Low temperature tolerance of kudzu bug, Megacopta cribraria

Kudzu bug, Megacopta cribraria, is an invasive insect in the United States (US). Since the discovery of kudzu bug in Georgia in 2009, it has rapidly spread across southeastern states using kudzu (Pueraria montana) as the host plant. When overcrowding occurs, kudzu bugs can shift oviposition sites to soybean. This poses a potential threat to US soybean oil production. Understanding the thermal tolerance of invasive insects can assist in predicting potential spread, and in this case provide data of whether kudzu bug may survive winters in soybean regions in the Midwest. Here, we investigated the low temperature tolerance of a population of adult kudzu bug in western Tennessee. Every month from September 2023, adults were collected off kudzu at the University of Memphis Meeman Biological Station. Low temperature tolerance was measured by determining chill coma recovery time (CCRT, recovery from cold exposure), supercooling point (SCP, freezing temperature), and lower lethal temperature. Over the first nine months, SCP, but not CCRT, differed significantly (SCP: F_8,236=235.44, p< 0.05). The average SCP in September 2023 was -14.6±0.3°C, (n=32) while in April 2024 it was -7.1±0.2°C, (n=32; t=-22.5, p< 0.05). Lower lethal temperature was close to the SCP, but additional durations and temperature combinations are being tested. Thus, kudzu bugs in western Tennessee have similar low temperature tolerance to populations previously studied in Virginia, and adults show strong seasonal variation in low temperature tolerance.