摘要：

To determine the likelihood of introgressive hybridisation between and , interbreeding experiments were performed. Of 240 trials involving 24 reciprocal crosses (ten trials per cross, ten virgin females and ten virgin males per trial) between three isolates and four isolates under conditions that allowed F1 hybrids to backcross with parents, 174 produced hybrid juveniles. The others failed to generate juveniles. Twenty trials in four crosses successfully established populations which persisted for 65.8-179.5 days, corresponding to 10-40 generations. Analyses of ribosomal DNA (rDNA) fragments for 20 hybrid-derived populations and analysis of inheritance mode of mitochondrial DNA indicated that three crosses produced populations whose members had the nuclear genome and or cytoplasm, whereas the remaining interbreeding produced populations in which 79% of members examined had the rDNA and cytoplasm and 17% had rDNA fragments of the two species. Populations composed of heterospecific cytonuclear individuals took longer to eat up mycelial mat in a rearing flask than others. Formation of a tail tip mucro in adult females, a characteristic of , was suggested to be controlled by nuclear and cytoplasmic genes. The results suggested that the introgression of genes into the genome was easier than introgression in the opposite direction.

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