Abstract:
The effective control of tsetse flies (Diptera; Glossinidae), the biological vectors of trypanosome
parasites that cause human African trypanosomosis and African animal trypanosomosis
throughout sub-Saharan Africa, is crucial for the development of productive livestock systems.
The degree of genetic isolation of the targeted populations, which indicate reinvasion potential
from uncontrolled areas, will be critical to establish a control strategy. Molecular and
morphometrics markers were used to assess the degree of genetic isolation between seemingly
fragmented populations of Glossina brevipalpis Newstead and Glossina austeni Newstead
present in South Africa. These populations were also compared with flies from adjacent areas
in Mozambique and Eswatini. For the molecular markers, deoxyribonucleic acid was extracted,
a r16S2 Polymerase chain reaction (PCR) was performed and the PCR product sequenced.
Nine landmarks were used for the morphometrics study as defined by vein intersections in the
right wings of female flies. Generalised Procrustes analyses and regression on centroid size
were used to determine the Cartesian coordinates for comparison between populations. Both
methods indicated an absence of significant barriers to gene flow between the G. brevipalpis
and G. austeni populations of South Africa and southern Mozambique. Sustainable control can
only be achieved if implemented following an area-wide management approach against the
entire G. brevipalpis and G. austeni populations of South Africa and southern Mozambique.
Limited gene flow detected between the G. austeni population from Eswatini and that of South
Africa or Mozambique may imply that these two populations are in the proses of becoming
isolated.
