Entomologia Experimentalis et Applicata最新文献

Hoverflies (Diptera: Syrphidae) provide valuable ecosystem services, such as pollination, to a large variety of wild and cultivated sexually reproducing plant species. In this study, we examined the diversity, number of visits, visitation rate and foraging time of hoverfly species in three main cucurbit crops (cucumbers (Cucumis sativus L.), watermelons (Citrullus lanatus (Thunb.) Matsum & Nakai) and squash (Cucurbita moschata D.)) in two agroecological zones (mountainous and plateau) of the Morogoro region in Tanzania, between March and July 2020. We recorded 801 hoverflies of 12 species, of which the most common were Toxomerus floralis (Fabricius, 1798) (37.7% of total records), Eristalinus megacephalus (Rossi, 1794) (25.3%) and Mesembrius caffer (Loew, 1858) (16.4%). Hoverfly diversity was significantly higher in watermelon and squash crops within the mountainous zone as compared to the plateau zone. Toxomerus floralis was the most frequent visitor across all crops and agroecological zones. Eristalinus megacephalus showed a higher visitation frequency than M. caffer in cucumber and watermelon in the mountainous zone. Visitation rates for E. megacephalus, T. floralis and M. caffer were markedly higher in the mountainous zone than in the plateau zone. Of all hoverfly species, T. floralis displayed the longest foraging times in the mountainous zone. Seasonality appeared to have no significant impact on foraging duration and number of flower visits. These findings provide a valuable baseline for understanding hoverfly diversity and foraging behaviour on cucurbit crops and serve as a crucial stepping stone towards a deeper understanding of hoverfly feeding behaviour and its implications for agriculture. Additional studies are required to describe the actual role in pollination of the hoverflies and the factors that may enhance their potential as pollinators of cucurbit crops.

Determining the movement characteristics under real-world conditions of insect pests, such as tephritid fruit flies, is critical to increase the effectiveness of detection, response, and control strategies. In this study, we conducted two experiments using harmonic radar to track wild-caught male Queensland fruit flies (Qflies), Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), a major horticultural pest in Australia. In Experiment 1, we continuously tracked individual Qflies, which were prodded to induce movement in a high-density papaya (Carica papaya, L., Caricaceae) field. We conducted Experiment 2 in a field with lower papaya density and tracked flies were allowed to move without disturbance. This latter natural movement experiment showed that Qflies move at a rate of (mean ± SE) 19 ± 3 m h⁻¹. In both experiments, overall and between-tree flight directions were found to be correlated with wind direction, whereas within-tree movement directions were not. Further, the effect of wind direction on fly trajectories varied by step distance but not strongly with wind speed, whereas step-distance distributions were consistent with Lévy walks (i.e., short random steps with occasional larger steps). Qfly movements were well fitted by two-state hidden Markov models, further supporting the observation that Qflies move differently within (short steps with random direction) and between (longer more directional steps) trees. Data on flight directionality, step distances, and movement speed determined in this study provide parameters that may help enhance current surveillance, control, and eradication methods, such as optimizing trap placements and pesticide applications, determining release sites for parasitoids, and setting quarantine boundaries after incursions.

Agroecosystems are frequently disrupted by aggressive management practices. In the case of alfalfa, regular cutting events during the season cause abrupt resource depletion, often leading to the spillover of insects into nearby areas. In this study, we assessed whether alfalfa populations of the polyphagous aphid Aphis craccivora Koch (Hemiptera: Aphididae) can utilize black locust and vetch, two common plants found near alfalfa fields, as alternative hosts following cutting events. We also determined the ability of these plants to act as A. craccivora reservoirs for the recolonization of alfalfa stands once regrowth occurs. To address these questions, we conducted host specialization trials involving host shifting in three different A. craccivora populations collected from alfalfa, black locust, and vetch. We recorded a comprehensive set of life history parameters using the two-sex life table procedure. The degree of host specialization varied among different A. craccivora populations. The alfalfa-origin population showed relatively good performance when shifted to either black locust or vetch, suggesting these plants may act as refuges for population rebuilding after cutting events, until alfalfa regrowth allows for recolonization. In contrast, populations originating from black locust or vetch performed very poorly on alfalfa, suggesting the colonization of alfalfa fields by these populations is unlikely. The mechanisms underlying host specialization in different A. craccivora populations and the observed differences in dietary diversity are discussed. This study provides valuable insights into the ecology of this insect in the most significant Spanish alfalfa-producing region.

Populations of pest insects can differ in their responses to resistant plants, which can significantly impact the durability of plant resistance. Differential fitness of populations of thrips Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) has been reported previously and other thrips species, such as Thrips tabaci Lindeman (Thysanoptera: Thripidae) and Thrips parvispinus Karny (Thysanoptera: Thripidae), may not be affected by plant resistance. In this study, we assessed the performance of F. occidentalis populations collected in the Netherlands on various Chrysanthemum accessions (Asteraceae) and characterized the genetic diversity of these populations. Analysis of the mitochondrial CO1 gene revealed five distinct haplotypes among F. occidentalis individuals from different populations, belonging to both the glasshouse and lupin strains. Significant differences in the development of thrips larvae (from the L1 to L2 stage) across five F. occidentalis populations on the five evaluated Chrysanthemum accessions were found. Two accessions, Chrysanthemum seticuspe (Maxim.) Hand.-Mazz. PB-MB133 and Chrysanthemum x morifolium Ramat. cv. Penny Lane, were consistently resistant, exhibiting low larval development for all F. occidentalis populations. We also examined the resistance of the Chrysanthemum accessions against T. tabaci and T. parvispinus. When comparing thrips larval performance on various Chrysanthemum accessions for the three thrips species, we found significant effects of plant accession, thrips species and their interactions on larval development. Penny Lane exhibited suppression of larval development for only F. occidentalis, whereas C. seticuspe PB-MB133 suppressed larval development of all three thrips species tested. Interestingly, C. seticuspe PB-MB132, previously identified as susceptible to F. occidentalis, suppressed T. parvispinus development, indicating that in C. seticuspe multiple mechanisms of resistance might be present. In conclusion, our findings demonstrate that thrips populations infesting Chrysanthemum differ in virulence, highlighting the importance of screening for resistance with multiple populations. Moreover, our study identified Chrysanthemum accessions exhibiting resistance against multiple thrips species.

Host plant quality is recognized to have a significant impact on the performance of herbivorous insects. Nitrogen, a fundamental element, plays a crucial role in plant life cycles, serving as a limiting resource for both plants and herbivores. Despite nitrogen-fertilized plants generally exhibiting enhanced nutritional content, responses to nitrogen variations remain non-uniform, depending on specific insect feeding guilds and the nature of herbivore–plant interactions. In the context of modern agriculture, fertilizers are essential for maintaining soil fertility and crop productivity. Focusing on corn, a fundamental crop in the American continent, heightened fertilizer input has significantly increased yields. However, the intricate relationship between pest behavior and fertilization practices necessitates elucidation. This study aimed to examine the effects of varying levels of nitrogen fertilization on the survivorship, developmental time, and performance of the corn leafhopper Dalbulus maidis (DeLong & Wolcott) (Hemiptera: Cicadellidae), a major maize pest and vector of the corn stunt disease. Bioassays were carried out under controlled conditions, and the vector was fed on maize plants subjected to three fertilization levels (100, 200, and 300 ppm). The results indicate that higher levels of nitrogen fertilization doubled the survival rate of nymphs and accelerated their development into adults. Additionally, adults that received high levels of nitrogen fertilization exhibited twice the longevity and fecundity. The reported findings could contribute to predicting the population dynamics of this crop pest and would enable rational decision-making when intervening for D. maidis control.

This study investigates the impact of light intensity on the physical defenses of sugar maple (Acer saccharum Marshall [Sapindaceae]) saplings and how these defenses affect interactions with insect herbivores. The study conducted at the Kenauk Nature Reserve in Quebec involved 12 sites representing both shaded and sunlit environments. Leaf traits, including thickness, specific leaf area (SLA), water content, and toughness, were measured from 216 leaves collected in 2021 and 40 in 2022. To explore herbivore interactions, we used two Erebid caterpillar species, the invasive spongy moth (Lymantria dispar (Linnaeus) [Lepidoptera: Erebidae]) and the native white-marked tussock moth (Orgyia leucostigma (J. E. Smith) [Lepidoptera: Erebidae]), in controlled bioassays that assessed caterpillar feeding preference and performance. The results revealed that sunlit leaves were significantly thicker and had lower SLA compared with shaded leaves across both years. While water content was lower in sunlit leaves in 2021, it showed no significant difference in 2022. Leaf toughness, measured only in 2022, did not significantly differ between sunlit and shaded leaves. Caterpillar feeding preference tests indicated that white-marked tussock moth caterpillars consumed more sunlit leaves, showing a significant preference for them. However, spongy moth caterpillars did not exhibit a significant preference. In terms of performance, white-marked tussock moth caterpillars had a higher survival rate and larger pupal mass on sunlit saplings in 2021. However, no significant differences were observed in laboratory feeding initiation assays with first-instar caterpillars in 2022. These findings suggest that trees' investment in sun leaves to maximize photosynthesis is not necessarily followed by increased defense against herbivory. This research contributes to our understanding of how environmental factors like light can shape plant defense strategies and impact insect herbivore dynamics in temperate forests.

Production insects are cultured by humans to yield an agent or product of (commercial) interest. Four main categories are as follows: insects produced for biological pest control, for sterile insect technique, for human food and animal feed, and for technical products and services. Trait selection in production insects refers to the choice of traits that are important for the insect producer, or it refers to the improvement of a production trait through insect breeding. This special journal issue comprises a series of articles on trait selection, dealing with the outcomes of selection programmes as well as the choice of traits to select. Although the traits of interest occasionally differ substantially between production areas, methodologies for trait improvement may overlap and results of studies will be informative across fields. In this introduction, we first discuss the main aspects of trait selection, and we briefly summarize all contributions to this special issue. Then we systematically review the literature on effect sizes and correlated responses of artificial selection for trait improvement in production insects. We finish with several general conclusions and recommendations for future research, based on our literature review as well as the articles in this journal issue.

The traditional methods of sourcing and semi-domesticating the African palm weevil Rhynchophorus phoenicis Fabricius (Coleoptera: Curculionidae) larvae persist among the inhabitants of Ghana. However, these methods produce only a small proportion of the market demand for the larvae in Ghana. A containerized system of producing larvae has been found to facilitate production for socioeconomic purposes, thereby enhancing the sustainable utilization of the larvae all year round. We evaluated the life history parameters of R. phoenicis on three different rearing protocols that used different agricultural by-products, container types, and number of adult pairs for production. The different protocols were laid out using the Completely Randomized Design (CRD) with 10 replications. The fecundity of the adults differed significantly among the protocols. The highest fecundity was recorded on Protocol 2 (145.50 ± 16.55), followed by control (98.50 ± 12.05), Protocol 3 (84.50 ± 9.50), and Protocol 1 (45.00 ± 11.58). Protocol 2 recorded the highest larval survival rate, followed by Protocols 1, control, and 3. Among the rearing protocols, the highest intrinsic rate of natural increase (rm) (days) and net reproductive rate (Ro) were observed in Protocol 2. The lowest mean generational time (T) was recorded on Protocol 2 (76 days) while the highest (92 days) was recorded on Protocol 3. Our findings showed that Protocol 2 supports fecundity, larval development, cocooning formation, and adult emergence. The adoption of Protocol 2 by smallholder insect farmers can contribute to the development of future commercial rearing systems for R. phoenicis larvae.

The zoophytophagous predator Dicyphus hesperus Knight (Hemiptera: Miridae) is effective in the biological control of whiteflies in greenhouses, but it can also cause damage to fruits and plants. Artificial selection on foraging behavior allows the development of more zoophagous lines that have the potential to be both more effective and less likely to cause damage. Moreover, highly zoophagous lines could affect other biological control agents through increased intraguild predation or competition. This study tests the biological control efficacy against tobacco whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) and damage by highly and lowly zoophagous lines of D. hesperus in tomato greenhouses. The effect of these lines on Encarsia formosa Gahan (Hymenoptera: Aphelinidae) parasitoid wasp populations was also tested. In cage tests, we introduced D. hesperus from lowly or highly zoophagous and non-selected lines. In half of the cage, E. formosa was introduced. The ability of predators and parasitoids to reduce B. tabaci populations was monitored for 12 weeks. Tomatoes produced were harvested and graded according to damage by D. hesperus. Highly zoophagous lines had a rapid and lasting impact on pest populations. Lowly zoophagous lines take longer to achieve the same level of pest control as highly zoophagous lines. Introductions of E. formosa also reduce populations, but without interacting with D. hesperus. Dicyphus hesperus did not affect E. formosa abundance. Lowly zoophagous lines generated higher proportions of damage. The results show that artificial selection based on zoophagy produces more efficient and less damaging lines in the greenhouse tomato crop. Over time, lines with low zoophagy compensated for low individual efficiency by increasing their numbers. Highly zoophagous lines are compatible with parasitoid wasps, which were little affected by D. hesperus.

Understanding the molecular mechanisms used by phytophagous insects to survive and feed on new hosts is key to explaining their mechanisms of range expansion and diversification. However, only a few Neotropical biological models have been used to understand these mechanisms. In this study, we investigated the differences in gene expression of the Neotropical phytophagous insect Anastrepha obliqua Macquart (Diptera: Tephritidae), the West Indian Fruit Fly, when feeding on three different host plant species under sympatric and synchronous conditions. Third-instar larvae of A. obliqua infesting red mombin (Spondias purpurea L.), mango (Mangifera indica L.), and carambola (Averrhoa carambola L.) were collected in two localities in southwestern Colombia. After assembling a de novo transcriptome, differences in gene expression between larvae infesting the three host species were established using a batch effect design, controlling the variability introduced by location. Sixty-four differentially expressed unigenes were identified among flies infesting the different hosts, with the greatest number of genes differentially expressed between red mombin and carambola. Digestive genes, such as alpha-amylases and serine proteases, were upregulated in larvae from red mombin compared with mango (six genes) and carambola (four genes), suggesting the response of A. obliqua to the nutritional composition in red mombin. Also, two genes related to immune system responses, glutactin and acidic phospholipase A2, were upregulated in mango compared to carambola. Notably, genes annotated as transposable elements (TEs) were consistently upregulated in larvae infesting carambola and mango compared to larvae infesting red mombin. This may suggest the activation of these TEs in acclimation or adaptation to new hosts. Based on our results, the main categories of differentially expressed genes in A. obliqua were serine proteases, detoxification proteins, and proteins associated with the regulation of gene expression. These results support the potential of A. obliqua to adapt to host plants and its qualification as a generalist species.