Biological traits and field distribution of introducedArhopalusspecies in Central Argentina

Arhopalus rusticus rusticusandArhopalus syriacus(Coleoptera: Cerambycidae) are exotic forestry pests that coexist in Cordoba (Argentina). To contribute to forest management strategies, we examined how their emergence, development, and abundance affect the sex ratio. We found a dispersal sex ratio of 0.5:0.5 (males:females) in both species. The birth sex ratio was 0.5:0.5 inA. syriacusand 0.6:0.4 inA. r. rusticus. In rearing experiments,A. r. rusticushad larger individuals, with several larval instars and high survival ratio, but developmental time was shorter inA. syriacus. We found an asymmetric distribution, but there are indications that the range ofA. syriacusis advancing northward.