Imran Afzal

BACKGROUND: Cuticular microbial communities influence insect–pathogen interactions, yet their protective roles remain incompletely understood. These microbial defenses are critical in pest species like Bactrocera dorsalis , where microbial symbionts may shape resistance to biological control agents. RESULTS: We show that the cuticular microbiota of Bactrocera dorsalis enhances resistance to the entomopathogenic fungi (EPF) Beauveria bassiana and Isaria fumosorosea through dual immune and chemical mechanisms. Gnotobiotic assays demonstrate that specific bacterial isolates ( Microbacterium , Psychrobacter , and Staphylococcus ) promote host survival and defense by stimulating Toll/IMD signaling pathway and up‐regulating antimicrobial peptides (AMPs) such as defensin , attacin , and cecropin . In contrast, non‐cuticle‐associated bacteria ( Escherichia coli and Staphylococcus aureus ) failed to enhance survival and immune responses, indicating that protection is microbiota‐specific rather than a result of general bacterial exposure. In parallel, bacterial volatiles, such as phenol, indole, and eicosane, along with extracellular enzymes including chitinase, cellulase, protease, and lipase, suppressed fungal germination and hyphal growth. Importantly, these protective effects were found to vary with host age, indicating age‐dependent modulation of microbiota‐mediated defense. CONCLUSIONS: Our findings revealed that cuticle‐associated bacteria protect their host through complementary immune and chemical pathways. These microbiota act as an active barrier, and microbial metabolism interacts with host immune signaling. By distinguishing specific cuticle‐derived effects from non‐specific bacterial stimulation, this study highlighted the role of microbiota in modulating fungal susceptibility and supports their application in developing next‐generation biocontrol strategies in pest management. © 2026 Society of Chemical Industry.

Tephritid flies employ visual and chemical cues to locate and assess suitable habitats, food sources, mating sites, and ovipositional resources. Bactrocera dorsalis and Zeugodacus tau are economically significant pests that infest a wide range of fruits and fleshy vegetables. Understanding their visual sensitivity is crucial for developing effective and ecologically friendly management strategies. Thus, in this study, we compare the responses of these two species to various visual stimuli across laboratory, greenhouse, and closed-orchard environments. Our experiments reveal that, across the tested physiological states, both species exhibit a preference for certain wavelengths in the laboratory, particularly 520 nm and 560 nm. In the greenhouse, green and yellow models captured significantly more females of both species. Z. tau females showed greater sensitivity to the yellow model than B. dorsalis females. Additionally, Z. tau showed a higher affinity for both spherical and cylindrical shapes, while B. dorsalis flies were only attracted to the spherical model. In a closed orchard area, traps modified according to the best-performing combination used in the laboratory and greenhouse (shape and light) increased the capture counts of both species over time, with Z. tau exhibiting greater visual attraction sensitivity than B. dorsalis. These findings provide a theoretical and scientific foundation for improving trapping techniques targeting these two species.