Wing length of tsetse caught by stationary and mobile sampling methods

Mweempwa, Cornelius; Mbewe, Njelembo J.; Deken, R. De

doi:10.1016/j.actatropica.2020.105333

Cited by 4 publications

(8 citation statements)

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“…Translocation has been demonstrated to significantly increase the attractiveness of an object to tsetse [28] and mobile baits are more effective in trapping G. m. morsitans than stationary baits [18,29]. Mobile baits used for sampling G. morsitans include the vehicle-mounted electric target [30] and black-screen fly round (BFR) [31,32].…”

Section: Introductionmentioning

confidence: 99%

A novel vehicle-mounted sticky trap; an effective sampling tool for savannah tsetse flies Glossina morsitans morsitans Westwood and Glossina morsitans centralis Machado

et al. 2021

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Background Black screen fly round (BFR) is a mobile sampling method for Glossina morsitans. This technique relies on the ability of operator(s) to capture flies landing on the screen with hand nets. In this study, we aimed to evaluate a vehicle-mounted sticky panel trap (VST) that is independent of the operator’s ability to capture flies against BFR, for effective and rapid sampling of G. m. morsitans Westwood and G. m. centralis Machado. We also determined the influence of the VST colour (all-blue, all-black or 1:1 blue-black), orientation and presence of odour attractants on tsetse catch. Methodology/Principal findings Using randomised block design experiments conducted in Zambia, we compared and modelled the number of tsetse flies caught in the treatment arms using negative binomial regression. There were no significant differences in the catch indices of the three colour designs and for in-line or transversely oriented panels for both subspecies (P > 0.05). When baited with butanone and 1-octen-3-ol, VST caught 1.38 (1.11–1.72; P < 0.01) times more G. m. centralis flies than the un-baited trap. Attractants did not significantly increase the VST catch index for G. m. morsitans (P > 0.05). Overall, the VST caught 2.42 (1.91–3.10; P < 0.001) and 2.60 (1.50–3.21; P < 0.001) times more G. m. centralis and G. m. morsitans respectively, than the BFR. The VST and BFR took 10 and 35 min respectively to cover a 1 km transect. Conclusion/Significance The VST is several times more effective for sampling G. m. morsitans and G. m. centralis than the BFR and we recommend its use as an alternative sampling tool.

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Section: Introductionmentioning

confidence: 99%

A novel vehicle-mounted sticky trap; an effective sampling tool for savannah tsetse flies Glossina morsitans morsitans Westwood and Glossina morsitans centralis Machado

et al. 2021

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“…Detecting its importance in doing so, however, required that the data set analyzed comprised data from both sampling methods and both sexes, as shown from results of the analysis of the whole data set, model 1c (Table 2). Probably because of the sampling bias inherent in individual methods with respect to wing length [5], analysis of one-method data set, did not show the importance of the wing length variable as an important factor for prevalence of trypanosomes -the in uence on prevalence seemed suppressed in the analysis. Probably, in analysis of methods pooled data, there was compensation for sampling bias short-comings of one method by the other.…”

Section: Discussionmentioning

confidence: 93%

“…The data used in this study was collected in eastern Zambia during a study on the status of tsetse populations and epidemiology of trypanosomiasis in areas of varying degrees of habitat fragmentation [17]. The description of the study area, methods used to sample tsetse populations and laboratory examinations of tsetse ies, were described in previous studies [5,18,19].…”

Section: Methodsmentioning

confidence: 99%

“…pallidipes than G. morsitans; more females than males; and more old than young ies, whereas mobile methods (such as " y rounds") are known to sample more G. morsitans than G. pallidipes; more males than females and more young than old ies [2,4]. Stationary methods (trap devices) are known to sample more of the larger than the small ies [5]. In a study by Hargrove [2], age structures determined from samples of tsetse ies caught using different methods differed signi cantly in six out of ten pair comparison in Glossina m. morsitans and in all ten pair comparisons in G. pallidipes, and the differences were attributed to increased ight activity with age.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Wing Length on the Prevalence of Trypanosomes in Glossina Morsitans Morsitans in Eastern Zambia

Mweempwa¹,

Chilongo

Hayashida

et al. 2021

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BackgroundTsetse flies (Diptera: Glossinidae) transmit trypanosomiasis (sleeping sickness in humans and nagana in livestock). Several studies have indicated that the age, sex, site of capture, starvation and microbiome symbionts, among others, are important factors influencing trypanosome infection in tsetse flies. However, reasons for a higher infection rate in females than in males still largely remain unknown. As species and sexes of tsetse flies of larger body size are the most mobile and the most available to stationary baits, it was hypothesized in this study that, the higher trypanosome prevalence in female than in male tsetse flies was because females were larger than males.Materials and methodsBlack screen fly rounds and epsilon traps were used to collect tsetse flies in eastern Zambia. Wing vein length was measured and the presence of trypanosomes was examined by microscopy. Principal component method was carried out to determine which variables had potential to be used as predictor variables. The multilevel binary logistic regression method was applied on whole data, one-method data and one-sex data sets to evaluate the hypothesis. ResultsA total of 2,195 Glossina m. morsitans data were evaluated (1,491 and 704 males and females, respectively). The wing length variable contributed the highest variance percentage (39.15%) to the first principal component. The wing length variable showed significant influence on prevalence of trypanosomes when the whole data set was analyzed. The log odds for the prevalence of trypanosomes significantly increased by 0.123 (p = 0.032), per unit increase in wing length. Moreover, moving from females to males, wing length significantly reduced by 0.150 (p < 0.0001) and females had higher trypanosome prevalence rates than males, though not always significant. ConclusionWing length is an important determinant factor for trypanosome prevalence in G. m. morsitans and could partially explain the higher prevalence of trypanosomes in females than in males. To verify this status, however, it’s clear that, reasonably representative population data is required for analysis – a serious challenge with the current tsetse sampling methods. Nonetheless, analysis of combined data from mobile and stationary methods that includes both sexes data, could verify the status.

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“…On the other hand, mobile methods (such as “fly rounds”) are known to sample more G. m. morsitans than G. pallidipes , more males than females and more young than old flies [ 2 , 3 ]. Stationary methods (trap devices) are known to sample more of the larger than the small flies [ 4 ]. In a study by Hargrove [ 2 ], age structures determined from samples of tsetse flies caught using different methods differed significantly in six out of ten pair comparisons in G. m. morsitans and in all ten pair comparisons in G. pallidipes , and the differences were attributed to increased flight activity with age.…”

Section: Introductionmentioning

confidence: 99%

Effect of wing length on the prevalence of trypanosomes in Glossina morsitans morsitans in eastern Zambia

et al. 2021

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Background Tsetse flies (Diptera: Glossinidae) transmit trypanosomiasis (sleeping sickness in humans and nagana in livestock). Several studies have indicated that age, sex, site of capture, starvation and microbiome symbionts, among others, are important factors that influence trypanosome infection in tsetse flies. However, reasons for a higher infection rate in females than in males still largely remain unknown. Considering that tsetse species and sexes of larger body size are the most mobile and the most available to stationary baits, it was hypothesized in this study that the higher trypanosome prevalence in female than in male tsetse flies was a consequence of females being larger than males. Methods Black screen fly rounds and Epsilon traps were used to collect tsetse flies in eastern Zambia. Measurement of wing vein length and examination for presence of trypanosomes in the flies were carried out by microscopy. Principal component method was carried out to assess the potential of wing vein length as a predictor variable. The multilevel binary logistic regression method was applied on whole data, one-method data and one-sex data sets to evaluate the hypothesis. Results Data derived from a total of 2195 Glossina morsitans morsitans were evaluated (1491 males and 704 females). The wing length variable contributed the highest variance percentage (39.2%) to the first principal component. The variable showed significant influence on prevalence of trypanosomes when the analysis was applied on the whole data set, with the log odds for the prevalence of trypanosomes significantly increasing by 0.1 (P = 0.032), per unit increase in wing length. Females had higher trypanosome prevalence rates than males, though not always significant. Furthermore, moving from females to males, wing length significantly reduced by 0.2 (P < 0.0001). Conclusions We conclude that wing length is an important predictor variable for trypanosome prevalence in Glossina morsitans morsitans and could partially explain the higher prevalence of trypanosomes in females than in males. However, reasonably representative population data are required for analysis—a serious challenge with the current tsetse sampling methods. Thus, analysis combining data from mobile and stationary methods that include both sexes' data could be useful to verify this hypothesis. Graphical abstract

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Wing length of tsetse caught by stationary and mobile sampling methods

Cited by 4 publications

References 28 publications

A novel vehicle-mounted sticky trap; an effective sampling tool for savannah tsetse flies Glossina morsitans morsitans Westwood and Glossina morsitans centralis Machado

A novel vehicle-mounted sticky trap; an effective sampling tool for savannah tsetse flies Glossina morsitans morsitans Westwood and Glossina morsitans centralis Machado

Effect of Wing Length on the Prevalence of Trypanosomes in Glossina Morsitans Morsitans in Eastern Zambia

Effect of wing length on the prevalence of trypanosomes in Glossina morsitans morsitans in eastern Zambia

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