Recent reading: 1 April 2022

(Flickr: Germán Poo-Caamaño)

April Fool’s Day is no one’s favorite holiday, as far as I can tell. I do remember a time when it was sort of fun to be listening to Morning Edition over breakfast and slowly realize that the totally serious-sounding report about (say) New England maple trees exploding because the syrup market had slowed down was a gag. But decades later, the internet is a year-’round stream of content pretending seriousness to deliver jokes of highly variable taste, and that’s not even getting into the news pretending to be real with no intention of a punchline.

On the other hand, this year I absolutely used the one April Fool’s appropriate article in the history of the journal Evolution (it was published in September) as the first reading assignment of my systematic botany course — for the third time. I don’t think students resent it, though they definitely miss the significance of the Steve Martin quote at the beginning.

Seriously, though, here’s some of what I’ve been reading, recently: Nifty new landscape genetics, an experiment in community genetics, and a paper I’m going to start using in class, I think.

Dellinger AS et al. 2022. Population structure in Neotropical plants: Integrating pollination biology, topography and climatic niches. Molecular Ecology. doi: 10.1111/mec.16403

Attempts to parse out the effect of pollinator mobility on gene flow among plant populations, by comparing differentiation among populations of Adelobotrys adescensAxinaea costaricensis, and four species of Meriania in Central and South America. Four of these are bird and/or bat pollinated, two are bee pollinated; the understanding is that bees travel less than the vertebrates. Controls for topographic complexity and SDM-based estimate of habitat suitability, which may also limit dispersal on the landscape. The two bee-pollinated species do indeed show stronger isolation by distance, and to a lesser extent isolation by environmental conditions.

Really nice paper, showing the power of RADseq to make data collection across taxa possible in a way it really wasn’t just a few years ago.

Barbour MA et al. 2022. A keystone gene underlies the persistence of an experimental food web. Science. doi: 10.1126/science.abf2232

Experiment with two aphid species and a parasitoid wasp on four different lines of Arabidopsis thaliana, which differ in genes involved in production of key defensive glucosinolydes. The resulting food web occurs in nature, but is simple enough for experimental setup; the authors test 11 combinations of A. thaliana genotypes and compare stability of the aphid and parasitoid populations. Plant populations with more genotypes supported the full food web for longer; in particular variation at one of the three genes had a significant effect in reducing the rate of extinctions. The null allele at that gene, AOP2, was associated with greater plant growth, which helped maintain aphid and parasitoid populations at high enough intrinsic growth rates to avoid extinctions. Thus: a “keystone” gene.

Worth noting, however, that the result here is slowed progress toward species extinctions and food-web collapse, rather than actual long-term stability. The experimental plant-insect community (like microbial forerunners) often loses species by the end of the 17-week experimental period even with the AOP2 null allele present.

Grossenbacher DL and JB Whittall. 2011. Increased floral divergence in sympatric monkeyflowers. Evolution. doi: 10.1111/j.1558-5646.2011.01306.x

A real classic, looking at floral and vegetative trait divergence in sympatric and allopatric sister pairs of Mimulus species (which are all now Eryanthe, I think?). The headline result is one two-panel barplot showing that across species pairs, sympatric pairs differ more in floral traits than allopatric pairs do; but sympatric and allopatric pairs differ in vegetative traits to about the same degree. Species in sympatric pairs are also more likely to include floral morphologies allowing selfing by stigma-anther contact (none of the species in allopatric pairs have this). So what we’ve got here is evidence of pollinator isolation and selfing maintaining species isolation in sympatry.

About Jeremy Yoder

Jeremy B. Yoder is an Associate Professor of Biology at California State University Northridge, studying the evolution and coevolution of interacting species, especially mutualists. He is a collaborator with the Joshua Tree Genome Project and the Queer in STEM study of LGBTQ experiences in scientific careers. He has written for the website of Scientific American, the LA Review of Books, the Chronicle of Higher Education, The Awl, and Slate.
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