No differences in reproductive success of burying beetles after adaption to laboratory conditions on lab versus field soil

Laboratory experiments enable controlled testing of ecological and evolutionary processes. However, the conditions imposed under laboratory rearing can also generate artificial selection and limit the broader application of experimental findings. Burying beetles are an increasingly popular model organism for understanding behavioural ecology and evolution. Laboratory populations are typically reared on artificial composted breeding substrate, which could have dramatic effects on their ecology. To this end, we compared reproductive success, offspring fitness, and parental care in fifth-generation laboratory-reared burying beetles beetle Nicrophorus vespilloides when mating on either artificial compost or soil sampled from the original collection sites of the wild-caught beetles. We found no evidence for breeding substrate specialisation despite five generations of lab adaptation, as there was no difference in the mean or variance any of the reproductive success traits between beetles breeding on lab versus field soil. Our findings indicate that Nicrophorus species may be robust to variation in laboratory environmental conditions but also highlight the importance of assessing whether adaptation to standardised laboratory conditions affects fitness in broader ecological contexts.