Helpful female subordinate cichlids are more likely to reproduce.
BACKGROUND
In many cooperatively breeding vertebrates, subordinates assist a dominant pair to raise the dominants' offspring. Previously, it has been suggested that subordinates may help in payment for continued residency on the territory (the 'pay-to-stay hypothesis'), but payment might also be reciprocated or might allow subordinates access to reproductive opportunities.


RESULTS
We measured dominant and subordinate female alloparental brood care and reproductive success in four separate experiments and show that unrelated female dominant and subordinate cichlid fish care for each other's broods (alloparental brood care), but that there is no evidence for reciprocal 'altruism' (no correlation between alloparental care received and given). Instead, subordinate females appear to pay with alloparental care for own direct reproduction.


CONCLUSIONS
Our results suggest subordinate females pay with alloparental care to ensure access to the breeding substrate and thereby increase their opportunities to lay their own clutches. Subordinates' eggs are laid, on average, five days after the dominant female has produced her first brood. We suggest that immediate reproductive benefits need to be considered in tests of the pay-to-stay hypothesis.
Department of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Hinterkappelen, Switzerland. dik.heg@iee.unibe.ch
Dik
D
Heg
Eva
E
Jutzeler
Jeremy S
JS
Mitchell
Ian M
IM
Hamilton
D000818:Animals; D023681:Cichlids / Q000502:physiology*; D003299:Cooperative Behavior; D004291:Dominance-Subordination; D005260:Female; D052287:Oviparity / Q000502:physiology; D012098:Reproduction / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000502:physiology*