02742nas a2200241   4500008004100000022001300041245012300054210006900177260001600246300001400262490000800276520181500284653001802099653002502117653002202142653002002164653001202184653002402196653001302220100001802233700001602251856023302267       2018                        eng d  a0003347200aSocial context-dependent provisioning rules in red-winged fairy-wrens do not vary with signals of increased chick need0 aSocial contextdependent provisioning rules in redwinged fairywre  cJan-09-2018  a105 - 1110 v1433 a<p>Individuals should adjust investment in parental care in order to maximize current and future reproductive success. In cooperative breeders, where helpers assist with raising offspring, larger groups may allow for a reduction in investment (load lightening) of each individual. Additionally, the type of individual, and thus the social context, can play an important role in individual investment. Less attention has been paid to how provisioning rules vary across ecological contexts, although theory suggests that individuals can only afford to reduce their investment when nestling starvation is unlikely, thus under mild conditions. Here, we tested whether previously reported provisioning rules based on social context vary with ecological conditions, by experimental manipulation of signals of chick need, in the cooperatively breeding red-winged fairy-wren, Malurus elegans. Previous work in this species has shown that all group members load-lighten with additional male helpers, but not in response to the number of female helpers in the group (additive care). We show that experimental begging playback resulted in all individuals increasing their provisioning rates, indicating that our treatment was perceived as increased chick need. However, in contrast to our prediction that load lightening should only occur when individuals can afford to do so, signals of increased chick need did not stop individuals from reducing their investment with an increasing number of male helpers in the group. These results suggest that despite some flexibility in parental effort, individuals use strict rules with respect to group composition, suggesting that individual provisioning effort is based on multiple integrated cues, and responses to changes in the environment are highly context dependent.</p>
10aadditive care10acooperative breeding10ahelping behaviour10aload lightening10aMalurus10aparental investment10aplayback1 aMacLeod, K.J.1 aBrouwer, L.  uhttps://linkinghub.elsevier.com/retrieve/pii/S0003347218302252https://api.elsevier.com/content/article/PII:S0003347218302252?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0003347218302252?httpAccept=text/plain