Parental distribution of resources in relation to larval hunger and size rank in the burying beetle Nicrophorus vespilloides

In altricial birds, the parents' distribution of resources within the brood is influenced by variation in at least two components of nestling condition: hunger level and size rank. Here, we examine whether variation in larval hunger and size rank had similar influences on the parents' distribution of resources in the burying beetle Nicrophorus vespilloides. To this end, we analyzed hitherto unpublished data on parental resource distribution among individual larvae derived from three previous experiments. Our first experiment showed that resource distribution was biased towards hungry larvae at the expense of control larvae, but that actively begging hungry larvae were as likely to obtain resources from parents as actively begging control larvae. Thus, resource distribution was biased towards hungry larvae because hungry larvae spent more time begging than control larvae. Our second experiment showed that actively begging senior larvae (i.e. larvae that were older and larger) were more likely to obtain resources than actively begging junior larvae, suggesting that senior larvae had a competitive advantage or were treated preferentially by the parents. Our third experiment found no evidence that the interaction between larval hunger and size rank had an effect on parental resource distribution, suggesting that hunger level had a similar effect on resource distribution to seniors and juniors. We conclude that offspring hunger and size rank have remarkably similar effects in the burying beetle N. vespilloides as reported in studies on altricial birds.