Abai, MR

6th International Congress of DipterologyThe Tree of Love: The Evolution of Mating behaviour inSepsidae (Diptera)Puniamoorthy, N. & R. MeierDepartment of Biological Sciences, National University of Singapore, 14 Science Drive 4,Singapore 117543.Sepsid flies are well known for strongly modified male fore legs, which areused to grasp the female wing base during mounting, and genitalia that areremarkably diverse. Here, we document how these structures are actuallybeing used during mating. We describe the behavior of sixteen speciesacross the family in order to investigate if morphological structures changein response to changes in mating behaviours. We find that sepsid matingbehaviour is amazingly diverse with each species having its own profileand we describe more than 40 different behavioural elements across thefamily. A detailed morphological study using SEM shows that most of thestructures involved in male behaviours are not sexually dimorphic and attimes even more or less unmodified between species. We also find thatwhen we map the male fore leg interaction with the female wings onto thetree, the different types of armature have different evolutionary origins. Inorder to investigate the evolution of mating behaviour, we code thebehavioral elements as characters and trace them on the phylogenetic treefor the family. Most characters show much homoplasy thus indicating thatcourtship behaviour in Sepsidae is evolutionarily labile. Our resultsdemonstrate that studying behaviour in line with morphology providesvaluable additional insights and adds meaning to reconstructing the tree oflife for Sepsidae.Key Words: Sepsidae, mating behaviour, morphology, evolution∗∗∗∗∗∗∗∗∗∗203