Geographic Variation Of Body Size And Immunoreaction Related In Eupolyphaga Sinensis

Eupolyphaga sinensis Walker (Blattaria) is an insect of medical importance. The high quality is required along with the market demand of it. However, the quality is different between populations. This paper focused on variation in body size, ootheca size, sexual dimorphism and antimicrobial peptides in E. sinensis among populations and we also showed the mechanism.A. Latitudinal shifts in body size in cockroach, Eupolyphaga sinensis (Blattaria)In the present study we investigated the geographic variation in body size of the Chinese cockroach, Eupolyphaga sinensis, which has a variable life cycle length. Adults collected from fourteen localities across temperate zone to subtropical zone in China were measured by using body length, body width and pronotum width and 10 variables were examined to test whether climatic factors affect body size. We found that the body size of E. sinensis varied considerably with latitude, demonstrating a U-shaped pattern. Cockroaches were larger at low and high latitudes, but smaller at intermediate latitudes. Thus the relationship between climate and body size conformed to a U-shaped pattern. Results indicate that two factors were significantly associated with body size clines: season length and variability in life cycle length with latitude. Our results also demonstrated that climate variables contribute to latitudinal clines in body size, which has important ecological and evolutionary implications. It can be expected that global climate change may alter latitudinal clines in body size of E. sinensis.B. Geographic variation in ootheca size along a latitudinal gradient from ChinaBody size has a considerable effect on offspring. In the first chapter, body size of E. sinensis varies with latitude and we expect that there is a relationship between ootheca size and latitude. We observed the colour of ootheca size and measured latitude-related ootheca size variation in field-collected E. sinensis individuals. We selected seven major collection locations that are the main distribution regions. We measured field-collected oothecas in terms of ootheca length, eggs per ootheca and crest numbers that are correlated with oothecas, and found that ootheca size demonstrated a U-shaped pattern with latitude, showing large size at low and high latitudes and small at intermediate latitudes. We conclude that there is clinal variation in ootheca size of E. sinensis and the variation is likely to be the result of maternal effect or local adaptation to environment. C. Effect of temperatures on development time and body size in Eupolyphaga sinensis along a latitudinal gradient from ChinaThe development of six population of Eupolyphaga sinensis were studied at 31℃in the laboratory. The relationship of the body length and the body width was the univaniate correlation of linear regression, which was extremely significance in the six population as well as the slopes (shape). The results showed that the duration of the nymph did not increased as the instar stage increased. The female developmental duration of Tianjin population was significantly greater than other populations, and there were no significant difference lies among the other populations except Jiangsu population. The male developmental duration of Tianjin was significant higher than the other five populations which had no significant difference. As far as the same population, the developmental duration of female was longer than that of the male. The results suggested that the six population had some difference in morphology and biology.We examined the effects of various temperatures (of 22,25,28 and 31℃) on development time, adult body size and pre-adult survivorship in three populations of the cockroach, E. sinensis, collected at different latitudes. We found substantial temperature-induced plasticity in development time, body size and pre-adult survivorship, indicating that developmental temperatures have strong impacts on growth and life history traits of E. sinensis. Genetic differences for development time, body size and pre-adult survivorship were detected among populations, and the three traits exhibited highly significant variations in the responses of different populations to various temperature conditions, indicating genetic differences among populations in terms of thermal reaction norms. We also found that two populations seem to support the beneficial acclimation hypothesis whereas the third mid-latitude population does not. The results are likely due to differences in season length and voltinism, indicating that not only temperature regime but also its interactions with generation time (and development time), voltinism, and season length are likely to have considerable effects on insect development time and body size. Overall, changes in development time, body size and pre-adult survivorship in E. sinensis can all be regarded as adaptations to changing thermal regimes.D. Variation in sexual size dimorphism among populations:testing the differential-plasticity hypothesisWe test the differential-plasticity hypothesis that sex-differential plasticity to environmental variables generates among-population variation in the degree of sexual dimorphism in this study. We examined the effects of rearing animals at various temperatures (of 22,25,28 and 31℃) on sexual dimorphism in four populations of the cockroach, Eupolyphaga sinensis, collected at different latitudes. We found that females were larger than males at all temperatures and the degree of this dimorphism was largest at the highest temperature (31℃) but smallest at the lowest temperatures (22℃). There is variation in the degree of sexual size dimorphism among population (sex×population interaction), but differences between the sexes in their plastic responses (sex×temperature interaction) were not observed for body size. Our results indicated that sex-differential plasticity to temperature was not the cause of differences among populations in the degree of sexual dimorphism in body size.E. Antimicrobial peptides and antimicrobial mechanisms of Eupolyphaga sinensisWe have confirmed that body size varied among populations along latitude. Body size is considered as one of the most important traits of an organism, because it influences nearly every aspect of the biology of the organism, especially in immunoreaction. Are antimicrobial peptides different among populations in Eupolophyga sinensis? Antimicrobial peptides were isolated from the E. sinensis by a four-step protocol including one step Sephadex G-50, one step Sephadex G-25 and two steps of RP-HPLC. We found that there seem to be no difference in antimicrobial peptides among populations. The antimicrobial mechanisms were also investigated. They may exert their antimicrobial functions by various means, including forming lamellar mesosome-like structures, and peeling off the cell walls, forming pores.