樟叶蜂两性生殖与孤雌生殖方式下雌虫生殖适合度及子代生活史特征的比较

Comparison of female reproductive fitness and offspring life history traits between gamogenesis and parthenogenesis in the camphor sawfly,Mesoneura rufonota (Hymenoptera: Tenthredinidae)

【目的】樟叶蜂Mesoneura rufonota是危害樟树Cinnamonum campora的重要食叶性害虫,该虫的繁殖策略包括两性生殖和孤雌生殖两种模式。本研究旨在明确孤雌生殖在樟叶蜂生活史中的生物学意义。【方法】在室内25℃恒温条件下,测定并分析了樟叶蜂孤雌生殖和两性生殖两种生殖方式在亲代生殖适合度(雌虫寿命、产卵量和卵孵化率)和子代生活史(各虫态发育历期、死亡率、子代性比和产卵量等)特征上的差异。【结果】孤雌生殖的樟叶蜂雌虫寿命显著长于两性生殖的雌虫寿命,而雌虫产卵量和卵孵化率在两种生殖方式间均无差异。子代各虫态的发育历期和死亡率以及子代单雌产卵量在两种生殖方式间均无差异,但子代成虫性比在两种生殖方式间存在显著差异,表现为孤雌生殖大多产雄性子代,而两性生殖大多产雌性子代。【结论】樟叶蜂的孤雌生殖延长了亲代雌虫的寿命,且为产雄孤雌生殖。这些研究结果表明,樟叶蜂的孤雌生殖不但具有自身建群的能力,同时在种群繁衍中可以提供大量的雄虫以弥补两性生殖后代雄性个体的不足。

【Aim】The camphor sawfly,Mesoneura rufonota,is an important defoliator of the camphor tree Cinnamonum campora.The reproduction strategy of this insect includes gamogenesis and parthenogenesis.This study aims to clarify the biological significance of parthenogenesis in the life history of the camphor sawfly.【Methods】The differences in female reproductive fitness of M.rufonota including female adult longevity,fecundity and egg hatching rate and offspring life history traits including the duration of various developmental stages,mortality,sex ratio and fecundity of offspring between parthenogenesis and gamogenesis at the constant temperature of 25℃were determined and analyzed.【Results】The female adult longevity of M.rufonota was longer for parthenogenesis than for gamogenesis,while the fecundity and egg hatching rate were similar between the two reproduction modes.There were no differences in the duration and mortality of various developmental stages and the fecundity of female offspring between parthenogenesis and gamogenesis.However,significant difference was found in the sex ratio of the offspring between parthenogenesis and gamogenesis,being displayed by that parthenogenesis resulted in male-biased sex ratio,while gamogenesis resulted in female-biased sex ratio.【Conclusion】The parthenogenesis of the camphor sawfly prolongs the longevity of female adult,which has been confirmed as arrhenotoky.These results showed that parthenogenesis of the camphor sawfly not only makes it possible to establish population,but also can provide a large number of males to offset the insufficient male individuals in gamogenesis.