性比调节机制是进化生物学的热点问题之一，这是由于性比是繁殖策略成功

与否的主要标准，并使生物的适合度得到衡量。适用于局域交配竞争理论(LMC)

的榕树榕小蜂系统成为研究性比理论良好的实验材料。在自然条件下，榕小蜂的

后代性比总是比局域交配竞争的性比理论预测值更低，即更加偏雌。出现该现象

与榕小蜂通过何种依据识别环境以调节其后代性比及其对性比调节的灵敏度有

关。那么，榕小蜂是否能自主调节其后代性比，以及其调节后代性比的依据是什

么呢？我们通过对榕小蜂进行生理解剖及野外实验尝试对性比的调节机制作进

一步研究，本文研究结论如下：

1、 解剖发现聚果榕榕小蜂 Ceratosolen fusciceps 的生殖系统主要由两个卵巢，

两条侧输卵管，一条主输卵管，一个受精囊及其附属腺体组成，受精囊中的

精子活力充足。

2、 依据自然条件下的平均进蜂量，通过同时放蜂及间隔放蜂实验，发现榕小蜂

入果的间隔时间对其后代总体性比并无显著影响，也说明榕小蜂并非通过识

别建群蜂数量来调整后代性比。但这两个处理间榕小蜂后代雌雄蜂数量有显

著变化，进蜂的间隔时间越长，榕小蜂后代数量越少，榕小蜂通过其调节机

制总是能使后代性比稳定在一定的范围内。

3、 榕小蜂能灵敏识别环境的变化并及时调整后代性比。将榕小蜂引入第二个榕

果的梯度实验发现小蜂具有性比调节重启机制，即当榕小蜂进入新榕果（资

源充足）时，又重新开始先产雄性后产雌性的产卵模式，且无论小蜂寿命长

短期性比调节重启机制始终发生作用。

4、 榕小蜂对环境变化的识别并非是通过产卵数量或传粉效率。不同的产卵数量

或传粉效率，榕小蜂后代性比没有显著性差异。

最后，我们主要讨论了已有的对性比调节机制的假说的有效性、产生性比调

节重启的原因，以及性比调控重启机制对环境的适应及进化地位。

The mechanism of sex ratio regulation is one of the heat fields in evolution

biology, because sex ratio is the main assessment of reproductive strategies and it

plays important role in measuring the fitness of organisms. Fig and fig wasp

mutualistic system meets the assumption of Local Mate Competition theory ( LMC),

which makes it an ideal material for sex ratio researches. Generally the sex ratio of fig

wasp in field study is lower than predicted, namely, more female-biased. The reason

of the more female-biased sex ratio remains unclear. It might probably attribute to the

way fig wasps assess the surrounding environment and how sensitive they are. To

explore the mechanism of sex ratio regulation, we conducted insect anatomy and field

experiments. Conclusions of our research are as followed.

1) Through anatomy, we found that the reproductive system of Ceratosolen fusciceps

included two ovaries, two lateral oviduct, a primary oviduct, a spermatheca, and

accessory glands. In spermatheca, the sperms are moving actively.

2) According to the investigation on the mean number of foundresses per fig, we

conducted fig wasps introduction experiment under different treatment

(introducing wasps simultaneously and sequentially). We found that interval time

of fig wasps entering the fig shows no significant impacts on the sex ratio of fig

wasps offspring, indicating fig wasp could not assess the number of foundresses.

But interval time has significant effects on the number of fig wasps offspring

however the sex ratio are stabilized.

3) Fig wasp can sensitively assess the environment and adjust the sex ratio of

offspring. We introduced fig wasp in a fig, and reintroduced it to another fig after

specific interval time. The results show that with the increase of the interval time,

the sex ratio of fig wasp offspring inclined, indicating that fig wasp could “reset”

the mechanism of sex ratio regulation. When the same fig wasp came across to a

new environment (with sufficient female flowers), they started the “oviposit male

first and female after” oviposition pattern over again, whatever the longevity the fig wasp had.

4) It is not through the number of egg the foundresses laid or the number of

pollinated flower that fig wasp assess the environment. Under different conditions

of egg-laid number or pollinated flower number, the sex ratio of offspring shows

no significant difference.

Finally, we mainly discuss the existing hypothesis of mechanism in sex ratio

regulation, the reasons generating “reset” mechanism of sex ratio, and the evolution

possibility of this “reset” mechanism and its adaptation to environment.