Abstract
‘Pay to stay’ is a mechanism generating cooperation in some highly social vertebrates. However, it is
unknown which behaviours subordinate helpers preferentially use to pay for the commodities provided
by resource owners. Helpers could either provide ‘cheap’ service to save costs or trade expensive actions
for the benefit of being tolerated. In the cichlid Neolamprologus pulcher, unrelated helpers pay to stay in
a safe territory of dominant breeders by performing a range of behaviours including direct brood care,
territory maintenance and defence. We investigated which behaviours helpers differing in size and sex
showed in response to increased demands. By presenting high or low perceived intruder pressure we tested
(1) whether helpers adjust their level of payment to the intensity of competition, (2) which behaviours are
used for payment, and (3) whether the response to the treatment differs between helper size and sex. All
helpers performed more defence behaviour in the high-density situation and large helpers put significantly
more effort into digging and defence than small helpers did in both treatments. In the low-density treatment,
large helpers reacted to breeder aggression by increased submissiveness, whereas in the high-density
treatment they responded by increased territory defence, as predicted by the pay-to-stay hypothesis.
Helper sex did not influence their behavioural responses. Our results suggest that helpers respond to
demand and large helpers pay generally more than small ones to remain tolerated in the breeders’ territory.
Translated title of the contribution | Helpers in a cooperative breeder pay a high price to stay: effects of demand, helper size and sex |
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Original language | English |
Pages (from-to) | 1843 - 1850 |
Journal | Animal Behaviour |
Volume | 75 |
Publication status | Published - 2008 |