Brief summaries of our weekly reads …
Andy: I had this article by Holmes et al. (2016) open in a tab on my browser for seems like forever, and this week I finally cleared some time for a thorough reading. The authors review the fundamental importance and utility of natural history collections, which, given certain disconcerting events at the National Science Foundation (NSF), is a topic all biologists should be mindful of right now.
Our recent hosting of Julian Avery‘s Natural History Collections and Techniques (WFS 497C) course was the catalyst for me to finally read this article. I was asked a great question about natural history collections as sources for data for research on evolution in observable time and whether there were good examples from insects … and like a total chump I didn’t have a good story to tell these vertebratologists (they, however, had tons). Holmes et al. (2016) reminded me of the soapberry bug story, and they provided tons of robust examples of collections in research that I can use in my own lecture (Google slides) on the relevance of natural history collections.
Emily: Zhu et al. (2016) sought to examine the range expansion and change of the brown marmorated stink bug (Pentatomidae: Halyomorpha halys) in East Asia since the Pleistocene in order to make predictions to its future population spread. Utilizing phylogeography and ecological niche modeling, the researchers looked at past population changes in order to determine areas at risk for invasion by brown marmorated stink bug. Mitochondrial markers revealed 183 haplotypes from the 234 specimens examined, and 8 unique haplotypes were identified from the 40 specimens examined for nuclear sequences. Classes were identified via Bayesian inference analysis, separating into a clade in Taiwan and a second clade of mainland China, Korea, and Japan; divergence was estimated to be in the middle of the Pleistocene (.79 mya). Clade I had little structure, indicative of major range expansion. Niche modeling using Maxent and principle component analysis showed that the temperature was a driving factor, causing the species to move northward. This can be expected in the future, with populations of brown marmorated stink bug expecting to creep north in the US and Europe.
Kyle: I read an article by Leibinger et al. (2016) this week that closely relates to my current work on the steering mechanisms of ichneumonoid ovipositors. This article is about a biomimetic needle inspired by Donald Quicke’s (a collaborator on my project) work on hymenopteran ovipositors. This research compares the resistance and substrate deformation of the steerable needle when it is drilling actively (like a wasp would) versus being pushed straight in (how most needles work). The authors found that the sliding of the “valves” that make up the steerable needle reduce damage to surrounding tissue and decrease resistance because the backwards movement of one “valve” can help brace and support the forward movement of another.
This bracing also helps hold the substrate in place, improving accuracy for micro-surgery. While it is good to keep in mind that the substrate of this article (flesh-like) differs greatly from the substrates of my wasps (hard wood), this effect of holding the substrate in place and reducing stress and friction on it gave me insight into an issue that’s been bothering me about my own system. Quicke points out in his 2015 book, The Braconid and Ichneumonid Parasitoid Wasps: Biology, Systematics, Evolution and Ecology, that the proposed mechanisms should produce some sawdust and/or broken wood fibers, but that this debris has never been observed. I think that, after reading this paper, the answer may be that the “drilling” mechanism works by crushing the wood fibers and then wedging itself between them, ratcheting ever-forward without throwing back a lot of debris because it reduces stress along the borehole and holds the substrate in place, rather than rasping all of the broken fibers out.
Carolyn: Tooker and Hanks (2000) revisited a study by C. Robertson, published in 1928, where he identified over 15,000 insects visiting 453 species of flowers over a 33 year period in Carlinville, IL. Tooker and Hanks (2000) provide updated taxonomic information (i.e., species names) for the parasitic Hymenoptera and the flowers they visited, which is important because planting flowers that attract or support agriculturally-useful parasitoids could supplement biological control efforts. Unfortunately, there is no mention of Ceraphronidae or Megaspilidae; was this because these wasps don’t visit flowers, or because Robertson couldn’t identify them?
Jonah: Judith Korb (2016) describes the underlying genetic causes for social behaviour in termites. Termite sociality evolved independently from social hymenopterans. Several known genes for fecundity in Cryptotermes secundus the model organism for termite social evolution were analyzed and their specific functionality was determined. These were then compared to the genes found in social hymenopterans that cause division of labour. This comparative analysis showed not only the idiosyncrasies but some points of convergence in genetic functionality between the two separate social constructs that evolved.
István: Epigenetics could/should be an important topic for taxonomists since it explains or at least aims to understand mechanisms through which maternal environmental experiences might affect offspring phenotypes and extends phenotypic plasticity across generation boundaries. In this light I read a great article by Verhoeven et al. (2016).
Leave a Reply