Entomologia Experimentalis et Applicata最新文献

Predation exerts a profound influence on the evolution of camouflage and detection abilities in both predators and prey. For instance, flower-visiting spiders need to ensure their concealment when ambushing on flowers, which compels pollinators to check any spider cues cautiously before landing. Although numerous studies have examined the visual camouflage of spiders deceiving bees, little is known regarding whether spiders also employ olfactory camouflage. Additionally, the detection of spiders by dipteran insects is often overlooked, despite them being major non-bee pollinators. Here, we explored the detection ability of dipteran pollinators and the crypsis skill of spiders from both olfactory and vision perspectives using the housefly Musca domestica L. (Diptera: Muscidae) as prey, the crab spider Ebrechtella tricuspidata (Fabricius) (Araneae: Thomisidae) as predators and chamomile Matricaria recutita L. (Asteraceae) as substrates. Our olfactory experiments revealed that experienced houseflies could respond to and avoid spider odour. However, this response did not appear to be innate, as naive individuals showed no aversion. Moreover, experienced houseflies did not have any avoidance behaviours to the mixed odours of spider and flower, indicating that spiders achieved olfactory crypsis utilizing floral scent. Our vision experiments and visual modelling demonstrated that houseflies could detect spiders positioned on flower. Surprisingly, instead of avoiding them, houseflies exhibited a preference for flowers occupied by female spiders, suggesting the attractive nature of female spider colouration. This paper provides evidence for the first time that crab spiders use floral scent to achieve olfactory crypsis and proposes a potential yellow-signalling mechanism for crab spiders to attract insects.

Several European and North American countries have started releasing the Japanese knotweed psyllid, Aphalara itadori (Shinji) (Hemiptera: Aphalaridae), to control the Japanese knotweed, Reynoutria japonica Houtt. (Polygonaceae), and its relatives, which are among the worst invasive exotic plants. However, establishing populations of the currently released strains in the field has not been successful, desiring newly collected lineages. Moreover, little is known about the microbiome of the current strains, which potentially impacts properties as biocontrol agents. Hence, this study analyzed the microbiota of an A. itadori strain newly collected on Honshu Island, Japan, along with related species of the family Aphalaridae, using amplicon sequencing of 16S rRNA genes. The localization of symbionts identified in A. itadori was further analyzed using fluorescence in situ hybridization. The results demonstrated that the A. itadori bacteriome, a specialized organ for microbial symbiosis, maintains a dual symbiotic system with the primary symbiont “Candidatus Carsonella ruddii” (Gammaproteobacteria: Oceanospirillales: Halomonadaceae) and the secondary symbiont Sodalis sp. (Gammaproteobacteria: Enterobacterales: Pectobacteriaceae), suggesting that they are evolutionarily stable obligate mutualists for A. itadori. The central area of the bacteriome containing Sodalis comprised uninucleate bacteriocytes with nuclei larger than those of bacteriocytes harboring Carsonella. This observation contrasted previous reports on various psyllid lineages in which secondary symbionts are housed in a central syncytium with nuclei smaller than those of bacteriocytes for Carsonella. No known plant pathogens or parasitic manipulators of insect reproduction were identified in the analyzed A. itadori strain, indicating its suitability as a biocontrol agent, posing a minimum risk to the ecosystem. Besides distinct Carsonella lineages, Sodalis independently acquired by Craspedolepta miyatakeai Klimaszewski and an ambiguous Enterobacterales symbiont in Epheloscyta kalopanacis Loginova were identified. Only Carsonella was found in Togepsylla matsumurana Kuwayama. These results indicate repeated infections and replacements of bacterial symbionts during the evolution of Psylloidea, providing deeper insights into the microbe-psyllid interactions.

Black soldier fly larva (BSFL), Hermetia illucens (L.) (Diptera: Stratiomyidae), presents an attractive waste management solution that not only addresses the issue of waste but also generates alternative proteins and fats. Substrate quality and pre-treatment by fermentation may play a crucial role in waste reduction efficiency and larval quality. The aim of this study was to investigate the growth performance, waste reduction efficiency and nutritional composition of BSFL rearing using different ratios of coconut endosperm (CE) and soybean curd residue (SC) with pre-treatment by self-fermentation (F), fermentation with baker's yeast (Y) and without pre-treatment (C). Seven-day-old larvae were randomly separated into 15 experimental groups with three replicates. The experiment ended when the prepupae appeared. Based on the results, the larvae fed a diet with a high percentage of fresh SC exhibited the highest weight and growth rate, whereas the shortest development time was observed in larvae reared on Y. Pre-treatment of the substrate with fermentation proved effective in waste reduction. The nutritional composition of the larvae showed that the highest crude protein was produced in larva reared on fresh 100% SC, and the highest ether extract was found when fed CE at 100% with pre-treatment with F or Y. In conclusion, it is recommended to employ a fresh diet with a high SC content to optimise protein production, whereas a high level of CE with F or Y may be performed to obtain a high ether extract content. However, incorporating yeast fermentation with an SC content exceeding 25% provided high efficiency in waste reduction. Therefore, the selection of the ratio between CE and SC and of pre-treatment techniques depends on the producer's objective.

To be effective, a biocontrol agent must survive and persist in the same habitat as the target species and reduce target population growth. When multiple biocontrol agents are used against a single invasive species, they may each perform better under a subset of the habitat in which the target lives. This complementarity allows for a more consistent level of control and a higher resilience to environmental variability. Two species that feed on the same plant tissues would compete, but niche partitioning in the native range may be replicated when both species are introduced to the invasive range. When biocontrol agents are released, they may self-sort to perform best in their respective niches. We hypothesized that two biocontrol agents—Scotch broom seed beetle, Bruchidius villosus (Fabricius) (Coleoptera: Chrysomelidae) and Scotch broom seed weevil, Exapion fuscirostre (Fabricius) (Coleoptera: Brentidae)—that both feed on seeds of the invasive legume Scotch broom, Cytisus scoparius L. Link (Fabaceae), would be impacted differently by different weather conditions and plant traits, and would show different success rates at field sites with different conditions. We used a 5-year study to reveal that the two biocontrol agents are not uniformly distributed in the field and that weather and plant factors influence their success. We confirmed that weather conditions of the previous year influenced biocontrol agent attack rate and found that weather patterns at a field site may predict the impact of each biocontrol agent.

Factors that mediate insect herbivore sabotaging behaviour of host plant latex defences remain under debate. The most prominent hypothesis suggests that the anatomy of the host plant's laticifers determines trenching or vein-cutting behaviour, but there are inconsistencies in the literature. In addition to latex, other plant defences have been shown to affect plant natural enemies, but experimental studies comparing the effects of multiple defences on herbivore performance and behaviour are scarce. In this study, we investigated the anatomy of the laticifers of Calotropis procera (Aiton) W.T. Aiton (Apocynaceae), an exotic milkweed of southeastern Brazil, as well as the sabotaging behaviour of larvae of southern monarch, Danaus erippus (Cramer), and queen butterfly, Danaus gilippus (Cramer) (Lepidoptera: Nymphalidae) on this host plant. We also reviewed the sabotaging behaviour of larvae reared on the native milkweed Asclepias curassavica L. (Apocynaceae) from previous studies, as well as the description of the anatomy of its laticifers. As we found no correspondence between sabotaging behaviour of southern monarchs and queens and the anatomy of the host plants' laticifers, we tested whether structural defences of C. procera leaves (latex, waxes and trichomes) affected sabotaging behaviour and larval performance of southern monarch larvae. The structural barriers of this well-defended host affected larvae in different ways: Southern monarchs developed more slowly on control leaves than on leaves from which wax had been removed, and only latex removal reduced the frequency of sabotaging behaviour. Regardless of the defence removal treatment, frequencies of trenching behaviour decreased and vein-cutting behaviour increased as larvae developed. Overall, our results show that several factors in addition to the anatomy of laticifers affect sabotaging behaviour of southern monarchs and queens, including larval ontogeny, danaine species and latex outflow. This evidence suggests a behavioural plasticity in the sabotaging behaviour of larvae of both southern monarchs and queens.

Arthropods in the spotlight – identifying predators of vineyard pest insects with infrared photography – J. M. Reiff, K. Theiss, C. Hoffmann & M. H. Entling (https://doi.org/10.1111/eea.13456).

Artificial selection of zoophagous lines of the biological control agent Dicyphus hesperus - F. Dumont, M. Solà Cassi, M. Lemay & C. Provost (https://doi.org/10.1111/eea.13483).

The blister beetle Epicauta atomaria (Germar) (Coleoptera: Meloidae) is a phytophagous pest of various agricultural crops, especially in Amaranthaceae, Solanaceae, and Fabaceae. Currently, this insect is managed through the spraying of synthetic insecticides that cause serious human health and environmental damage. To reduce the use of synthetic insecticides, the integrated pest management (IPM) programs for other crop pests rely on the use of semiochemical compounds, such as pheromones, kairomones, and allomones, to manipulate the insects' behavior to prevent crop damage. However, studies on semiochemical compounds related to E. atomaria have never been carried out. For this reason, the aim of this study was to explore the chemical communication of E. atomaria. This includes the existence of (i) a sex and/or an aggregation pheromone, (ii) attractant volatile kairomones from host plants, and (iii) repellent volatile allomones from non-host plants. Tests were carried out using olfactometers and an experimental arena. First, olfactometer tests failed to show the existence of volatile sex and/or aggregation pheromones of these insects. Second, olfactometer and experimental arena tests failed to demonstrate attraction of E. atomaria via volatile kairomonal compounds from host plants (chard, bell pepper, and cock's-eggs). However, olfactometer tests showed that non-host plants of E. atomaria (thyme and lavender) emit allomonal volatile compounds with repellent activity. This work represents a first step toward the elucidation of the chemical ecology of E. atomaria and suggests that volatiles from non-host plants help shape the host preferences of these insects. Those volatiles could be used as a “push” component in a “push–pull” strategy against this pest.

The use of pathogens and other natural enemies to suppress pest populations is a key component of integrated pest management (IPM) strategies. As biocontrol agents may interact synergistically, additively, or antagonistically, it is crucial to assess their interactions for effective pest management. In this study, we investigated the effect of three entomopathogenic fungus (EPF) species—Beauveria bassiana (Bals.-Criv.) Vuill. CEP 091, Akanthomyces muscarius (Petch) Spatafora, Kepler & B. Shrestha CEP 182, and Cordyceps fumosorosea (Wize) Kepler, B. Shrestha & Spatafora CEP 315 (all Hypocreales)—on the survival, fecundity, and searching behavior of Orius insidiosus (Say) (Hemiptera: Anthocoridae). All three EPF species were found to be pathogenic to O. insidiosus, resulting in a significant decrease in survival compared with the control group. Fecundity remained unaffected by the fungal treatments. No effect of EPF on searching behavior of the predator was found. In relation to the searching behavior, individuals of 2 days post-infections remained in the food patch longer than individuals of 7 days post-infections, regardless of treatment. These findings provide valuable insights into the compatibility of EPF and O. insidiosus as combined biocontrol agents for managing whiteflies, aphids, and thrips. Understanding the interactions between EPF and predatory insects is crucial for developing IPM strategies that maximize pest control efficacy. Further studies should explore the long-term effects of EPF on O. insidiosus populations and their overall impact on pest management in agricultural systems.

Koinobiont parasitoids do not prevent host development immediately after the attack, hence the quality of their resource units may vary over time. Potential advantages exist, though less clear, of choosing a host of better initial nutritional quality. We studied the effect of host nutritional quality on Mallophora ruficauda Wiedemann (Diptera: Asilidae), a solitary, koinobiont ectoparasitoid that preferentially attacks larvae of Cyclocephala signaticollis Burmeister (Coleoptera: Scarabaeidae). In the field, lighter hosts were parasitized more often than heavier hosts, but sex did not explain parasitism patterns. Our experiments showed that parasitoid larvae did not differentially attack heavier or lighter hosts in either two- or four-choice selection experiments, but do show differential selection based on the size of the host. Experiments simulating a host patch showed that parasitoid larvae choose larger hosts, but at a finer scale, as the size of the hosts increased, larvae chose the smaller host in a dyad. These results suggest that M. ruficauda larvae may select hosts of higher nutritional quality (i.e., larger hosts) but that there is an upper limit where a trade-off between nutrient acquisition and survival (related to life expectancy or host defenses) may drive the larval decisions.