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Acclimation to desiccating conditions and cross-tolerance with thermal stress in the lesser mealworm Alphitobius diaperinus (Coleoptera: Tenebrionidae)

Abstract : The ability of invasive species to rapidly expand into new regions may be related to their greater phenotypic plasticity. In addition, cross-tolerance, i.e. a response by which tolerance to one stress can enhance tolerance to another stress, may contribute to the invasive success of some alien insects. For instance, a certain level of cold hardiness has been documented in several tropical insects, although these species never experience cool or freezing temperatures in their natural environments. Similar observations were reported in the lesser mealworm Alphitobius diaperinus (Coleoptera: Tenebrionidae), an invasive beetle of tropical origin that thrives in stored products. This species shows a high basal desiccation tolerance, and cross-tolerance between desiccation and cold could have facilitated its successful establishment in temperate areas. In this study, we examined if dry pre-exposed beetles have increased ability to survive desiccation (7 % RH), cold (5°C), or heat stress (38°C). Survival duration remained similar between dry pre-exposed and control beetles that were subjected to desiccation or cold stress. However, we found that dry pre-exposed beetles had increased heat tolerance (Lt50 postponed by 4 days). In a second experiment, dry pre-exposed insects were allowed to recover either with water supply or with moderate humidity (50 % RH) before being assessed for desiccation, cold and heat tolerance. We found that rehydration changed cross-tolerance patterns: cold survival was promoted (Lt50 postponed by 3 days), while heat tolerance was not affected anymore. We found no effect of dry pre-exposure on the subsequent ability to survive dry condition. In summary, we found some evidence of cross-tolerance between desiccating and heat conditions, and between desiccating and cold conditions, but these effects depended on whether the beetles were allowed to recover or rehydrate before being exposed to another stress. These findings suggest complex and differential cross-tolerance mechanisms.
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Submitted on : Friday, February 24, 2017 - 3:19:54 PM
Last modification on : Tuesday, May 26, 2020 - 1:02:08 AM

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  • HAL Id : hal-01476061, version 1

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David Renault, Youn Henry, Hervé Colinet. Acclimation to desiccating conditions and cross-tolerance with thermal stress in the lesser mealworm Alphitobius diaperinus (Coleoptera: Tenebrionidae). Revue d'Ecologie, Terre et Vie, Société nationale de protection de la nature, 2015, 70 (Supplément 12), pp.33-41. ⟨hal-01476061⟩

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