THE DENSITY DEPENDENCE OF PARASITISM BY TEPHRITID FRUIT-FLIES

Individual Rhagoletis pomonella foraged with direct density dependence but a population of flies of the sibling species Rhagoletis cornivora showed either no relationship between parasitism and host density (density vagueness) or inverse density dependence. Results resolve the apparent conflict: individual behaviors may not translate to the same population level patterns due to 1) a lack of defined patch boundaries (from the parasite's perspective), 2) repeated visits by parasites to patches, 3) uneven rates of host acceptance, and 4) egg limitation. -from Authors