Characterization of Cold Tolerance of Immature Stages of Small Hive Beetle (SHB) Aethina tumida Murray (Coleoptera: Nitidulidae)

Abstract

The small hive beetle (SHB) Aethina tumida Murray, (Coleoptera: Nitidulidae) is now a global invasive pest of honey bees, but its cold tolerance potential has not been yet explored. Therefore, we measured the supercooling point (SCP) of different stages of SHBs and also the impact of acclimation on their SCPs and survival as a measure for cold tolerance. Combinations of different temperatures (0, 3, 5, 7, and 10 ∘C) for different hours (1, 3, 5, 7, 12, 24, 35, and 48 h) were used to assess SHB survival. The supercooling points occurred at lower temperatures (−19.4 ∘C) in wandering larvae than in the other stages (pupae: −12.5 ∘C, and feeding larvae: −10.7 ∘C). A lethal temperature (LT50) of feeding larvae was achieved earlier at 4.9 ∘C after 7 h exposure than the wandering larvae (3.7 ∘C at 48 h) and pupae (5.6 ∘C at 48 h). The sum of injurious temperature (SIT) is the most suitable estimation to describe cold resistance of the SHB immatures. The wandering larvae were the most cold tolerant, followed by pupae and feeding larvae based on SIT values of −286.8, −153.7 and −28.7 DD, respectively, and also showed more phenotypic plasticity after acclimation than feeding larvae and slightly more than pupae. Our results show that all stages, i.e., feeding larvae, wandering larvae and pupae, are chill susceptible. However, these stages, especially wandering larvae and pupae, showed the capacity to acclimate to cold temperatures, which may help them to survive in winter for the continuity of the SHB population, especially in a scenario of climate change.

Cold tolerance strategy and cryoprotectants of Megabruchidius dorsalis in different temperature and time stresses

“…Rapid cold hardening (after minutes to about 3 h of exposure to low temperatures) can affect a range of cold hardiness parameters, and cold acclimation (days to weeks) also has a significant effect on cold tolerance ( Teets and Denlinger, 2013 ; Jakobs et al, 2015 ). According to the beneficial acclimation hypothesis, the association of insect adaptive acclimation with SCP can support the cold limit, which is related to acclimation temperature and exposure time ( Hemmati et al, 2014 ; Noor-Ul-ane and Jung, 2021 ). The SCP of Phthorimaea operculella ( Aryal and Jung, 2018 ) and Helicopter assulta ( Cha and Lee, 2016 ) decreased significantly after cold acclimation.…”