Biology and ecology of the coffee berry fruit flies (diptera: tephritidae) at the University of Nairobi Farm, Kabete
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Date
2012Author
Mugambi, Ann Murugi
Type
ThesisLanguage
enMetadata
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Past literature reveals that basic biological and ecological studies in Kenya on the coffee fruit
flies were conducted nearly half a century ago. These studies were therefore initiated to
update knowledge on the biology and ecology of the coffee berry fruit flies in view of
changing fanning practices and the influences of climate change. The experiments were
carried out at the University of Nairobi farm at Kabete Campus and also laboratory studies
were conducted at Kabete laboratory. The specific objectives of this study were to compare
the life cycles of coffee berry fruit flies, to determine the timing of the emergence activities
of both larva and adults and to determine the ovipositional behaviour of coffee fruit flies on
coffee berries at different stages of their maturation. The flies were identified by analysis of
their morphological features under a light microscope. Three species of coffee fruit flies were
identified (Ceratitis capitata Wied, Ceratitis rosa Karsch and Trirhithrum coffeae Bezzi) and
their biology studied. Durations taken by the immature stages were studied and Friedman test
used to test the hypothesis that there are no differences in the number of days required to
complete development between the three species. The timing of emergence activities of
Ceratitis capitata was studied by dividing mature larvae into two groups where one group
was held indoors at a constant temperature of 200e while the second group was studied out
door under fluctuating temperature. To study ovipositional behaviour, five categories of
berries namely; immature green, mature green, mature green- yellow, mature yellow- red and
mature red berries were presented to gravid females. The ovipuntured berries were dissected
under a microscope to examine for eggs. Statistical analysis by Analysis Of Variance
(ANOVA) was used to test whether there were significant differences in the berry categories
preferred for oviposition at p ~ 0.05 level. There were no significance differences in the
number of days taken by eggs of the three species to complete development. The durations
taken by larvae of the three species were different. There were significant differences at 0.05
level of significance in the number of days taken by larvae to complete development between
the species ( Friedman test P< 0.05). The pupal duration for the three species was similar as
shown by Friedman test (P> 0.05). There were no statistical differences between the species
inthe number of days taken by pupae to complete development. There was synchronization in
the life cycles of the coffee berry fruit flies with ripe coffee berries. The emergence activities
of flies were observed to occur in the early hours of the day when temperatures were low
whichreduces mortality rate of the emerging larvae and adults. The emergence pattern of fruit
flies was influenced by diurnal periodicity. The flies preferred to oviposit on mature ripe
coffee berries compared to green berries. No eggs were oviposited in the immature green
berries while in other categories, there were varying amount of eggs. In conclusion, there was
no much change in the biology and ecology in the three species of coffee fruit flies over the
years. Most of the observations recorded in the life cycles were similar to those recorded by
earlier authors. The sychronization of the life cycles of the three species of fruit flies provides
sound ecological knowledge for planning effective management programmes. This makes
controlprogrammes cost effective and easy.
Citation
Master of Science (M.Sc.) Degree in Entomology (Agricultural option)Sponsorhip
University of NairobiPublisher
University of Nairobi School of Biological Sciences