Moisture and competition constrain ephemeral resource quality for burying beetle reproduction

Abstract

Shifts in abiotic factors such as temperature and moisture can change the availability of resources, especially under climate change. Both abiotic and biotic drivers can have profound, rapid effects on species distribution, survival, and reproduction. Little is known about how abiotic factors affect the availability of ephemeral resources. Burying beetles (Nicrophorus spp.) are specialist users of ephemeral resources, as their reproduction requires locating, defending, and burying a small carcass. Environmental moisture, such as coastal fog, could change how quickly carcasses dry out. We tested the role of carcass moisture and interspecific competition with a generalist scavenger, Heterosilpha spp., on reproduction by placing pairs of Nicrophorus guttula in field chambers with fresh and experimentally dehydrated mouse carcasses. Pairs that were given fresh mouse carcasses were more likely to carry out reproductive behaviors and produce viable offspring than pairs that were given a partially dehydrated mouse. For those pairs that reproduced, competition limited the number of offspring. These results indicate that shifts in abiotic factors under climate change, along with biotic factors like competition, can reduce the availability of ephemeral resource patches for consumers.