Trichogramma japonicum Ashmead (TJ) is an important egg parasitoid used for biological control of the rice stem borer, Chilo suppressalis Walker. However, large-scale production of TJ relies on small eggs of Corcyra cephalonica (Stainton). Each C. cephalonica egg supports only a single parasitoid, which severely limits production efficiency. Although the large eggs of Samia ricini William Jones are parasitized by TJ, successful adult emergence does not occur. To overcome this limitation, we established two multiparasitism-based rearing systems using Trichogramma dendrolimi Matsumura (TD) or Trichogramma chilonis Ishii (TC) as helper parasitoids. We evaluated the effects of helper species, parasitoid ratio, and inoculation sequence on multiparasitism performance and assessed the biological fitness and performance of TJ offspring. A TJ-to-helper ratio of 4:1 was optimal for both systems. In the TJ-TD system, simultaneous inoculation showed the highest TJ emergence rate (58.95
Pesticides remain indispensable for crop protection, although their use continues to generate debate. Yet their ecological costs are often assessed using endpoints that emphasize survival while overlooking how insects perform and interact in the field. Sublethal effects on beneficial insects, including pollinators, parasitoids, and predators, may compromise ecological performance long before mortality becomes apparent. Among the most consequential but underappreciated effects are disruptions of olfactory systems and neural circuits that support odor-guided behavior, learning, memory, and decision-making. Growing evidence suggests that pesticide exposure can alter chemosensory signaling and neural processing, leading to impaired host and prey location, foraging, navigation, oviposition, and mating. These effects may culminate in functional mortality, a condition in which insects survive exposure but fail to provide effective pollination or biological control services. While previous work has examined sublethal toxicity, insect olfaction, or pesticide compatibility separately, fewer studies have considered how these processes interact across mechanistic, behavioral, and ecological scales. We argue that pesticides often act as information disruptors, and this perspective helps explain why compounds considered compatible based on survival alone may still undermine ecosystem services. To address this gap, we propose a tiered sensory-neuroecological framework for pesticide risk assessment and pest-management compatibility testing that integrates sensory, behavioral, and ecological endpoints with conventional lethality metrics. By linking sensory disruption to ecological outcomes, this framework provides a more realistic basis for evaluating pesticide selectivity and safeguarding the ecosystem services delivered by beneficial insects.
The rapid evolution of insecticide resistance threatens the long-term sustainability of crop protection by diminishing the effectiveness of existing agrochemicals and driving greater chemical inputs. Although nanocarrier-based formulations have been developed to improve pesticide performance, how resistance evolves under sustained exposure to nanopesticides remains largely unknown. To address this gap, we developed a clothianidin formulation enabled by mesoporous organosilica nanoparticles (Clo@MON). Using the brown planthopper Nilaparvata lugens as a model pest, we evaluated the insecticidal efficacy, resistance risk, and field durability of Clo@MON. Compared with conventional clothianidin, Clo@MON enhanced insecticidal activity, with a 1.90-fold synergistic effect, and provided more durable field control over two consecutive years. Continuous selection over 20 generations showed that Clo@MON significantly delayed resistance evolution, resulting in a 28.55-fold increase in resistance versus a 48.17-fold increase under clothianidin selection. This slower resistance evolution was accompanied by lower realized heritability and lower observed cross-resistance ratios to alternative insecticides. Clo@MON also showed comparable safety toward pollinators while reducing toxicity to representative natural enemies. Together, these findings indicate that nanocarrier-based formulation design can improve insecticide efficacy and slow resistance evolution while maintaining a favorable toxicity profile toward the tested non-target species.
Understanding the spatio-temporal dynamics of vectors is essential for developing effective management of Xylella fastidiosa, yet the landscape-scale population dynamics of its main European vector, Philaenus spumarius, remain poorly understood. Here, we investigated the spatial and temporal distribution of P. spumarius populations across five heterogeneous agricultural landscapes in Apulia (southern Italy) over two consecutive years. Juvenile and adult populations were monitored at the landscape scale (n = 168) in woody crops and unmanaged habitats to assess the effects of herbaceous vegetation, soil disturbance, and seasonality on their abundance. In addition, 111 plots were sampled along transects to test the role of habitat refugia (i.e. topographical depressions) on P. spumarius abundance during dry summer periods. In woody crops, nymph abundance was markedly lower in plots with recent soil management and showed positive associations with vegetation structure (height and cover) and vigour. In non-crop habitats, juvenile abundance was positively associated with plant species richness. Adult abundance declined sharply after emergence in most landscapes, with near-complete disappearance during summer followed by recolonization in autumn when herbaceous vegetation cover and vigour increased. Despite comparable initial juvenile populations across landscapes, persistent summer populations were only observed in the landscapes characterized by an extensive presence of unmanaged habitats and in proximity to mesic habitat refugia. Together, our results reveal context-dependent population dynamics shaped by local management and topographical conditions. These findings highlight the limitations of local control measures and the need to consider landscape heterogeneity and seasonal connectivity when designing strategies to limit X. fastidiosa spread.
The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is an anautogenous species that requires substantial protein and carbohydrate intake after eclosion to achieve sexual maturity; however, the gustatory sensory mechanisms underlying this transition remain poorly understood. In this study, we found that adult B. dorsalis exhibited age-dependent changes in feeding preference, shifting from sucrose preference during the early post-eclosion stage to amino acid preference during the middle stage and returning to sucrose preference during the later stage. Notably, sucrose deprivation caused high mortality, whereas amino acid omission impaired ovarian development and egg production in females. Two-choice assays revealed a preference for sucrose at the early and late stages (days 1–2 and 12–15), while amino acid preference predominated during the mid-stage (days 4–11). Candidate sucrose-associated receptors BdGR64a and BdGR64f were highly expressed in the proboscis immediately after eclosion, with expression patterns coinciding with sucrose feeding peaks, whereas BdIR25a and BdIR76b peaked later, in association with increased amino acid intake. RNA interference (RNAi)-mediated knockdown of BdGR64a/f significantly decreased sucrose consumption, and silencing BdIR25a/76b reduced amino acid intake and ovarian size in females. Sucrose restriction delayed the onset of sustained high amino acid intake and lowered BdIR25a and BdIR76b transcript abundance in the proboscis. This delay was accompanied by reduced transcript abundance of BdPI3K, BdTOR, BdIR25a, and BdIR76b. Furthermore, BdTOR knockdown reduced BdIR25a and BdIR76b transcript abundance and amino acid intake, indicating an association between BdTOR-related signaling, IR expression, and amino acid feeding. These findings support a working model in which sucrose availability is associated with BdTOR-related signaling and subsequent changes in IR transcript abundance and amino acid feeding. This working framework provides testable hypotheses for understanding the coordination between nutrient availability, gustatory receptor expression, and feeding behavior in insects.
