Wing length and host location in tsetse (Glossina spp.) : implications for control using stationary baits
Date
2019-01-11
Journal Title
Journal ISSN
Volume Title
Publisher
BMC (part of Springer Nature)
Abstract
Background: It has been suggested that attempts to eradicate populations of tsetse (Glossina spp.) using stationary
targets might fail because smaller, less mobile individuals are unlikely to be killed by the targets. If true, tsetse
caught in stationary traps should be larger than those from mobile baits, which require less mobility on the part
of the flies.
Results: Sampling tsetse in the Zambezi Valley of Zimbabwe, we found that the number of tsetse caught from
stationary traps, as a percent of total numbers from traps plus a mobile vehicle, was ~5% for male G. morsitans
morsitans (mean wing length 5.830 mm; 95% CI: 5.800–5.859 mm) and ~10% for females (6.334 mm; 95% CI: 6.329–
6.338 mm); for G. pallidipes the figures were ~50% for males (6.830 mm; 95% CI: 6.821–6.838 mm) and ~75% for
females (7.303 mm, 95% CI: 7.302–7.305 mm). As expected, flies of the smaller species (and the smaller sex) were
less likely to be captured using stationary, rather than mobile sampling devices. For flies of a given sex and species
the situation was more complex. Multivariable analysis showed that, for females of both species, wing lengths
changed with ovarian age and the month, year and method of capture. For G. pallidipes, there were statistically
significant interactions between ovarian age and capture month, year and method. For G. m. morsitans, there was
only a significant interaction between ovarian age and capture month. The effect of capture method was, however,
small in absolute terms: for G. pallidipes and G. m. morsitans flies caught on the mobile vehicle had wings only 0.24
and 0.48% shorter, respectively, than flies caught in stationary traps. In summary, wing length in field samples of
tsetse varies with ovarian age, capture month and year and, weakly, with capture method. Suggestions that a
target-based operation against G. f. fuscipes in Kenya caused a shift towards a smaller, less mobile population of
tsetse, unavailable to the targets, failed to account for factors other than capture method.
Conclusions: The results are consistent with the successful use of targets to eradicate populations of tsetse in
Zimbabwe. Until further, more nuanced, studies are conducted, it is premature to conclude that targets alone could
not, similarly, be used to eradicate G. f. fuscipes populations in Kenya.
Description
CITATION: Hargrove, J., et al. 2019. Wing length and host location in tsetse (Glossina spp.) : implications for control using stationary baits. Parasites & Vectors, 12:24, doi:10.1186/s13071-018-3274-x.
The original publication is available at https://parasitesandvectors.biomedcentral.com
The original publication is available at https://parasitesandvectors.biomedcentral.com
Keywords
Stationary and mobile baits, Tsetse-flies -- Control, Tsetse-flies -- Physiology, Bait markers
Citation
Hargrove, J., et al. 2019. Wing length and host location in tsetse (Glossina spp.) : implications for control using stationary baits. Parasites & Vectors, 12:24, doi:10.1186/s13071-018-3274-x