A Background of a Volatile Plant Compound Alters Neural and Behavioral Responses to the Sex Pheromone Blend in a Moth.

Recognition of intra-specific olfactory signals within a complex environment of plant-related volatiles is crucial for reproduction in male moths. Sex pheromone information is detected by specific olfactory receptor neurons (Phe-ORNs), highly abundant on the male antenna. The information is then transmitted to the pheromone processing macroglomerular complex (MGC) within the primary olfactory center, the antennal lobe, where it is processed by local interneurons and projection neurons.

Unexpected plant odor responses in a moth pheromone system.

Male moths rely on olfactory cues to find females for reproduction. Males also use volatile plant compounds (VPCs) to find food sources and might use host-plant odor cues to identify the habitat of calling females. Both the sex pheromone released by conspecific females and VPCs trigger well-described oriented flight behavior toward the odor source.

Synaptotagmin I, a molecular target for steroid hormone signaling controlling the maturation of sexual behavior in an insect.

Unlabelled: As in vertebrates, the insect steroid hormones, especially 20-hydroxyecdysone (20E), initiate and regulate sexual behavior by acting on the central nervous system. This 20E action is, in part, triggered by transcriptional events mediated through the binding of 20E to a heterodimer comprising the ecdysone receptor (EcR) and ultraspiracle (USP). However, to date, our knowledge about this genomic steroid pathway remains incomplete.

The dilemma of Fisherian sexual selection: mate choice for indirect benefits despite rarity and overall weakness of trait-preference genetic correlation.

Fisher's mechanism of sexual selection is a fundamental element of evolutionary theory. In it nonrandom mate choice causes a genetic covariance between a male trait and female preference for that trait and thereby generates a positive feedback process sustaining accelerated coevolution of the trait and preference. Numerous theoretical models of Fisher's mechanism have confirmed its mathematical underpinnings, yet biologists have often failed to find evidence for trait-preference genetic correlation in populations in which the mechanism was expected to function.

Genetic architecture of sensory exploitation: QTL mapping of female and male receiver traits in an acoustic moth.

The evolution of extravagant sexual traits by sensory exploitation occurs if males incidentally evolve features that stimulate females owing to a pre-existing environmental response that arose in the context of natural selection. The sensory exploitation process is thus expected to leave a specific genetic imprint, a pleiotropic control of the original environmental response and the novel sexual response in females. However, females may be subsequently selected to improve their discrimination of environmental and sexual stimuli.