Temperature dependence in locomotion of the parasitoid Aphelinus asychis (Hymenoptera: Aphelinidae) from geographical regions with different climates

In biological control, introduction of insect agents from regions with similar climatic conditions to those of the target host habitat have been an important consideration for successful implementation. Yet, there is little documentation of genetic variation in response to climate among natural enemy populations. In experiments on Aphelinus asychis Walker collected from China France, and Morocco for release against Diuraphis noxia (Mordvilko) in North America, the relationship between locomotion (i.e., mean and maximum walking speeds and proportion of time walking) and temperature did not differ among geographical regions with different climates. Mean and maximum walking speeds increased with temperature from 8.5 to 28.5 degrees C. Mean walking speed increased with hind tibia length, and because hind tibia length varied among geographical regions, it was used as a covariate in analyses comparing regions. Our results suggest that although locomotion depended on temperature, this dependence has not led to selection for adaptation to different temperature regimes. Thus, for mean and maximum walking speeds and proportion of time walking, insects collected from all 3 geographical areas were suited to the same climate.