Alford Lucy, Kishani Farahani Hossein, Pierre Jean-Sébastien, Burel Françoise, van Baaren Joan
UMR 6553 ECOBIO, Université de Rennes I, Avenue du Général Leclerc, 35042 Rennes Cedex, France; Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Davidson Building, Glasgow G12 8QQ, UK.
Equipe Recherches Agronomiques, Agronutrition, Carbonne, France.
J Insect Physiol. 2017 Nov;103:71-77. doi: 10.1016/j.jinsphys.2017.10.008. Epub 2017 Oct 14.
For generalist parasitoids such as those belonging to the Genus Aphidius, the choice of host species can have profound implications for the emerging parasitoid. Host species is known to affect a variety of life history traits. However, the impact of the host on thermal tolerance has never been studied. Physiological thermal tolerance, enabling survival at unfavourable temperatures, is not a fixed trait and may be influenced by a number of external factors including characteristics of the stress, of the individual exposed to the stress, and of the biological and physical environment. As such, the choice of host species is likely to also have implications for the thermal tolerance of the emerging parasitoid. The current study aimed to investigate the effect of cereal aphid host species (Sitobion avenae, Rhopalosiphum padi and Metopolophium dirhodum) on adult thermal tolerance, in addition to sex and size, of the aphid parasitoids Aphidius avenae, Aphidius matricariae and Aphidius rhopalosiphi. Results revealed no effect of host species on the cold tolerance of the emerging parasitoid, as determined by CT and Chill Coma, for all parasitoid species. Host species significantly affected the size of the emerging parasitoid for A. rhopalosiphi only, with individuals emerging from R. padi being significantly larger than those emerging from S. avenae, although this did not correspond to a difference in thermal tolerance. Furthermore, a significant difference in the size of male and female parasitoids was observed for A. avenae and A. matricariae, although, once again this did not correspond to a difference in cold tolerance. It is suggested that potential behavioural thermoregulation via host manipulation may act to influence the thermal environment experienced by the wasp and thus wasp thermal tolerance and, in doing so, may negate physiological thermal tolerance or any impact of the aphid host.
对于诸如蚜茧蜂属的那些多食性寄生蜂而言，寄主物种的选择对羽化出的寄生蜂可能具有深远影响。已知寄主物种会影响多种生活史特征。然而，寄主对耐热性的影响从未被研究过。生理耐热性，即能够在不利温度下存活，并非一个固定特征，可能会受到许多外部因素的影响，包括应激的特征、暴露于应激的个体的特征以及生物和物理环境的特征。因此，寄主物种的选择可能也会对羽化出的寄生蜂的耐热性产生影响。当前的研究旨在调查谷物蚜虫寄主物种（麦长管蚜、禾谷缢管蚜和荻草谷网蚜）对燕麦蚜茧蜂、菊小长管蚜茧蜂和高粱蚜茧蜂的成虫耐热性以及性别和体型的影响。结果表明，对于所有寄生蜂物种，寄主物种对羽化出的寄生蜂的耐寒性没有影响，这是通过低温昏迷试验（CT）和冷昏迷试验确定的。寄主物种仅对高粱蚜茧蜂羽化出的个体大小有显著影响，从禾谷缢管蚜羽化出的个体显著大于从麦长管蚜羽化出的个体，尽管这与耐热性差异并不对应。此外，对于燕麦蚜茧蜂和菊小长管蚜茧蜂，观察到雄性和雌性寄生蜂在体型上存在显著差异，尽管这再次与耐寒性差异不对应。有人认为，通过寄主操控进行的潜在行为体温调节可能会影响黄蜂所经历的热环境，从而影响黄蜂的耐热性，并且这样做可能会抵消生理耐热性或蚜虫寄主的任何影响。
