Submitted to: Annals of the Entomological Society of America
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/15/2004
Publication Date: 5/1/2004
Citation: Sivinski, J.M., Aluja, M., Pinero, J., Ojeda, M. 2004. Novel analysis of spatial and temporal patterns of resource use in a group of tephritid fruit flies of the genus anastrepha. Annals of the Entomological Society of America. v. 97. pp. 504-412. Interpretive Summary: Fruit flies attack scores of species of fruits and vegetables, and are responsible for the erection of trade barriers where ever they occur. Understanding the ecology of these flies, particularly what environmental factors regulate their abundances and distributions is an important step in designing Integrated Pest Management programs that are both effective and limit the use of insecticides. Researchers at the Center for Medical, Agricultural, and Veterinary Entomology (Gainesville, FL) in collaboration with colleagues at the instituto de Ecologia (Xalapa, Veracruz, Mexico) examined the distributions of several fruit fly spp. in the canopies of their host trees and along an altitudinal gradient. At the same time they made detailed measurements of temperature, relative humidity, and light intensity in various portions of the fruit trees. They were among the first entomologists to use a newly developed statistical technique, and employed it to determine when and where fruit flies lay their eggs. Research is now being planned to look at the role of natural enemies in the evolution of fruit fly distribution patterns, and if fruit flies are particularly vulnerable in certain portions of their habitats.
Technical Abstract: The spatial and temporal patterns of oviposition-resource use of various Anastrepha spp. fruit flies within the canopies of fruit trees were determined over periods of 4-6 years in the state of Veracruz, Mexico. The flies examined were A. obliqua (Macquart), A. striata Schiner, A. fracterculus (Wiedemann), and A. alveata Stone, and their respective hosts were Spondias mombin L. (Anacardiaceae), Psidium guajava L. and P. sartorianum (Berg.) Ndzu (Myrtacaea), and Ximenia americana L. (Olacaceae). The canopies were divided into six sectors: three strata (vertical planes of lower, mid and upper canopy) and an exterior and interior component of the various heights. All ripe fruits produced by each tree species were individually harvested, weighed and maintained until all larvae had exited and pupated. Because of the commonly positive correlation between fruit size and infestation, fly distributions were described using a novel technique, two-level hierarchal regression analysis, as deviations from th expected numbers of insects in a sector given the distributions of fruit weights within the canopy. Overall, there was a tendency for A. alveata to be more abundant in the lower portions of the tree, for A. striata to be more abundant in the upper, for A. obliqua to be less abundant in the upper, and for A. fraterculus to be uniformly distributed. Along an altitudinal gradient (0-1,800 m), A. striata was more abundant than A. fraterculus at sea level, and relatively less abundant at altitudes of 1000 m and higher. We suggest that habitat characteristics, intraspecific competition, and the behaviors of natural enemies and frugivores are potentially important interactive factors that influence the distribution of resource use to a different extent in each of the tephritid species.