母体亲缘关系在杨氏榕树金小蜂后代性比调节中的作用

The role of foundress relatedness in the offspring sex ratio of fig wasp Diaziella yangi (Hymenoptera:Pteromalidae)

局域配偶竞争(local mate competition,LMC)理论问世以来在很多方面获得了发展,其中一个观点就是相互作用的繁殖母体之间的亲缘关系越近,后代性比越低,即产生更多的雌性后代。本研究以西双版纳广泛分布的钝叶榕Ficus curtipes上寄生的非传粉小蜂杨氏榕树金小蜂Diaziella yangi为研究对象,研究在同一榕果上产卵的繁殖雌蜂之间的亲缘关系对后代性比的影响。处理1:在同一榕果产卵的2头繁殖雌蜂来自蜂源1号树的同一个榕果;处理2:在同一榕果产卵的2头繁殖雌蜂来自蜂源2号树的同一个榕果,处理3:在同一榕果上产卵的2头繁殖蜂分别来自1、2号蜂源树。实验结果却显示出与理论预测值不一致。实验结果中,具有姐妹关系的2头繁殖雌蜂的2个处理的后代性比分别为0.195±0.028和0.189±0.043;亲缘关系较远的2头繁殖雌蜂的后代性比为0.240±0.030;不同处理的后代性比并没有显著差异。说明杨氏榕树金小蜂没有识别相互作用的繁殖雌蜂之间的亲缘关系以及据此调整后代性比的能力,这与其他大量研究结果一致。

Local mate competition （LMC） theory had developed in many aspects, including that the offspring sex ratio should be more female-biased when the foundress oviposited with related females than with unrelated females. We studied the influence of relatedness of Diaziella yangi females oviposited on a fig on sex ratio of offsprings, which was a species of non-pollinator hosting on Ficus curtipes. Treatment 1 ： The 2 foundresses of D. yangi were from the same fig of maturing tree No. 1 ; treatment 2： the 2 foundresses were from the same fig of maturing tree No. 2 ; treatment 3 ： one foundress was from maturing tree No. 1, and the other one was from maturing tree No. 2. The experimental results, however, were not consistent with the predicted values. In the experimental results, the sex ratio of offsprings in two treatments with two foundresses of sister relationship were 0.195 ± 0.028 and 0. 189 ± 0.043, respectively; the sex ratio of offsprings produced by two foundresses of non-sister relationship was 0.240 ± 0.030; and there were no significant difference among the three treatments. The results suggest that fig-wasps have no capabilities of kin recognition and adjusting the sex ratio of offsprings accordingly, and this is consistent with many other studies.