Entomologia Experimentalis et Applicata最新文献

This study investigated autodetection in female corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae), revealing that their sensitivity to conspecific pheromones is environmentally modulated. We developed an “ungrouped” rearing strategy to minimize pre-exposure. Electroantennogram recordings showed differential responses between ungrouped (naïve) and grouped (pheromone-pre-exposed) females, demonstrating female sensitivity to their own pheromones, influenced by environmental history. Behaviorally, autodetection elicited spacing behavior, most pronounced in naïve females. These findings highlight that pre-exposure can decrease peripheral sensitivity, a crucial consideration for laboratory studies and the development of effective pheromone-based pest management strategies that account for female behavioral adaptation.

Closterocerus coffeellae Ihering (Hymenoptera: Eulophidae) is a parasitoid with potential for application in biocontrol programs of the coffee leaf miner, Leucoptera coffeella (Guérin-Mèneville & Perrottet) (Lepidoptera: Lyonetiidae). Establishing a rearing method for this species is a crucial step in the development of new biological agent control strategies. The study evaluated various food sources to assess adult survival and examined the oviposition behavior of C. coffeellae on its host under laboratory conditions. Adult survival bioassays were conducted using the following food sources: a 10% honey solution (diluted in distilled water), Hibiscus sp. nectar, an artificial diet (water, agar, ascorbic acid, Nipagin, and honey), and a control treatment (no feeding). In the oviposition behavior bioassay, females with and without oviposition experience were selected and offered L. coffeella hosts of three sizes (2, 4, and 6 mm) for oviposition. Adult survival varied among females and males and among the food sources. Males exhibited higher survival rates when fed the artificial diet, whereas females demonstrated greater survival when offered the honey (10%). Females without oviposition experience exhibited the lowest number of searching events and the highest searching time on 4-mm mines, whereas experienced females showed a lower number of searching events and longer searching time when exposed to 6-mm mine. Under laboratory conditions, the females successfully punctured their hosts. The results of this study may be helpful the development basis for the development of a C. coffeellae rearing method that is suitable for implementation in biocontrol programs.

Invasive insects often feed on novel plant species related to hosts in their native range, including species of conservation concern. The lily leaf beetle, Lilioceris lilii Scopoli (Coleoptera: Chrysomelidae), a Eurasian pest of cultivated lilies, is one such invader first detected in Canada in 1943 that has spread throughout the Northeastern United States and Canada, reaching the Pacific coast by 2011. Although L. lilii is known to feed on nearly 100 plant species across several genera, it is unknown what hosts it will feed on in its new range. We addressed this knowledge gap with experiments of L. lilii on native host plants found in the Pacific Northwest, United States, where it is now well-established and has the potential for population expansion. We conducted oviposition and larval feeding trials with Calochortus tolmiei Hook. & Arn. (Liliaceae), Fritillaria affinis (Schult. & Schult.f.) Sealy (Liliaceae), Lilium columbianum Leichtlin (Liliaceae), and Prosartes hookeri Torr. (Liliaceae). Trials showed that female L. lilii oviposited on all hosts tested, and larvae fed on all hosts except P. hookeri. Larvae reared on L. columbianum performed similarly well to larvae that fed on the control lilies. Individuals were only able to be reared to the adult stage on L. columbianum and C. tolmiei, although survival rates were low for C. tolmiei. With numerous susceptible native Liliaceae species of conservation concern in the Pacific Northwest, the establishment of the lily leaf beetle may constitute a new threat to these already vulnerable species across broad regions.

Western bean cutworm, Striacosta albicosta (Smith; Lepidoptera: Noctuidae), is a major pest of corn and dry beans in its historic and expanded ranges in the North American western Great Plains and Great Lakes Region, respectively. In corn, S. albicosta ear feeding damage can significantly reduce yield and introduce avenues for secondary fungal infections. Management practices currently rely on transgenic crops expressing effective Bacillus thuringiensis (Bt) protein, of which only the VIP3A protein is effective against S. albicosta, and/or labor-intensive scouting and chemical control. However, limited research on biological control options for this critical pest has been conducted. This study identifies key trophic interactions between S. albicosta and predatory arthropods in corn fields. Field surveys identified a community of 21 predator taxa present in Nebraska corn fields where S. albicosta eggs and larvae were present. The most common taxa were as follows: Hippodamia convergens (Guérin-Méneville; Coleoptera: Coccinellidae), Coleomegilla maculata (De Geer; Coleoptera: Coccinellidae), Orius insidiosus (Say; Hemiptera: Anthocoridae), and green lacewings (Neuroptera: Chrysopidae). Additionally, molecular gut-content analysis via PCR confirmed the predation of S. albicosta by several well-known biological control agents, including H. convergens, O. insidiosus, C. maculata, and Chrysopidae larvae and adults. Coleomegilla maculata consumed more S. albicosta eggs and larvae than H. convergens in feeding trials, although egg consumption by C. maculata was unaffected by the presence of corn pollen, an important supplemental food for this species. Exploring the trophic interactions between S. albicosta and its predators will provide information necessary to improve conservation biological control for S. albicosta integrated pest management.

Phytozoophagous insects, whose diets mainly consist of plant resources, can also feed on animal resources. Within populations, individuals' diets may vary according to their food preferences. The environment and their genetics determine these preferences. The degree of prey voracity (zoophagy) is likely to influence the ecological interactions of individuals. In the case of crop pests, these ecological interactions determine their economic impact. This study aimed to measure the genetic variation in the degree of zoophagy of a phytozoophagous pest, the tarnished plant bug Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae). Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs were offered, as animal resources, to L. lineolaris individuals from 15 isofemale lines in a laboratory experiment, where individuals from each line did or did not have access to an alternative plant resource. The results indicate that tarnished plant bugs consume a significant quantity of E. kuehniella eggs per day and that this behaviour varies according to the availability of a plant resource. Additionally, the broad-sense heritability (H²) in zoophagy is significant, with an estimated 0.27. Moreover, highly zoophagous lines are less responsive to the availability of plant resources than lowly zoophagous lines. The results suggest that individuals within tarnished plant bug populations exhibit varying levels of prey consumption, which may indicate potential differences in trophic behaviour. However, the relationship between fitness and prey consumption in this phytozoophagous insect has yet to be established.

Interspecific competition among insect herbivores is widely regarded as a significant selection pressure that impacts the distribution, abundance, and structure of their populations. Facilitator-mediated interactions, such as mutualism, have the capacity to modify the dynamics of competition. Furthermore, temporal fluctuations have been demonstrated to modify the outcome of competition. This study reanalyzes data on competition for space between two phytophagous insects commonly known as scales, namely Toumeyella martinezae Kondo and González (Hemiptera: Coccidae) and Opuntiaspis philococcus Cockerell (Hemiptera: Diaspididae), considering the presence or absence of Liometopum apiculatum Mayr (Hymenoptera: Formicidae) (a mutualistic ant species of T. martinezae) and the associated effects on their population structures. A total of 27 Myrtillocactus geometrizans (Mart. ex Pfeiff.) Console 1897 (Cactaceae) plants were selected for the study, with the presence of the study insects. The plants were then classified into one of five conditions: (1) O. philococcus in the absence of competition; (2) T. martinezae in conjunction with the mutualistic ant, L. apiculatum, in the absence of competition; (3) T. martinezae without competition; (4) T. martinezae and O. philococcus in competition, with the mutualistic ant; and (5) T. martinezae and O. philococcus in competition, without the mutualistic ant. A photographic record was maintained for a period of 6 months, during which the population structure was determined according to the size of each individual scale. The total abundance and relative space appropriation for each scale species were then estimated. The study revealed variations in spatial occupation over time. Toumeyella martinezae occupied more space during the initial months of the study, whereas O. philococcus predominated toward the termination of the study period. Competitive interaction significantly affected the population structure, changing over time and between species. In conclusion, the competitive dynamics changed over time, and the presence of the mutualistic ant had a significant effect, allowing the two competitors to coexist.

Since its first report in Brazil in 1938, Dalbulus maidis (DeLong & Wolcott) (Hemiptera: Cicadellidae) has been considered a secondary pest for maize. However, this insect has now become a key corn pest and the main phytosanitary threat to production in Brazil due to its potential to transmit pathogens. This study investigates sustainable tactics for managing the corn leafhopper in an integrated field approach. We evaluated the potential synergistic effects between formulations based on entomopathogenic fungi and corn hybrids with varying resistance levels to maize stunt complex. Along with assessing the incidence and severity of diseases, we evaluated the corn leafhopper's infestation in symptomatic and asymptomatic plants and the correlation with the symptoms caused by the disease at various plant development stages. We studied the following management practices, comprising applications of (i) Beauveria bassiana Balsamo (Hypocreales); (ii) B. bassiana + Cordyceps fumosorosea Wize (Hypocreales); (iii) C. fumosorosea; (iv) Metarhizium anisopliae Metschnikoff (Hypocreales); (v) M. anisopliae + B. bassiana; (vi) chemical control (methomyl—positive control). Dalbulus maidis preferentially infested the low-resistance hybrid, and this hybrid plant also showed higher disease symptom scores. There was a significant interaction between control timing and pathogen incidence; this correlation occurred up to the V6 phenological stage. The combined management of M. anisopliae + B. bassiana and M. anisopliae (alone) resulted in a reduction in D. maidis infestation. We found lower disease scores when these treatments were applied. Our results showed that combining resistant hybrids with entomopathogens results in more productive harvests.

Gonatopus chilensis (Olmi) (Hymenoptera: Dryinidae) is a host-feeding parasitoid of delphacid planthoppers (Hemiptera: Auchenorrhyncha) with economic importance for maize crops. Several factors, including host acceptance, suitability, and defenses, significantly influence parasitoid–host dynamics and, consequently, the efficacy of parasitoids as biological control agents. Many biological attributes and traits of dryinids in general, and G. chilensis in particular, remain largely unexplored. This study aimed to evaluate the foraging behavior and effectiveness of G. chilensis and to identify biological factors influencing its performance when using the planthopper Delphacodes sitarea Remes Lenicov & Tesón (Hemiptera: Delphacidae) as hosts. Free-choice and non-choice tests conducted under laboratory conditions revealed that female G. chilensis could forage on host individuals ranging from the first nymphal instar to females of D. sitarea. Notably, the nymphal developmental stage of the host significantly impacted parasitoid effectiveness. Female parasitoids predominantly engaged in host feeding on small nymphs but preferred oviposition on larger nymphs and females. Furthermore, the size and likely the fitness of female parasitoid offspring increased with the instar or stage of the parasitized host. These findings suggest that the biological traits and effectiveness of G. chilensis are directly influenced by the developmental stage of the D. sitarea host.

Beauveria pseudobassiana S.A. Rehner & Humber (Hypocreales) and Metarhizium pingshaense Q.T. Chen & H.L. Guo (Hypocreales) are fungal pathogens that infect Phyllophaga larvae in the field. Previous laboratory bioassays showed less than 30% mortality in larvae inoculated with conidia of these pathogens, indicating strong resistance to fungal infection. However, injecting M. pingshaense blastospores directly into the larvae's hemocoel caused 100% mortality, suggesting external barriers may limit infection. As some insect-associated bacteria can provide protection against invading pathogens, we hypothesized that bacteria associated with Phyllophaga larvae might offer such protection. We isolated bacteria from the cuticle of Phyllophaga larvae, identified morphotypes based on colony morphology and determined their antagonistic activity against B. pseudobassiana and M. pingshaense. Selected bacterial morphotypes were identified using partial 16S rRNA gene sequencing. Based on antagonism results, eight isolates were selected and their effect on the germination of conidia from both fungal species was evaluated. Finally, the mortality of antibiotic-treated and untreated Phyllophaga polyphylla Bates (Coleoptera: Scarabaeidae) larvae was evaluated after inoculation with B. pseudobassiana and M. pingshaense. Of the 90 bacterial isolates obtained, all but two exhibited antagonistic activity against M. pingshaense, and 10 showed antagonism against B. pseudobassiana. Molecular analysis of selected morphotypes (62 isolates) revealed that the two most common genera were Acinetobacter (Moraxellales: Moraxellaceae) with 22 isolates and Serratia (Enterobacterales: Yersiniaceae) with 12 isolates. The remaining isolates were distributed among the families Flavobacteriaceae, Comamonadaceae, Enterobacteriaceae, Weeksellaceae and Pseudomonadaceae. Conidial germination of B. pseudobassiana was reduced to below 20% by most isolates, and only two allowed over 80% germination. For M. pingshaense, germination was suppressed to between 6% and 56% in most cases; only one isolate allowed 98% germination. When exposed to M. pingshaense, antibiotic-treated larvae showed 68% mortality, whereas untreated larvae had only 26% mortality. In contrast, mortality from B. pseudobassiana was statistically similar between treated (23%) and untreated (7%) groups. Overall, our results suggest that bacteria can provide protection against M. pingshaense but not B. pseudobassiana.