Distribution, abundance and host association of two parasitoid species attacking frugivorous drosophilid larvae in central Japan

Abstract

Abstract. In central Japan Ganaspis xanthopoda and Asobara japonica commonly parasitize the larvae of frugivorous drosophilids, mainly in montane forests, and urban environments and small groves, respectively. These two parasitoids start reproduction about one month later than their host drosophilids, probably to avoid searching for hosts when host density is low in early spring. It is likely that the local variation in the abundance of these parasitoids and a temporal refuge for their hosts contribute to the persistence of this parasitoid-host community. The forest species, G. xanthopoda, parasitized at least three Drosophila species that are abundant in forests, supporting the hypothesis that parasitoids are better adapted to attack frequently-encountered host species. This parasitoid did not parasitize drosophilid species that are phylogenetically distantly-related to the three host species or less frequent in forests.Benefits of using such species as host would not exceed the costs of evolving virulence to them. Another parasitoid, A. japonica, parasitized various indigenous and exotic drosophilid species including those that it rarely encountered in the field. It is not clear why this species has such a wide host range.

Altitudinal patterns of abundances and parasitism in frugivorous drosophilids in west Java, Indonesia

“…In our previous studies on parasitoids attacking frugivorous drosophilids, on the other hand, the species diversity did not so much differ between the tropical, subtropical and temperate regions, and the parasitism rate was much higher in the tropics compared to the subtropical and temperate regions (Mitsui and Kimura 2010;Novković et al 2012;Kimura and Suwito 2012). On the other hand, no information is available on the altitudinal pattern of parasitism in drosophilid flies, although a number of references have been published on the altitudinal distributions and temperature adaptations of drosophilid flies in the temperate regions (Kimura et al 1978;Bächli 1979;Bächli & Burla 1992;Beppu et al 1996;Mitsui et al 2010). High-altitude temperate Drosophila species are usually heat-susceptible and are assumed to suffer high mortality in summer if they occur at low altitudes (Kimura et al 1994;Beppu et al 1996).…”

“…High-altitude temperate Drosophila species are usually heat-susceptible and are assumed to suffer high mortality in summer if they occur at low altitudes (Kimura et al 1994;Beppu et al 1996). In addition, some temperate species perform seasonal migration between low and high altitudes to avoid summer heat at low altitudes (Kimura and Beppu 1993;Beppu et al 1996;Mitsui et al 2010). In the tropics, however, there are few studies on the altitudinal distributions of drosophilid flies except for fragmental reports on their occurrence at different altitudes (Suwito et al 2002).…”

Development of Asian parasitoids in larvae Of Drosophila Suzukii feeding on blueberry and artificial diet

“…Consequently, there is an urgent need to revise the taxonomy of the G. brasiliensis complex as this taxonomic uncertainty may prevent its use for biological control. Asobara japonica and L. japonica are both known to attack D. suzukii and other Drosophila species in Asia Guerrieri, Giorgini, Cascone, Carpenito, & van Achterberg, 2016;Ideo et al, 2008;Mitsui & Kimura, 2010;Novković et al, 2011;Wachi, Nomano, Mitsui, Kasuya, & Kimura, 2015), but for these species too, the occurrence of biotypes or cryptic species, potentially showing different levels of host specificity, should be further investigated. Host range tests are currently underway with these Asian parasitoids and European Drosophila spp.…”

“…This involves cells of the insects' haemolymph that attach to the surface of a parasitoid egg or larva and then melanize to form a capsule, leading to the death of the parasitoid (Carton & Nappi, 1997). In D. suzukii's native range, larval parasitoids in the genera Asobara, Leptopilina and Ganaspis can successfully develop on the host (Buffington & Forshage, 2016;Daane et al, 2016;Kasuya, Mitsui, Ideo, Watada, & Kimura, 2013;Mitsui & Kimura, 2010;Novković, Mitsui, Suwito, & Kimura, 2011). In parasitoids of Drosophila spp., as in other systems, the success in host-parasitoid interaction and the evolution of this interaction are related to two major factors: (i) the immune response of the host and the virulence of the parasitoid (Poyet et al, 2013); (ii) host detection mechanisms at both long and short distances, which can be very different among parasitoids of Drosophila spp.…”

Prospects for the biological control of Drosophila suzukii

“…Although several species of D. suzukii larval and pupal parasitoids have been recorded in Japan (Ideo et al 2008;Mitsui and Kimura 2010;Kasuya et al 2013) only one parasitoid species has been found parasitizing D. suzukii in the new invaded areas (Rossi Stacconi et al 2013). Since the diversity of natural enemies tends to increase with residence time of the pest in an area (Cornell and Hawkins 1993), an increase in number of natural enemies involved in natural biological control of D. suzukii may be expected.…”