Laroche, R. A. S. | Search bioRxiv

bioRxiv2023

A genomic test of subspecies in the Eunota togata species group (Coleoptera: Cicindelidae): Morphology masks evolutionary relationships and taxonomy

Most of the worlds biodiversity is described primarily or exclusively using morphological traits that may not always reflect the true evolutionary units. Accurate taxonomy is critical for conservation efforts and re-evaluation of traditional taxonomy may often be warranted since species and subspecies are frequently the focus of conservation and faunistic studies. Here, we test comprehensive taxonomic hypotheses of morphologically defined subspecies in the tiger beetle, Eunota togata (LaFerte-Senectere, 1841). The four recognized subspecies were delineated based mainly on the dorsal coloration and extent of white markings termed maculations. We combine inferences from mtDNA genealogies and genome-wide multilocus data to elucidate the evolutionary relationships within the group and assess the taxonomic implications. Three of the four subspecific taxa delineated by morphology were not supported by the genomic or mtDNA data. In fact, the species-level diversity in this group was underestimated, as E. togata was found to represent three well-supported distinct species in all genetic analyses. Emerging from these analyses, we also document an intriguing example of convergent evolution in lighter colored E. togata adapting to similar white sand backgrounds. Our collective work underscores the importance of integrating molecular methods with morphology for species and subspecies delimitation and conservation.

evolutionary biology↗

bioRxiv2021

Is energetics or competition a stronger driver of male smallmouth bass seasonal reproductive timing?

Intraspecific competitive ability is often associated with body size and has been shown to influence reproductive timing in many species. However, energetic constraints provide an alternative explanation for size-related differences of reproductive timing. In temperate fishes that experience a winter starvation period, for instance, a negative allometric relationship between body size and winter energy loss might explain why larger males spawn earlier in a season than smaller males, especially in fishes that exhibit paternal care, which is energetically costly and limits parental foraging opportunities. Male smallmouth bass, Micropterus dolomieu, defend nesting territories in which they care for offspring over an extended period. In northern populations, males rely on energy reserves over a winter starvation period and in spring must recoup energy losses before initiating reproduction, making them ideal systems in which to study contributions of competition and energetic allometry on differences of reproductive timing. Here, we harness data on parental male M. dolomieu from a 10-year study and show that larger males required fewer degree days-a measure of thermal energy experienced-in spring before they spawned each year and that the time of peak seasonal reproduction in the population was negatively related to the number of degree days accumulated before reproduction started. Furthermore, we found that growth of individual males between seasons better predicted changes in timing of reproduction than changes in size relative to competitors. Together, these results suggest that timing of reproduction in this population is more strongly influenced by energetic constraints than size-based competition amongst males.

animal behavior and cognition↗