Behavioural field experiments assessing the habitat and host preference of D. sechellia in the wild

The extensive studies on D. sechellia have made it a familiar example of chemosen-sory evolution and speciation. This specialist drosphilid species is well-known for its ability to tolerate and actively seek out its toxic host Morinda citrifolia (noni). It was originally thought that this toxic fruit was the exclusive host of D. sechellia because most drosophilids cannot tolerate and are deterred by the characterizing odour components, hexanoic and octanoic acid, given off by noni. However, the origins of noni are questionable and it has been proposed that D. sechellia may have evolved on an older endemic pandanus in the Seychelles. This study tests the viability of this claim by comparative behavioural field studies of D. sechellia abundances in various habitats and chemcial analysis of two pandanus sp. (P. tec-torius and P. hornei) in The Seychelles. The results revealed that despite extensive research D. sechellia is not exclusive to noni as a host or noni groves as a habitat. Furthermore, it questions the possiblity of P. tectorius and P. hornei as the original hosts. (Less)