桔小实蝇和番石榴实蝇对6种寄主果实的产卵选择适应性

植食性昆虫对寄主植物的选择适应性是研究昆虫和植物协同进化关系的核心内容之一。评估寄主植物对植食性昆虫种群的适合度,需要综合分析昆虫对寄主的产卵选择性和寄主对昆虫的取食适合性。以桔小实蝇和番石榴实蝇为研究对象,分别测定了这两种实蝇对6种寄主果实:番石榴、香蕉、杨桃、木瓜、甜橙、番茄的产卵选择性以及幼虫取食后对其生长发育的影响。寄主产卵选择性实验分别采用完整寄主果实直接供试产卵和块状寄主果实气味引诱产卵两种处理方式;在生长发育适应性实验中,以幼虫和蛹的存活和生长发育等相关参数作为评价指标。实验结果表明,寄主的供试方式不同,两种实蝇的选择性均有明显差异;对寄主气味选择性强的寄主更适合于两种实蝇后代的生长发育。两种实蝇对6种寄主果实的产卵选择性和后代发育适合性两者相关性不显著,与许多文献报道单一地采用发育适合性(如发育历期、存活率或蛹重等)作为评价寄主选择性的结果不一致。两种实蝇之间对6种寄主果实的产卵选择和幼虫取食适合性既具相似性也具差异性,表明这两种实蝇在寄主生态位上既有重叠性又有分化性。

Oviposition preference and offspring performance of the oriental fruit fly Bactrocera dorsalis and guava fruit fly B.correcta (Diptera: Tephritidae) on six host fruits

The host selection and adaptation of phytophagous insects is a key issue in unravelling the interactions between plants and insects during their co-evolution.An integrative analysis of adult oviposition preference and the offspring's performance on host plants may provide useful information that aids in uncovering the mechanism behind these plant-insect interactions.In this paper, we report on the oviposition preference and offspring performance of two polyphagous fruit flies, Bactrocera dorsalis and Bactrocera correcta on six different host fruits, guava, banana, papaya, orange, tomato and carambola.Adult oviposition preference was tested by exposing adults to intact host fruit and by placing sliced fruit, to release the host odor, in egg collectors.The fecundity on each host was investigated.In feeding tests, parameters, such as larval and pupal development, and survival, were used to evaluate suitability of the feeding fruit fly to the host fruit.The results showed that the selectivity of oviposition on the six host fruits was significantly different regardless of whether the adult was exposed directly to intact host fruit or only induced by the sliced fruit's odor from the egg collector.Guava was the most readily chosen host for oviposition by both B.dorsalis and B.correcta with oviposition rates of 53.3% and 69.7%, respectively.The least chosen hosts for oviposition by these two fruit flies were papaya and tomato.A significant oviposition aversion to oranges was observed in the oviposition selectivity tests of both B.dorsalis and B.correcta, with very few or even no eggs laid directly on this intact fruit.In contrast, the highest oviposition preference was found in egg collectors containing sliced orange.For the host fruit guava and carambola, the oviposition rates of both B.dorsalis and B.correcta were higher on intact host fruit directly exposed to adults than on the same host fruit placed in egg collectors.In short, the same host fruit presented in different ways for oviposition can result in significantly different oviposition selectivity in both B.dorsalis and B.correcta.The feeding suitability of these two species of fruit flies on six different host fruits was significantly different.For B.dorsalis, the highest and lowest pupation percentages were observed on guava (87.3%) and tomato (52.7%), respectively.For B.correcta, the highest and lowest pupation percentages were observed on papaya (91.3%) and tomato (66.0%), respectively.The development period for both female and male flies was insignificantly different on all of the host fruits supplied, but the weights of the female pupae were heavier than those of the male pupae.For each fruit fly, developmental suitability indices indicated that the suitability of offspring was correlated with the strength of the olfactory response induced by the host fruit.However, there was no significant relationship between the oviposition selectivity rate and the offspring's developmental fitness and survival.This result corroborated previous reports in the literature.Furthermore, the oviposition preferences and offspring performances between B.dorsalis and B.correcta were similar in certain aspects, but not all, which indicates that the host ecological niches of the two fruit flies overlap to a certain degree.