orcomutagenesis causes loss of antennal lobe glomeruli and impaired social behavior in ants

Abstract

Life inside ant colonies is orchestrated with a diverse set of pheromones, but it is not clear how ants perceive these social cues. It has been proposed that pheromone perception in ants evolved via expansions in the numbers of odorant receptors (ORs) and antennal lobe glomeruli. Here we generate the first mutant lines in ants by disrupting orco, a gene required for the function of all ORs. We find that orco mutants exhibit severe deficiencies in social behavior and fitness, suggesting that they are unable to perceive pheromones. Surprisingly, unlike in Drosophila melanogaster, orco mutant ants also lack most of the approximately 500 antennal lobe glomeruli found in wild-types. These results illustrate that ORs are essential for ant social organization, and raise the possibility that, similar to mammals, receptor function is required for the development and/or maintenance of the highly complex olfactory processing areas in the ant brain.

Molecular characterization and evolution of a chemosensory receptor gene family in three notorious rice planthoppers, Nilaparvata lugens, Sogatella furcifera and Laodelphax striatellus, based on genome and transcriptome analyses

“…In addition, these ants were largely missing their antennal lobe glomeruli. 101,102 This study is an addition to the knowledge of the olfactory mechanism in rice planthoppers. Odorant binding proteins are important for binding odorants and in rice-plant seeking behavior.…”

Olfactory co‐receptor Orco stimulated by Rice stripe virus is essential for host seeking behavior in small brown planthopper

“…16,23,24 In ants, Orco mutagenesis also impaired neural development. 24,25 Therefore, Orco is required for insect normal olfactory responses. Interestingly, OR genes exhibit very little sequence similarity even within the same insect order, while the sequences of Orco are highly conserved among insects, underscoring its central importance in the olfaction.…”

Promises and challenges in insect–plant interactions

“…CRISPR is also creating knowledge about insects that could be used to inform selection of candidate plant traits for plant resistance to insects. In 2017, CRISPR was used to manipulate genes involved in recognition of olfactory cues in ants, thereby altering behaviour and brain development in ways that adversely affected ant fitness (Trible et al, 2017).…”