ABSTRACT
The eucoiline species Ganaspis brasiliensis (von Ihering) (Hymenoptera: Figitidae) is recorded for the first time in Argentina, with confirmation of parasitism of Drosophila suzukii (Matsumura) infesting healthy raspberry fruit (Rubus idaeus L. cv. "Heritage") still on the plant. Drosophila suzukii puparia were recovered from fruit collected in an organic farm in Tafí del Valle, Tucumán, Argentina. One G. brasiliensis specimen was obtained from an isolated D. suzukii puparium. An additional 83 specimens, deposited in the entomological collection of the Museo de la Plata, Argentina, were also identified as G. brasiliensis. This parasitoid species is distributed in four biogeographical provinces of Argentina. The specimens of G. brasiliensis collected in Argentina are assumed to belong to a worldwide distributed and generalist lineage, parasitizing several Drosophila species. A taxonomic key of known Ganaspis species from Argentina is provided.
Subject(s)
Hymenoptera , Rubus , Animals , Argentina , Drosophila , Fruit , Insect ControlABSTRACT
Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is an invasive alien species and a key agricultural pest. Its native parasitoids (Trissolcus japonicus Ashmead and Tr. mitsukurii Ashmead) have been registered in several countries where H. halys brought dramatic economic losses and where biological control is considered to be the most effective long-term solution. By searching for stink bug egg masses and exposing sentinel egg masses, we monitored the distribution of native and exotic egg parasitoids in Trentino-Alto Adige (Italy), an area where both the host and parasitoids are in expansion. We recorded ten pentatomids, seven parasitoid species, with the first report of Tr. japonicus in this area and a hyperparasitoid. In the assemblage, Anastatus bifasciatus (Geoffroy) and Tr. mitsukurii were the dominant parasitoids, with a different distribution in terms of context and host plants. Sycamore was the host plant where the highest number of naturally laid parasitized egg masses (26%) were recorded. Trissolcus mitsukurii showed the highest parasitism rate, and was often found in apple orchards. The emergence of exotic parasitoids showed a temporal delay compared to native ones. Sequence analysis of 823 bp of the CO1 mitochondrial gene revealed that the recovered Tr. japonicus and Tr. mitsukurii harbored one single haplotype each. These haplotypes were previously found in 2018 in Northern Italy. While sentinel egg masses proved to be very effective in tracking the arrival of exotic Trissolcus species, the collection of stink bug egg masses provided fundamental data on the plant host species. The results lend strong support to the adaptation of exotic Trissolcus species to the environmental conditions of the range of introduction, providing new information on plant host-associations, fundamental for the development of biological control programs.
ABSTRACT
Abstract Eucharitid wasps are exclusive parasitoids of ants and certain groups of eucharitids have specific associations with their hosts. This type of specificity is widely documented in more inclusive groups (subfamilies and/or genus-groups). However, we do not know if this specificity occurs in less inclusive groups (such as species or populations) or if it is more strongly influenced by local and/or regional environmental constraints. We provide a new association record between Pheidole gibba Mayr, 1887 and Orasema chunpi Burks, Heraty & Dominguez, 2018, while expanding their known distribution to the Brazilian state of Bahia.
ABSTRACT
The relative importance of phylogenetic affinity of hosts versus their ecological characteristics in determining the composition of their parasitoid complexes was examined using the parasitoid complexes of six species of frugivorous fruit flies from Central Europe. The hosts were four Rhagoletis and two other trypetine species, ranging in their relatedness from host races to members of different genera. They also differed in ecological characteristics, utilizing host plants of three different families, and developing either as pulp- or seedfeeders inside the host fruit. These features made it feasible to test the following pair of hypotheses. The ecological hypothesis predicts that ecological traits such as host-plant and fruit fly phenologies and host-fruit texture should be more important for the composition of parasitoid complexes than the taxonomic relatedness of the fly species. Assuming that ecological relationships do not parallel phylogenetic ones, the alternative phylogenetic hypothesis predicts the opposite. In fruit and soil samples, taken between 1983 and 1989, three guilds of parasitoids comprising 20 species were found: guild 1 - koinobiotic larval parasitoids (e.g. Opius spp., which attack the host larvae but develop inside the host puparia); guild 2 - idiobiotic larval parasitoids (e.g. Pteromalus spp., which consume the host larvae at once); and guild 3 - idiobiotic puparium parasitoids (e.g. Phygadeuon spp.). Although some results support the phylogenetic hypothesis, the majority of results support the ecological hypothesis.
