Raising Red Flags: Exploring Phenotypic Change in Tiger Moths (Apantesis) of Coastal SC over 50 Years' Time

Organismal phenotypes play a critical role in ecological interactions and individual fitness, and they may undergo rapid shifts through evolutionary adaptation or phenotypic plasticity in response to climate change and environmental disturbances. As morphological traits such as body size, melanization, and aposematic coloration are especially significant for thermoregulation and predator deterrence, it is important to understand the ways in which these traits may be changing on a regional level. Here, I examined the change in phenotype in populations of three tiger moth (Apantesis) species from a single site in coastal South Carolina over a fifty-year period, testing for differences in body size, forewing melanization, and hindwing coloration. Utilizing the Richard B. Dominick Moth & Butterfly Collection as a historical baseline (1965-1975), I engaged in modern sampling efforts of Apantesis vittata, A. phalerata, and A. parthenice at the same site throughout 2023-2024. A comparison of forewing length and area in historic and modern Apantesis specimens revealed that these species experienced a body size reduction over the past half-century. Apantesis vittata and A. phalerata demonstrated reduced forewing melanization as expected. Interestingly, Apantesis vittata hindwing coloration was found to be redder, less saturated, and lighter in coloration in the modern population, potentially hinting at shifting predation or mating interactions.