Biology of Oulema

Abstract

There are approximately 100 Oulema spp., primarily distributed in the temperate-tropical areas on plants in the families Amaranthacae, Commelinaceae, Compositae, Cyperaceae, Gramineae, Leguminosae. Rosaceae, and Solanaceae (R.E. White, personal communication). In the subfamily Criocerinae, the genus Oulema Gozis (1886) can be distinguished from the closely related Lema Fabricius (1798) (Grison et al. 1963) by the shape of the pronotum and converging angle of the frontal grooves. Mittal et al. (1984) compiled a list of chromosome numbers for 23 species of criocerids and noted that 17 Lema spp. had n = 7 to 16, 2 Oulema spp. had n = 8 to 10, and three Crioceris spp. had n = 9 chromosomes. In view of the past difficulty in separating Lema and Oulema spp., and the paucity of information on chromosome numbers, it is premature to suggest that Lema spp. have more chromosomes than Oulema spp. (Ninan et al. 1968). Much of the biological data reported herein is about the cereal leaf beetle, Oulema melanopus (Linnaeus 1758) (Battenfeld et al. 1982). Information is also presented about two other economically important Oulema species: the rice leaf beetle, O. oryzae (Kuwayama 1931) and the cereal pest. O. gallaeciana (von Heyden 1870) (= Lema (Oulema) lichenis Weise 1882; see Möhr 1985), often found sympatrically with the cereal leaf beetle in Europe.