虎斑蝶实验种群生物学特征研究

Biological characteristics of an experimental population of the common tiger butterfly, Danaus genutia(Lepidoptera:Nymphalidae)

[目的]记述了云南元江虎斑蝶Danaus genutia(Cramer)种群的全虫期形态特征、幼期发育历期、在云南昆明温室中的代生活史和生殖力、寄主范围、成虫及幼虫的行为习性,为该高观赏价值蝶种的规模化养殖提供依据。[方法]通过在气候箱内单虫饲养观察个体发育史,建立温室实验种群收集种群生活史资料,结合实验种群和野生个体观察了解幼虫和成虫习性;根据成虫对多种植物的同时选择产卵、成虫对单种植物的顺序选择产卵及幼虫取食和发育情况判定幼虫寄主植物。[结果]在25℃恒温条件下,虎斑蝶从卵到成虫羽化历时22~27 d;在温室自然变温条件下(16.5~36.4℃),雌成虫从卵发育至产卵需35~40 d;成虫雌雄性比为1:1.26,单雌平均产卵量为64.84粒;虎斑蝶元江种群的唯一确认寄主为鹅绒藤属的两种植物,青羊参Cynanchum otophyllum和峨眉牛皮消C.giraldii。[结论]虎斑蝶元江种群中存在明显的体表色斑多态性,这种警戒色多态性可能是地理种群间基因交流的结果,也可能是种群内的稳定多态性,有待进一步研究;除了萝藦科鹅绒藤属的2种植物,其他多种被文献报道为虎斑蝶寄主的植物被证明非元江虎斑蝶种群的寄主植物。

[Objectives] To investigate the morphological characteristics, developmental duration, generation time, fecundity, and behavioral features, of immature stages and adults of Danaus genutia （Cramer）, collected from Yuanjiang county, Yunnan province. Some potential host plants reported in the literature were also investigated. [Methods] Life-cycle stages and duration of each stage were observed by rearing eggs, larvae and pupae individually in a climatic chamber. An experimental green-house population was founded to collect life history data. The behavior of larvae and adults were observed in both the green house and the field. Simultaneous choice, and sequential no-choice, experiments to determine adult oviposition and larval food preferences were conducted to identify likely host plants. [Results] At 25℃, the period from egg to adult eclosion was 22-27 days, whereas that from egg to oviposition was 35-40 days. The sex ratio of the experimental population was 1∶1.26 and the average fecundity was 64.84 eggs per female. Two plant species in the genus Cynanchum （Asclepiadaceae）; Cynanchum otophyllum and C. giraldii, were confirmed to be host plants of local Danaus genutia populations. [Conclusion] There are obvious morphological differences among the larvae of different geographic populations of D. genutia, polymorphism in larval color and pattern, and local host-plant specificity. Two species of Cynanchum were confirmed to be host plants of the local D. genutia population but there was no evidence that the other nine previously reported host plants are, in fact, host plants of this species.