Behavioral syndromes influence mating systems: floater pairs of a lizard have heavier offspring

Variation in correlated behaviors or behavioral syndromes could have interesting effects on mating systems, especially if the variation in syndrome exists in both sexes. Both males and females of the lizard Eulamprus heatwolei display two behavioral types of a behavioral syndrome, defined by correlations between territorial, exploratory, and predator avoidance behaviors. We tested how this variation in behavioral syndrome influences reproductive success, pairing patterns, and offspring weight. We used spatial behavior and residency in the field to identify territorial and floater individuals. Females were relocated to the laboratory to give birth, and all offspring, dams, and potential sires were genotyped to determine offspring paternity. During field surveys, 164 lizards were caught of which 27.5% were territorial and the rest were floaters. Paternity was assigned to 66% of the 104 offspring produced by 33 dams. Territorial sires fathered a greater proportion of the offspring of territorial dams than floater sires. Larger territorial males were more likely to sire the entire clutch or share paternity with fewer additional sires than smaller territorial males. Floater sire size, however, did not influence the number of fathers per litter. Floater females produced heavier offspring than their territorial counterparts, and offspring fathered by floaters were heavier than maternal half-sibs fathered by territorial males. We speculate that differences in offspring weight may be the result of differences in yolk provisioning by females and parent genetic compatibility.