MATE SAMPLING IN A POPULATION OF SAND GOBIES

Female mate-sampling behaviour and mate choice were investigated in a natural population of sand gobies, Pomatoschistus minutus. The sand go by is a promiscuous fish with paternal care. Gravid females were relea sed in the field and watched while they inspected potential mates. In total, 26 females were observed until they spawned. Half of the female s spawned with the first male encountered. The other females inspected two or more males in sequence and never returned to a previously insp ected male to mate. Females mated preferentially with males that court ed intensively. The mate-sampling behaviour of the female sand gobies was most consistent with a threshold-criterion tactic, which is to be expected if search costs are important. Moreover, there was an effect of season, such that females sampled very few males early but apparent ly became more selective later in the breeding season. This is discuss ed and interpreted as an effect of varying costs and benefits of being choosy over the season. (C) 1997 The Association for the Study of Ani mal Behaviour.