Molly Huggett | 2025 I.S. Symposium

Name: Molly Huggett
Title: The Influence of Instar on the Anti-Predator Freeze Response of Juvenile Carolina Grasshoppers (Dissosteira carolina)
Major: Biology
Minor: French and Francophone Studies
Advisor: Nick Brandley

Anti-predator behaviors, such as freezing, are a vital part of the survival of any prey species and are often influenced by visual ability. Visual ability can be broken down into visual acuity (how fine or coarse vision is) and sensitivity (ability to see in different lightings). Carolina Grasshoppers (Dissosteira carolina) have an anti-predator behavior known as the freeze response in which they will avoid moving to camouflage themselves while preparing to jump away. Additionally, we know that Carolina grasshoppers have a relatively constant visual acuity throughout development during instars 2-5 due to limited morphology changes. Here, we test whether juvenile Carolina grasshoppers have a difference in ability to perform the freeze response throughout development. We found that there is no significant difference in the rate of freeze response between the instars. However, previous studies have found that adult grasshoppers freeze around 85% of the time at looming stimuli while the juveniles only freeze around 50% of the time, therefore, there is likely some further development in visual ability before adulthood. Development of sensory systems vary from species to species, so it is possible that the final changes in the eye-brain communication systems help improve the frequency of the freeze response in adults. Understanding how sensory systems, such as vision, influence behavior in Carolina grasshoppers allows us to learn more about sensory development in invertebrate species.

Posted in Symposium 2025 on May 1, 2025.