Phylogeny of Utetheisa s. str. (Lepidoptera:Noctuidae:Arctinae) with comments on the evolution of colour, hind wing scales and origin of New World species

Abstract

Species of Utetheisa Hübner incorporate pyrrolizidine alkaloids into their defence strategy where they are protective against both invertebrate and vertebrate predators, and courtship behaviours by males incorporate the alkaloids into their pheromones. Although Utetheisa’s chemical ecology is well understood, the systematics is less clear. A phylogeny of Utetheisa was constructed based on adult morphology. The final data matrix consisted of 29 species and 105 characters (268 states) from adults scored from both nongenitalic and genitalic characters as follows: 3 head (8 states), 4 leg (8 states), 21 wing (49 states), 44 male abdominal and genitalic characters (124 states), and 33 female abdominal and genitalic characters (79 states). The resulting parsimony and Bayesian analyses demonstrated that Utetheisa s. str. is monophyletic and sister to U. Pitasila (Moore). UtetheisaAtasca (Swinhoe) is more closely related to outgroup taxa than it is to other Utetheisa species. Monophyly of Utetheisa s. str. is strongly supported by a posterior probability of 0.98. Colour was lost once and male wing androconia evolved independently in several species, all of which feed on hosts in Boraginaceae. Forbes’ hypothesis of an Old World origin for the genus is corroborated and two origins for New World species are supported.