Sampling problems with tsetse flies (Diptera: Glossinidae).
In Rhodesia, studies were made of Glossina morsitans morsitans Westw. and G. pallidipes Aust. captured from stationary sources of ox odour (electric trapping), natural refuges and branch resting places (hand-net catching), artificial refuges (curtain trapping), a mobile ox (hand-net) and mobile screens (electric and hand-net). Temperature, time of day, type of refuge and site affected the magnitude or composition of some of the catches, but generally the odour sources and refuges gave samples that roughly represented the sex composition and species composition of the wild populations, whereas mobile baits gave catches with low proportions of females and relatively few G. pallidipes. From refuges were collected samples with a wide range of nutritional states, but from electrocuting grids used in conjunction with odour sources samples that were in a late stage of the hunger cycle were collected. Mobile baits attracted few flies that had fed recently, but the balance between flies in intermediate, late and very late stages of the hunger cycle varied according to bait or catching method. The convenience of odour-baited traps and their ability to attract large samples with representative sex and species composition indicated their value for ecological studies.