Insects最新文献

Insect diapause and response to thermal stress are similar in the variety of manifestations. However, the influence of thermal shocks on the incidence of insect diapause has not been sufficiently studied. Our laboratory experiments showed that both cold (-10 °C) and heat (43 °C) shocks experienced for at least 20-30 min significantly reduced the incidence of facultative larval winter diapause in the insect egg parasitoid Trichogramma telengai. However, the patterns of these responses were substantially different. In particular, the peaks of the sensitivity to diapause-averting effects of heat and of cold shocks fell, correspondingly, on middle-stage (5 days of development at 15 °C) and late-stage (9-11 days of development at 15 °C) larvae. Heat shocks influence the incidence of diapause mostly via the changes in the initial proportions of diapause-destined and non-diapause-destined individuals, whereas the effect of cold shocks is mostly based on differential mortality (i.e., the difference in mortality among treatments of the same experiment) with better survival of non-diapause-destined individuals. These results elucidate the peculiarities of the interaction between stress and diapause, allowing us to specify the methods for Trichogramma mass rearing and storage.

Italian honey bees (IHBs, Apis mellifera ligustica) exhibit superior comb-building abilities compared with Chinese honey bees (CHBs, Apis cerana cerana), which often fail to fully utilize wax foundations, resulting in incomplete comb structures. The present study aimed to accelerate comb construction in CHB colonies using IHBs. In the experiment, IHB colonies, each with approximately 42,000 adult workers, required over four hours to construct a semi-drawn comb on CHB wax foundations. These semi-drawn combs were then transferred to experimental CHB colonies, where they were left to complete the comb-building process for an additional 24 h (4 + 24 h relay). In contrast, control CHB colonies were allowed to build combs on fresh CHB wax foundations for 28 h. The results showed that the combs built by CHBs in 28 h, those built by IHBs in 4 h, and the 4 + 24 h relay combs all shared a foundation size of 41.7 cm × 19.7 cm, with average thicknesses of 10.40 mm, 5.60 mm, and 12.20 mm, respectively. The average percentage of cells built in the 4 + 24 h relay combs was significantly higher than that in the 28 h combs. Additionally, cells in the relay combs were significantly larger and deeper than those in the combs built solely by CHBs. Although these findings prove that utilizing IHB colonies to form a base structure can enhance the efficiency of comb construction in CHB colonies, further research is needed to confirm the effects of 4 + 24 h operation on brood rearing and worker bee size.

Food-baited traps are an important part of early detection programs for invasive tephritid fruit fly species, as they are attractive to both sexes of all targeted species. Torula yeast borax (TYB) mixture is a standard food bait, but its longevity is limited (1-2 weeks). Synthetic food-based lures have been developed, including ammonium acetate, putrescine, and trimethylamine. However, the different formulations of these synthetic lures vary greatly in their attractiveness and longevity. Here, we present the results of field trapping in several Central and South American countries as well as Hawaii that compared captures of Ceratitis capitata, Anastrepha spp., and Bactrocera dorsalis in traps baited with torula yeast borax, which was replaced weekly, versus traps baited with newly developed vial-lures, which contained the same three components noted above and were not replaced over 6-10 weeks of trapping. In all countries, captures of C. capitata in vial-lure-baited traps were equal to or greater than captures in TYB-baited traps. However, the vial-lures attracted fewer B. dorsalis than TYB, and data were inconsistent for Anastrepha spp. The implications of these results for large-scale detection programs are discussed.

The increasing reliance of modern agriculture on honey bee (Apis mellifera) pollination has driven efforts to preserve and enhance bee populations. The cryopreservation of drone semen presents a promising solution for preserving genetic diversity and supporting breeding programs without live animal transport risks. This study aimed to evaluate a one-step dilution antibiotic-free drone semen slow-freezing protocol under field conditions with in vitro and in vivo parameters. Semen viability was tested by two different mixes of dyes, and both techniques gave similar results, showing a post-thaw viability drop of 37%. Virgin queens were inseminated either with fresh or frozen-thawed semen. Survival rates until egg-laying onset and female brood production were similar for both groups; however, colonies with queens inseminated with fresh semen were more likely to go into wintering. Results suggest that frozen-thawed semen can support viable queen insemination, with potential for female brood production even without antibiotics in the diluent. This study highlights the need for further refinement of cryopreservation protocols, particularly regarding semen quality and queen longevity, to improve the feasibility of cryobanking for Apis mellifera conservation and breeding.

Plant-based oils have a long history of use as insect repellents. In an earlier study, we showed that in a 10% concentration, geraniol, 2-phenylethl propionate, and the plant-based essential oils clove and cinnamon effectively protected from mosquito bites for over 60 min. To expand on this study, we reanalyzed our GC-MS data to identify the short organic constituents of these oils. We then used an arm-in-cage assay to test the repellency of different concentrations and combinations of these oils and pure compounds. We found a sigmoidal relationship between the complete protection time from mosquito bites and the concentration of these oils. The complete protection times we recorded for combinations of these oils suggest an absence of additive effects. The results of this study can inform the development of novel, effective, and plant-based insect repellents.

The gut bacterial community plays many important roles in the production of nutrients and digestion. Antheraea pernyi and A. yamamai (Lepidoptera: Saturniidae) are two traditional sources of human food, as well as being silk-producing insects. In the present study, the influences of rearing season (spring and autumn), silkworm species (A. pernyi and A. yamamai), and host plant (Quercus wutaishanica and Salix viminalis) on gut microbiota diversity were tested using Illumina MiSeq technology. We found that the bacterial composition and diversity of larvae reared in the autumn are elevated compared to those of larvae from the spring. Silkworm species played an important role in the gut bacterial community. Host plants also affected the diversity of the intestinal flora of the insects: the diversity of the intestinal flora of A. pernyi reared using S. viminalis was higher than those reared using Q. wutaishanica. Our findings provide insights into the gut microbial environment in edible insects.

This study aims to establish the pest management approach for pests of stored maize and determine the current control practices. Semi-structured questionnaires were administered to 77 smallholder farmers from 16 villages at King Sabata Dalindyebo local municipality in the Eastern Cape Province of South Africa. The results revealed that about 50% of the farmers had a formal education, the average farm size was 1 hectare, and they were predominantly cultivating yellow maize. Most farmers (57%) cultivated maize for human consumption, income generation, and livestock feeding. The results also showed that metal tanks tended to be the most preferred (81.82%) storage facility for storing maize. Furthermore, the study found that Sitophilus zeamais Motschulsky and Sitotroga cerealella (Olivier) were the major storage insect pests of maize. The storage pests were managed using synthetic pesticides (84.42%), namely aluminium phosphide. This pesticide is a solid formulation for generating gas phosphine for fumigation. The continued indiscriminate use of this pesticide in protecting stored maize in this region could be a health hazard to humans and may result in the development of pest resistance.

A new genus for the tribe Pseudotarsonemoidini of the family Tarsonemidae is established in order to accommodate undescribed mites associated with bark beetles in Mexico. The new, monotypic genus Ochyronemus, with the type species O. jaliscoe being diagnostically and phylogenetically closest to the derived Pseudotarsonemoides-Tarsobisulcus cluster of the Pseudotarsonemoidini, possesses an intermediate position between these two genera. Details of the morphology related to its genus-level affiliation, primarily tibiotarsal I claw and leg setation, are compared in the context of the other genera of the tribe.

Aggressive interactions between males are common when victors gain increased mating success but can result in severe injury or death for the defeated. Anastatus japonicus (Hymenoptera: Eupelmidae) is a solitary egg parasitoid of hemipteran and lepidopteran species. Here, we investigated lethal interactions between A. japonicus males and analyzed aggression behavior scaled with the male condition, number of competitors, number of presented females, and female mating status. The intensity of A. japonicus male aggressiveness increased with the number of competitors and the number of presented females but was not affected by male relatedness. The intensity and frequency of A. japonicus male aggressive interactions were greater when males competed for virgin females compared to mated females. Larger A. japonicus males won more contests than smaller males and honey-fed males defeated starved ones, where defeated males suffered the loss of appendages and/or died. Fighting appeared to be the norm in all-male groupings, regardless of the presence of females. A number of biological and ecological factors are deducted that likely contribute to the evolution of male aggressive behavior in A. japonicus.

This study focuses on the regulatory effects of genes encoding the juvenile hormone (JH) receptor methoprene-tolerant (Met) and transcription factor krüppel homolog 1 (Kr-h1) on the reproductive capacity of Coccinella septempunctata male adults. Met and Kr-h1 expression levels were analyzed in males fed on artificial diets with and without JH by quantitative real-time PCR, and the effects of Met and Kr-h1 on male reproduction were analyzed by RNA interference technology. Met transcription levels in 5- and 10-day-old males fed with a JH-supplemented diet were lower than those without JH. Kr-h1 expression in 5-day-old adult males was lower in diets lacking JH but was higher in 10-day-old males fed on a diet lacking JH. There were no significant differences in the testes sizes of male ladybugs injected with Met-dsRNA when compared to GFP-dsRNA; however, the testis volume of ladybugs injected with Kr-h1-dsRNA was smaller than those injected with GFP-dsRNA. After males were injected with Met-dsRNA and Kr-h1-dsRNA, the mean egg production by females decreased by 12.75% and 23.10%, respectively, at 20 d postinjection. Our results show that Met and Kr-h1 have important roles in regulating reproduction by directly affecting testes development in males and egg production in females.