Genetic history, structure and gene flow among populations of Belgica antarctica, the only free-living insect in the western Antarctic Peninsula

Hilary Edgington, Vitor A.C. Pavinato, Drew Spacht, J.D. Gantz, Peter Convey, Richard E. Lee Jr., David L. Denlinger, Andy Michel. Polar Science, Volume 36, June 2023, 100945

Abstract

Changes in climate and environment can impact the sustainability of populations and biodiversity. Understanding population genetic diversity in the past and present can help us better predict species' responses to future environmental change. Antarctica has experienced drastic environmental change which threatens its biodiversity. In this study, we characterized the phylogeography and population genetic structure of Belgica antarctica, a wingless midge that is endemic to the western Antarctic Peninsula. This insect has adaptive features to withstand extremes in temperature, salinity, humidity, anoxia and pH. Belgica antarctica is widespread on widely dispersed islands of ice-free habitat, but questions remain regarding its genetic history, diversity and gene flow. We created nuclear-based, single nucleotide polymorphism (SNP) markers and genotyped 229 individuals from 11 populations to examine historical and current population genetic patterns. Our results support recent divergence among populations on different islands within the last 1 Mya. Furthermore, despite a lack of wings, B. antarctica exhibited frequent migration among islands, perhaps via ocean currents or phoresy with Antarctic vertebrates (e.g. seabirds). The close link between the evolutionary history of B. antarctica and the region's environment and ecology emphasize the importance of understanding its population dynamics to predict its persistence under environmental change.

Lazy lizards in a drought: Science modeling and English learners

Kristina Cameron, Kathy L. Malone, Zakee Sabree, & Anita Schuchardt. 2023. https://doi.org/10.1080/00368121.2023.2200918

Abstract

The use of modeling-based instruction is very effective when learning science content in multiple disciplines for native speakers. However, the benefits of using this pedagogy with students learning English as a second language or English Learners (ELs) have not been widespread, especially at the upper secondary level. This article discusses the use of a modeling-based natural selection unit that was developed for 14–16-year-old ELs in a sheltered EL biology class in the United States. The activity described for ELs includes not only activity details but also specifics about the inclusion and use of research-based scaffolding techniques. The efficacy of the unit was assessed in terms of changes to both conceptual understanding and scientific reasoning skills for the ELs and two inquiry-based non-EL biology classrooms. This modeling-based pedagogy allowed the ELs to not only increase their conceptual understanding of evolution but also their reasoning skills while also removing any knowledge gap with their non-EL peers in terms of evolution. The implication is that modeling-based science activities might hold the key to allowing EL students to achieve at the same conceptual levels as their non-EL peers.

Anthropogenic change decouples a freshwater predator’s density feedback

J. S. Sinclair, R. Briland, M. E. Fraker, J. M. Hood, K. T. Frank, M. D. Faust, C. Knight & S. A. Ludsin. Scientific Reports volume 13, Article number: 7613 (2023)

Abstract

Intraspecific interactions within predator populations can affect predator–prey dynamics and community structure, highlighting the need to better understand how these interactions respond to anthropogenic change. To this end, we used a half-century (1969–2018) of abundance and size-at-age data from Lake Erie’s walleye (Sander vitreus) population to determine how anthropogenic alterations have influenced intraspecific interactions. Before the 1980s, the length-at-age of younger walleye (ages 1 and 2) negatively correlated with older (age 3 +) walleye abundance, signaling a ‘density feedback’ in which intraspecific competition limited growth. However, after the early 1980s this signal of intraspecific competition disappeared. This decoupling of the density feedback was related to multiple anthropogenic changes, including a larger walleye population resulting from better fisheries management, planned nutrient reductions to improve water quality and transparency, warmer water temperatures, and the proliferation of a non-native fish with novel traits (white perch, Morone americana). We argue that these changes may have reduced competitive interactions by reducing the spatial overlap between older and younger walleye and by introducing novel prey. Our findings illustrate the potential for anthropogenic change to diminish density dependent intraspecific interactions within top predator populations, which has important ramifications for predicting predator dynamics and managing natural resources.

The Influence of Roost Type and Diet on Energy Expenditure in Bats

Cynthia Marroquin, Thomas Gerth and Agustí Muñoz-Garcia. Diversity 2023, 15(5), 655

Abstract

Bats spend most of their lives resting, socializing, and raising their young in roosts. Roost conditions may affect the lifetime energy expenditure of bats, and this could, in turn, influence fitness of individuals. Different kinds of roosts impose different microclimatic conditions that can affect the thermal balances of bats that use them. Bats thermoregulate by using both physiological mechanisms (such as changes in conductance) and behavioral responses (huddling or active search of certain microclimates). We hypothesized that the contribution of these thermoregulatory strategies would differ depending on the roost type that bats use. To test this idea, we collated data from the literature on metabolic rate (MR), body temperature (Tb), ambient temperature at which MR and Tb were collected, roost type, and diet for 43 species of bats spanning eleven families. From these data, we calculated, for each species, the wet conductance and the area of the thermoregulatory polygon (TRP) as a proxy for the physiological thermoregulatory capabilities of bats. We found that, after controlling for phylogeny, wet conductance and the area of the TRP were higher in bats that use more exposed roosts than in those bats who use roosts that can buffer environmental conditions. Our results suggest that energy expenditure is similar for all species, but in bats that live in more exposed roosts, the contribution of physiological responses was more important than behavior at the entire range of environmental temperatures, whereas bats in more protected roosts seem to rely more on behavioral responses to thermoregulate. Considering that roosts represent valuable resources, the availability of roosts with the proper microclimatic conditions could determine the patterns of distribution of bat populations.

A global phylogeny of butterflies reveals their evolutionary history, ancestral hosts and biogeographic origins

Akito Y. Kawahara, Caroline Storer, Ana Paula S. Carvalho, David M. Plotkin, Fabien L. Condamine, Mariana P. Braga, Emily A. Ellis, Ryan A. St Laurent, Xuankun Li, Vijay Barve, Liming Cai, Chandra Earl, Paul B. Frandsen, Hannah L. Owens, Wendy A. Valencia-Montoya, Kwaku Aduse-Poku, Emmanuel F. A. Toussaint, Kelly M. Dexter, Tenzing Doleck, Amanda Markee, Rebeccah Messcher, Y-Lan Nguyen, Jade Aster T. Badon, Hugo A. Benítez, Michael F. Braby, Perry A. C. Buenavente, Wei-Ping Chan, Steve C. Collins, Richard A. Rabideau Childers, Even Dankowicz, Rod Eastwood, Zdenek F. Fric, Riley J. Gott, Jason P. W. Hall, Winnie Hallwachs, Nate B. Hardy, Rachel L. Hawkins Sipe, Alan Heath, Jomar D. Hinolan, Nicholas T. Homziak, Yu-Feng Hsu, Yutaka Inayoshi, Micael G. A. Itliong, Daniel H. Janzen, Ian J. Kitching, Krushnamegh Kunte, Gerardo Lamas, Michael J. Landis, Elise A. Larsen, Torben B. Larsen, Jing V. Leong, Vladimir Lukhtanov, Crystal A. Maier, Jose I. Martinez, Dino J. Martins, Kiyoshi Maruyama, Sarah C. Maunsell, Nicolás Oliveira Mega, Alexander Monastyrskii, Ana B. B. Morais, Chris J. Müller, Mark Arcebal K. Naive, Gregory Nielsen, Pablo Sebastián Padrón, Djunijanti Peggie, Helena Piccoli Romanowski, Szabolcs Sáfián, Motoki Saito, Stefan Schröder, Vaughn Shirey, Doug Soltis, Pamela Soltis, Andrei Sourakov, Gerard Talavera, Roger Vila, Petr Vlasanek, Houshuai Wang, Andrew D. Warren, Keith R. Willmott, Masaya Yago, Walter Jetz, Marta A. Jarzyna, Jesse W. Breinholt, Marianne Espeland, Leslie Ries, Robert P. Guralnick, Naomi E. Pierce & David J. Lohman. Nature Ecology & Evolution volume 7, pages 903–913 (2023)

Abstract

Butterflies are a diverse and charismatic insect group that are thought to have evolved with plants and dispersed throughout the world in response to key geological events. However, these hypotheses have not been extensively tested because a comprehensive phylogenetic framework and datasets for butterfly larval hosts and global distributions are lacking. We sequenced 391 genes from nearly 2,300 butterfly species, sampled from 90 countries and 28 specimen collections, to reconstruct a new phylogenomic tree of butterflies representing 92% of all genera. Our phylogeny has strong support for nearly all nodes and demonstrates that at least 36 butterfly tribes require reclassification. Divergence time analyses imply an origin ~100 million years ago for butterflies and indicate that all but one family were present before the K/Pg extinction event. We aggregated larval host datasets and global distribution records and found that butterflies are likely to have first fed on Fabaceae and originated in what is now the Americas. Soon after the Cretaceous Thermal Maximum, butterflies crossed Beringia and diversified in the Palaeotropics. Our results also reveal that most butterfly species are specialists that feed on only one larval host plant family. However, generalist butterflies that consume two or more plant families usually feed on closely related plants.