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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

Field 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.

Larvae 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. (C) 2010 Elsevier Ltd All rights reserved.