Effect Of The Overwintering And Biochemical Substances Of Carposina Sasakii Matsumura:A Simulation Study

Insects are highly successful animals inhabiting marine, freshwater and terrestrial habitats from the equator to the poles. As a group, insects have limited ability to regulate their body temperature and have thus required a range of strategies to support life in thermally stressful environments, including behavioural avoidance through migration and seasonal changes in cold tolerance. Also, in temperate and colder climates, the overwintering ability of many species is closely linked to the diapause state, which often increases cold tolerance ahead of temperature-induced seasonal acclimation. Importantly, even though most species can invoke one or both of these responses, the majority of insects die from the effects of cold rather than freezing. Most studies on the effects of a changing climate on insects have focused on processes that occur predominantly in summer (development, reproduction) and on changes in distributions rather than winter survival per se. For species that routinely experience cold stress, a general hypothesis would be that predicted temperature increases of 1℃ to 5℃over the next 50-100 years would increase winter survival in some climate zones. However, this is unlikely to be a universal effect. Negative impacts may occur if climate warming leads to a reduction or loss of winter snow cover in polar and sub-polar areas, resulting in exposure to more severe air temperatures, increasing frequency of freeze-thaw cycles. Therefore, the changes in insect overwinter caused by ongoing climate warming and their ecological consequences should be more concerned.By simulating the changes in temperatures within the Carposina sasakii’s microhabitats to describe the Carposina’s overwinter. The effect of warming winter on survival and unearthed and reproduction of the Carposina diapause larvae were studied at different stages of the process of winter. The effect of different induction temperatures on winter hardiness was studied. The main conclusions were showed as follows:(1) Late-summer and pre-winter climate warming has significant effects on diapause induction and the post-diapause development of Carposina. Late-summer and pre-winter temperature rose, Development rate of Carposina were increased. Unearthed time weren’t effected. Larvae survival decreased. Emergence time of adults was postponed.(2) Winter climate warming has significant effects on the overwintering and post-diapause development of Carposina. Winter cold phase temperature rose, all behaviors of Carposina were not significantly changed. These results suggest that Carposina winter low temperature range was extensive. That may be the result of long-term evolution and adaptation.(3) Spring climate warming has significant effects on the diapause termination and post-diapause development of Carposina. Spring temperature rose, Survival rate of Carposina was first down then up. Unearthed time was ahead. Unearthed peak reduced. Emergence of adults was first up then down. Longevity of adults was shortened. Reproductive declined.(4) Winter warming has significant effects on the diapause termination and post-diapause development of Carposina. Temperature throughout the year rose, the larval survival increased from 46.2% to 62.2%. But the difference was not significant. The pupal stage was shortened. Emergence of adults was in advance. Adult longevity is shortened. Fecundity of adults decreased. That reduced the number of second-generation population. These results suggest that winter high temperature was unfavorable in Carposina overwinter. That may be the result of long-term evolution and adaptation. Temperature rose, so early emergence and unearthed date is more concentrated. The dispersion of the population was reduced. If food was abundant, that was greatest harmful.(5) Alternating temperature has significant effects on physiological indices of Carposina diapause larvae. The supercooling ability (supercooling point, SCP; freezing point, FP) and the contents of water, fat and small molecules antifreeze substances of diapause larvae were investigated. The two-step alternating temperature did not affect diapause rates of C.sasakii under short photoperiod, all mature larvae from the fruit entered diapause. SCP and FP rose with daytime temperatures increasing and decreased significantly with the nighttime temperature 18℃ to 20℃ increasing; Water contents increased with daytime temperature increasing; Contents of fat decreased with nighttime and daytime temperature increasing. Glycerol contents decreased with nighttime temperature rising; Trehalose contents decreased with nighttime and daytime temperature increasing. Contents of Glucose decreased with nighttime and daytime temperature increasing. Contents of Erythritol and Inositol and Sorbitol were largely different under daytime or nighttime temperature.These results suggest that climate warming will has more complex effects on physiology and ecology development of insect. Climate warming may consequently affect the Carposina’s individual development and population growth. Results of this study provided us with valuable information on the effects of climate warming on Carposina’s dispersal and distribution within their microhabitats. The results are of great significance to field sampling and pest management.