| Sericinus montelus is a medium-sized butterfly,which is an ornamental and economic insect.It is widely distributed in China as one of rare butterflies,but the number of its population was smaller.Its main hosts are aristolochic Aristolochia debilis S.et Z.and North aristolochic A.contorta Bge.In this paper,the mechanism of physiology and ecological adaptation about different geographic populations in S.montelus was firstly studied systematically.In addition,population genetic differentiations in S.montelus were analyzed by molecular biology.1 Effect of temperature and photoperiod on development of S.montelus in Wuhan areaThis butterfly could complete 6 generations in Wuhan.Within the range of 15-35℃combined with a photoperiod of 14L:10D,egg hatching,survival of larva and pupa was the highest at 25,25 and 20℃respectively.The developmental periods of eggs,larvae and pupae decreased significantly with temperature increasing.Optimal temperature for development ranged from 20 to 30℃.Sericinus montelus overwinters as diapause pupae,which belong to facultative diapause insect Its photoperiod response was short-day photoperiods,and the larval stage was photoperiodic sensitivity for diapause,illumination played important roles in the pupal diapause.Long days and high-temperature inhibit the incidence of diapause,but the pupal diapause of Sericinus montelus was induced by the short days,and the critical photoperiod for its induction was between 14L-10D and 12L-12D under conditions of 25℃.the diapause rate was about 100%in daily average illumination 8-12 h.in the conditions of short-day, there were diapause individual,but diapause rate was below 25%at 30℃.High-temperature and long daylight were propitious to diapause termination of pupal.The average period of diapause pupae was about 130.8 d at the temperature of 25℃and photoperiod of LD12:12,73 d at photoperiod of LD16:8,but between them at photoperiod of LD14:10,about 105.2 days.At the same time,there were greater heterogeneity to photoperiod in the population of diapause pupae,for diapause intensity induced at the temperature of 25℃was higher than at others and under LD6:18 and LD12:12 in the same conditions of temperature.2 Effect of photoperiod on metabolic reserves of pupae induced by diapauseUnder conditions of 25℃and photoperiod regimes(16L:8D,14L:10D,12L:12D, 10L:14D and 8L:16D),average developmental periods of larvae(less than 19 days)under long days were shorter than those(greater than 20 days)under short days.Dry-weights of feculae in the larval stage under short days were significantly greater than those under long days. Average weights of pupae obtained under short days were significantly greater than those under long days in terms of fresh and dry weight.However,the water content of pupae showed a reverse tendency.Average contents of lipoids of pupae obtained under short days were significantly higher than those obtained under long days except the female obtained under 8L:16D.Carbohydrate analysis revealed similar results except the male obtained under 8L:16D.No significant differences were found in the analysis of proteic substances.3 The EAG responses of Sericinus montelus adults to the extractions of Aristolochia debilis.The tests on the EAG responses of S.montelus adults to A.debilis showed that both sexes had EAG response to 6 extraction crudes.For males,the responses to 100ul by steam distillation extraction reached the highest level and the response values were significantly correlated with the dose of extraction,and was more intense than female.The difference of female EAG response values were not significant to any extract crude.4 Morphologic differences of different geographic populations in S.montelusThere was an obvious geographical differences among the population in seven different latitudes,latitudes more higher and temperature more lower,egg,larva,pupa and adult individuals gradually become smaller,the body color of larvae would vary from dark as night to black ash,hump with hair from red to yellow,the color of pupae gradually deepen,the back spike from yellow,orange yellow,brown,orange to dark brown.The stripe of adult did in the many- less- many spots process.5 Adaptation mechanisms of different geographic populations in temperature The optimum temperature of hatching eggs was at 28℃in the test range of 19-31℃. However there were significant differences to growth for the larvae among population,the north group(Zibo and Jiamusi were not optimum to the higher temperature,about 31℃, the population in Beijing could do to every temperature,Huaihua and Chibi populations kept constant temperature was worst,the optimum temperature of pupae was 25℃,but the Beijing population adapted to a wider temperature scope.Under the trial conditions,the development periods of eggs,larvae and pupae of Sericinus montelus would lengthened,which were collected with the latitude increasing. there are some differences among these groups,but not significantly.The developmental threshold temperature among different geographic populations were different,but their egg,larva and pupa would be higher gradually.The highest developmental threshold temperature among different geographic populations in Zibo,Jiamusi and Wuhan were 11.05℃,9.95℃;larval developmental threshold temperature showed an upward trend as borderline of Chibi not only lower latitude or higher.It was higher as increasing latitudes in their pupae,with the exception of Huaihua,the highest for the population of Jiamusi about14.94℃and lowest for Wuhan about 12.25℃.About the effective accumulated temperature among different geographic populations,larvae were higher than its pupae and egg,and eggs was minimum among them.There were not different on egg,but gradually increased with latitude increased,the effective accumulated temperature of larvae and pupae showed a downward trend as borderline of Fangxian not only reducing latitude or increasing.6 Diapause induction of photoperiod on different geographic populationsUnder the same light conditions,the high-latitude populations development periods were longer than low-latitude populations,and the development periods of larvae in long days were significantly shorter than in short days to the same species.Under the same light conditions,the pupal diapause rate of South population is less than the northern population, HH populations in the eight processing diapause rate did not reach 100%,JMS populations of non-diapause rate did not reach 100 percent.As the latitude increased,the critical photoperiod of JMS,HH,WH,FX,ZB,BJ also did,about 16h,12.46h,13.14h,13.28h, 14.19h,14.28,respectively. 7 Effect of diapause intensity butterfly pupae treated with its larvae by photoperiod and the role of low temperature on diapause terminationThe different Response of different geographic larvae to all Photoperiods were shown directly through the pupal diapause intensity,which the diapause intensity of South diapause pupae was lower than the northern one,and the eclosion time of population in low-latitude species was short and concentrated,but the high-latitude species was reverse.The effect of diapause period of diapause pupae treated with low temperature showed that the pupal diapause development periods of three geographic populations were all the shortest under 4℃low temperature for 15 days,and the emergence time of individual was concentrated.In the same treatment at 7℃,Beijing and Zibo population had been treated longer,the sooner and concentrated in the emergence time,exceptly fangxian population.8 Analysis of genetic diversity of S.montelus in different geographic populations in ChinaBy the material of total DNA,The mtDNACOⅡof seven Sericinus montelus geographcal populations was amplified,and we got the fragment length of 500bp.Through the sequence analysis of product,we built the genetic and evolutional tree.The results showed the southern populations of Huaihua,Wuhan,Fangxian and Chin districts are different with the northern populations of Shandong,Beijing and Jiamosi districts.The primary factor which results in the genetic differentiation is the geographical isolation. |
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