellular organisms that grow in thread-like strands called “mycelia.” The mycelia interweave themselves around the fungus’ habitat components and secrete digestive enzymes and absorb digested food products and other nutrients. Fungi can be quite large (the largest organism on Earth, in fact, is a soil dwelling, honey fungus (Armillaria solidipes) in Oregon that has spread out over an area of 3.7 square miles and weighs an estimated 605 tons! It is also may be over eight thousand years old!).

Fungi inhabit many different types of habitats. Some (like the honey mushroom) live in soil while others live in close associations with other complex organisms. Plants often have specific fungi associated with their roots. These fungi are called “mycorrhizae” and for many plants they are absolutely essential for the plant roots to work properly and for the plant to survive and grow! Other types of fungi can be found in and on plant leaves and inner tissues. These fungi may be important symbionts in the plant’s metabolism, or they may be potential pathogens or decomposing agents when the plant dies or begins to senesce. Fungi can also be found on and in animals (including humans) and are a part of the animal’s microbiome. Fungal microbiome cells are much less numerous than bacterial microbiome cells, but recent research suggests that they may have very specific and very significant physiological functions.

Morel mushroom. Photo by M. Smiley, Wikimedia Commons

Fungi were once classified with the plants, but a more modern approach puts them in a group (or set of groups!) all by themselves. This large group classification can then be broken down using a variety of features and characteristics including mechanisms of reproduction. Some fungal groups make spore producing, reproductive structures called mushrooms. For many people, these mushrooms (which quite literally are the tiniest tip of the fungal “iceberg!”) are the only visible and only recognizable parts of all of the fungi that surround them!

Fungi are extremely old and extremely complex organisms. They synthesize a wide variety of primary and secondary chemicals that have enabled them to survive and thrive in their environments and in their symbiotic relationships. The robustness of fungal chemistry has led some researchers to refer to them as “pharmaceutical factories” that may be sources of untold types of new drugs that could contribute to human health.

A research group at Penn State just published an article describing the concentration of two anti-oxidant chemicals (ergothioneine and glutathione) in thirteen species of edible mushrooms (Food Chemistry, October 15, 2017) . These anti-oxidants may, if they can survive the digestive processes and be absorbed into the blood stream intact, help the body to control damaging free radical chemcials that are generated in every cell of the body as a consequence of energy metabolism.

Free radicals have been implicated as causative or contributory agents in variety of neurodegenerative disorders (like Parkinson’s and Alzheimer’s diseases), in many types of cancer and in the overall process of aging. In a recent Penn State Newswire story related to the Food Chemistry article, Dr. Robert Beelman  (professor emeritus of food science, Penn State University) pointed out that in countries where these anti-oxidant rich mushrooms are traditionally consumed (like France and Italy) there is a lower incidence  of both Parkinson’s and Alzheimer’s diseases than in the United States (where these mushrooms are not traditionally eaten).

Boletus edulis. Photo by Dezidor, Wikimedia Commons

Not all mushrooms have the same levels of anti-oxidants, but all mushrooms tested did have significant levels of them. Further, the concentrations of ergothioneine and glutathione are correlated with each other (mushrooms with high concentrations of one also have high concentrations of the other), and cooking does not affect the molecular structure or anti-oxidant properties of either chemical. Wild porcini mushrooms (Boletus edulis), by the way, had the highest levels of anti-oxidants in this study.

Another glimpse into the chemical potential of mushrooms comes from a 20012 review article in 3Biotech by S. Patel and A. Goyal. Twenty genera of mushrooms and the chemicals that they produce are discussed in this article. Many of these chemicals (which range from polysaccharides, to proteins, to fats) have already shown to be efficacious in treating conditions like diabetes, allergies, high blood cholesterol, kidney diseases, and disorders of the immune system. Some of these chemicals also had novel anti-bacterial (i.e. “antibiotic”) and anti-oxidant properties! Some of these chemicals also via their impacts on steps in cell replication may have use as chemotherapy agents in the treatment of cancers.

The authors encourage more intense evaluation and exploration of wild and exotic mushroom species for their possible novel chemical constituents. They also note the long history of the use of mushrooms in traditional medical practices from a wide variety of cultures.

Which then gets us to wild mushrooms.

Over the years I have had a number of friends who hunted and harvested wild mushrooms. Many of the mushrooms collected in the wild cannot be grown in mushroom farms because they are generated by mycorrhizal fungi or grow out of recently deceased trees! I have always hesitated, though, to join in the hunt for two divergent reasons: 1. The fear of making a mistake and picking and gobbling down some poisonous mushroom variety, and 2. An ecological concern that removing the mushrooms (and all of their reproductive spores) from an ecosystem would seriously impact the local viability of the species.

Now, Reason #1 can be minimized by only harvesting extremely recognizable types of mushrooms and by going out with someone who is experienced with mushrooms. Reason #2, though, is a very compelling brake on wild mushroom harvesting (so mushroom people, leave some ‘shrooms behind!).

There are four species of mushroom that I would feel comfortable picking and eating:

  1. Puffball. Photo by Grindlemutter, Wikimedia Commons

    Puffballs: puffballs look like their name, rounded, globe-like sometimes extremely large. You find them usually in late summer or fall in open woods or pastures (they are soil dwelling fungi). The only thing that might look like a puffball is an early stage “death cup” mushroom (clear enough name for you?), but if you cut into the puffball the inside with be a homogenous white (you will see the forming stalked mushroom inside the death cup).

  2. Morels (pictured above): I have written about morels before (see Signs of Summer 2, 2015)). They are extremely popular, high quality mushrooms that look like little pine cone trees or cylindrical brains. They are very distinctive looking. They can be found in April or May usually near old elm trees (they are mycorrhizae fungal associated especially with elm roots). They are also hollow inside and this feature can be used to make absolutely sure that you have a morel.

    Chanterelle. Photo by User.Strobilomyces, Wikimedia Commons

    3. Chanterelles: chanterelles are yellow to orange, trumpet-shaped mushrooms that grow singly or in clumps. They are found in summer and in fall and are associated with many types of trees (both a variety of hardwoods and conifers). They are, like the morels, mycorrhizal on the tree roots but are not nearly as selective about their trees as morels.

    4. Chicken of the woods: chicken of the woods mushrooms are also yellow to orange and, like the chanterelles, very brightly colored. Chicken of the woods grows on dying to

    Chicken of the woods. Photo by Gargoyle888, Wikimedia Commons

    dead trees (especially oaks). This fungus is breaking down the old tree’s organic materials and, via its mushroom, sending out its spores on to find anew home to linger in.

This past summer I was given two bags of freshly collected chanterelles by a generous friend. I found a really great recipe for preparing them and enjoyed them very much. I also spotted,while on a bike ride, a fallen oak tree covered with chicken of the woods mushrooms but let that one go its natural course. It is hard to pick and choose when the mushrooms are so delicious!


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Signs of Spring 9: Insecta vs. Vertebrata!

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Beetles vs. Toads:

Photo by Osaka University, Wikimedia Commons

Bombardier beetles are a diverse (500 species) subset of carabid (“ground”) beetles that are found on every continent except Antarctica. These beetles, when disturbed, are able to spray a hot, caustic defensive secretion out of a gland at the tip of their abdomens. In these remarkable glands, bombardier beetles mix hydroquinone (a chemical produced by skin glands in all species of carabid beetles) with hydrogen peroxide (a chemical that is a common waste product of energy metabolism) in an abdominal sack that is lined with specific enzymes (catalase and peroxidase). The enzymes catalyze an extremely vigorous, exothermic (heat producing) reaction that generates 1,4-benzoquinone (a very toxic and irritating chemical) that is then explosively ejected out through the opening of the gland. An individual beetle has sufficient stores of hydroquinone and hydrogen peroxide to produce twenty benzoquinone ejections (more than enough to deter a whole array of potential predators!).

Two scientists from Kobe University in Japan just published a study that explored the effectiveness of these bombardier defense mechanisms in resisting predation by two species of toads. Toads are generalized, opportunistic predators, and any prey item that is small enough to fit in their mouths is likely to be taken. One of the toad species in the study was from a habitat in which bombardier beetles were common (and were, thus, a regular part of the toad’s potential prey cohort), while the other toad species was from a habitat in which bombardier beetles did not occur.

Japanese common toad. Photo by Y. Koide, Wikimedia Commons

When either type of toad ingested a bombardier beetle, the beetle responded with a ejection of hot, benzoquinone (the scientists could hear the explosive “pops” coming from inside the toad). The toad, then, just under half of the time, vomited up the bombardier beetle (although this sometimes took over an hour and half to occur!). The remarkable thing about the regurgitated beetles, though, was that they all were still alive (and lived for another two weeks (the time period of the experiment) after being vomited up. Even 107 minutes of emersion in the secretions of the toad’s digestive tract did not kill the bombardier beetles! Whether the beetles have developed some specific resistance to the toad’s digestive secretions or if the impact of the released benzoquinone inhibited normal digestive activity is not known.

There were some very distinct and very logical size relationships in the results of this study: Larger toads of both species vomited up beetles less often than smaller toads (probably reflecting the reduced impact of a benzoquinone dose on a larger digestive systems), and larger beetles were more likely to be vomited up than were smaller beetles (probably reflecting the larger doses of benzoquinone that they could produce).

There were also some interesting ecological (and, possibly, evolutionary) relationships highlighted in this study: Toads that were from a habitat that contained bombardier beetles vomited up the beetles much less often than toad’s without prior bombardier beetle exposure. These results suggest either an acquired (learned) tolerance to the benzoquinone in the previously exposed toads or, possibly, an evolved resistance to the caustic secretions of the beetles.

This paper was published in Biology Letters (February 7, 2018).

Midges vs. Frogs:

Tungara frog. Photo by B. Gratwicker, Wikimedia Commons

In another amphibian/insect interaction study, Dr. X. Bernal of Purdue University noted that blood sucking midges were densely clustering around the males of the Central American tungara frog while the frogs were in their mating pools. Exploring this more closely, Dr. Bernal determined that the midges were detecting and zeroing in on the male frog’s mating songs in order to locate them for their blood meals. Blood feeding flies (like midges or mosquitoes) are known to detect and follow chemical cues to their potential blood hosts, but sound has never been shown to be a possible attractant. Interestingly, the same features of a male tungara frog’s call that are most likely to attract female frogs also attracts the most blood feeding midges! These midges, by the way, are not only significant blood feeders on these male frogs but also carry trypanosome blood parasites that may be preferentially infecting, and debilitating the male frogs!

Dr. Bernal’s findings can be found in papers published in Ethiology (January 6, 2016) and the Journal of Vector Ecology (June 5, 2015).

And, finally, one more interesting insect interaction with a “higher” life form:

Caterpillars vs. birds.

We all know that birds eat caterpillars, and, overall, we are glad that they do! Caterpillars are very hard on leaves and would probably defoliate all  of our forests if left to feed unchecked. One caterpillar, though, the North American walnut sphinx moth caterpillar, has developed a very unique defense mechanism by which it tries to avoid becoming some bird’s dinner. When this caterpillar is pecked at by a bird it is able to contract its body wall muscles and compress itself (“like an accordion,” one researcher commented) forcing air out through a series of holes in the sides of its body. The sound generated by this sudden air expulsion is quite loud (about 85 decibels 5 cm away from the caterpillar) and also quite distinctive. The sound mimics the avian alarm call referred to as the “seet” call and not only startles the hunting bird but tells it that danger is near!

Researchers at the University of Montana demonstrated that this caterpillar generated alarm sound does indeed affect potential caterpillar-eating birds like a true avian community distress call. It’s very hard to both eat and take cover!

(These results were presented at the International Symposium on Acoustic Communication by Animals (2017)).



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Signs of Spring 8: Mason Bees!

Photo by B. Moisset, Wikimedia Commons

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Mason bees (Osmia spp.) are solitary bees that have very short life spans (only six weeks or so). These bees nest in tubes or holes and have earned the name “mason” because they build wall-like partitions made of mud inside of their tubular nests. A mason bee gathers pollen and nectar from the flowers that are blooming during its short life and packs it around the eggs that it lays in the mud-wall partitions of its nest. A mason bee may fill up more than one nest with its eggs and its accumulated nectar and pollen.

The eggs then hatch into larvae that feed on the stored food and steadily grow and develop. The nest walls are extremely important here because they keep each larvae isolated with their own food supply! The mature larvae then spin cocoons and develop into pupae which will, still inside the cocoon, then molt into their adult forms. It is inside of this protective and insulating cocoon that the mason bee overwinters. In the spring, male mason bees emerge first and wait outside of the nest for the later emerging females. As the females emerge, the males immediately mate with them. After they mate, the males die, and the females then find a suitable tubular structure for its nest and begin to lay eggs, gather nectar and pollen, and, as a great ecological tie-in to this activity, pollinate many different species of flowering plants.

Photo by D. Sillman

Last Fall an old friend (and regular reader of this blog) gave me a beautiful, tear-drop shaped, bamboo basket of sealed up mason bee tubes. My instructions were to put it somewhere where it would stay cold all winter and to watch it carefully until Spring finally arrived. I hung the basket in my unheated garage and admired it regularly whenever I went down to get into my car.

The tubes remained quiet all winter, but suddenly, two weeks ago, they became active. A sticky, powdery dust layered out on my bicycle (which was parked right below the basket). Tiny holes showed up in some of the tube-sealing materials, and a small mason bee somehow flew up through the garage ceiling (maybe through the cold air return?) and ended up in my bedroom where I found him, immobile and, very sadly, deceased.

Outside our endless winter was still going on. Cold and snow and no flowers or nectar or pollen for the little bees. I had failed them and let them emerge too soon to survive.

Or so I thought!

Last Thursday it was sunny and 70 degrees. My forsythia along the driveway had started to flower a few days before. I opened my garage to work on my bicycle (a ride down on my local trail was actually possible that afternoon!). As I stood in the opening of the garage and let the sunshine pour in, I saw movement on the floor: mason bees!

The bees were exhibiting a vigorously positive phototropism and were moving slowly but steadily toward the sunlight. At first there were just a handful of them, and I gently picked each of them up and deposited them in the sunshine underneath the branches of the forsythia. Then there were more of them: ten, twenty, thirty, forty or more mason bees walking very zombie-like toward the sunshine.

Close up of mason bees in tubes

Photo by D. Sillman

When each bee got an inch or two into the sunny section of the garage floor they stopped as if stunned by how good the sunlight felt! They then wiggled their abdomens, groomed their wings with their legs, fluttered their wings and then, after two or three minutes of warming up and cleaning the garage dust off of their bodies, they launched themselves into the air. None of them flew very straight or with anything that resembled skill. They careened to the right or to the left and smacked into the wheel of my bike, or into my leg, or into the concrete block of the driveway wall. After they landed, though, they picked themselves up, readjusted their wings and then re-launched themselves into the air.

I watched at least twenty-five of the bees take their first flights. Often they would cycle back toward the garage before they finally found the forsythia. They frequently landed on my pant leg or on the top of my shoe before flight 2.0 ensued. Almost all of them, though, eventually ended up in the branches of the forsythia.

Photo by D. Sillman

I put the tube basket out in the sun next to the forsythia. As it warmed up I could hear scraping inside of the some of the still sealed tubes. A tiny flutter of powder began to float down in front of the basket. More bees were going to emerge! When I went back down to check on the basket after going up to my computer to write all of this down, there were active mason bees (the males) on the tube basket poking at the still sealed tubes. The scratching inside the tubes was even louder than before! The females were about to emerge!

An hour later the females were emerging from their tubes. The males were right there to mate with them and nature was taking its course!

I can’t tell you how much better I feel now that my mason bees survived my inept care! The very slow start to the spring made the timing of their emergence a very delicate thing. I am glad that they survived in the garage in their zombie-cold state, and I am very glad that the forsythia flowered in time to provide them a source of food. Survival is never guaranteed even with an abundance of clumsy human help: there are hungry birds waiting to pick off slow flying bees, there are old spider webs around the edges of the garage and up in the branches of the forsythia, and we had snow showers all day on Tuesday and today (Thursday) it is snowing again! There must be dozens of fatal traps lurking out there that could abruptly end this apian experiment.

The bees, though, are moving ahead as fast as they can! Here’s a video of them that Deborah made!



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Signs of Spring 7: Two Invasive Bugs

Photo by J. F. Orth, FLickr

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The spotted lanternfly (Lycorma delicatula) is one of the latest species in a long line of destructive, exotic insects that have invaded our agricultural and forested ecosystems. The lanternfly in spite its name is not a fly, nor is it, in spite of its often photographed spread-winged, moth-like appearance, a lepidopteran. It is a hemipteran (a true bug) with piercing, sucking mouthparts that is capable of doing great damage to a wide range of plants.

The lanternfly was first reported in Berk’s County in southeastern Pennsylvania in 2014. It is a native to China, India and Vietnam and is also a recent, and very destructive, invasive species in South Korea. It is thought to have initially entered Pennsylvania in 2012. In November 2014, the Pennsylvania Department of Agriculture established a quarantine of five townships in Berk’s County prohibiting the movement of firewood, lawn mowers, outdoor furniture, RV’s, wreaths, Christmas trees, etc. out of the area. This quarantine area has since been expanded to include a total of thirteen counties in the southeast corner of the state. The lanternfly is not a strong flyer and relies on human-aided transport to move significant distances, so this quarantine has been fairly effective in stopping the spread of this pest.

Photo by MTSOfan, Flcikr

Adult lanternflies are only 1 to 1 ¼ inches long and are fairly inconspicuous until they open their underwings to fly. The underwings are brightly colored (orange and red and white) and present a very distinctive, highly recognizable appearance. In the fall adult females lay eggs in grayish, mud-colored masses of 30 to 50 eggs that they attach to almost any solid object (including tree trunks and branches, outdoor furniture, rocks, etc.). The long list of objects enumerated in the quarantine regulations reflects the wide range of possible lanternfly egg deposition sites.

Eggs hatch in the spring, and the tiny nymphs (the first of four rapidly growing instars) find and feed on a wide variety of woody plants (including hardwood trees like willow, maple and poplar), pine trees, many types of fruit trees (including apple, plum, cherry and peach) and grape vines. The adults may continue to feed on this broad array of plant hosts but seem to prefer the exotic invasive tree called the tree-or-heaven (Ailanthus altissima) (see Signs of Fall 9, November 2, 2017). Large numbers of adult lantern flies and large numbers of egg masses can be found on tree-of-heaven, and proximity to tree-of-heaven in this quarantine area is major factor in the likelihood of finding lanternfly egg masses on surrounding objects.

Direct damage to the plants being fed upon by lanternflies can be severe, but even more extensive harm can be caused by secondary consequences associated with this initial feeding. Lanternflies feeding on a plant secrete a frothy substance called “honeydew.” The presence of this honeydew is often the way that a lanternfly infested plant is identified. This honeydew may attract other plant damaging insects and may also serve as the growth medium for some plant damaging fungi such as sooty mold.

Ongoing research at Penn State on these invasive hemipterans have involved genetic sequencing of the invasive population in order to determine the precise location from which they originated. Determining this location could then allow on-site evaluation of the native population to look for biological control agents like parasites, predators or parasitoids. The lanternfly’s microbiome is also being explored to look for potential pathogens or symbionts that may be useful in its control. The microbiomes of the plants on which the lanternfly feeds are also being evaluated to look for changes triggered by the lanternfly’s feeding and production of honeydew. The chemical ecology of the tree-of-heaven is also being examined to try to determine the exact nature of the lanternfly attraction and symbiosis.

Photo by D. Sillman

Another exotic invasive hemipteran that has been raising havoc in Pennsylvania is the brown, marmorated stink bug (Halyomorpha halys). These stink bugs are natives of northeast Asia (Japan, Korea, and China) and over the past twenty years have become a serious invasive pest throughout the United States. It is thought that this insect was first released into the United States in Allentown, PA in 1996. It apparently traveled from northeast Asia in a shipping container that was delivered either to the port of Philadelphia or Elizabeth, New Jersey and then trucked to Allentown. In 2001 this new, alien, invasive species was recognized and identified by entomologists at Cornell University, but by then large populations were being observed throughout eastern Pennsylvania, New Jersey and New York. This insect has now spread to forty states and is especially abundant in the eastern United States. It has very large populations in Pennsylvania, Maryland, Virginia, New York, New Jersey, Massachusetts, Delaware, Ohio, and North and South Carolina. Its spread to California and Oregon was allegedly via a car driven by a person traveling from Pennsylvania to California in 2005!

Many of these stink bugs find their way into our houses where they spend the winter months hibernating in tiny crevices and hideouts all around us. Their periodic emergence through the winter is often the only reminder that they are close by! Their mass emergence in May and June has become a very unfortunate sign of spring!

Brown marmorated stink bugs feed on over one hundred and fifty plant species including a number of crops that are of great economic importance to humans. Fruit trees (especially apple and pear), soybeans, and peanuts can all be significantly damaged by these insects. I have also seen adult stink bugs in my yard feeding avidly on the grapes growing on my grape vine.

Spider Eating Stink Bug  Photo by D. Sillman

I have talked in previous blogs about how local predators of insects (spiders and a variety of birds) have overcome their initial aversion to the protective secretions of these stink bugs and have begun to consume these slow moving bugs. Apparently, these emerging natural control systems in conjunction with increasingly sophisticated agricultural control regimes have reduced the overall impact of these pests considerably.

Dr. Greg Krawczk, a fruit tree entomologist and associate research professor in the Penn State College of Agricultural Sciences, says that the brown marmorated stink bug explosion peaked between 2010 and 2013 and that “we now know how to manage them.” In an October 25, 2017 article on the Penn State Newswire, Dr. Krawczk states that crop losses from these invasive bugs have been greatly reduced and that Penn State is exporting its knowledge and pest control technologies to many countries. For example, agricultural researchers from the Republic of Georgia are working with Dr. Krawczk and other scientists from Penn State, the USDA and Virginia Tech to develop programs to control their own recent explosions of brown marmorated stink bugs.

I hope the Georgian spiders and chickadee-equivalents learn how to feast on the bugs, too!

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Signs of Spring 6: Snail Kites and Rapid Evolution

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(Great thanks to Ty Bauman for permission to use several of his photographs in this week’s blog. Ty and his wife Linda have a bird/travel blog that is full of absolutely stunning pictures! I recommend it highly!)

Photo by T. Bauman

I have written about snail kites (formerly called the “Everglades snail kite”) (Rostrhamus sociabilis plubeas) before. They were one of the species that was hammered by Hurricane Irma when it hit the Florida peninsula last September (see Signs of Fall 7, October 19, 2017). All forty-eight of the snail kite nests around Lake Okeechobee were destroyed by Irma, and biologists were worried about the lasting impact of this reproductive disaster on this locally, very endangered sub-species.

But the snail kite had many more stresses prior to this latest hurricane. For example, this bird is a very specialized predator that feeds primarily on a single species of freshwater snail called the Florida apple snail (Pomacea paludosa). The importance of these snails to the snail kite is reflected in the very anatomy of the kite itself. The snail kite has evolved a highly specialized, sharp-pointed beak that is curved and aligned perfectly to allow it to pull the soft-bodied Florida apple snail out of its shell with great ease and efficiency. Now the snail kite does, at need, take and eat other prey items including crayfish and small fish, but apple snails are its overwhelmingly obligatory food of choice.

The snail kite also needs a very open vegetative habitat so that it easily locate the apple snails and then swoop down unimpeded and grab them at water level. They then take the captured snail to a perch to eat it.

There have been a number of impacts on the snail kite’s habitat that have interfered with both its food supply and its hunting strategies. Exotic snail species including the island apple snail (Pomacea maculata) have invaded the snail kites’ marshes and caused declines in the vital Florida apple snail. The island apple snails are two to five times larger than the Florida apple snail and are not as easily taken or de-shelled by a typical snail kite. Most of these invasive snail species are thought to have entered these Florida wetlands after being released by careless, tropical aquaria owners.

USGS, Public Domain

The Everglades is a vast, tropical wetland that once covered almost all of southern Florida. In wet seasons water flows slowly in a sixty mile wide front from Lake Okeechobee southward, down to Florida Bay. The flatness of the water surface hides the complex topography of the underlying, limestone bedrock. Small lifts or slight valleys in the bedrock can generate vastly different conditions for vegetative habitats. The open waters of the ponds over the deeper sections can transition into the wet prairies of slightly shallower sites, or the saw grass marshes, or the still only slightly drier “islands” of hardwood or pine forest in the shallower sections of wetland. This complex patchwork of wetland habitats supports and sustains a rich diversity of both plant and animal life.

Photo by Ty Bauman

The present day Everglades represents about half of its original area in southern Florida. Much of the primal wetland has been drained for agriculture and other human uses. Ongoing drought in Florida has also caused great loss of previously untouched wetlands and marshes. This shrinkage of essential habitat has greatly affected the snail kite. More insidiously, though, pollution from sewage and septic systems and nutrient runoff from agricultural fields has stimulated inappropriate plant growth and expansion of invasive plant species (like cattails and water hyacinths) throughout the remaining Everglades. This denser vegetative system makes the snail kite’s style of hunting less efficient and less productive.

In 2000 there were 3500 snail kites in Florida. By 2007 there were only 700 snail kites left. There was also a surge in the numbers of the larger, invasive island apple snail (coupled to a precipitous decline in the Florida apple snail) starting in 2004. Many scientists felt that this would be the final straw for the snail kites.

But they were wrong!

Photo by Ty Bauman

In the last ten years the population of snail kites has increased to 2000 birds. Further, these present day birds are different from the typical snail kite of a decade ago. In the past ten years the snail kites have gotten larger (on average 8% larger and at maximum 12% larger!) and their beaks have gotten bigger, too! Their larger body size and bigger beaks have enabled them to much more easily take and eat the larger island apple snails! Scientists like Robert Fletcher, Jr. of the University of Florida have been studying these changes in the snail kites and feel that they represent a classic example of Natural Selection at work. In the original population of snail kites there were some individuals that were larger than average. Those individuals (and their offspring) took advantage of the new abundance of the larger, exotic snails and fed extensively upon them. With each breeding cycle the larger kites had more food resources and produced more offspring, until the entire size profile of the population changed. That evolution could occur over such a short time period was surprising, but underlying logic of Nature Selection is compelling (Dr. Fletcher’s work is published in the November 27, 2017 issue of Nature, Ecology and Evolution).

We hope that the Irma-induced disruption of the snail kite’s breeding will not seriously sidetrack the recovery of its Florida population. Hurricanes are natural phenomena, and native species have persisted though a long history of these massive storms. The human generated stresses in the Everglades, though, may be more than what the native species can handle. That the snail kite has been able to re-model itself in the face of such a radical and rapid  transformation of its food supply is an incredibly hopeful sign. We wish the snail kite bon appetite and continued good escargot hunting!





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Signs of Spring 5: Skunks!

A close up of a skunk under a bird feeder

Photo by D. Sillman

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The scientific name of the striped skunk is Mephitis mephitis. “Mephitis” is Latin for “noxious vapor” and is an extremely appropriate genus and species name for this shy, unassuming member of  the mustelid (“weasel”) family of carnivores. The ability of the skunk to use its mercaptan rich musk as a defensive spray has been well represented in fiction and in the real life experiences of many people (not to mention their dogs).  The name “skunk” comes from the Algonquin name for the animal “seganku”. There are a number of less common, but often highly descriptive names for this animal including “polecat” and “infant du diable” (child of the devil) (a term of less than endearment from the early French Canadian trappers and voyageurs).

My son in law, Lee, just sent me a copy of the first historical mention of skunks. It is from an account of a Jesuit Priest in 1634:

“The other is a low animal, about the size of a little dog or cat. I mention it here, not on account of its excellence, but to make of it a symbol of sin. I have seen three or four of them. It has black fur, quite beautiful and shining; and has upon its back two perfectly white stripes, which join near the neck and tail, making an oval which adds greatly to their grace. The tail is bushy and well furnished with hair, like the tail of a Fox; it carries it curled back like that of a Squirrel. It is more white than black; and, at the first glance, you would say, especially when it walks, that it ought to be called Jupiter’s little dog. But it is so stinking, and casts so foul an odor, that it is unworthy of being called the dog of Pluto. No sewer ever smelled so bad. I would not have believed it if I had not smelled it myself. Your heart almost fails you when you approach the animal; two have been killed in our court, and several days afterward there was such a dreadful odor throughout our house that we could not endure it. I believe the sin smelled by Saint Catherine de Sienne must have had the same vile odor.”

Photo by D. Sillman

A couple of nights ago my dog, Izzy, found one of these “foul dogs of Pluto” out bumbling around under one of our bird feeders. The result was predictable although unfortunate. Deborah scooped Izzy up and deposited her into the bath tub while I mixed up a jug of hydrogen peroxide, baking soda and dish soap to scrub her with (here’s the recipe from the Humane Society website). The concoction worked well, and Izzy didn’t have to go sleep in the garage!  We’ll get the “dreadful odor throughout our house” cleared up eventually (I hope). I plan to research Saint Catherine de Sienne to see if she might have had some ideas that could help me with the clean up!

This is Izzy’s first skunk encounter. We installed a yard light out front to try to avoid unexpected night-time interactions like this. Our former dog, Kozmo, hated skunks with a deep passion and, as a result, got sprayed repeatedly. He would usually get hit the hardest in his open mouth as he was lunging at the skunk. Fortunately, I came across the de-skunking recipe about halfway through Kozmo’s skunk career. It works so much better than tomato juice! My good friend Steve Hoops (retired chemistry professor from Penn State) once explained to me how the hydrogen peroxide worked to shut off the volatile mercaptan and erase the stench of the skunk, but I forget the details. If he reads this post, maybe he will add the explanation in a comment!

No one who owns a dog has any reason to love skunks. They are, though, useful members of our suburban and rural ecosystems. They help to keep rodent populations under control, and they eat a variety of garden pests (including potato bugs and Japanese beetles) especially when they are in their larval (“grub”) stages.

Photo by D. Sillman

Skunks are omnivorous and will eat whatever is available. Seasonal foods include: in spring and summer, insects (both adult and larval forms) (especially grasshoppers, crickets, beetles, bees and wasps), spiders, toads, frogs, lizards, snakes, mice, chipmunks, turtle eggs and the eggs of ground nesting birds. In the fall and winter, they eat a variety of fruits (including wild grapes, and the fruits of wild vines like Virginia Creeper), carrion, and a many types of plants and plant  parts  (including grasses, leaves, buds) and nuts.  Skunks, like one Izzy met last night, also eat bird seed and may even rip into garbage bags and tip over trash cans.

The skunk is a slow, deliberate creature that is capable under extreme need of a clumsy gallop that can  reach up to 10 mph. It is a very poor climber but is capable of swimming. Its sense of sight, smell and hearing are poor but it is reported to have a very acute sense of touch. It is a nocturnal animal typically becoming active just before sunset and then inactive just prior to sunrise.   During this night-time activity period it typically takes a single rest period of one to two hours usually away from its sleeping den.

Photo by D. Sillman

Skunks by common account are not very intelligent animals. They display, though, good problem solving behaviors to acquire food. They have been described as scratching on the outside of a bee hive to induce the bees to fly out to investigate the noise and intrusion. The skunk then catches and eats the bees as they emerge. Skunks also eat tenebrionid beetles (“stink beetles”) by taking the large beetle in their front paws and rolling it around in the soil until it has exhausted its reserve of irritating, quinone spray. The skunk then is able to eat the beetle without the unpleasantness of the quinones.

Skunks are solitary creatures except during a very brief mating period in late winter or early spring. Adult  males are very active during this mating season and travel widely in search of a receptive mate. During this courtship and mating period large numbers of skunks end up as roadkill on our roads and highways. Males fight each other over females during this courtship and mating period, too. It is interesting, though, that in these aggressive conflicts the males do not utilize their musk as offensive weapons.

Photo by D. Sillman

Last night, two nights after Izzy’s skunk encounter, Deborah and I watched a skunk (probably THE skunk) amble slowly across our field just before sunset and work his/her way to our front yard and the bird feeders. The pictures in this post are all from that encounter. It was interesting to watch a skunk that closely! He/she did not seem at all anxious about returning to the place of its Izzy-interactions.  It is useful in Nature not to dwell on unpleasant or frightening events! I just hope that he/she is not planning to den up under my new sun porch!

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