Begging behaviour can provide information on offspring hunger levels and be used by parents to adjust food provisioning efforts. In cooperative breeders, helpers also care feeding the young. However, how of different sex relatedness respond begging has rarely been studied in cooperatively breeding species, which limits our understanding indirect and/or direct benefits that may obtain responding...

Parent-offspring communication remains an unresolved challenge for biologist. The difficulty of the challenge comes from the fact that it is a multifaceted problem with connections to life-history evolution, parent-offspring conflict, kin selection and signalling. Previous efforts mainly focused on modelling resource allocation at the expense of the dynamic interaction during a reproductive sea...

Sibling competition mediated by begging behavior is extremely common in avian species and recent studies have highlighted the role of endogenous testosterone in regulating such phenomenon. However, current literature depicts an inconsistent pattern in altricial vs. semi-precocial species, with stimulating versus inhibitory effects of the hormone respectively. This is possibly due to a differenc...

Game theoretical models of biparental care predict that a change in work rate by one parent should be met by incomplete compensation by its partner. However, in empirical studies on biparental birds, there has been some inconsistency in the direction and extent of the response, and the mechanism behind it has so far been unclear. Parents could be responding directly to partner work rate or indi...

Parents of a variety of animal species distribute critical resources among their offspring according to the intensity of begging displays. Kin selection theory predicts that offspring behave more selfishly in monopolizing parental care as relatedness with competitors declines. We cross-fostered two eggs between barn swallow (Hirundo rustica) clutches and compared the loudness of begging between...

Brood reduction may be a strategy by which, when food is scarce, parents provision chicks differentially — this usually leads to the death of the smaller nestlings. In contrast, in species where brood reduction does not normally occur, parents may allocate food equally among nestlings. The Rufous-tailed Scrub-robin Cercotrichas galactotes is a species in which brood reduction does not occur (it...

A nest of begging chicks invites an intuitive explanation: needy chicks want to be fed and parents want to feed them. Surprisingly, however, in a quarter of species studied, parents ignore begging chicks. Furthermore, parents in some species even neglect smaller chicks that beg more, and preferentially feed the biggest chicks that beg less. This extreme variation across species, which contradic...

Theoretical models suggest that begging should be costly in order to be evolutionarily stable. However, evidence for such a cost is contradictory (e.g. for growth costs) or scant (e.g. for immunological costs). Here, we experimentally test the existence of both costs in southern shrike (Lanius meridionalis) nestlings. Nestlings were paired by nest of origin and similar body mass. In each pair, ...

Parental food provisioning and offspring begging influence each other reciprocally. This makes both traits agents and targets of selection, which may ultimately lead to co-adaptation. The latter may reflect co-adapted parent and offspring genotypes or could be due to maternal effects. Maternal effects are in turn likely to facilitate in particular mother-offspring co-adaptation, further emphasi...