ExoticCrotalariaSpecies (Fabales: Fabaceae) as Host Plants of the Ornate Bella Moth,Utetheisa ornatrix(Lepidoptera: Erebidae), in Florida: Laboratory Biology

Abstract

The caterpillars of Utetheisa ornatrix, the ornate bella moth, feed on host plants in the genus Crotalaria (Fabales: Fabaceae), which, in Florida, encompasses 4 native and 10 introduced species. In the laboratory, Utetheisa ornatrix male larvae developed faster and resulted in larger adults, when raised on Crotalaria incana vs. Crotalaria lanceolata (2 species native to Africa). In the wild, this can potentially give a selective advantage to individuals that develop on C. incana. The presence of these and other exotic host plants, some of which are quite common (e.g. C. pallida, C. spectabilis, C. retusa), may be skewing the evolution of U. ornatrix, as well as its phenology and distribution. A constant temperature of 60 °F (15.6 °C) caused U. ornatrix to develop twice as slowly as it did at 72 °F (22.2 °C), but it was sufficiently high for successful development. Sentinel larvae placed in cages in the field during Oct–Dec, when temperatures averaged ≈ 62 °F, developed successfully. Regardless of the rearing conditions and the host plants used in the laboratory, male larvae developed slightly more slowly than female larvae. This translated in their emerging from the pupae later than the females, which is supported by field observations.