ABSTRACT
Drosophila suzukii (Matsumura), commonly known as Spotted Wing Drosophila (SWD), is a worldwide serious economic threat to the production of berries and stone fruits. The chemical control widely used against this pest is often not able to preventing yield losses because wild flora offers an abundance of fruits to D. suzukii where the pest is able to reproduce and from where it recolonizes neighbouring cultivated fields. Alternatively, within Integrated Pest Management protocols for D. suzukii, biological control could play a key role by reducing its populations particularly in non-cultivated habitats, thus increasing the effectiveness and reducing the side negative effects of other management strategies. Because of the scarcity and of the low efficiency of autochthonous parasitoids in the new invaded territories, in the last few years, a number of surveys started in the native area of D. suzukii to find parasitoid species to be evaluated in quarantine structures and eventually released in the field, following a classical biological control approach. This paper reports the results of these surveys carried out in South Korea and for the first time in China. Among the parasitoids collected, those belonging to the genus Asobara Foerster resulted dominant both by number and species diversity. By combining morphological characters and the mitochondrial COI gene as a molecular marker, we identified seven species of Asobara, of which two associated with D. suzukii, namely A. japonica and A leveri, and five new to science, namely Asobara brevicauda, A. elongata, A mesocauda, A unicolorata, A. triangulata. Our findings offer new opportunity to find effective parasitoids to be introduced in classical biological control programmes in the territories recently invaded by D. suzukii.
Subject(s)
Biological Control Agents , Drosophila/classification , Hymenoptera/classification , Insect Control/methods , Predatory Behavior/physiology , Animals , Biodiversity , China , Crops, Agricultural , Drosophila/genetics , Food Chain , Hymenoptera/genetics , PhylogenyABSTRACT
Two new species of the genus Leptotrema van Achterberg, 1988 and one new genus of the Alysiinae from Mt Wilhelm, Madang Province, Papua New Guinea are described and illustrated. The distribution of the genus Leptotrema is extended to the Australasian region. Three new combinations are established Idiasta fulmeki (Fischer, 2010) comb. n. (=Microcrasis fulmeki Fischer, 2010), Apiasta postfurcata (Papp, 1966) comb. n. (= Microcrasis postfurcata (Papp, 1966)), and Leptotrema. bovefemora (Bhat, 1979) comb. nov. (=Aspilota bovefemora Bhat, 1979). The status of the genus Apiasta Wharton, 2002 (stat. n.) is reviewed. Keys are provided to enable their identification.
Subject(s)
Wasps/anatomy & histology , Wasps/classification , Animals , Female , Papua New GuineaABSTRACT
The family Trigonalyidae is considered to be one of the most basal lineages in the suborder Apocrita of Hymenoptera. Here, we determine the first complete mitochondrial genome of the Trigonalyidae, from the species Taeniogonalos taihorina (Bischoff, 1914). This mitochondrial genome is 15,927bp long, with a high A+T-content of 84.60%. It contains all of the 37 typical animal mitochondrial genes and an A+T-rich region. The orders and directions of all genes are different from those of previously reported hymenopteran mitochondrial genomes. Eight tRNA genes, three protein-coding genes and the A+T-rich region were rearranged, with the dominant gene rearrangement events being translocation and local inversion. The arrangements of three tRNA clusters, trnY-trnM-trnI-trnQ, trnW-trnL2-trnC, and trnH-trnA-trnR-trnN-trnS-trnE-trnF, and the position of the cox1 gene, are novel to the Hymenoptera, even the insects. Six long intergenic spacers are present in the genome. The secondary structures of the RNA genes are normal, except for trnS2, in which the D-stem pairing is absent.
Subject(s)
Gene Rearrangement , Genome, Mitochondrial , Hymenoptera/genetics , Animals , Base Composition , Base Sequence , Female , Gene Order , Genes, Insect , Genes, Mitochondrial , Molecular Sequence Data , Nucleic Acid Conformation , RNA/genetics , RNA, Mitochondrial , Sequence Analysis, DNAABSTRACT
Syconia of figs (Moraceae: Ficus spp.) harbour many wasp species, mostly belonging to several genera of chalcidoids (Hymenoptera: Chalcidoidea). In contrast, only two genera of Braconidae (Hymenoptera: Ichneumonoidea) with a few known species are found in syconia belonging to the subgenus Urostigma. The braconid fig wasps have an infrequent occurrence with low population density and are rarely encountered. Two new species, Ficobracon rhiknosus sp. nov. from figs of the subgenus Urostigma, and F. codonatus sp. nov. from figs of the subgenus Sycidium are described. Our previous experiments firmly support the suggestion that the Ficobracon species are parasitoids of non-pollinating chalcidoid fig wasps in the syconia.
Subject(s)
Ficus/parasitology , Host Specificity , Plant Diseases/parasitology , Wasps/classification , Animal Distribution , Animal Structures/anatomy & histology , Animal Structures/growth & development , Animals , Body Size , China , Female , Male , Wasps/anatomy & histology , Wasps/growth & developmentABSTRACT
PREMISE OF THE STUDY: Although many species in the orchid genus Coelogyne are horticulturally popular, hardly anything is known about their pollination. Pollinators of three species were observed in the field in Nepal. This information is urgently needed because many orchid species in Nepal are endangered. Whether the exudates produced by extrafloral nectaries played a role in protection against herbivory was also investigated. METHODS: Pollinators of C. flaccida, C. nitida, and Otochilus albus were filmed, captured, and identified. Ant surveys and exclusion experiments were carried out. To investigate whether pollinators are needed for fruit set, plants were wrapped in mesh wire bags. Inflorescence stems were examined with microscopy. Fehling's reagent was used to detect sugars in extrafloral exudates. KEY RESULTS: Coelogyne flaccida and C. nitida need pollinators to set fruit and are pollinated by wild bees identified as Apis cerana. Otochilus albus was found to be pollinated by Bombus kashmirensis. Extrafloral nectar was found to be exuded by nectary-modified stomata and contained high amounts of sugars. Different species of ants were observed collecting these exudates. A significant difference was found in damage inflicted by flower and leaf-eating beetles between C. nitida plants living in trees with ant nests and those in ant-free trees. CONCLUSIONS: Floral syndromes include scented and colored trap flowers without reward to their pollinators. All orchids investigated exude extrafloral nectar by nectary-modified stomata. This nectar was found to flow from the phloem to the stomata through intercellular spaces in the outer parenchymatous layer of the inflorescence.
Subject(s)
Herbivory/physiology , Orchidaceae/physiology , Pollination/physiology , Animals , Ants/physiology , Bees/physiology , Coleoptera/physiology , Inflorescence/cytology , Inflorescence/ultrastructure , Nepal , Orchidaceae/parasitology , Plant Exudates/metabolism , Plant Nectar/metabolism , Plant Stomata/physiology , Plant Stomata/ultrastructure , Species SpecificityABSTRACT
Olfactometer tests with Asobara tabida (Nees 1834), a larval endo-parasitoid of frugivorous Drosophilidae showed that females are attracted to the odour of host food: a suspension of living yeast. This attraction decreased as the fermenting medium grew older and became less likely to contain suitable host stages. Olfactometer tests with - what was considered to be - A. tabida from two different microhabitats (fermenting fruits and decaying plants) showed a genetically determined difference in microhabitat odour preference between the two microhabitat 'strains'. Each 'strain' preferred the odour of its own microhabitat. This odour preference was not modified by larval conditioning. Hybridization tests indicated that we were dealing with two sibling species: A. tabida and A. rufescens (Foerster 1862), reproductively isolated by a pre-mating isolation mechanism only. Enforced matings resulted in fertile female offspring. Some small morphological differences were detected. The two species live sympatrically, although each inhabits and is most attracted to its own microhabitat.