Paternity and paternal effort in the pumpkinseed sunfish

Theoretical models suggest that males should adjust their parental effort according to paternity when parental effort is costly, paternity varies among clutches, and males have a cue to assess paternity. To date, nearly all tests of this theory have been conducted using birds as model organisms. In this study we examined these three factors and the relationship between paternity and male parental care in a fish system. In the pumpkinseed sunfish (Lepomis gibbosus), parental care is provided exclusively by males (parentals), but some males (sneakers) parasitize others by sneaking fertilizations. Parental males significantly lost weight during the parental care period. Clutch size and amount of parental effort did not affect a male's probability of obtaining more eggs. Paternity was variable among broods. The proportion of young sired by a parental male was not associated with frequency of fanning eggs or defense of hatched young, but was positively correlated 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. Parental males did not adjust their care when we experimentally manipulated one possible cue of paternity. Together, these results indicate that male pumpkinseeds do adjust their care in relation to paternity, but the cues used to assess paternity are not clear. Copyright 2005.