Social effects of inbreeding associated with parental care
Mattey, Sarah Nadine
Inbreeding is associated with reduced fitness, a phenomenon known as inbreeding depression. I investigated direct and indirect effects of inbreeding on social traits associated with parental care in the burying beetle, Nicrophorus vespilloides. This species breeds on small vertebrate carcasses and the parents provide care by maintaining the carcass and regurgitating food to begging larvae. I quantified the survival of outbred offspring produced by inbred and outbred parents. I found that inbred offspring had reduced survival compared to outbred offspring, and that outbred offspring produced by inbred parents survived less well. Such intergenerational effects of inbreeding suggests that inbreeding may affect the amount of parental care provided to offspring. I tested this by investigating the amount of care inbred and outbred male and female parents provided to outbred offspring. I found no reductions in the amount of care provided by inbred parents but found that parents provided more care when their partner was inbred. In addition, I investigated effects of inbreeding on parent-offspring communication, when either female parents or their offspring were inbred. I found that whilst inbred offspring begged less, parents provided inbred offspring with more care. The effects of inbreeding had significant consequences affecting biparental negotiation and parent-offspring communication. Next, I tested for the effects of inbreeding on the antimicrobial properties of secretions that both parents apply to the carcass during larval development. I found that the bactericidal activity of inbred male parents was reduced compared to outbred male parents during the dispersal stages and no evidence for the secretions of inbred and outbred female parents differing. Finally, to test whether the strong inbreeding depression found in this species influenced the mating decisions, I presented females with related or unrelated males, and found no evidence that females avoided inbreeding. These results show that to accurately estimate the fitness consequences of inbreeding the social effects on all individuals within a family must be accounted for.