Olycella aff. junctolineella (Lepidoptera: Pyralidae) florivory on Opuntia microdasys, a Chihuahuan Desert endemic cactus

摘要

The object of this study was to provide the first data on the natural history of the little known plant-florivore interaction between Opuntia microdasys and Olycella aff. junctolineella larvae and to study interindividual variability in the number of reproductive structures attacked as a function of plant resource availability.rnField observations of larval activity and a quantification of the damages produced were done at the Southern Chihuahuan Desert, Mexico. To quantify the interindividual variation of florivory damage as a function of resource availability (water and nutrients), a resource addition experiment was carried out.rnLarvae caused 21% of buds and 7% of flowers to abort. Adding resources (water and nutrients) to plants had no effect on bud production, although more buds developed into flowers and fruits in fertilized plants, suggesting a selective abortion against ill-nourished reproductive structures. The number of buds and flowers attacked by larvae were higher for non-fertilized than for fertilized plants, indicating that reproductive structures of plants under abiotic stress become more suitable as food for florivores. The number of structures attacked was a non-linear function of the number of buds originally produced, suggesting a florivore satiation threshold.