Study On The Cold Hardiness And Thermal Tolerance Of Flies From Different Latitudes

Flies are important hygienic insects that carry many kinds of disease germ, so they can cause serious environmental pollution and threaten human beings'health. Insects are poikilothermal animals, therefore, temperature is considered to be a critical determinant of the geographical range of them. To study the difference of the cold hardiness and thermal tolerance of flies from different latitudes, in this paper, we mainly determined the difference of supercooling point (SCP), cold and thermal survival ability of Chrysomya megaclphala Fabricius, Lucilia sericata Meigen and Boettcherisca peregrine Robineau-Desvoidy collected from Hangzhou and Shenyang.Major research results were as follows: For C. megaclphala, the larva of the Shenyang population was cold hardier than the Hangzhou population. The cold exposure experiment of the pupa and the adult of the two populations showed that there was no significant difference between them. For B. peregrine, results of the cold exposure experiments of the larvae, pupae and adults of the two populations were consistent with the comparison result of the SCP, indicating that the Shenyang population had higher cold tolerance than the Hangzhou population. For L. sericata, cold tolerance of all stages of the Shenyang population did not have significant difference compared with the Hangzhou population. The thermal tolerances of C. megaclphala from Hangzhou and Shenyang were compared. Results indicated that the heat tolerance of larvae and pupae of the Hangzhou population was significantly higher than the Shenyang population. However, the heat tolerances of the two populations of B. peregrine didn't show clear difference between them. All of the results indicated that cold hardiness and thermal tolerance of flies not only related to geographic latitude, but also related to the kind of flies. So under the condition of climate warming, when monitoring the population emergence dynamic of flies, we not only need to set monitoring point at different sites , but also should consider the kinds of flies that appeared in the area.