Interspecific competition in Trichopria anastrephae parasitism (Hymenoptera: Diapriidae) and Pachycrepoideus vindemmiae (Hymenoptera: Pteromalidae) parasitism on pupae of Drosophila suzukii (Diptera: Drosophilidae)

Implications of the Niche Partitioning and Coexistence of Two Resident Parasitoids for Drosophila suzukii Management in Non-Crop Areas

“…Similarly, mass releases of T. drosophilae in berry crops at Colima and Jalisco, Mexico, reduced SWD populations by 50 to 55% [ 66 ]. Given the contrast between the field findings of the current study and those from both laboratory [ 25 , 31 ] and semi-field [ 59 , 61 ] studies, it is relevant to assess Argentinian population lines of both pupal parasitoids under lab conditions. This would enable a comparative assessment of P. vindemiae and T. anastrephae as biocontrol agents of D. suzukii by determining host preference, regulating offered host densities, and analyzing the interspecific competition.…”

“…That is, given a competitive interaction with T. anastrephae for the resource, P. vindemiae probably faces a disadvantageous situation. Laboratory trials previously reported by da Costa Oliveira et al [ 25 ] showed that T. anastrephae from the Brazilian population lineage was competitively superior to P. vindemiae , and achieved substantially higher levels of parasitism in SWD puparia when the two parasitoids interacted with each other. Similar results were also reported in interspecific competition studies between T. drosophilae and P. vindemiae under lab conditions [ 31 ] or in semi-field trials [ 59 ], where P. vindemiae only achieved the highest parasitism when released alone.…”

“…However, laboratory establishment of the population lines of both pupal parasitoids tested in the current field study is foreseen as a later research step. In this context, studies with Brazilian population lines of T. anastrephae and P. vindemiae lab-reared on SWD puparia showed a significant prevalence of the former parasitoid species over the latter in terms of parasitism and adult emergence rates [ 25 ]. Similar findings were reported by Wang et al [ 31 ], who found a strong predominance of lab-reared T. drosophilae over lab-reared P. vindemiae as a parasitoid of both D. suzukii and D. melanogaster .…”

“…Among all these species, two pupal parasitoids, Trichopria anastrephae Lima (Hymenoptera: Diapriidae) and Pachycrepoideus vindemiae Rondani (Hymenoptera: Ptromalidae) are commonly abundant, and are often found foraging in search of host puparia on the same fallen fruit [ 16 ]. The diapriid T. anastrephae , native to South America [ 24 ], is a pupal endoparasitoid whose female lays the egg into the hemocoel of the host fly pupa [ 25 ]. In contrast, the cosmopolitan P. vindemiae not only attacks a wide range of dipteran species but is also a pupal ectoparasitoid, because the female lays the egg inside the space between the puparium shell and host pupal body [ 26 ].…”

“…Both P. vindemiae [ 31 , 32 ] and T. anastrephae [ 33 , 34 ] can be successfully lab-reared on SWD puparia and have shown high potentials as D. suzukii biocontrol agents [ 21 , 22 ]. However, competitive tests, undertaken under lab conditions, between P. vindemiae and T. anastrephae [ 25 ], and also with the cosmopolitan Trichopria drosophilae Perkins [ 31 ], showed that both diaprid species out-competed the pteromalid. The studies above revealed the superiority of the two Trichopria species over P. vindemiae in intrinsic competitiveness and foraging efficiency.…”