Transporting Behavior?

Abstract

Courtship behavior in male Drosophila is influenced by various sensory cues. For instance, the pheromone 7-tricosene inhibits male flies from courting other males. Grosjean et al . found that male flies in which a mutation disrupted the production of mRNA and protein for the amino acid transporter genderblind ( gb [ KG07905 ] mutants) frequently courted other males. Analysis of several genotypes revealed an inverse relationship between male-male courtship and abundance of genderblind protein, and gb RNAi mimicked the gb mutant phenotype. Moreover, conditional expression of RNAi directed against gb indicated that its effects on courtship involved modulation of adult brain function rather than development. Whereas wild-type males preferred courting decapitated females to courting decapitated males, gb mutants failed to show this preference, effects that persisted in the absence of visual cues. Courtship of males deficient in various pheromones (including 7-tricosene) by gb mutants decreased to levels comparable to courtship of pheromone-deficient males by wild-type males, a decrease that was reversed by 7-tricosene. Genderblind immunoreactivity was present in glia, but not neurons, and, noting that their previous research had shown decreased ambient extracellular glutamate concentrations in the gb [ KG07905 ] mutants (predicted to enhance glutamatergic synaptic strength), the authors determined that genderblind was present in brain regions containing glutamatergic neurons. Increasing glutamatergic synaptic strength by overloading synaptic vesicles with glutamate promoted male-male courtship, whereas a glutamate-receptor antagonist inhibited male-male courtship in gb mutants. Thus, the authors conclude that glial modulation of extracellular glutamate concentration and thereby glutamatergic transmission affects male Drosophila courtship behavior. Levine discusses the research and notes the importance of precision in language as applied to insect behavior. Y. Grosjean, M. Grillet, H. Augustin, J.-F. Ferveur, D. E. Featherstone, A glial amino-acid transporter controls synapse strength and courtship in Drosophila . Nat. Neurosci. 11 , 54-61 (2008). [PubMed] J. D. Levine, Glia and romance. Nat. Neurosci. 11 , 8-10 (2008). [PubMed]