Seasonality and abundance of Metamasius callizona (Coleoptera: Dryophthoridae), an invasive insect herbivore, on two species of Tillandsia (Bromeliaceae) in Florida

Seasonality and abundance of an insect herbivore population are regulated by a complex array of forces from the bottom up, from the top down, and from competition and the environment. This paper examines the effect that two host plants have on an insect herbivore in the absence of top-down regulation or competition. Metamasius callizona is an invasive bromeliad-eating weevil in south Florida that has escaped its natural parasitoid in its home range. A 4-year field study shows the weevil to be present and active year-round, but to exhibit different patterns of seasonality and abundance on two of its host plants. It is argued that this demographic variability is generated by the differences in leaf type and growth habit that exist between the two host plants.