Abstract: 　AIM: To observe whether there were any intra-species differences between Anopheles minimus from Hainan(H) and Yunnan(Y). METHODS: Anopheles minimus were collected from cattle shed on the spot. Each isofemale line was set up in the laboratory. Hybridization experiments were conducted by using forced mating between Anopheles minimus from Hainan and Yunnan ,for observing the reproductive ability of F1 hybrids.Ovarian nurse cell polytene chromosomes of F1 hybrid females were examined, to observe any synapsis in different zones of chromosomes.RESULTS: No embryo formation was found within the eggs produced by group Y♀×H♂, the hatching rate was zero. Low hatching rate was shown in other groups with (H♀×Y♂)F1, except for groups with (H×Y)F1×Y. Ovarian nurse cell polytene chromosomes from (H×Y)F1 hybrid females showed constant asynapsis at the 29th,36th and 37th zones in the chromosome 3R, and at the 4th and 6th zones in the chromosome X. CONCLUSION: Reproductive isolation did appear in An.minimus from Hainan and Yunnan.

Key words: Anopheles minimus, hybridization, polytene chromosome, sibling species