Sexual Differences in Parental Investment in Response to Parent‐Absent Calls

Abstract

Begging in birds is a complex behaviour used by nestlings to solicit feeds from caregivers. Besides calling when parents are present, nestlings of some species also perform less conspicuous repeat calls when parents are absent. The fact that these calls are produced when parents are not at the nest does not mean that parents cannot hear them when they approach the nest or forage in its vicinity. In this study, we experimentally investigated the relationship between parent‐absent repeat calls (ARC) and frequency of parental visits, considering parent/offspring communication as a possible implication of these acoustic signals. A playback experiment was conducted to detect changes in parental investment in response to increases in parent‐ARC, expecting a differential sexual response. Results showed that females clearly responded to repeat calls, increasing their visit rate significantly with respect to females that received the control treatment. Males, on the contrary, did not change their visit rate in response to the treatment. This result provides evidence for a role of parent/offspring communication in parent‐absent repeat calling, an additional function to sibling negotiation processes. The sex‐specific response that we found is in agreement with previous studies that have found that females are more responsive than males to variation in solicitation and hunger signals performed by nestlings.

Context‐dependent effects of yolk androgens on nestling growth and immune function in a multibrooded passerine

“…Modal clutch size is five eggs (López‐Rull et al ., ), and fledglings leave the nest around 22 days of age (Cramp, ). Generally, females invest more than males in rearing the brood (Jimeno et al ., ), although paternal care varies widely (Moreno et al ., ). In our study area, most spotless starling pairs rear two broods.…”

Diverse dose-response effects of yolk androgens on embryo development and nestling growth in a wild passerine

“…Incubation usually starts before the last egg is laid (3-6 eggs per clutch), and it is done mainly by females (lasting for approximately 12 days). Although parental care is provided by both pair members (Moreno et al, 1999), females invest more than males in rearing the brood (Jimeno et al, 2014). The nestling period lasts about 21-22 days (Cramp, 1998).…”

Season-dependent processing of innate conspecific vocalizations in the male and female European starling (Sturnus vulgaris)

“…As the starlings that were used in this study were wild-caught and did not breed in captivity, it is unclear whether they were unfamiliar with begging calls. CMM neurons are also sensitive to social context as they can differentiate between directed and undirected songs (Van Ruijssevelt et al, 2018), and like learned courtship vocalization, begging calls also have directed and undirected renditions (Bulmer, Celis and Gil, 2008;Woolley and Doupe, 2008;Jimeno et al, 2014). However, no differences were observed in the CMM between the different stimuli or the seasons.…”

“…A study on the spotless Starling (Sturnus unicolor), which is closely related to the European starling, revealed a sex bias in their behavioral responsiveness towards begging call playbacks. Only females increase their food provisioning rate in response to nestling begging calls (Kolliker et al, 2000;Jimeno et al, 2014) even though this species of starlings participate in biparental care (Jimeno et al, 2014). One would expect in this case also a sexual difference in the neural substrate responsible for this behavior.…”