Biology subjects

Rebar, D.

Publications and source records attributed to Rebar, D..

4 recordsLinked to original sources

bioRxiv2022

Multilevel selection leads to divergent coadaptation of care-giving parents during pre-hatching parental care

The joint actions of animals in partnerships or social groups evolve under both natural selection, from the wider environment, and social selection, imposed by other members of the pair or group. We used experimental evolution to investigate how jointly expressed actions evolve upon exposure to a new environmental challenge. Our work focused on the evolution of carrion nest preparation by pairs of burying beetles Nicrophorus vespilloides, a joint activity undertaken by the pair but typically led by the male. In previous work, we found that carrion nest preparation evolved to be faster in experimental populations without post-hatching care (No Care lines) than with post-hatching care (Full Care lines). Here we investigate how this joint activity evolved. After 15 generations of experimental evolution, we created heterotypic pairs (No Care females with Full Care males, and No Care males with Full Care females) and compared their carrion nest making with homotypic No Care and Full Care pairs. We found that pairs with No Care males prepared the nest more rapidly than pairs with Full Care males, regardless of the females line of origin. This suggests that males led the way by adapting their nest preparation behaviour to the No Care environment first, with females secondarily co-adapting their behaviour to the males behaviour by reducing their nest preparation behaviour. We discuss how social coadaptations within pairs or groups could act as a post-mating barrier to gene flow.

evolutionary biology↗

bioRxiv2020

Phenotypic plasticity explains violation of Dollo's law

Over the last few decades, numerous examples have been described where a trait that was once lost during the course of evolution had been regained. Here, we argue that such reverse evolution can also become apparent when trait expression is plastic in response to the environment. We tested this hypothesis for the loss and regain of fat synthesis in parasitic wasps. Wasps from lineages that supposedly regained lipogenic ability ~80 million years ago were grown under a fat-poor or fat-rich environment. In line with our hypothesis, it turned out that fat synthesis had not been lost and regained, but was only switched on in low-fat environments. Functional protein domains of key lipogenesis genes were also found in other parasitoid species, suggesting that plasticity of fat synthesis may be more widespread in parasitoids. Individual-based simulations then revealed that a switch for plastic expression can remain functional in the genome for thousands of generations, even if it is only used sporadically. The evolution of plasticity may thus also explain other examples of apparent reverse evolution.

evolutionary biology↗

bioRxiv2018

The evolution of a beneficial association between an animal and a microbial community

Animals are now known to be intimately associated with microbial communities, some of which enhance animal fitness. Yet relatively little is known about how these beneficial associations initially arose. We investigated this problem with an experiment on burying beetles, Nicrophorus vespilloides, which breed on the body of a small dead vertebrate. We found that burying beetles breeding on germ-free mice produced smaller larvae, with lower fitness, than those breeding on conventional germ-laden mice. Thus, burying beetles gain benefits from the microbial community associated with their carrion breeding resource, because they lose fitness when this community is removed experimentally. Our experiment suggests that a symbiosis between an animal and a microbial community might begin as an adaptation to the microbial ecosystem in which the animal lives, even when these microbes exist outside the animal, are transiently associated with it at each generation and are not directly transmitted from parents to offspring.

animal behavior and cognition↗

bioRxiv2017

Social interactions within the family enhance the capacity for evolutionary change

Classical models of evolution seldom predict evolution in the wild. One explanation is that the social environment has important, yet overlooked, effects on how traits change in response to natural selection. We tested this idea with selection experiments on burying beetles (Nicrophorus vespilloides), sub-social insects that exhibit biparental care. Populations responded to selection for larger adults only when parents cared for their offspring, and responded to selection for smaller adults only when we prevented parents from providing care. Comparative analyses revealed a similar pattern: evolutionary increases in species size within the genus Nicrophorus are associated with the obligate provision of care. Synthesising our results with previous studies, we suggest that cooperative social environments enhance the response to selection whereas conflict can prevent further directional selection.

evolutionary biology↗