Compensatory and additive helper effects in the cooperatively breeding Seychelles warbler (Acrocephalus sechellensis). Issue 5 (14th February 2019)

• Record Type: Journal Article
• Authors: van Boheemen, Lotte A.; Hammers, Martijn; Kingma, Sjouke A.; Richardson, David S.; Burke, Terry; Komdeur, Jan; Dugdale, Hannah L.
• Is Part Of: Ecology and evolution. Volume 9:Issue 5(2019)
• Page Start: 2986
• Page End: 2995
• Publication Date: 2019-02-14
• Subjects: additive care -- compensatory care -- cooperative breeding -- investment strategies -- load‐lightening -- parental care -- Seychelles warbler; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.4982
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: In cooperatively breeding species, care provided by helpers may affect the dominant breeders' investment trade‐offs between current and future reproduction. By negatively compensating for such additional care, breeders can reduce costs of reproduction and improve their own chances of survival. Alternatively, helper care can be additive to that of dominants, increasing the fledging fitness of the current brood. However, the influence helpers have on brood care may be affected by group size and territory quality. Therefore, the impact of helping needs to be disentangled from other factors determining offspring investment before conclusive inferences about the effect of help on additive and compensatory care can be made. We used 20 years of provisioning data to investigate the effect of helping on provisioning rates in the facultative cooperatively breeding Seychelles warbler Acrocephalus sechellensis . Our extensive dataset allowed us to statistically disentangle the effects of helper presence, living in larger groups and different food availability. We show compensatory and additive care (i.e., partial compensation) in response to helper provisioning. Helpers lightened the provisioning load of the dominant male and female and increased total provisioning to nestlings. This was irrespective of group size or territory quality (food availability). Moreover, our results illustrate sex‐specific variation in parental care over the course of the breeding event. We discriminate between temporal variation, group size, and territory quality processes affecting cooperative care and as such, gain further insight into the importance of these factors to the evolutionary maintenance of helping behavior. Abstract : The influence of helper presence on brood care depends on various ecological factors, including group size and territory quality. We use 20 years of brood provisioning data from the Seychelles warbler Acrocephalus sechellensis to investigate the effect of helping on provisioning, while controlling for the effects of territory quality, food availability, and group size. We show compensatory and additive care of dominant breeders in response to helper provisioning.