Standardising Visual Control Devices for Tsetse Flies: Central and West African Species Glossina palpalis palpalis

Abstract

Background Glossina palpalis palpalis (G. p. palpalis) is one of the principal vectors of sleeping sickness and nagana in Africa with a geographical range stretching from Liberia in West Africa to Angola in Central Africa. It inhabits tropical rain forest but has also adapted to urban settlements. We set out to standardize a long-lasting, practical and cost-effective visually attractive device that would induce the strongest landing response by G. p. palpalis for future use as an insecticide-impregnated tool in area-wide population suppression of this fly across its range.Methodology/Principal FindingsTrials were conducted in wet and dry seasons in the Ivory Coast, Cameroon, the Democratic Republic of Congo and Angola to measure the performance of traps (biconical, monoconical and pyramidal) and targets of different sizes and colours, with and without chemical baits, at different population densities and under different environmental conditions. Adhesive film was used as a practical enumerator at these remote locations to compare landing efficiencies of devices. Independent of season and country, both phthalogen blue-black and blue-black-blue 1 m2 targets covered with adhesive film proved to be as good as traps in phthalogen blue or turquoise blue for capturing G. p. palpalis. Trap efficiency varied (8–51%). There was no difference between the performance of blue-black and blue-black-blue 1 m2 targets. Baiting with chemicals augmented the overall performance of targets relative to traps. Landings on smaller phthalogen blue-black 0.25 m2 square targets were not significantly different from either 1 m2 blue-black-blue or blue-black square targets. Three times more flies were captured per unit area on the smaller device.Conclusions/SignificanceBlue-black 0.25 m2 cloth targets show promise as simple cost effective devices for management of G. p. palpalis as they can be used for both control when impregnated with insecticide and for population sampling when covered with adhesive film.

Standardizing Visual Control Devices for Tsetse Flies: East African Species Glossina fuscipes fuscipes and Glossina tachinoides

“…In coordinated field trials in West Africa, we have already shown that 1 m 2 black and blue targets covered with adhesive film capture 4–5 times more G. tachinoides than biconical traps [22] . Electric net results from interpretative experiments elsewhere in Africa [22] , [26] imply that tsetse attraction to targets could be underestimated when adhesive film is used by up to 50% (for some riverine species). This may mean that targets are even better at attracting G. f. fuscipes and G. tachinoides to land than our East African data suggest.…”

“…This is worth emphasising, as it is the landing response that underlies the principle of using insecticide-impregnated targets as control devices for tsetse. It is already well established for a range of tsetse species that only some of the flies attracted to the vicinity of traps or landing on their surfaces are eventually captured [18] , [23] , [26] . In the absence of a gold standard against which to assess the efficiency of electric nets and/or adhesive film in enumerating tsetse (e.g.…”

“…A second objective of these coordinated trials was to test whether behavioural responses were the same under diverse circumstances as in core regional populations studied here and elsewhere in Africa. The trials were based on trap/target/bait technology in actual use at each location following a coordinated experimental protocol throughout Africa targeting different tsetse vectors [22] , [25] , [26] .…”

Tsetse blood-meal sources, endosymbionts, and trypanosome infections provide insight into African trypanosomiasis transmission in the Maasai Mara National Reserve, a wildlife-human-livestock interface

“…A tsetse repellant formulation mimicking the odor of waterbuck ( Kobus ellipsiprymnus defassa ), a non-host animal, was recently developed and used as an innovative collar device to protect cattle from tsetse bites and AAT [60]. Visual cues have been extensively exploited in the development of improved traps – stationery and mobile targets impregnated with insecticides for riverine/”palpalis” [61–63] and savannah/”morsitans” [49,64] groups of tsetse. However, it has been noted that for the morsitans group of tsetse flies, including G. pallidipes and G. swynnertoni , host odors play a more significant role than visual cues as they strongly attract the tsetse flies across long ranges of up to 100 m [65].…”

Variasi Warna Pipet pada Stik Perangkap Lalat terhadap Jumlah Lalat yang Tertangkap

“…Pengamatan dilakukan pada jam aktifnya lalat yaitu pada pukul 08.00 sampai 14.00 , setelah jam 14.00 perangkap pipet yang sudah dipasang diambil dan lakukan pengamatan serta penghitungan berapa jumlah lalat yang terperangkap pada stik perangkap lalat pada masing-masing warna. 8,21,[26][27][28] Penelitian ini dilakukan pengulangan sebanyak 6 kali pengulangan. 29 Data yang diperoleh dari observasi dikelompokan dalam bentuk tabel kemudian dianalisis secara deskriptif dan dilanjutkan dengan uji statistik.…”