Applied Entomology and Zoology最新文献

Trunk injection is a relatively new, environmentally friendly method to apply insecticides to trees which does not cause insecticide drift and environmental runoff. However, little is known about the effect of insecticide trunk injection on non-target arboreal ants (Hymenoptera: Formicidae) which can act as biological control agents of target tree pests. This study evaluated the effect of trunk injections on arboreal ants found on cherry trees treated with neonicotinoids (dinotefuran and thiamethoxam) for controlling the invasive longhorn beetle Aromia bungii (Faldermann) (Coleoptera: Cerambycidae). Arboreal ants represented by Crematogaster matsumurai Forel can prey on A. bungii eggs. Results of visual sampling 1 and 3 months after injections showed that injections did not reduce the number of ant species occurring on tree trunks. Additionally, injections did not eliminate 3 of 4 most abundant species on tree trunks or extrafloral nectaries including C. matsumurai. However, a decline of Lasius japonicus Santschi was observed on injected trees. Our preliminary short-term survey suggests the possibility that chemical control by trunk injection and biological control by arboreal ants are compatible in A. bungii management. However, further research is needed to clarify the mechanism of L. japonicus decline and long-term consequences of trunk injection on arboreal ant composition.

Originally endemic to Asia, Drosophila suzukii (Matsumura, 1931) is a serious agricultural pest that is spreading rapidly throughout the world. To suppress the growing D. suzukii populations, several pest management programs have been implemented. Researchers have searched for natural enemies, such as predators, parasites, parasitoids, and pathogens. We discovered an obligate ectobiont fungus, Stigmatomyces majewskii H. L. Dainat, Manier & Balazuc, 1974, which is associated with D. suzukii. Our laboratory experiments revealed that S. majewskii infection was successfully transmitted through self-grooming and sexual contact during the courtship behavior of D. suzukii, although non-sexual contact through other behaviors may also be involved. Infected flies lived long enough for S. majewskii to mature on the host. Other fitness traits, such as fecundity, are necessary to evaluate the effect of S. majewskii on D. suzukii.

The gut bacteria of insects are associated with digestion, nutrition, and reproduction. The midgut bacteria of Anopheles mosquitoes have been examined predominantly for their effects on the transmission of Plasmodium parasites. However, the effects of midgut bacteria on Anopheles mosquitoes have not been studied. In this study, we investigated the effects of midgut bacteria on adult female An. stephensi mosquitoes. These mosquitoes were fed antibiotics mixed with 10% sucrose for 2 weeks to alter the composition of their midgut bacteria. The results showed that the mosquitoes fed with streptomycin (ST) or kanamycin (KM) showed inhibited egg maturation 2 days after blood feeding. Methylobacterium sp. was the predominant bacterium in the midgut of mosquitoes fed KM or ST for 2 weeks (ST/2 weeks). Mosquitoes that were fed suspensions of Methylobacterium sp. isolated from the midgut of ST/2 weeks after blood feeding for 3 days showed inhibited egg maturation. Furthermore, egg maturation was inhibited in mosquitoes that were fed supernatant and precipitate obtained by boiling and centrifuging Methylobacterium sp. suspension. Thus, this study demonstrated that Methylobacterium sp. isolated from the midgut of An. stephensi mosquitoes after blood feeding inhibited egg maturation.

The insect integument, which consists mainly of chitin microfibrils and cuticular proteins, is an extracellular matrix that covers the entire external and some internal surfaces of the insect body and serves as a primary barrier against several environmental stresses. Using RNAi-mediated gene knockdown procedure, we performed functional analyses of three adult-specific cuticular protein genes, CPR4, CPR18, and CPR27, regarding their involvement in repelling chemical insecticides in the red flour beetles, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). The depletion of these CPRs produced adult phenotypes with malformed (wrinkled/dimpled) elytra as well as thinner and disorganized cuticle of abdominal sternite. After knocking down the CPR genes, the beetles were exposed to six types of neonicotinoid-class insecticides, and the short-term neurotoxic effects were evaluated. The knockdown of any of CPR genes, either singly or in combination, increased the beetles’ susceptibility to neonicotinoids compared to negative control beetles. The results suggested that CPR4, CPR18, and CPR27 have an indispensable role in organizing the insect integument structure that can regulate the penetration rate of xenobiotics such as neonicotinoid insecticides, presumably by helping built proper structural features of cuticular layer.

The concealed gall inducers represent a significant challenge for both study and control within the realm of pest management. Gaining an understanding of the natural enemies that influence gall inducer populations is essential for the development of effective integrated pest control strategies. Haloxylon spp. are dominant xerophyte species that possess substantial ecological importance due to their roles in shelter provision and sand fixation. This study aimed to determine the main gall inducers that induce globular galls on both H. ammodendron and H. persicum and the parasitoid complex associated with them. Totally, two species of gall inducers and four species of parasitoids were obtained from the globular galls. Suaediola sp. was recorded as the predominant gall inducer, exhibiting biannual generational turnover. Both Torymus sp. and Mesopolobus quadrimaculatus were primary solitary koinobiont ectoparasitoids of gall midges, while only Platygaster sp. was endoparasitoid. Torymus sp. established dominance among the parasitoids, demonstrating a predilection for attacking first instar larvae. We also found that temperature variations significantly influenced the emergence and lifespan of the insects recorded from the galls, with a consistent trend of shortened wasp lifespan correlating with increasing temperature. According to these results, we conclude Torymus sp. could have an important potential to control gall inducers within closed galls and, therefore, should be considered for inclusion in the integrated pest management programs of Haloxylon forests in China.