A Chemosensory Protein Detects Antifeedant in Locust (Locusta migratoria)

Genetic mechanisms modulating behaviour through plastic chemosensory responses in insects

The ability to transition between different behavioural stages is a widespread phenomenon across the animal kingdom. Such behavioural adaptations are often linked to changes in the sensitivity of those neurons that sense chemical cues associated with the respective behaviours. To identify the genetic mechanisms that regulate neuronal sensitivity, and by that behaviour, typically *omics approaches, such as RNA- and protein-sequencing, are applied to sensory organs of individuals displaying differences in behaviour. In this review, we discuss these genetic mechanisms and how they impact neuronal sensitivity, summarize the correlative and functional evidence for their role in regulating behaviour and discuss future directions. As such, this review can help interpret *omics data by providing a comprehensive list of already identified genes and mechanisms that impact behaviour through changes in neuronal sensitivity.

Chemical Ecology and Olfaction in Short-Horned Grasshoppers (Orthoptera: Acrididae)

Chemoreception plays a crucial role in the reproduction and survival of insects, which often rely on their sense of smell and taste to find partners, suitable habitats, and food sources, and to avoid predators and noxious substances. There is a substantial body of work investigating the chemoreception and chemical ecology of Diptera (flies) and Lepidoptera (moths and butterflies); but less is known about the Orthoptera (grasshoppers, locusts, crickets, and wēta). Within the Orthoptera, the family Acrididae contains about 6700 species of short-horned grasshoppers. Grasshoppers are fascinating organisms to study due to their significant taxonomic and ecological divergence, however, most chemoreception and chemical ecology studies have focused on locusts because they are agricultural pests (e.g., Schistocerca gregaria and Locusta migratoria). Here we review studies of chemosensory systems and chemical ecology of all short-horned grasshoppers. Applications of genome editing tools and entomopathogenic microorganism to control locusts in association with their chemical ecology are also discussed. Finally, we identify gaps in the current knowledge and suggest topics of interest for future studies.

The role of complement in the tick cellular immune defense against the entomopathogenic fungus Metarhizium robertsii

Entomopathogenic fungi (EPF) have been widely explored for their potential in the biological control of insect pests and as an environmentally friendly alternative to acaricides for limiting tick infestation in the field. The arthropod cuticle is the main barrier against fungal infection, however, an understanding of internal defense mechanisms after EPF intrusion into the invertebrate hemocoel is still rather limited. Using an infection model of the European Lyme borreliosis vector Ixodes ricinus with the EPF Metarhizium robertsii, we demonstrated that ticks are capable of protecting themselves to a certain extent against mild fungal infections. However, tick mortality dramatically increases when the capability of tick hemocytes to phagocytose fungal conidia is impaired. Using RNAi-mediated silencing of tick thioester-containing proteins (TEPs), followed by in vitro and/or in vivo phagocytic assays, we found that C3-like complement components and α2-macroglobulin pan-protease inhibitors secreted to the hemolymph play pivotal roles in M. robertsii phagocytosis.