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1. DNA methylation of the endothelin receptor B makes blue fish yellow

   https://doi.org/10.1101/2022.09.27.509821  

   Fang, W; Blakkan, D; Lee, G; Bashier, R; Fernald, RD; Alvarado, SG (September 2022, bioRxiv)

   TBD (Ed.)

   ABSTRACT Natural selection shapes traits during evolution including animal coloration known to be important for concealment and communication and color has been particularly salient in the explosive radiation of cichlid fish species in the rift valley lakes of East Africa. Though selection can produce variation in color via genetic substrates during early development, plasticity in coloration can occur through endocrine, neural and transcriptional cues in response to various environmental stimuli. It is well known that some animals often change color to match their visual ecology. Adult male cichlid fish (Astatotilapia burtoni, Lake Tanganyika) can switch between blue and yellow body colors. Different colors result from the expression of pigment-bearing cells, which differ in density and function between these two color morphs. We show thatA. burtoniswitches from yellow to blue depending on their visual environment by downregulating endothelin receptor B (EdnRB) mRNA via DNA hypermethylation at a single cytosine residue within its promoter. EdnRB functions in yellow chromatophores to signal the aggregation of yellow pigments, making yellow less visible. Taken together, the regulation ofEdnRBthrough DNA methylation in yellow chromatophores, in part, contributes to pigmentation changes from blue to yellow, depending on visual environment. 

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2. Rugosporella, a new genus to accommodate the North American species Peziza atrovinosa (Pezizaceae) and its predicted ectomycorrhizal status

   https://doi.org/10.25664/ART-0398  

   Pfister, Donald H; Lemmond, Benjamin; Healy, Rosanne; LoBuglio, Katherine F; Bonito, Gregory; Smith, Matthew E (January 2024, Ascomyceteorg)

   The genus Rugosporella is proposed to accommodate Peziza atrovinosa in the modern classification scheme of the Pezizaceae. We used DNA sequences of ITS, LSU and RPB2 to resolve the phylogenetic placement of this taxon. The species occupies a distinct position within a large and diverse clade of hypogeous and epigeous taxa, all of which are either known to be or presumed to be ectomycorrhizal. Although no DNA sequences of this species have been identified from ectomycorrhizal roots, we provide isotopic data supporting its ectomycorrhizal lifestyle. Peziza atrovinosa is distinctive in its moderately large vinaceous brown apothecia with thick flesh and the relatively small ascospores that are ornamented with a high reticulum and that become yellow-brown at maturity. This species is found across eastern North America. 

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3. Large-scale connectivity of the sandy beach clam Mesodesma mactroides along the Atlantic coast of South America, and climate change implications

   https://doi.org/10.1016/j.marenvres.2022.105591  

   Meerhoff, Erika; Combes, Vincent; Matano, Ricardo; Barrier, Nicolas; Franco, Barbara; Piola, Alberto; Hernández-Vaca, Freddy; Defeo, Omar (April 2022, Marine Environmental Research)

   The yellow clam Mesodesma mactroides is a cool-water species that typifies sandy beaches of the Southwestern Atlantic Ocean (SAO), which embraces one of the strongest ocean warming hotspots. The region is influenced by the Rio de la Plata (RdlP), which represents a zoogeographic barrier that restricts its larval exchange. We investigated yellow clam larval connectivity patterns using an individual based model (IBM). The IBM combined outputs from a 3D hydrodynamic model with a clam submodel that considered salinity- and temperature dependent mortality for the planktonic larvae. Connectivity across the RdlP estuary occurred only for larvae released in spring during a strong La Ni˜na event. Mortality due to freshwater precluded larval transport across the RdlP, whereas larval mortality induced by warmer waters reduced connectivity, leading to self-recruitment in most areas. Warming acceleration in this hotspot could further restrict larval connectivity between populations in the SAO, with conservation implications for this threatened species. 

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4. A colorful legacy of hybridization in wood-warblers includes frequent sharing of carotenoid genes among species and genera

   https://doi.org/10.1371/journal.pbio.3003501  

   Bennett, Kevin; Wood, Andrew; Baiz, Marcella; Phung, Lan_Nhi; Lovette, Irby; Toews, David (December 2025, PLOS Biology)

   Jiggins, Chris D (Ed.)

   Introgression between species has the potential to shape evolutionary trajectories in important ways, but uncovering complex introgression dynamics has only recently been made possible by advances in genomics. Warblers of the avian family Parulidae exemplify rapid diversification and sexual trait divergence, and we endeavored to study historical introgression in the family. We sequenced multiple genomes of nearly every species, constructed a phylogeny for the family, and investigated gene flow across the genome and at genes known for controlling feather color. We found that DNA haplotypes including the geneBCO2, which encodes an enzyme that degrades yellow carotenoids, have spread among genera multiple times—fromVermivoratoGeothlypisand fromLeiothlypisto multipleCardellinaandSetophagaspecies. Patterns of inheritance in the latter case point to introgression that occurred 0.5 to 2 million years ago, and the shared haplotype among recipient species is less than 100 nucleotides long. Separately, we found evidence of introgression from redCardellinaspecies to both of the two redMyioborusspecies atBDH1Land from one redMyioborusspecies to the other atCYP2J19; both are key genes in the pathway that converts yellow carotenoids to red ketocarotenoids. Our results show that introgression is a common mechanism for the evolution of colorful plumage in parulid warblers and hint at complex histories of gene flow behind some of the Western Hemisphere’s most colorful birds. 

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5. Responses of Female Yellow Warblers to Playbacks Signaling Brood Parasitism or Predation Risk: A Quasi-Replication Study

   https://doi.org/10.26451/abc.08.02.08.2021  

   Lawson, Shelby L.; Enos, Janice K.; Mendes, Niko C.; Gill, Sharon A.; Hauber, Mark E. (May 2021, Animal Behavior and Cognition)

   Many avian species are negatively impacted by obligate avian brood parasites, which lay their eggs in the nests of host species. The yellow warbler (Setophaga petechia), which is host to the brood-parasitic brown-headed cowbird (Molothrus ater), represents one of the best-replicated study systems assessing antiparasitic host defenses. Over 15 prior studies on yellow warblers have used model-presentation experiments, whereby breeding hosts are exposed to models of brown-headed cowbirds or other nest threats, to test for anti-parasitic defenses unique to this species. Here we present results from our own quasi-replication study of the yellow warbler/brown-headed cowbird system, which used a novel design compared to previous experiments by pivoting to conduct acoustic playback treatments only, rather than presenting visual models with or without calls. We exposed active yellow warbler nests to playbacks of brown-headed cowbird chatters (brood parasite), blue jay (Cyanocitta cristata; nest predator) calls, conspecific “seet” calls (a referential alarm call for brood parasitism risk), conspecific “chip” calls (a generic alarm call), or control wood thrush (Hylocichla mustelina; harmless heterospecific) songs during the incubation stage. Similar to previous studies, we found that female yellow warblers seet called more frequently in response to playbacks of both brood parasitic chatter calls and conspecific seet calls whereas they produced more chip calls in response to the playback of nest predator calls. In contrast, female yellow warblers approached all playbacks to similar distances, which was different from the proximity patterns seen in previous studies. Our study demonstrates the importance of both replicating, and also pivoting, experimental studies on nest defense behaviors, as differences in experimental design can elicit novel behavioral response patterns in the same species. 

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