Weekly reads 14–20.v.2016

Istvan stands with aspirator, while three students walk away with sweep nets for collecting insects

István sucks up gall wasps, while the rest of the crew sets out to get live megaspilids. Photo (CC BY 2.0) by Andy Deans https://flic.kr/p/GVDjr7

We held our weekly lab meeting at Sunset Park, so that we could collect live Megaspilidae and Cynipini for histology and other data collection. Therefore we didn’t spend much time discussing our weekly readings. Some of us did put together narratives though, which you can find below.

Andy: I am part of a collaborative team that aims to understand the mechanisms that underly gall initiation and development in Cynipini (gall wasps). Some of this research has appeared here before, and we will certainly post a lot more soon (We have results!). At first my contributions were more or less advisory, but since January my interest in the biology of this group has been exploding. This week I stepped back from reviewing contemporary research on gall wasps (e.g., Ronquist et al., 2015), and read instead the deep natural history papers of Adler (1894) and Kinsey (1920) … before going off the rails a bit with Derham (1720) and Malpighi (1679).

As stated above, part of our lab meeting was spent collecting adult gall wasps for further analysis. The sexual generation of one of our target taxa is ovipositing right now!

three tiny wasps on oak leaves

Acraspis gall wasps ovipositing on young oak leaves. Photo (CC BY 2.0) by Andy Deans https://flic.kr/p/Gqv542

Kyle: I chose to read this article by Kittel et al. (2016) because like chelonine wasps; the group I study is also a diverse lineage of parasitoid wasps. I also use a mixture of morphology and molecular data and am interested in calculating divergence times, so the methods of this study could be very useful for me.

In this study, they estimate divergence times using three different methods (fixed-rate, node, and total-evidence dating) and compare those results. Fixed-rate dating uses an estimation of the number of substitutions per million yeas as a molecular clock. Node dating calibrates specific nodes with fossils of a known age. Total-evidence dating includes fossils as branch terminals.

After the authors of this study evaluated the three methods, they found too much variation in divergence time estimates and suggest that multiple approaches should be used whenever possible. They found that all of these methods were very sensitive to the prior on tree age, and that plausible modifications to priors could drastically change the results.

Emily: I have been reading Dragonflies: Behavior and Ecology of Odonata by Philip S. Corbet to prepare for a grant proposal. I have been focusing on environmental factors affecting Odonata larva distribution and have learned some interesting facts about ranges for species in very cold climes. There are odes collected all the way in northern Siberia, and some larvae spend 5 months frozen in ice! Much about the habitat of larval odes can be examined, but it can be difficult to separate the many different factors. Over the coming months, I hope to delve deeper into this idea…stay tuned!

Carolyn: This week I started to dissect male genitalia from pinned Megaspilus and Conostigmus specimens, so I thought it would be a good idea to reread a paper by Mikó et al. (2013). In this paper the authors discuss 48 male genitalia characters and score them for 106 taxa, providing the very first phylogeny of the superfamily Ceraphronoidea. The paper also contains annotated brightfield, CLSM and SEM micrography images of the male genitalia of different species, which I have found very useful.

I have also been working on translating a paper by Paul Dessart (1997) concerning three Conostigmus species found in North America. So far I have translated the introduction, in which Dessart discusses the difficulty of trying to look at Provancher’s holotype specimen of Conostigmus nigrorufus, which was deposited in the Royal Ontario Museum. Dessart was upset that he could not borrow the holotype and complains about the curators jealously guarding their materials as “sacred”, preventing the holotype specimen from being used as a reference.

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Weekly reads 7–13.v.2016

Carolyn: This week, I’ve been looking at several of the original descriptions for Conostigmus species to see what diagnoses each species and where the holotype specimens were found. But several descriptions are in different languages; Alekseev wrote in Russian, and Kieffer and Dessart wrote in French. Even recent species descriptions in English can be difficult to interpret. Conostigmus neotubifer was described in 2014 and the publication includes pictures of the male genitalia, but the male genitalia are damaged in the picture. Male genitalia differences are one of the best ways to distinguish between species, and the damaged genitalia of this holotype specimen makes it difficult to know if this species is different from the species it was named after and closely resembles, Conostigmus tubifer.

I also read Randy Olson’s Houston, we have a narrative: why science needs story. This is a book about science communication that stresses the importance of having a narrative or a story to your research, since storytelling is such a universal method of human communication. He also stresses the importance of simplicity and writing in a clear and concise manner. Though the book does contain some useful advice, the author tends to ramble and focus on himself instead of the topic at hand (the writing is peppered with mentions of his degree, his training, his movies, famous people that he knows and works with, etc.). I feel that this book would have been much more effective as a short essay.

Kyle: I read a recent article by Renner (2016), in which she discusses the pros, cons, and differences between species diagnoses and descriptions and how molecular data fit in with these concepts. She argues that molecular diagnoses (the difference between the genetic code of two taxa) should serve to name a species, and she draws a lot of inspiration from bacteria and fungal systematists and taxonomists.

Andy: I’m always on the hunt for exemplars of research based on natural history collections, and I was excited to see specimen digitization featured in Science (Rogers 2016) last week. I am especially interested in research on phenotypes and have been looking for research that exploits the massive number of micrographs and photos that are now available for collections. Rogers (2016) points to a paper by Fenberg et al. (2016), in which, among other things, they measure wings of Hesperia comma (Silver-spotted Skipper; Hesperiidae), using images from the NHM’s digitization process, to understand how global warming impacts body size. I think the latent potential of museum images is huge.

Our Penn State Museums Consortium listserv lit up last week with questions and suggestions about loan and other policies. This topic has been on my mind for awhile, as we try to bring the Frost back online with the latest best practices. I’ll be at the ECN’s collections workshop this summer and expect to have a lot more to say soon about our own various policies. Until then I will be reading any and all policies I can find on the Web, starting with … (Googles “natural history museum policies“) … the Florida Museum of Natural History.

Emily: Using 8 nuclear & mitochondrial genes, Letsch et al. (2016) construct the phylogenetic relationships and divergence time estimates for all families of dragonflies, comparing the effects of lentic and lotic habitats on speciation. It had been proposed that lentic habitats increase speciation due to the fact that they are more transient in nature than that of lotic water bodies, causing higher dispersal. However, ancestral state reconstruction analysis in this study showed that the Anisoptera evolved from lotic habitats and had three independent shifts to lentic environments. Lentic species were also found to have higher extinction rates, contradicting the former ‘habitat-stability’ hypothesis that lotic waters were associated with higher diversification.

dragonfly on a leaf emerging from its larval skin

A gomphid emerges from its lotic larval environment. Photo (CC BT-SA 2.0) by Didier Bier https://flic.kr/p/6D4114

István: “Smooth and shiny” is an expression that bothered me for a some time, when I would review a manuscript. What is the sense in writing “shiny”? Of course the cuticle of many hairless insects is shiny if no light diffuser is used(!), but why not use a light diffuser? Without a Mylar sheet basically nothing can be properly described due to the extreme high reflectance “shininess” of the specimen obscuring finer surface sculpture.

Well, I have recently learned (by working with ant and Cynipini specialists) that some taxonomists, indeed, are actually using reflectance as an important property of morphological descriptions. But really, why is something shiny and something matte? Of course the answer is, as usual, in the cuticular hydrocarbon profile. An extreme case reflectance and cuticular hydorcarbon profile was published by da Hora et al. (2010).

Jonah: Reading this paper—Dew et al. (2016)—stemmed from a discussion I had with István over the need for not only sociobiology but social evolution as a science to begin to update itself and try to intertwine with the other sub disciplines of biology. Dew et al. discuss not only a need for new terminology in the field but a more defined protocol for what we know and how to improve on the practices that have brought us to this point in understanding social behaviour. So many terms in the field are outdated and its very difficult to incorporate new concepts without great resistance from peers. This not only segregates us from the other branches and prevents collaboration and further understanding but stifles our own progress. Dew et al. provide an example of how a new system of taxon specific terms could allow for not only better in house understanding but create a more solid foundation for further experiments and ideas. A systematics approach is given as the best way to categorize all the nuances and caveats that are seen in social insects and develop a ‘social tree’ to see where this concept evolved from and how its still evolving rather than the current rulings of clumping groups together simply on pattern recognition and not on an analytical base.

More and more people in the field are feeling this way and breaking away from the traditional methods of describing social evolution. And while the field is still young compared to others its never too early to develop a plastic mentality and allow much needed change and communication in a field that seeks to understand these very traits.

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Insects of the States:Pennsylvania

Call it what you want, a lightning bug or a firefly, Photuris pennsylvanica (De Geer,1774) is the state insect of Pennsylvania! Since P. pennsylvanica is in the order Coleoptera, it is actually a beetle…not a true bug or a fly!

A unit tray of Pennsylvania fireflies

From our own collection! Photo by Autumn Busbee (CC BY 2.0). Click for source.

In general, fireflies can be found worldwide in warm to temperate environments that are humid; they have a preference for grassy to woodland habitats near bodies of water.

The lifecycle begins as larval fireflies hatch from eggs on the ground. While larval fireflies are known to eat invertebrates such as slugs and snails, the diet of adult fireflies is highly variable from nectar to other fireflies. Larvae burrow underground to overwinter, then emerge in the spring to feast again. In the late spring larvae burrow underground again to pupate, emerging as mature fireflies in the early summer. (Buschman, 1984)

Image of a larval firefly hunting on moss

This larval firefly is likely on the prowl for a tasty slug or snail! Photo by Mario Quevedo (CC BY-NC 2.0). Click for source.

As the temperature rises, mature fireflies light up the night as a form of communicating with one another. Luciferin, luciferase, and ATP are the chemicals responsible for the fireflies’ glow (McElroy and DeLuca, 1978). This reaction is highly efficient, barely any of the energy is emitted as heat! (Click here for a quick lesson on bioluminescence.) Along with attracting a mate, fireflies use light to signal to predators that they are distasteful as well as to defend their territory. Flash patterns vary between species of fireflies and can be used to help identify different species (Lloyd, 1969). (Click here for a quick lesson on flash patterns.) Certain species (such as photinus) mimic the patterns of other species (like photuris) to attract mates (Lloyd, 1965).

Swarm of fireflies glowing at night.

But, oh, those summer nights! Photo by tsaiian (CC BY-NC 2.0). Click for source.

Fireflies serve as good indicator species, in which species distribution and population sizes indicate the health and quality of an environment. Unfortunately, firefly populations are on the decline. Potential causes of their decline include light pollution, land development, and environmental degradation.

To learn more about this phenomenon, researchers at institutes such as Clemson University are engaging citizen scientists to help track and record firefly populations. Last year, Clemson hosted the Vanishing Firefly Project to create a firefly census. To successfully do this, researchers created firefly counter apps for Android phones and iPhones that allowed volunteers to record fireflies based on the type of light flashes produced. More information on this project can be found here and here.

A firefly perched on a small plant

Waitin’ for a matin’! Photo by Terry Priest (CC BY-SA 2.0). Click for source.

Each year, the Pennsylvania Firefly Festival takes place near Tionesta, PA. Don’t forget to mark your calendar, this year the festival will take place on June 25th at the Black Caddis Ranch!

Lastly, the firefly, specifically the common eastern firefly (Photinus pyralis), is also one of the state insects of Tennessee.

The next post in this series will showcase the state insect of quite a few states…the European honey bee (Apis mellifera)!

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Weekly reads 1–6.v.2016

Carolyn: This week I did some reading on the cephalic pits in Ceraphronoidea, mainly a paper by Bin and Dessart (1983). There are three kinds of pits that have associated internal apodemes: the interocellar pit, the preoccipital pit, and the facial pit. Megaspilinae have both the preoccipital pit and the facial pit present, but they are different between Conostigmus and Dendrocerus (in Conostigmus, the facial pit is much more developed). The authors propose that the pits might have some sort of sensory function, especially in Conostigmus triangularis, where the pit is more developed and associated with a facial chamber.

The full reference is:
Bin, F. Dessart, P. 1983. Cephalic pits in Proctotrupoidea Scelionidae and Ceraphronoidea (Hymenoptera). Redia, 66: 563-575

Emily: Erythemis, a genus of libellulids, has a great deal of intraspecific variability in the morphological characters. Rodríguez et al. (2015) sought to examine the 53 characters in the original description as well as proposed 81 in the hopes of generating a key with greater diagnostic potential. The original key for this genus was written in 1928 by Fraser and seems to have a large amount of qualitative characters (i.e. proposing that the abdominal segments are different between species, but not providing measurements). Examining 3,300 Erythemis specimens, a subsample was taken of both sexes in order to evaluate morphometry. They ran statistics on the characters to determine if they were delineating species in the key, determining that 23 characters from the original description were not varying between species or were redundant. Using a ratio between some characters, the researchers were able to eliminate the overlapping tendency of characters between species that was in the original description. In reading the key, I realized the intraspecific variability in color within Erythemis—from brown to green to red to blue—was something that I missed in looking at the specimens that have been sitting in our collection for decades and have mostly dried to brown.

Andy: It was a busy week, in which I focused on administrative duties and our ongoing exhibit development. That means I entered a rabbit hole of papers that are mostly irrelevant to my current research but which nevertheless were exhilarating.

My first distraction: One of the species we’re highlighting in an exhibit about parasites is a Nearctic rabbit flea. In doing research for our narrative about this species, I was reminded of Dame Miriam Rothschild‘s work on the close physiological relationship between the reproductive state of the host (two rabbit spp.) and parasite (a couple flea spp.)—work that resulted in no less than four Nature papers (Rothschild and Ford (1964a), Rothschild and Ford (1964b)Rothschild and Ford (1966), Rothschild and Ford (1969)) and one Science paper (Rothschild and Ford (1972)), all of which I read. Amazing! But did this research by Rothschild and Ford, which was obviously groundbreaking, lead to similar research on other parasitic arthropods, like lice (the focus of our exhibit), ticks, and flies? Not so much, as far as I can tell, but I have plenty of fodder for an exhibit narrative.

Distraction number two: One of our highlighted specimens in this parasite exhibit is a chewing louse that was collected off of a Snowy Owl (Bubo scandiacus) but which was identified as a louse (Strigiphilus oculatus (Rudow, 1870)) that exclusively parasitizes Great Horned Owls (Bubo virginianus). Is this a host-switching event? Was our specimen misidentified? I read papers about owl phylogeny (mainly Wink et al. 2009; is there really nothing more recent nor any pubs based on more than two genes? I am shocked!) and owl lice (mainly Clayton and Price 1984) to sort this one out. I think I have an answer … stay tuned.

snowy owl with anthropomorphized expression that reads

Tell me again about the louse you found on me. Photo of Snowy Owl (CC BY-NC-SA) by David Pilbrow https://flic.kr/p/eaeFwo

Other discussions we had based on recent readings: Should I share the letters I write with the subjects of those letters? Maybe I should … but man, does that make me self-conscious. Why, though?! We had an interesting deliberation on the subject, including stories of advisors who make their students write their own letters of rec. SRSLY?! How lazy can you be?!

In light of recent #psubreakingnews and a political science pub in PLoS ONE—two more readings of mine last week—our lab meeting discussion touched on the roles/perils of social media and professionalism more generally in science.

István: It is good to see where tissue (gland / fat body) specific transcriptomics is and how far can/should we go with our conclusions. Two of our present projects, characterizing fat body like structures in the gasteruptiid hind tibia and evaluating the role of larval/female Cynipini glands in gall induction, are really closely related to this paper. Plus, it is also exciting to witness the birth of a new model system (Bombus spp.), especially that one of the main architects of this transformation works in the next door (Hines lab!).

Jonah: The paper I read (Buechel and Schmid-Hempel 2016) discusses colony pace as a way of granting further social immunity. Social hymenopterans will alter their life history pace such as death/birth rate in order to combat spreads of parasites within a colony. There are advantages and disadvantages to high pace (high death/birth rate) and low pace (low death/birth rate) and a steady balance must be made to match resource input into the colony and have a high enough concentration of mature workers to maintain daughter queens through over wintering. While high pace colonies were found to be more effective at resisting colony wide infections low pace colonies have a greater fitness level with longer lived workers that are provided with more nutrients to fully develop on a singular scale. The colony in these kinds of socio studies can be treated much in the way a single organism could be when fighting an infection with apoptosis occurring in cells to prevent development of viral or parasitic intruders.

Kyle read the paper by Marshall and Evenhuis (2015), in which a species is described sans specimen, and a recent response by Santos et al. (2016). After a short but stimulating conversation about the issues and the ICZN, we decided the topic (and other, related nomenclatural issues) warrants its own journal club.

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Cool Frass at the Frost: Entry 2

This post’s featured specimen earned its place in this series by leaving me clueless as to what exactly I was looking at. The Apis mellifera Linnaeus, 1758 specimen exhibits interconnected seed- and paddle-like growths attached to or protruding from the specimen’s mouth and feet.

A close-up of the structures on the specimen's proboscis.

Have a closer look. Photo by Michael Przybys (CC BY 2.0).

A close-up of the proboscis growths from a different angle.

Photo by Michael Przybys (CC BY 2.0).

The structures do not appear to be a fungal growth, nor do they resemble any common honey bee parasites.

A close-up of the mysterious structures on the mouth and feet of the specimen.

Photo by Michael Przybys (CC BY 2.0)

If you have an idea of what is growing on this specimen, help a curious entomologist out, and leave an answer in the comments.

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