<p><strong>Chemosensory systems in predatory mites: from ecology to genome</strong></p>

Abstract

The reception of chemical cues in the environment is essential for the survival of almost all organisms, including phytoseiid mites. Compared with the progress made in the field of insect olfaction, the understanding of how predatory mites perceive chemical compounds and react to their surroundings is merely fragmentarily documented in past decades. In this review, we provide a guide in the field from chemoecology of herbivore-induced plant volatiles (HIPVs) as early as 1980s to the advances made in comparative genomics of predatory mites in 2019. We present from three aspects, i.e., chemosensory-guided feeding behavior, sensory structures and chemoreceptors predicted from genomes. The molecular principles of chemosensory system remain exciting areas for future research, since insights into the mechanisms underlying the sensing of chemical signals will not only contribute to a better understanding of predator behavior and physiology but may also open new avenues for the development of more specific and sustainable approaches to control pests by manipulating behaviors in predators. We then suggest three directions for future research: 1) chemoreceptor gene identification and function verification; 2) neural response circuit to stimuli and 3) application of chemoperception on feeding behavior. The potential methods and techniques are provided as well.

Kin recognition by cannibals is modulated by hunger level in a generalist predatory mite Amblyseius herbicolus (Chant) (Acari: Phytoseiidae)

“…Several species in Phytoseiidae can sense volatiles using sensory organs on their legs (van Wijk et al, 2006) and learn chemosensory cues (reviewed in Christiansen & Schausberger, 2017;Su et al, 2021). Faraji et al (2000) suggested that I. degenerans could use the physical and chemical properties of eggs to determine relatedness by frequently checking their eggs after oviposition and other eggs found in the experiment.…”

“…Predatory mites have no vision, where tactile and chemical cues are their predominant ways of exploration (van Wijk et al., 2006). Several species in Phytoseiidae can sense volatiles using sensory organs on their legs (van Wijk et al., 2006) and learn chemosensory cues (reviewed in Christiansen & Schausberger, 2017; Schausberger et al., 2020; Su et al., 2021). Faraji et al.…”

Lethal and sublethal effects of carlina oxide on Tetranychus urticae (Acari: Tetranychidae) and Neoseiulus californicus (Acari: Phytoseiidae)

“…The different behavioral responses of the two mite species exposed to the same compound dose could be linked to their chemoreceptor types. Recently, Su et al 82 reported that predatory mites, like N. cucumeris, rely mostly on gustatory receptors and ionotropic receptors for chemosensation. Ionotropic receptors represent the largest class of chemoreceptors in Acari and are particularly abundant in phytoseiid mites, with approximately 60 homologs, ten times those in spider mites.…”

“…Ionotropic receptors represent the largest class of chemoreceptors in Acari and are particularly abundant in phytoseiid mites, with approximately 60 homologs, ten times those in spider mites. 82 Thus, the abundance of chemoreceptor genes in predatory mites may imply a different chemosensory ability. 82 The repellent effect, as also confirmed by our behavioral tests, vanishes after 48 h, allowing the predatory mite to again colonize the treated area.…”

“…82 Thus, the abundance of chemoreceptor genes in predatory mites may imply a different chemosensory ability. 82 The repellent effect, as also confirmed by our behavioral tests, vanishes after 48 h, allowing the predatory mite to again colonize the treated area.…”