Reproductive interference between Aedes albopictus and Aedes flavopictus at a place of their origin.

Aedes (Stegomyia) albopictus and Aedes (Stegomyia) flavopictus are related species that have overlapping distributions from southern to central Japan. To understand how they interact, we studied reproductive interference between them, particularly focusing on the body size difference between the mating pair. Here, we examined the effects of conspecific, heterospecific and double mating (i.e. heterospecific mating followed by conspecific mating) on copulation duration, egg production and hatchability of eggs using mosquitoes that varied in body size. Females mated only with heterospecific males produced few viable eggs, indicating that post-mating isolation is almost complete. When mated with heterospecific males before conspecific mating, the production of viable eggs was lower than when mated only with conspecific males, revealing the occurrence of reproductive interference. The degree of reproductive interference was larger in Ae. flavopictus than in Ae. albopictus when the female size was small but did not differ between them when the female size was large. Aedes albopictus females appear to be able to distinguish Ae. flavopictus males from conspecific males and larger females are more successful in the rejection of heterospecific males. On the other hand, Ae. flavopictus were not able to discriminate between conspecific and heterospecific males.

Mosquito immatures in drought-prone and drought-resistant bamboo stumps in Flores, Indonesia.

Mosquito species in water-filled bamboo stumps were compared with those emerged from dormant eggs in dry stumps. Tripteroides spp. was more abundant than Aedes (Stegomyia) spp. (mainly annandalei and albopictus) in water-filled stumps, whereas the latter was more abundant than the former in dry stumps. During 5 days after inundation, Aedes (Stegomyia) spp. developed faster than Tripteroides spp. Density of Tripteroides spp. was high in narrow and deep stumps. Both taxa of mosquitoes were at low densities in water-filled stumps with large detritivores (Tipulidae and Oligochaeta).

Mosquito and aquatic predator communities in ground pools on lands deforested for rice field development in central Sulawesi, Indonesia.

Aquatic habitats, mosquitoes, and larvivorous predators were studied on deforested lands in Central Sulawesi, Indonesia. Open ground pools, mainly in depressions made by the treads of bulldozers and other heavy equipment, were numerous but because of their small size, comprised ca. 1% or less of the total area of the deforested lands studied. The dominant mosquitoes in these pools were Anopheles vagus, Culex vishnui, Culex tritaeniorhynchus, and Culex gelidus. The 1st 2 species were dominant in clear pools, whereas the latter 2 species were dominant in turbid pools. The dominant metazoans other than mosquitoes were Crustacea, Ephemeroptera, and Chironomidae. Both aquatic and surface predators were abundant. Dominant among aquatic predators were Anisoptera and Zygoptera nymphs, Dytiscidae, and Notonectidae. These results are discussed in relation to mosquito control on deforested lands that transitionally but inevitably appear during the course of rice field development projects in Indonesia.