Meeting Abstract
Signals can vary substantially, even within a somewhat closely-related taxon. In Sceloporus lizards, many species are dimorphic and signal via blue ventral and throat patches. In the most common scenario, males are larger and have more extensive blue patches, whereas females are smaller with lesser/no blue patches. In southeast Arizona, two sympatric species deviate from this typical pattern and have contrasting modes of visual signals. In S. jarrovii, both males and females are characterized by large body size and extensive blue ventral and throat patches, whereas both sexes of S. virgatus have smaller body size, no ventral blue patches, and minimal throat patches. Our aims were to explore dimorphism in body size, ventral patch size, and throat patch size in both species and determine if these signals correlated with a measure of whole-animal performance: bite force. We found that S. jarrovii were not sexually dimorphic in body size or ventral patch size, but were significantly dimorphic in throat patch size and bite force (males being greater in both). However, after correcting for body size, we found no relationship between ventral or throat patch size and bite force in males. Surprisingly, in females, we found a negative relationship between both ventral and throat patch sizes and bite force. In contrast, S. virgatus were dimorphic in body size (females being larger) but with no statistical dimorphism in throat patch size. Although females had stronger absolute bite forces, there was no dimorphism in bite force after correcting for body size. There was no relationship between throat patch size and bite force in females, but there was a significant negative correlation between throat patch size and bite force in males. Our findings indicate that in these ‘atypical’ Sceloporus species, the relationship between signals and performance is complex.
