Optogenetic Activation of thefruitless-Labeled Circuitry inDrosophila subobscuraMales Induces Mating Motor Acts

Abstract

It remains an enigma how the nervous system of different animal species produces different behaviors. We studied the neural circuitry for mating behavior in , a species that displays unique courtship actions not shared by other members of the genera including the genetic model, in which the core courtship circuitry has been identified. We disrupted the () gene, a master regulator for the courtship circuitry formation in , resulting in complete loss of mating behavior. We also generated , which expresses the optogenetic activator Chrimson fused with a fluorescent marker under the native promoter. The-labeled circuitry in visualized by revealed differences between females and males, optogenetic activation of which in males induced mating behavior including attempted copulation. These findings provide a substrate for neurogenetic dissection and manipulation of behavior in non-model animals, and will help to elucidate the neural basis for behavioral diversification. How did behavioral specificity arise during evolution? Here we attempted to address this question by comparing the parallel genetically definable neural circuits controlling the courtship behavior of , a genetic model, and its relative,, which exhibits a courtship behavioral pattern unique to it, including nuptial gift transfer. We found that the circuit, which is required for male courtship behavior, was slightly but clearly different from its counterpart, and that optogenetic activation of this circuit induced -specific behavior, i.e., regurgitating crop contents, a key element of transfer of nuptial gift. Our study will pave the way for determining how and which distinctive cellular elements within the circuit determine the species-specific differences in courtship behavior.

Neural Changes Underlying Rapid Fly Song Evolution

“…D. melanogaster provides a powerful system for dissecting the neural circuitry underlying behaviour 30 and the genus Drosophila contains over 1,500 species displaying divergent adaptive behaviours 31 . Our functional comparative approach illustrates how we can leverage tools developed in D. melanogaster to study the homologous neural circuitry underlying the evolution of many behaviours across this genus 32 .…”

Alcohol Increases Aggression in Flies

“…3, D and E). Next, we measured Fru M protein levels in the whole brain using a Fru M antibody generously donated by Daisuke Yamamoto (12). PEA flies had increased Fru M throughout the brain ( Fig.…”

Evolution of the neural sex‐determination system in insects: does fruitless homologue regulate neural sexual dimorphism in basal insects?

“…As the fruitless homologue of the stink bug Halyomorpha halys is predicted to possess a P1-like promoter, the P1-like promoter originated in the common ancestors of holometabolous and paraneopteran lineages. This study Ustinova andMayer, 2006 Clynen et al, 2011 LOC110830709 This fruitless gene in the cricket sex-specific alternative splicing to produce male-specific Fru M proteins (Ryner et al, 1996;Tanaka et al, 2017). Similar sex-specific splicing of fruitless homologues has been reported in the house fly M. domestica (Meier et al, 2013) and two mosquito species (Anopheles gambiae and Aedes aegypti) (Gailey et al, 2006;Salvemini et al, 2013).…”

“…To date, histological expression analysis of fruitless homologues has been conducted in a limited number of dipteran insects, such as the fruit fly D. melanogaster (Ito et al, 1996;Ryner et al, 1996;Dornan et al, 2005;Vernes, 2014;Tanaka et al, 2017) and the house fly Musca domestica (Meier et al, 2013), with a particular interest in the distribution of the sex-specific isoform. In the brain of the adult male fruit fly, fruitless transcript transcribed from fruitless gene in the cricket 815 the P1 promoter (Fru M transcript) is exclusively expressed in the clustered neurones in the central nervous system (CNS) of adult flies (Ryner et al, 1996).…”