广西和云南两地微小按蚊的杂交试验

HYBRIDIZATION EXPERIMENTS USING ANOPHELES MINIMUS FROM GUANGXI AND YUNNAN

对广西和云南两地微小按蚊进行杂交试验。结果杂种F_1雌蚊都能育,卵巢发育正常。(Y×G)F_1雄蚊均不能育,其睾丸畸形胀大。(G×Y)F_1雄蚊虽能育,但睾丸略显萎缩,与亲本回交所产的卵孵化率均极低。杂种雌蚊卵巢营养细胞多线染色体的X染色体和常染色体均有不联会区段,以38区的不联会最为恒定。上述结果表明两地微小按蚊已出现不完全生殖隔离现象,有可能是微小按蚊复合体的两个亲缘蚊种。

Hybridization experiments were conducted by forced mating between Anopheles minimus from Guangxi (G) and Yunnan (Y).F1 hybrid females were all fertile with normally developed ovaries.(Y×G) F1 males were all sterile,with abnormally enlarged testes.(G×Y) F1 males,though fertile,showed somewhat atrophic testes,and when they were back crossed with parental females,the latter produced eggs with very low hatching rate.Ovarian nurse cell polytene chromosomes from F1 hybrid females showed partial asynapsis in X chromosome as well as in autosonles,asynapsis at 38 zone in 3L being the most constant.It was obvious that there was definite,though partial,reproductive isolation between An minimus from Guangxi and that from Yunnan.Whether they are sibling species remains to be further investigated (Figs.1-8).