Evolutionary timescale of chalcidoid wasps inferred from over one hundred mitochondrial genomes

Chalcidoidea is one of the most biologically diverse groups among Hymenoptera.Members are characterized by extraordinary parasitic lifestyles and extensive host ranges,among which several species attack plants or serve as pollinators.However,higher-level chalcidoid relationships remain controversial.Here,we performed mitochondrial phylogenomic analyses for major clades(18out of 25 families)of Chalcidoidea based on 139 mitochondrial genomes.The compositional heterogeneity and conflicting backbone relationships in Chalcidoidea were assessed using various datasets and tree inferences.Our phylogenetic results supported the monophyly of 16families and polyphyly of Aphelinidae and Pteromalidae.Our preferred topology recovered the relationship(Mymaridae+(Signiphoridae+Leucospidae)+(Chalcididae+((Perilampidae+Eucharitidae)+remaining Chalcidoidea))).The monophyly of Agaonidae and Sycophaginae was rejected,while the gall-associated((Megastigmidae+Ormyridae)+(Ormocerinae+Eurytomidae))relationship was supported in most results.A six-gene inversion may be a synapomorphy for most families,whereas other derived gene orders may introduce confusion in phylogenetic signals at deeper nodes.Dating estimates suggested that Chalcidoidea arose near the Jurassic/Cretaceous boundary and that two dynamic shifts in diversification occurred during the evolution of Chalcidoidea.We hypothesized that the potential codiversification between chalcidoids and their hosts may be crucial for accelerating the diversification of Chalcidoidea.Ancestral state reconstruction analyses supported the hypothesis that gallinducers were mainly derived from parasitoids of gallinducers,while other gall-inducers were derived from phytophagous groups.Taken together,these findings advance our understanding of mitochondrial genome evolution in the major interfamilial phylogeny of Chalcidoidea.

Transgenic plants expressing the AalT/GNA fusion protein show increased resistance and toxicity to both chewing and sucking pests

The adoption of pest-resistant transgenic plants to reduce yield losses and de- crease pesticide use has been successful. To achieve the goal of controlling both chewing and sucking pests in a given transgenic plant, we generated transgenic tobacco, Arabidopsis, and rice plants expressing the fusion protein, AalT/GNA, in which an insecticidal scor- pion venom neurotoxin （Androctonus australis toxin, AalT） is fused to snowdrop lectin （Galanthus nivalis agglutinin, GNA）. Compared with transgenic tobacco and Arabidop- sis plants expressing AaIT or GNA, transgenic plants expressing AalT/GNA exhibited increased resistance and toxicity to one chewing pest, the cotton bollworm, Helicoverpa armigera. Transgenic tobacco and rice plants expressing AalT/GNA showed increased resistance and toxicity to two sucking pests, the whitefly, Bemisia tabaci, and the rice brown planthopper, Nilaparvata lugens, respectively. Moreover, in the field, transgenic rice plants expressing AalT/GNA exhibited a significant improvement in grain yield when infested with N. lugens. This study shows that expressing the AalT/GNA fusion protein in transgenic plants can be a useful approach for controlling pests, particularly sucking pests which are not susceptible to the toxin in Bt crops.

Expression and functional characterization of odorant-binding protein genes in the endoparasitic wasp Cotesia vestalis

Odorant-binding proteins(OBPs)are crucial in insect's olfactory perception,which participate in the initial step of odorant molecules transporting from the external environment to olfactory receptor neurons.To better understand the roles for OBPs in olfactory perception in Cotesia vestalis,a solitary larval endoparasitoid of diamondback moth,Plutella xylostella,we have comprehensively screened the genome of C.vestalis,and obtained 20 CvesOBPs,including 18 classic OBPs and two minus-C OBPs.Motif-pattern analysis indicates that the motifs of C.vestalis OBPs are highly conserved in Hymenoptera.The results of tissue expression analysis show that five OBPs(CvesOBP1/11/12/14/16)are highly expressed in male antennae,whereas six other OBP genes(CvesOBP7/8/13/17/18/19)are significantly transcriptionally enriched in female antennae.The results of RNA interference experiments for three most highly expressed OBP genes(CvesOBP17/18/19)in female antennae demonstrate that they are likely involved in parasitic processes of female wasps,as the wasps take a longer time to target the hosts when they are knoc ked down.

Effects of starvation on the vitellogenesis, ovarian development and fecundity in the ectoparasitoid, Nasonia vitripennis （Hymenoptera： Pteromalidae）

A female-specific protein, vitellogenin （Vg）, and its corresponding egg vitellin （Vt） are identified in the ectoparasitic wasp Nasonia vitripennis. Both native Vt and Vg have a molecular mass of about 350 kDa, which is composed of two subunits of approximately 190 kDa and 165 kDa under reducing and denaturing conditions （sodium dodecyl sulfate-polyacrylamide gel electrophoresis）. An indirect sandwich enzyme-linked immunosorbent assay developed with both monoclonal and polyclonal antibodies against N. vitripennis Vt. Vg was first detected in the hemolymph on the 10th day after parasitism, and was first observed in oocytes on the 12th day. In adults deprived of food, the highest hemolymph Vg level occurred at the time of adult eclosion and the highest level of Vt in ovaries was found at 30 h after eclosion. In contrast, feeding adults with 20% sucrose resulted in the reduction of Vt uptake by ovaries and the extension of life span, but had little effect on Vg production. Deprived of hosts, starvation of female wasps had no significant effects on ovariole growth and oocyte maturation before the wasps died. However, starvation of female wasps supplied with hosts accelerated the wasps laying progeny into hosts, but resulted in a decrease of total progeny production by comparison with wasps fed with 20% sucrose.

CLP gene family,a new gene family of Cotesia vestalis bracovirus inhibits melanization of Plutella xylostella hemolymph

Polydnaviruses(PDVs)are obligatory symbionts of parasitoid wasps and play an important role in suppressing host immune defenses.Although PDV genes that inhibit host melanization are known in Microplitis bracovirus,the functional homologs in Cotesia bracoviruses remain unknown.Here,we find that Cotesia vestalis bracovirus(CvBV)can inhibit hemolymph melanization of its host,Plutella xylostella larvae,during the early stages of parasitization,and that overexpression of highly expressed CvBV genes reduced host phenoloxidase activity.Furthermore,CvBV-7-I in particular reduced host phenolox-idase activity within 12 h,and the injection of anti-CvBV-7-1 antibody increased the melanization of parasitized host larvae.Further analyses showed that CvBV-7-1 and three homologs from other Cotesia bracoviruses possessed a C-terminal leucine/isoleucine-rich region and had a similar flinction in inhibiting melanization.Therefore,a new family of bracovirus genes was proposed and named as C-terminal Leucine/isoleucine-rich Protein(CLP).Ectopic expression of CvBV-7-1 in Drosophila hemocytes increased susceptibility to bacterial repression of melanization and reduced the melanotic encapsulation of par-asitized D.melanogaster by the parasitoid Leptopilina boulardi.The formation rate of wasp pupae and the eclosion rate of C.vestalis were affected when the function of CvBV-7-1 was blocked.Our findings suggest that CLP genes from Cotesia bracoviruses encoded proteins that contain a C-terminal leucine/isoleucine-rich region and function as melanization inhibitors during the early stage of parasitization,which is important for successful parasitization.

New species of gallwasps inducing in Quercus fabri and its inquiline(Hymenoptera: Cynipidae) in China

New species of gallwasps, Andricus flavus sp. nov., and its inquiline related to its gall, Saphonecrusfabris sp. nov. are described. Both species are included and illustrated their distribution and biology here. The type materials are deposited in the Parasitic Hymenoptera Collection, Zhejiang Agricultural and Forest University, Lin＇an, China, and University of Barcelona Barcelona, Spain.

Taxonomic review of East Palearctic species of Synergus section I, with description of a new species from China (Hymenoptera: Cynipidae: Cynipinae)

A taxonomic review is provided for the Section I of the inquiline gallwasp genus Synergus, including the description of a new species from China, S. deqingensis Pujade-Villar, Wang ＆ Chen sp. nov. and redescription of all previously known species of the section from the that region. Synergus jezoensis Uchida ＆ Sakagami, 1948, a species previously considered of uncertain status from Japan, is treated herein as a valid species, and is redescribed and reported for the first time from China. Andricus mukaigawae（Mukaigawa, 1913） and its inquiline, S. japonicus, are reported for the first time from China. A key is provided to all four East Palearctic species in Section I of Synergus.