Comparative transcriptomics of the pheromone glands provides new insights into the differentiation of sex pheromone between two host populations of Chilo suppressalis.

Reproductive isolation between different host populations is often based on intraspecific sex pheromone differences. The mechanisms underlying these differences have not been thoroughly elucidated to date. Previous studies suggested that Chilo suppressalis has differentiated into rice and water-oat host populations, and these two populations manifest clear differences in sex pheromone titer and mating rhythm.

Divergence in larval diapause induction between the rice and water-oat populations of the striped stem borer, Chilo suppressalis (Walker) (Lepidoptera: Crambidae).

Differences in diapause traits can result in the seasonal reproductive isolation of host plant-associated insect populations and thereby facilitate the population divergence. The striped stem borer, Chilo suppressalis, has two host plant-associated populations: rice population and water-oat population. Several studies have found evidence that seasonal reproductive isolation between these populations is at least partially due to interpopulation differences in diapause.

Difference in diel mating time contributes to assortative mating between host plant-associated populations of Chilo suppressalis.

Behavioral isolation in animals can be mediated by inherent mating preferences and assortative traits, such as divergence in the diel timing of mating activity. Although divergence in the diel mating time could, in principle, promote the reproductive isolation of sympatric, conspecific populations, there is currently no unequivocal evidence of this. We conducted different mate-choice experiments to investigate the contribution of differences in diel mating activity to the reproductive isolation of the rice and water-oat populations of Chilo suppressalis.

Thermal effects on development and adult longevity of endoparasitoid Chelonus murakatae Munakata (Hymenoptera: Braconidae).

The effects of temperature on the development duration and longevity of adult of Chelonus murakatae were studied under five constant temperatures including 22.5, 25, 27.5, 30 and 32.

Do differences in life-history traits and the timing of peak mating activity between host-associated populations of Chilo suppressalis have a genetic basis?

The development of host races, genetically distinct populations of the same species with different hosts, is considered to be the initial stage of ecological speciation. Ecological and biological differences consistent with host race formation have been reported between water-oat and rice-associated populations of Chilo suppressalis. In order to confirm whether these differences have a genetic basis, we conducted experiments to determine the extent to which various life-history traits and the time of peak mating activity of these populations were influenced by the species of host plant larvae were raised on.