Field infestation, life history and demographic parameters of the fruit flyBactrocera invadens(Diptera: Tephritidae) in Africa

Abstract

AbstractField infestation rates of an invasive fruit fly species,Bactrocera invadensDrew Tsuruta & White on mango was determined at different localities in Kenya. At most of the locations and especially at low elevations,B. invadensfrequently shared the same fruit with the indigenous fruit fly speciesCeratitis cosyra(Walker) but often occurred at higher numbers thanC. cosyra. The level of infestation varied with location ranging from 3.0 to 97.2 flies per kg of fruit. There was a significant inverse relationship between numbers of flies per kg of fruit and elevation at which fruit was collected, suggesting thatB. invadensis a predominantly lowland pest. On an artificial diet, development ofB. invadensimmatures lasted 25 days; egg incubation required 1.2 days, larval development 11.1 days and puparia-adult development 12.4 days. About 55% of eggs developed to the adult stage. Life expectancy at pupal eclosion was 75.1 days in females and 86.4 days in males. Average net fecundity and net fertility were 794.6 and 608.1 eggs, respectively, while average daily oviposition was 18.2 eggs. Daily population increase was 11% and mean generation time was 31 days. Results are discussed in relation to the biology and ecology of the insect and in the development of mass rearing and control measures forB. invadens.