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Abstract

Sensing and interpreting the complex mixture of sensory input is a challenging task for all organisms. Most rely on many types of sensory inputs while specialising in one distinct form. Insects use olfaction to quickly adapt to their surroundings and this has given them the toolkit for fast evolution to occupy a wide range of ecological niches. Chemosensation is mediated through a set of receptors which bind in chemical ligands present in the insects direct surroundings mediating information about for example, presence of food resources, conspecific mates or oviposition sites. Odorant receptors (Ors) is the main family involved in olfaction and mediates a lot of the signalling for volatile organic compounds (VOC) in insects. These receptors form a heterotetrameric ion channel together with the odorant receptor co receptor (Orco) and when a VOC binds in the channel opens and there is an ion flux which generates a signal being sent to the brain, activating a behaviour. These receptors are tuned differently depending on the ecological niche of the insect and the coding of odours is not yet fully understood but new research indicates that several different members of the chemosensory receptor families can be co-expressed to improve the coding and spectrum of VOCs or ligands that an insect can sense and respond to. Ors evolved around 450 million years ago (Figure 3) most likely from terrestrial insects that developed flight where new ecological niches required new receptors with different function. Ors evolve through birth and death evolution where a gene that encodes for a receptor mutates and develops a receptor with a new function, depending on whether the new receptor increases or decreases fitness will “give birth” to a new gene and receptor or “die” and become a pseudogene without functionality.

Keywords

odorant receptor; orco; chemosensation; insects; evolution; olfaction

Published in

Introductory paper at the Faculty of Landscape Architecture, Horticulture and Crop Production Science
2026, number: 2026:1
Publisher: Faculty of Landscape Architecture, Horticulture and Crop Production Science, Swedish University of Agricultural Sciences

SLU Authors

UKÄ Subject classification

Biochemistry
Evolutionary Biology

Publication identifier

  • DOI: https://doi.org/10.54612/a.15k7962t3j
  • eISBN: 978-91-8124-303-1

Permanent link to this page (URI)

https://res.slu.se/id/publ/146656