PARENTAL BEHAVIOR IN RELATION TO FOOD AVAILABILITY IN THE COMMON GOBY

In the common goby, Pomatoschistus microps (Pisces, Gobiidae), males b uild nests under mussel shells where they care for the eggs until hatc hing. To investigate why male common gobies cannibalize their own eggs (filial cannibalism), we conducted a feeding experiment. Males given little food ate from their eggs more often than males given food in ex cess. However, males given mussel meat in excess did not eat more of t heir eggs than males fed with both mussel meat in excess and goby eggs . This may suggest that male common gobies cannibalize their eggs to o btain energy rather than essential nutrients lacking in other diets. M oreover, males ate their whole clutch if it was exceptionally small re gardless of food treatment, suggesting that males stop investing in th eir clutch if its reproductive value is less;than the cost of guarding it. Thus, whole clutch cannibalism and partial clutch cannibalism see m to be governed by different factors. Furthermore, poorly built nests were associated with starved males, suggesting that nest concealing i s costly. There was an association between how well the nest was built and partial clutch filial cannibalism, suggesting that the appearance of the nest may indicate the condition of the male, and thus the risk of filial cannibalism. (C) 1998 The Association for the Study of Anim al Behaviour.