Article

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

International Centre of Insect Physiology and Ecology, PO Box 30772-00100 GPO, Nairobi, Kenya.
Bulletin of Entomological Research (Impact Factor: 1.99). 08/2006; 96(4):379-86. DOI: 10.1079/BER2006442
Source: PubMed

ABSTRACT Field infestation rates of an invasive fruit fly species, Bactrocera invadens Drew Tsuruta & White on mango was determined at different localities in Kenya. At most of the locations and especially at low elevations, B. invadens frequently shared the same fruit with the indigenous fruit fly species Ceratitis cosyra (Walker) but often occurred at higher numbers than C. 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 that B. invadens is a predominantly lowland pest. On an artificial diet, development of B. invadens immatures 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 for B. invadens.

5 Bookmarks
 · 
362 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Bactrocera invadens, a fruit fly from Asia, is an invasive pest species across Africa. It appears to continue spreading, not only in latitude but also in altitude. To assess its capacity to infest a large variety of hosts and its competition with other fruit fly species, a study along an altitudinal gradient was conducted. At low altitudes, the high abundance in the field and high infestation of B. invadens in different fruit species make it a serious pest. At high altitudes, colonization has started and B. invadens occurs in low numbers by reproducing successfully in high altitude fruits. Overall the abundance and infestation of B. invadens is influenced by its direct competitor Ceratitis rosa and the presence of its preferred host species. C. rosa is still the dominant species in temperate fruits grown at high altitude. Ceratitis cosyra, however, is negatively affected by B. invadens, this species seems to have shifted hosts to avoid competition. The broad host range and competitive potential of B. invadens increase the risk for further spread not only to higher areas, but also to subtropical regions.
    Bulletin of entomological research 02/2014; 104(03):288-294. · 1.99 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To understand the evolution of local adaptation, the interplay between natural selection and gene flow should be considered. Rhagoletis cerasi L. (Diptera: Tephritidae) is a patchily distributed, stenophagous species of the temperate zone, and the geographical structure of its populations reveals substantial variation in gene flow rates across its distribution range. We studied the demographic components of R. cerasi adults from Greek and German populations by estimating the variability in fitness traits among allopatric populations, as well as among geographically discrete populations, with gene flow. Assuming that body size may exert a profound effect on adult fitness, both thorax and head sizes were considered as covariates in our analyses. Our data demonstrated that females were larger than males in all populations, and adult size varied significantly among populations within groups. Significant differences in a suite of life-history traits of R. cerasi adults were detected among populations with gene flow, whereas there were no consistent differences among allopatric populations. Therefore, the genetic differences among R. cerasi populations, driven mainly by geographical isolation, are poor predictors of variation in the life-history traits of adults.
    Biological Journal of the Linnean Society 09/2012; 107(1):137-152. · 2.41 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In frugivorous insects, the physiological state of the female (e.g. age, egg load) as well as environmental parameters like fruit availability and characteristics may affect oviposition decision, host choice and the resulting clutch size. We studied host acceptance and clutch size decision as a function of fly egg load as physiological state and mango variety and ripeness stage as the environmental parameter in two major mango pests in sub- Saharan Africa, Bactrocera invadens and Ceratitis cosyra, under laboratory conditions. In addiction, egg maturation dynamics were investigated because for both species, egg production had never been explored before. Female egg load was the most important factor influencing host acceptance in both species. With respect to fruit characteristics, ripeness stage was significant for oviposition decisions only in C. cosyra. In particular, ripe and fully ripe fruits had more probability of oviposition than unripe ones. In contrast, fruit variety affected clutch size in B. invadens, with, respectively, the local variety Ngowe receiving the biggest clutches and the export Kent the smallest. Moreover, the invasive species showed a significantly higher egg production compared with the native species. Implications in terms of competitive displacement between the two species are also discussed.
    Journal of Applied Entomology 01/2013; · 1.56 Impact Factor