Behaviour 2019
Female-Biased Vision in the Carolina Grasshopper: Behavior Matches Eye Morphology.
Nicholas C Brandley, Frederick R Gilbert. The College of Wooster, Wooster, OH, United States

Sexual dimorphisms in vision are common when behaviors differ between the biological sexes. In insects, most published sexual dimorphisms in vision are male-biased (e.g. the love spot of many male flying insects used to track mates). Contrastingly, we have previously demonstrated a female-biased sexual dimorphism in the eyes of the Carolina grasshopper (Dissosteira carolina), with biological females having larger eyes with more receptors and smaller interommatidial angles (Duncan et al. 2021). However, it is unknown whether these morphological differences correlate with behavioral differences. Here, we present Carolina grasshoppers (n=67) with a series of computer-generated mock predator stimuli while simultaneously tracking them via the EthoVision XT system. As predicted by eye morphology, female grasshoppers were more likely to freeze to a stimulus (p=0.016, Fisher’s Exact Test), and initiated their response to smaller stimuli (females had the 12 responses to smallest stimuli). Our results 1) show that differences in eye morphology correlate with performance in one behavioral context and 2) provide a female-biased counter example to the classic male-biased love spot.