Biological Journal of the Linnean Society

Guzmán, Noelia V; Gandini, Luciano M; Castillo, Elio R; Fernandez Campón, Florencia; Cigliano, Maria Marta; Confalonieri, Viviana A

doi: 10.1093/biolinnean/blad166pmid: N/A

The grasshopper Trimerotropis pallidipennis species complex is distributed across arid and semi-arid environments from North to South America, reaching high altitudes along the Andes Mountain range. Currently, there are four valid species of Trimerotropis in South America. However, some species were found to comprise several genetic lineages. Here, we describe the genetic structure, lineage diversification, and environmental requirements within the Trimerotropis species complex in South America based on sequences from the mitochondrial COI gene, 4048 single nucleotide polymorphisms, and ecological niche modelling. The analyses revealed the existence of at least five lineages: two with a restricted geographical distribution and three with a very wide one. The results provide evidence that glacial cycles promoted not only the presence of refuge areas but also the isolation of widely distributed lineages on the eastern and western sides of the southern Andes, potentially driving the emergence of the Trimerotropis sp. lineage, which can tolerate more temperate habitats. Our results provide evidence for the effects of Pleistocene climatic changes on the diversification history of a South American grasshopper species complex.

Xiao, Han-Wen; Huang, Yan-Bo; Liu, Qing-Shan; Claßen-Bockhoff, Regine; Tian, Ru-Nan; Wei, Yu-Kun

doi: 10.1093/biolinnean/blad164pmid: N/A

Flowers of Salvia are characterized by a diversity of staminal lever types mediating pollen transfer. In the East Asian subgenus Glutinaria, species have been categorized based on their distinct flower and stamen morphologies. A hypothesized advantage of degraded-lever types suggests they may optimize pollinator foraging time, increase visitation rates, and potentially trigger autonomous self-pollination. However, this hypothesis remains untested. Here, Salvia castanea, S. miltiorrhiza, and S. liguliloba were selected as test species representing the three major flower and stamen types of the East Asian sages. We compared the species with regard to their inflorescence architecture, floral display, nectar reward, pollinator efficiency, and seed set. We found that S. liguliloba had a degraded-lever type that significantly reduced pollinator foraging time did not significantly increase pollination efficiency. These species have a mixed mating pattern with high seed set, no pollen- or pollinator limitation, and no inbreeding depression. We conclude that the diversity of floral traits is addressed to pollinators, whereas reproductive success emerges from a complex interplay of factors encompassing floral characteristics, pollination efficiency, plant life history, or/and other biotic and abiotic factors. For this reason, the link between floral morphological traits and mating systems should not overestimated.

Nishita, Yoshinori; Väinölä, Risto; Abramov, Alexei V; Masuda, Ryuichi

doi: 10.1093/biolinnean/blad133pmid: N/A

Four mitochondrial phylogroups are distinguished in the European pine marten (Martes martes), two of which, FNR1/2, are shared with the more easterly sister species, the sable (Martes zibellina). Here, we found that the phylogroup frequencies differed markedly between the southern Finland and western Russia populations in the eastern part of the range of Martes martes, suggesting differential introgression from M. zibellina in these regions. We also examined the diversity of a protein-coding gene, MHC class II DRB, in these two Martes species. We detected 16 functional Martes martes DRB alleles (Mama-DRBs), including several codons that seem to have undergone positive selection, and eight presumed pseudogenes (Mama-DRB*PSs); some alleles/pseudogenes were geographically widespread and others restricted. In a broader carnivoran DRB tree, all Mama-DRBs grouped within a mustelid clade, four in a basal group comprising alleles from early-diverged species and the others in a derived group containing alleles from more recently diverged species. Many alleles showed trans-species polymorphism, suggesting that Mama-DRBs have evolved under pathogen-driven balancing selection. Three of six Mama-DRBs and one of four pseudogenes shared with Martes zibellina were restricted to the FNR1/2 mitochondrial DNA phylogroups, pointing to the possibility that genetic introgression from Martes zibellina might have contributed to Mama-DRB diversity and thus adaptability.

doi: 10.1093/biolinnean/blad158pmid: N/A

Pfeiler, Edward

doi: 10.1093/biolinnean/blad094pmid: N/A

Analysis of genetic divergence in published mitochondrial DNA barcodes from ‘juniper’ and ‘cedar’ hairstreaks, Callophrys gryneus (Hübner) and Callophrys muiri (Hy. Edwards), together with a comparison of phenotypic differences in populations from North America, have been used to address the long-standing controversy regarding subspecies and species assignments in this confusing group of hairstreaks. The most recent view holds that C. gryneus is a single polytypic species comprising 11 nominal subspecies and that C. muiri from California is a valid species. An alternative view subdivides C. gryneus into three nominal species, C. gryneus (s.s.), Callophrys siva and Callophrys nelsoni, each with several named subspecies, and retains C. muiri as a full species. Haplotype networks, phylogenetic analysis and analysis of molecular variance of barcodes provided evidence supporting the subspecies scenario. However, barcodes from closely related congeners of C. gryneus (s.l.) revealed pairwise genetic divergences that would also support elevating three subspecies (C. g. castalis, C. g. siva and C. g. nelsoni) to full species. The barcode data also raise the question of whether C. muiri warrants full species status. Larval host plant preference as a possible driver of genetic differentiation in western populations of this group is also discussed briefly.

Sato, Hajime; Sakai, Yoichi; Kuwamura, Tetsuo

doi: 10.1093/biolinnean/blad163pmid: N/A

Cleaning symbiosis of the bluestreak cleaner wrasse, Labroides dimidiatus (Labridae), is a well-known example of mutualism in coral reefs. The cleaner wrasse is characterized by its bluish body colour with black stripes, and the false cleanerfish, Aspidontus taeniatus (Blenniidae), mimics those characteristics precisely. Cleaner fish mimicry is believed to evolve as an aggressive mimicry to bite the fins of deceived fishes; however, protective mimicry to reduce predation risk has not been examined sufficiently. Here, we tested the effect of protective mimicry through field observations and aquarium experiments. Field observations revealed that false cleanerfish were occasionally attacked by piscivorous lizardfishes (Synodontidae). In the aquarium experiments, ambushing predators, the honeycomb grouper, Epinephelus merra (Serranidae), which did not show predatory behaviour to false cleanerfish in the field, attacked the cleaner wrasse (model), the false cleanerfish (mimic), and the lance blenny, Aspidontus dussumieri (non-mimic). When a shelter was provided in the tank, the false cleanerfish and the lance blenny immediately hid inside the shelter for a considerable duration to escape from the predator. These results suggest that cleaner fish coloration does not always decrease predation risks, and our conclusions support the possibility that this mimicry evolved primarily as aggressive mimicry.

Styga, Joseph M; Brown, Isobel G; McMullen, Margaret V

doi: 10.1093/biolinnean/blad162pmid: N/A

Survival in complex environments is dependent on whole-animal performance, a target of natural and sexual selection. Variation in whole-animal performance among mature individuals can become broadened by phenotypic plasticity driven by early life experiences. Thus, detailing the environmental factors that contribute to phenotypic plasticity, and the associated phenotypic responses governed by those environmental factors, is essential if we are to understand the evolution of whole-animal performance. Here, using isogenic lines established from the hermaphroditic mangrove rivulus fish (Kryptolebias marmoratus) housed in a ‘common garden’, we investigate the link between variation in adult terrestrial jumping performance and early life experience (i.e. egg density). First, we hypothesize that individuals from different isogenic lineages should vary in jumping performance independent of egg density, suggesting a strict genetic source of variation. Second, we hypothesize that phenotypic plasticity should also introduce variation in adult jumping performance. Specifically, we expect that hatchlings incubated at higher egg densities in early development should adopt better jumping performances as adults, because higher egg density might be a cue for greater intraspecific competition upon hatching.

Ma, Ruiyao; Jiang, Yiting; Wan, Dongmei

doi: 10.1093/biolinnean/blad150pmid: N/A

Signals conveyed by ornaments can be indicators in the process of sexual selection. Specifically, signals may be superimposed on each other to represent an individual’s quality, convey different information, or offer redundant information. As much of the research in this area has focused on relationships between diverse signals in males, those of females have largely been overlooked. From 2022 to 2023, we tested whether three traits, namely acoustic (song display) and visual ornaments (patch size and carotenoid-based plumage coloration), and morphology (wing and tail length), were interrelated in males and whether visual ornaments and morphology were interrelated in females in a wild population of varied tits (Sittiparus varius). We found that males with brighter and more reddish plumage sang at lower maximum and minimum frequencies, with narrower bandwidths and lower frequency peaks. Similarly, a negative correlation between tail length and carotenoid-based plumage coloration was observed in both sexes. Furthermore, a positive relationship was found between signals within traits. These results highlight the trade-offs in signals between different traits, as well as the consistency within the same traits.

Sato, Yu; Humble, Emily; Ogden, Rob

doi: 10.1093/biolinnean/blad172pmid: N/A

Understanding population structure and the extent and distribution of genetic diversity are recognized as central issues in endangered species research, with broad implications for effective conservation management. Advances in whole genome sequencing techniques provide greater resolution of genome-wide genetic diversity and inbreeding. Subspecies of golden eagles (Aquila chrysaetos) in Scotland (A. c. chrysaetos) and Japan (A. c. japonica) are endangered; it is therefore important to understand genetic diversity and inbreeding of these small island populations to increase the chances of conservation success. We investigated this using whole genome sequencing data from golden eagles in Scotland, continental Europe, Japan, and the USA. Following determination of population genetic structure, analysis of heterozygosity and nucleotide diversity revealed reduced levels of genetic diversity together with runs of homozygosity, suggesting evidence of inbreeding attributable to recent shared parental ancestry in the island populations. These results highlight the need to consider genetic reinforcement of small isolated golden eagle populations from neighbouring outbred populations, alongside existing efforts to boost population size through within-island conservation translocations and captive breeding programmes.

Archer, C Ruth; Alper, Cleo; Mack, Laura; Weedon, Melanie; Sharma, Manmohan D; Sutter, Andreas; Hosken, David J

doi: 10.1093/biolinnean/blad165pmid: N/A

Alcohol can alter sexual behaviour. However, our understanding of alcohol’s effects on sexual interactions is limited because males are usually the focus of nonhuman studies. Alcohol could in theory alter female mate-choice and, in turn, affect sexual selection, a major mechanism of evolution. Here we tested whether alcohol exposure affected female mate-preference, choosiness, and copulation duration in the fly Drosophila simulans, while simultaneously testing for genetic variation in these effects. We found that alcohol exposure did not affect copulation duration, but did weaken mate-preference, as females copulated with a broader range of males after exposure, and it tended to reduce female choosiness as females mated more quickly. Although female genotype significantly affected copulation duration and choosiness, the effects of alcohol appeared to be reasonably consistent across genotypes, but this depended on the analysis employed. Nonetheless, alcohol reduced female choosiness and weakened mate-preference, and may therefore reduce the strength of sexual selection. Testing whether these changes impact female fitness is now required.