Evaluation and improvement of sticky traps as monitoring tools for Glossina austeni and G. brevipalpis (Diptera: Glossinidae) in north-eastern KwaZulu-Natal, South Africa

Abstract

The attractiveness of various colours, colour combinations and sizes of sticky traps of the 3-dimensional trap (3DT), cross-shaped target (XT), rectangular screen (RT) and monopanels were evaluated for their efficacy to capture Glossina austeni Newstead and G. brevipalpis Newstead in north-eastern KwaZulu-Natal, South Africa. The 3-dimensional shapes of the XT and 3DT in light blue (l.blue) and white were significantly (ca. 3.1-6.9 times) better than the RT for G. austeni. On bicoloured XTs, G. austeni landed preferentially on electric blue (e.blue) (58%) and black (63%) surfaces when used with white; while for G. brevipalpis, significantly more landed on e.blue (60-66%) surfaces when used with l.blue, black or white surfaces. Increased trap size increased the catches of G. brevipalpis females and both sexes of G. austeni significantly. Temoocid and polybutene sticky materials were equally effective and remained durable for 2-3 weeks. The glossy shine of trap surfaces did not have any significant effect on the attraction and landing responses of the two species. The overall trap efficiency of the e.blue/l.blue XT was 23% for G. brevipalpis and 28% for G. austeni, and that of the e.blue/black XT was 16% for G. brevipalpis and 51% for G. austeni. Larger monopanels, painted e.blue/black on both sides, increased the catches of G. austeni females significantly by up to four times compared to the standard e.blue/black XT. This monopanel would be recommended for use as a simple and cost effective survey tool for both species in South Africa.

An update of the tsetse fly (Diptera: Glossinidae) distribution and African animal trypanosomosis prevalence in north-eastern KwaZulu-Natal, South Africa

“…Between 1993 and 1999, extensive tsetse fly surveys were conducted in an area of approximately 12 000 km 2 using odour-bated sticky XT traps (cross-shaped targets) to assess the distribution of each species ( Figure 1a, b ) (Kappmeier & Nevill 1999a , Kappmeier Green & Venter 2007 ). The survey indicated that G. brevipalpis was present in southern and northern bands, commonly associated with game reserves and other protected areas.…”

A distribution model for Glossina brevipalpis and Glossina austeni in Southern Mozambique, Eswatini and South Africa for enhanced area-wide integrated pest management approaches

“…In South Africa the envisaged tsetse infested area (16 000 km 2 ) stretches from around 10 km south of the Mfolozi River in the south, for approximately 190 km, to the border of Mozambique in the north, and from the Indian Ocean coast in the east for 80 km to the Hluhluwe-iMfolozi Park in the west ( Fig 1 ) [ 7 , 8 ]. The infested area extends into the Matutuine District (8 500 km 2 ) (MP) of Mozambique, the northern limit being the Boane and Namaacha Districts of Mozambique [ 6 , 11 ].…”

“…This southern population extends into the neighbouring Maputo Province (MP) of Mozambique [ 6 – 11 ]. Of the 31 described tsetse fly species and subspecies, only two species are found as far south as South Africa, i.e., Glossina brevipalpis Newstead belonging to the Fusca (forest) species group and Glossina austeni Newstead belonging to the Morsitans (savannah) species group [ 1 , 7 , 8 ].…”

“…austeni are confined to pockets of dense vegetation in north-eastern KZN [ 18 – 21 ]. This apparent patchy distribution, in addition to possible low migration potential [ 7 , 18 ], may have resulted in the development of localised genetically isolated population pockets [ 22 ]. Preliminary studies, using molecular and phenetic (geometric morphometrics) markers, however, suggested an absence of significant barriers to gene flow within the pockets of this southern population [ 23 ].…”

“…brevipalpis and G . austeni from north-eastern KZN was proposed in 2007 [ 7 ] and was based on an AW-IPM strategy that includes an SIT component. In the absence of significant barriers to gene flow between the populations of MP, Eswatini, and KZN [ 23 ], the proposed strategy [ 7 ] will have to be adapted to target sequentially the populations in all three countries.…”