Cold tolerance of the invasive oak lace bug, Corythucha arcuata

Abstract

The North American oak lace bug (OLB), Corythucha arcuata, is an invasive species in Europe and a serious threat to oak-dominated forests. Survival at low temperatures is one major factor determining the spread of invasive insects. Thus, we studied key traits, that is, cold-tolerance strategy, supercooling points (SCP) and chilling-related mortality, of overwintering adults to assess their potential to withstand harsh winters. Samples for SCP measurements were collected once a month from November 2020 until March 2021 at three different locations in Hungary; specimens for chilling experiments were sampled in November 2020, January 2021 and March 2021. SCPs of overwintering adults ranged from −29.68 to −7.49 °C, with only moderate variation among months; C. arcuata is a freeze-avoidant species. Mortality rates of adults exposed to two sub-zero temperatures above the SCP (−3 and −5 °C) for 1, 2 and 3 weeks ranged between 0% and 69.1%, suggesting that OLB has a moderate risk to die from chilling injuries. Exposure time and sampling date affected mortality, with lowest survival rates after 3 weeks, collected in March 2021.