Daily Paperfest: Finding natural selection, damselflies under climate change, spider egg sacs, and more

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When I’m not busy being in a new, stable relationship that has (temporarily!) replaced a significant amount of my working time with romance and love, I’m reading newish papers. Here are blurbs for the ones from today. Full discussions available on request!

I can’t really say much that would be of general interest about Kobayashi et al.‘s Embryonic development of Carabus insulicola (Insecta, Coleoptera, Carabidae) with special reference to external morphology and tangible evidence for the subcoxal theory. If you know your way around beetle development, you’ll enjoy it. If you don’t, just don’t bother, you wouldn’t care about it.

I’m generally not a fan of the model organism approach to research (hypocritical, since I use pholcid spiders as models for my own research). I see much more value in broadly studying a large section of biodiversity rather than cherry-picking a couple of species for ultra-intensive study. It’s more beneficial from a phylogenetic point of view, in any case. The only major exception is in biomedical research, where we are trying to tinker with the intricate nuts and bolts of highly-complex systems, and thus having an in-depth knowledge of singular species is imperative in order to understand what the effects of our treatments are. There is a widespread misconception that when it comes to neurological research, we should be focusing on mammals (mice and rats, primates) since they’re a much closer analogue than any invertebrate. Of course, there are many examples of invertebrate models being used in neurological research – Drosophila is ubiquitous, you have snails as models for memory, and of course Caenorhabditis elegans for cellular-level studies. If you want to know more about how invertebrates can be used as model organisms in this line of research, then you should read Søvik & Baron’s Invertebrate Models in Addiction Research. It’s open access too!

One of the main points I need tog et across in my lectures on natural selection is that natural selection is not an all-powerful force that is always acting. Natural selection is not a null hypothesis in evolution, but a working hypothesis that needs evidence to show whether it has any explanatory role in any given phenomenon. It’s a pretty difficult lesson to get across as adaptationist explanations are just too intuitive and easy to throw around, and natural selection is always highly-emphasised in popular treatments and introductory academic texts on evolution. The faults can also be perpetrated among researchers too, but thankfully we have tools to keep us in check, and Vitti et al. provide a very handy guide to Detecting Natural Selection in Genomic Data. Highly-recommended!

The precise details of Hashimoto & Kano’s Synapse elimination in the developing cerebellum flew over my head – this cellular stuff is beyond my expertise and interest. In the cerebellum, Purkinje cells are innervated by climbing fibers. In a newborn, each Purkinje cell is connected to many climbing fibers. In an adult, each Purkinje cell is connected to a single climbing fiber. So during development, a lot of synapses get removed. This paper reviews what we know of the molecular shenanigans that enable this process.

In Climate-Induced Range Shifts and Possible Hybridisation Consequences in Insects, Sánchez-Guillén et al. use Global Circulation Models to predict how the distribution of seven Mediterranean Ischnura damselflies will be affected by our ongoing anthropogenically-induced climate change. Unsurprisingly, ranges will shit northwards as the climate becomes warmer up there. There will also be a shift westward, something that is currently being observed in Spanish Ischnura elegans populations. These shifts will lead to several overlaps of currently allopatric species, which may lead to gene flow and hybridisation, aided by all these species’s rather similar ecologies.

Bearing children is an inherently risky venture. If an organism broods internally, its activity is compromised, leading to a higher risk of being eaten. If an organism lays eggs, those eggs need to survive environmental conditions and avoid being food – humans aren’t the only animals who stumbled on the great diea of using eggs as an excellent protein source. Spiders typically lay bundles of eggs in cocoons, and in Variation and possible function of egg sac coloration in spiders, Barrantes et al. investigate the visual properties of these bundles under different optical filters, to see how other organisms may see them. It turns out that the colours are not “random”, but may serve as camouflage to hide them from predators’ view.