How does diversity arise, and how is it maintained? In a model of microbial competition, Amicone and Gordo (2021) find that frequent mutations and the effects of genetic drift generate sufficient phenotypic variation to alter selection such that resource specialists are favored, potentially paving the way for speciation. Their results highlight that processes affecting the distribution of genotypic and phenotypic variation may affect not only population responses to selection, but also the direction of selection itself. This article is protected by copyright. All rights reserved ..read more

Abstract The coexistence of hermaphrodites and males (androdioecy) is rare in both plants and animals and has hitherto remained unknown in insects. Mongue et al. (2021) report a new case of androdioecy in the invasive haplodiploid insect Icerya purchasi, in which hermaphrodites can only self-fertilize, but occasionally mate with males. Revealingly, I. purchasi shares several features with other androdioecious species such as the consequences of evolution from separate sexes, low outcrossing rates, and its colonizing habit. This article is protected by copyright. All rights reserved ..read more

Abstract Do the relative size of the olfactory bulb, cochlea, and orbit correlate with diet in phyllostomid bats? Hall et al. (2021) found that the degree of frugivory is positively correlated with the relative size of the olfactory bulb and the orbit. The degree of animalivory is negatively correlated with the relative size of the olfactory bulb and the orbit. Finally, the degree of nectarivory is negatively correlated with the relative size of the cochlea. This article is protected by copyright. All rights reserved ..read more

How can we bridge the gap between studies concerning microevolution and those concerning macroevolution? Taverne et al. (2021) provide a framework for how to study both intraspecific and interspecific variation simultaneously through their examination of how craniomandibular skeletal and muscle shape responds to ecological pressures in Podarcis lizards. This article is protected by copyright. All rights reserved ..read more

Abstract Temperature differences over time and space has been hypothesized to cause variation in the rate of molecular evolution of species, but empirical evidence is mixed. To further test this hypothesis, we utilized a large exon-capture sequence data of Australian Eugongylinae skinks, exemplifying a radiation of temperature-sensitive ectotherms spanning a large latitudinal gradient. The association between temperature (and other species traits) and long-term substitution rate was assessed based on 1268 sequenced exons of 44 species pairs from the Eugongylinae subfamily using regression anal ..read more

Abstract Multicellular eukaryotes exhibit a remarkable diversity of sexual systems; however, trioecy, the co-existence of male, female, and cosexual or hermaphrodite individuals in a single species, is remarkably rare. Takahashi et al. (2021) reports the first known instance of trioecy in a haploid organism. In contrast to other known cases of trioecy, the authors report evidence for genetic control of all three sexes by two loci. These results complicate models for sexual system turnover and expand the known diversity of trioecy species in several ways. This article is protected by copyr ..read more

Hoverflies (Diptera: Syrphidae) provide an excellent opportunity to study the evolution of Batesian mimicry, where defenceless prey avoid predation by evolving to resemble defended ‘model’ species. While some hoverflies beautifully resemble their hymenopteran models, others seem to be poor mimics or are apparently non-mimetic. The reasons for this variation are still enigmatic despite decades of research. Here, we address this issue by mapping social-wasp mimicry across the phylogeny of Holarctic hoverflies. Using the ‘distance transform’ technique, we calculate an objective measure of the abd ..read more

Determining mechanisms that underlie reproductive isolation is key to understanding how species boundaries are maintained in nature. Transposable elements (TEs) are ubiquitous across eukaryotic genomes. However, the role of TEs in modulating the strength of reproductive isolation between species is poorly understood. Several species of Drosophila have been found to harbor P-elements (PEs), yet only D. simulans is known to be currently polymorphic for their presence in wild populations. PEs can cause reproductive isolation between PE-containing (P) and PE-lacking (M) lineages of the same specie ..read more

Recent studies have shown that intraspecific patterns of phenotypic plasticity can mirror patterns of evolutionary diversification among species. This appears to be the case in Nicrophorus beetles. Within species, body size is positively correlated with the size of carrion used to provision larvae and parental performance. Likewise, among species, variation in body size influences whether species exploit smaller or larger carrion and the extent to which larvae depend on parental care. However, it is unclear whether developmental plasticity in response to carcass size, parental care, or both un ..read more

Abstract The rate of divergence for Z or X chromosomes is usually observed to be greater than autosomes, but the proposed evolutionary causes for this pattern vary, as do empirical results from diverse taxa. Even among moths and butterflies (Lepidoptera), which generally share a single-origin Z chromosome, the handful of available studies give mixed support for faster or more adaptive evolution of the Z chromosome, depending on the species assayed. Here, we examine the molecular evolution of Z chromosomes in two additional lepidopteran species: the Carolina sphinx moth and the monarch butterfl ..read more