PAPER: More maternal effects in Sociable Weavers 2013-04-22 (356)
Paquet M, Covas R, Chastel O, Parenteau C, Doutrelant C. 2013. Maternal effects in relation to helper presence in the cooperatively breeding Sociable Weaver. PLoS One 8(3): e59336
Abstract. In egg laying species, breeding females may adjust the allocation of nutrients or other substances into eggs in order to
maximise offspring or maternal fitness. Cooperatively breeding species offer a particularly interesting context in which to
study maternal allocation because helpers create predictably improved conditions during offspring development. Some
recent studies on cooperative species showed that females assisted by helpers produced smaller eggs, as the additional
food brought by the helpers appeared to compensate for this reduction in egg size. However, it remains unclear how
common this effect might be. Also currently unknown is whether females change egg composition when assisted by
helpers. This effect is predicted by current maternal allocation theory, but has not been previously investigated. We studied
egg mass and contents in sociable weavers (Philetairus socius). We found that egg mass decreased with group size, while
fledgling mass did not vary, suggesting that helpers may compensate for the reduced investment in eggs. We found no
differences in eggs’ carotenoid contents, but females assisted by helpers produced eggs with lower hormonal content,
specifically testosterone, androstenedione (A4) and corticosterone levels. Taken together, these results suggest that the
environment created by helpers can influence maternal allocation and potentially offspring phenotypes.
The work was conducted between September 2010 and February 2011 at Benfontein Nature Reserve in the Northern
Cape, South Africa. Many studies have been conducted here, including the following:
Sociable weaver life-history.
Sociable Weaver helpers.
Oldest Sociable Weaver.
Maternal effects in Sociable Weavers.
Thermoregulation in Sociable Weaver nests.
Sociable weaver life-history.
See PHOWN records from Benfontein here.
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