Aspects of the population dynamics of adults of Haematobia thirouxi potans (Bezzi) (Diptera: Muscidae) in southern Africa

Abstract

AbstractChanges in adult populations of Haematobia thirouxi potans (Bezzi) were studied in Hluhluwe Game Reserve, Natal, South Africa, between October 1981 and May 1983. While there were no unequivocal seasonal changes in fly abundance, population increases were recorded late spring–early summer and mid–late autumn. Of the two measures of fly abundance, namely the number of flies that emerged from dung pads almost free of other fauna and counts of flies from culled buffalo (Syncerus caffer), the former was correlated with the proportion of nulliparous females in the population (r = 0·82). While the average female completed a minimum of 2·7 ovarian cycles, up to 78% of females during winter were in the 4th or subsequent cycle. The size of flies collected from buffalo and from dung pads showed an overall reduction during the study period and was an important factor in both survival and fecundity. Differences in the preference of flies for buffalo over an Afrikander-Shorthorn cross heifer, were manifested in the sex ratio and proportions of nulliparous females and fed flies.