Paternity and paternal effort in the pumpkinseed sunfish

Theoretical models suggest that males should adjust their parentaleffort according to paternity when parental effort is costly,paternity varies among clutches, and males have a cue to assesspaternity. To date, nearly all tests of this theory have beenconducted using birds as model organisms. In this study we examinedthese three factors and the relationship between paternity andmale parental care in a fish system. In the pumpkinseed sunfish(Lepomis gibbosus), parental care is provided exclusively bymales (parentals), but some males (sneakers) parasitize othersby sneaking fertilizations. Parental males significantly lostweight during the parental care period. Clutch size and amountof parental effort did not affect a male's probability of obtainingmore eggs. Paternity was variable among broods. The proportionof young sired by a parental male was not associated with frequencyof fanning eggs or defense of hatched young, but was positivelycorrelated with levels of nest defense during the egg stage.Egg survivorship might restrict an adjustment of fanning behavior,and a general decline in parental behavior (with brood age)might explain the lack of adjustment once the eggs hatch. Parentalmales did not adjust their care when we experimentally manipulatedone possible cue of paternity. Together, these results indicatethat male pumpkinseeds do adjust their care in relation to paternity,but the cues used to assess paternity are not clear.