Journal of Applied Entomology最新文献

This study provides a first characterisation of the bacterial communities of Dacus vertebratus, a widespread agricultural pest of Cucurbitaceae in Tanzania. We sampled Tephritidae larvae from infested watermelons in seven sites in the Morogoro area subjected to either agroecological or pesticide-based farming. We explored possible microbial shifts promoted by agroecological or pesticide-based farming, as well as the functional prediction of the microbiome. All larvae collected were identified via DNA barcoding and subjected to 16S rRNA metabarcoding. The analysis of the microbial communities of 43 larvae of D. vertebratus produced 2552 filtered Amplicon Sequence Variants (ASVs) assigned to 22 phyla, 212 families, and 465 bacterial genera. More than 99.8% of ASVs belonged to 10 phyla; Bacteroidota (50.1%) and Proteobacteria (33.5%) dominated the community. The 10 most abundant bacterial families contributed to 88.4% of the ASVs, with Rhizobiaceae (30.78%) and Weeksellaceae (20.62%) being the dominant taxa. More than 75.4% of the ASVs belonged to 10 genera, with Sphingobacterium (15.2%) and Flaschrobactrum (14.2%) as the most abundant taxa. Our screening reveals that 14% of all microbiome functions of D. vertebratus are metabolic. Amino acid metabolism, carbohydrate metabolism, and metabolism of co-factors and vitamins are the most common pathways observed, representing 3.1%, 2.9%, and 2.3% of all metabolic functions. A more in-depth analysis of the functional profiles shows that peptidases, oxidative phosphorylation, and purine metabolism are among the highest contributors to the metabolic functions of the microbiome of D. vertebratus. We observed significant differences between the microbiome and the bacterial metabolic functions of D. vertebratus and other fruit flies feeding on watermelon (D. bivittatus, D. ciliatus, and Zeugodacus cucurbitae) in the Morogoro area. We did not detect substantial differences in the microbiome of D. vertebratus from agroecological or pesticide-based agriculture. Regardless, we cannot exclude that larger experimental setups might allow the detection of more subtle effects promoted by agricultural practices.

The cotton bollworm, Helicoverpa armigera (Hübner), is one of the significant economic pests of agricultural crops. In the current study, the nutritional indices and digestive enzymatic activities of H. armigera were assessed on 10 sesame cultivars (Barekat, Mohajer, Shevin, Chamran, Jiroft, Behbahan, Sistan, Dashtestan, Dezful and Hamidieh). Furthermore, specific phytochemical metabolites of sesame cultivars (protein, starch, lipid, phenol, flavonoid and anthocyanin) were evaluated to investigate their relationships with the nutritional and physiological responses of the pest. The results revealed that the efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD) and relative growth rate (RGR) values of H. armigera larvae were highest on Mohajer and Barekat. However, the related lowest amounts were obtained on Chamran, Jiroft and Dezful. The highest level of amylolytic activity in H. armigera larvae was detected on Jiroft, whereas the lowest activity was found on Mohajer. The larvae fed on Barekat, Mohajer, Dashtestan and Dezful exhibited the maximum proteolytic activities. Quantifying the biochemical differences of the studied sesame cultivars revealed significant variation. Furthermore, significant negative or positive correlations were found between the nutritional indices with enzymatic activities of H. armigera larvae or both of these traits with the chemical components of the tested sesame cultivars. The cluster analysis results revealed that Mohajer and Barekat were the most suitable cultivars, while Chamran, Jiroft and Dezful were nutritionally unsuitable for H. armigera. Our findings suggest that the selective use of certain sesame cultivars as potential sources of antibiosis against H. armigera could be incorporated into integrated pest management (IPM) programmes or used to screen insect inhibitors for developing genetically modified pest-resistant plants.

The Mediterranean fruit fly (Medfly, Ceratitis capitata Wiedemann) is established in Western Australia, where it attacks a range of cultivated fruits and vegetables. In a long-term study, the number of male and female flies was recorded in towns and surrounding orchards in Manjimup (1991–2022) and Pemberton (1996–2022). Implementation of whole orchard integrated pest management (IPM) strategies included the use of insecticide treatments based on action thresholds. The application of early season insecticide + protein spot bait treatments eliminated the need for pesticide cover sprays. Synchronisation of treatment times within the same week or fortnight across all orchards in each district improved Medfly control within an area-wide management (AWM) program. From the initial 1992 baseline of 12.04 flies/trap/day (FTD) in Manjimup town and 0.42 FTD in commercial orchards, numbers were reduced 4-fold in the town (2.82 FTD) and 18.5-fold (0.0230 FTD) in the orchards. In Pemberton town, the Medfly population was very low (< 0.01 FTD) while in the surrounding orchards, high-density trapping detected only 29 adult Medfly over 27 years, with several years of zero numbers. A major contribution to the success of AWM in the two towns and surrounding orchards was the continuing awareness programs on Medfly control funded by industry, government, and town councils. These findings are valuable for designing AWM strategies for Medfly where growers and townspeople are motivated to cultivate pest-free produce for domestic consumption and market access.

The big-eyed bug, Geocoris ochropterus Fieber, is a polyphagous predator. Although there have been many publications on the rearing of big-eyed bugs by using other insects, their ability to use flowers as a source of nutrition or habitat has not been previously reported. The diets included Zinnia elegans (A), 10% honey solution (B) ant pupae and Zinnia elegans (C), mealybug and Zinnia elegans (D) treatments at 10°C, 20°C, and 30°C. Significant differences in survival rates were observed among the diets when the nymphs reached the first and second instars at 10°C. Significant differences in growth and development indicators of big-eyed bugs were found among the treatments during the second, third, fourth and fifth moults at 30°C. Additionally, body size and dry weight of adult G. ochropterus grown on different diets were measured at 20°C and 30°C. At 20°C, male body size parameters did not significantly differ among the diets, except for head width. At 30°C, body length and dry weight of males showed significant differences among the diets, while head width and dry weight of females also varied significantly among diets. The study indicates that the combination of floral resources and diet can affect the development of G. ochropterus at different temperatures.

Despite the legal approval, the use of edible insects in food for dogs and cats is still limited and there are still some fundamental questions before the widespread application will kick off. This research focused on the nutritional value of yellow mealworms (YMW) and black soldier fly larvae (BSFL) reared, harvested, and dried in different ways. For YMW, standard rearing crates were harvested over different sieve meshes, dividing them according to width. For BSFL, differences were created by different rearing densities (10,000, 20,000, 30,000 and 40,000 per crate of 60 by 40 cm). Concerning the effect of drying methods on nutritional quality, 3 different techniques— hot air at different temperatures (60°C, 90°C and 120°C), freeze-drying, and microwave drying — were evaluated using proximate analyses and in vitro digestibility trials. For YMW, larvae smaller than 2.5 mm had a higher protein content than the larger larvae (p = 0.002); however, this was compensated by a lower dry matter (DM) digestibility (p < 0.001) due to a higher crude fibre content (p < 0.001). Nitrogen digestibility was very high regardless of size (97%–98%). For BSFL, the only significant differences were in higher DM (p < 0.001) of the biggest larvae (10,000 per crate). In contrast to YMW, the biggest BSFL had the lowest in vitro digestibility (only 48% for DM and 83% for nitrogen compared to 60% for DM and 86% for nitrogen for the smaller sizes (p < 0.001)). The drying methods had no big impact on YMW on DM (85%–88%) and nitrogen (96%–98%) digestibility values. For BSFL, digestibility of DM and nitrogen were 57%–66% and 93%–97%, respectively, with the lowest values for drying at 120°C.

Spodoptera litura (Fabricius) (Lepidoptera, Noctuidae), known for its ravenous feeding habits, is a polyphagous pest with a high reproductive rate, often developing resistance to most of the conventional insecticides, posing a substantial pest management challenge. Chlorantraniliprole (CTPR) is an anthranilic diamide insecticide, which is widely used against lepidopteran pests, including S. litura. Understanding the physiological and biochemical alterations associated with CTPR resistance is crucial for effective resistance management. Our research aimed to investigate the overall impact of CTPR on nutritional parameters, and biochemical and immunological responses in laboratory-selected susceptible (Unsel-Lab) and resistant (CTPR-Sel) S. litura populations. Results showed a reduction in nutritional parameters and digestive enzyme activity, with a more pronounced decline in the CTPR-Sel population. In contrast, detoxification enzyme activities (MFO, GST, EST, ACP and AKP), along with AChE, were significantly elevated, suggesting an adaptive response to CTPR exposure, with the CTPR-Sel population exhibiting a stronger detoxification capacity. Antioxidant enzyme assay indicated increased SOD activity but decreased CAT activity in both populations, reflecting oxidative stress. Immune response markers, including total haemocyte count, lysozyme and phenoloxidase activity, showed significant variations between the two populations, suggesting differential immune-physiological adaptations. These findings highlight the physiological trade-offs associated with CTPR resistance in S. litura and emphasise the necessity of integrated pest management strategies to mitigate resistance development.