Differential thermal tolerance across life stages under extreme high temperatures crossed with feeding status in corn leaf aphid

Abstract

1. Climate change is expected to increase the frequency and duration of extreme heat events, which would pose significant challenges to most ectotherm species, such as insects. 2. In the study, we address the thermal tolerance of corn leaf aphid, Rhopalosiphummaidis (Hemiptera: Aphididae) under brief extreme high‐temperature events (i.e. heat waves) across life stages. Immature instars and adults of R. maidis were exposed to heat events of increasing temperatures (0.5 °C min−1), starting at 22 °C and reaching one of the selected maximal temperatures (from 38.5 to 44.5 °C with an increased interval of 0.5 °C). In each temperature regime, the mortality of R. maidis was compared with and without barley seedlings. 3. Results showed that the critical high temperature (CHT) of R. maidis was 39.0 °C in no feeding treatments, while it was 39.5 °C in feeding treatments. The upper lethal temperatures (ULTs) of R. maidis were significantly different between feeding and no feeding treatments. In addition, the ULTs varied significantly across life stages with the highest ULT values for 4th instars. Feeding significantly increased the thermal tolerance of phytophagous insects. 4. Variable balances in plant‐herbivore interactions will be induced according to the insect feeding diet status and instar stage when experiencing extreme temperatures resulting from the warming climate. The findings will provide valuable information for understanding the role of food intake in thermal adaptation of small arthropods to extreme high‐temperature events under climate change.

Negative carry‐over effects on larval thermal tolerances across a natural thermal gradient

“…S1). These stages also differ in thermal responses and sensitivity, with early life-history stages tending to have lower tolerances (higher sensitivity) to stress than older life stages (Pincebourde and Casas 2015, Qi et al 2019, Chen et al 2021). Therefore, it is essential to understand drivers of thermal tolerances across ontogeny for predicting the persistence of species.…”

Barley Yellow Dwarf Virus Influences Its Vector’s Endosymbionts but Not Its Thermotolerance

“…In addition, we only tested a single clonal type, but multiple R. padi clones are present in populations [ 72 , 73 ] and can differ substantially in terms of life history characteristics [ 74 ]. Other measures of thermotolerance beyond CT max and knockdown time could be considered given that the aphid life stage when heat exposure occurs can impact thermotolerance [ 75 , 76 , 77 ]. Sublethal life history traits are also influenced by stage-specific exposures to heat stress [ 78 , 79 ], which could shape the interactions between BYDV and R. padi under field conditions.…”

Secondary symbionts affect aphid fitness and the titer of primary symbiont

“…The corn leaf aphid, Rhopalosiphum maidis (Fitch), is one of the most economically damaging aphid pests on maize ( Zea mays ) and can transmit several damaging maize viruses, resulting in serious yield losses ( Chen et al., 2019 ; Chen et al., 2020 ), whereas only sporadic reports focus on R. maidis symbionts. Previous studies have tested the symbiont combination of R. maidis and other aphid species collected across Morocco and found that aphid symbiont combinations were mainly host-specific ( Fakhour et al., 2018 ), detected the infection patterns of seven facultative symbionts of R. maidis distributed in 37 geographical populations in China ( Guo et al., 2019 ), and demonstrated that some symbionts may have a direct effect on aphids’ adaptation to different maize management systems ( Csorba et al., 2022 ).…”