Catches of Glossina morsitans morsitans Westwood and G. pallidipes Austen (Diptera: Glossinidae) in odour-baited traps in riverine and deciduous woodlands in the Zambesi Valley of Zimbabwe

1980 ◽  
Vol 70 (4) ◽  
pp. 571-578 ◽  
Author(s):  
J. W. Hargrove ◽  
G. A. Vale
Keyword(s):  
Glossina Morsitans Morsitans ◽  
Dry Season ◽  
Glossina Morsitans ◽  
Male Ratio ◽  
Baited Traps ◽  
Deciduous Woodland ◽  
Hot Dry Season ◽  
Dramatic Rise ◽  
High Level ◽  
Cool Dry Season

AbstractCatches of Glossina morsitans morsitans Westw. and G. pallidipes Aust. were made on electric nets baited with the odour of one ox, in deciduous and riverine woodland in the Zambesi Valley of Zimbabwe. Catches of teneral and mature flies of both sexes and species declined sharply during the hot dry season (September to November) in the deciduous woodland. In the riverine woodland, catches of mature G. m. morsitans increased during this period; catches of mature G. pallidipes rose rapidly to a high level in June (early in the cool dry season), which was maintained for most of the dry season. Catches of teneral flies in the riverine woodland were fairly constant from June to September (the cool dry season and start of the hot dry season) and then declined, though not as sharply as in the deciduous woodland. The percentage of tenerals in the catch showed a minimum at the end of the hot dry season (October–November); at that time there was also a dramatic rise in the female: male ratio in the deciduous woodland, but no such change occurred in the riverine area.

Aspects of the feasibility of employing odour-baited traps for controlling tsetse flies (Diptera: Glossinidae)

1979 ◽  
Vol 69 (2) ◽  
pp. 283-290 ◽  
Author(s):  
J. W. Hargrove ◽  
G. A. Vale
Keyword(s):  
Glossina Morsitans Morsitans ◽  
Dry Season ◽  
Effective Control ◽  
Tsetse Flies ◽  
Population Densities ◽  
Glossina Morsitans ◽  
Baited Traps ◽  
Hot Dry Season ◽  
Trap Catches

AbstractCatches of Glossina morsitans morsitans Westw. and G. pallidipes Aust. attracted to an odour-baited trap in riverine woodland in Rhodesia declined by about three-quarters over a 50-day period in the hot dry season. Concurrent catches from refuges suggested that the decline in trap catches was due to a reduction in population densities rather than a decreasing responsiveness of tsetse to the trap. Of G. pallidipes marked and released 250, 1250 and 2250 m from the trap, the percentages recaptured in the trap after 5 days were about 20, 10 and 4, respectively, and after 40 days about 28, 15 and 13. The sustained responsiveness to the trap and efficiency with which marked flies were removed suggested that odour-baited traps at an economical spacing of roughly one per 10 km2 could produce effective control of G. pallidipes.

A study of the breeding distribution of Glossina morsitans Westw. in northern Botswana

1971 ◽  
Vol 60 (3) ◽  
pp. 415-426 ◽  
Author(s):  
P. R. Atkinson
Keyword(s):  
Total Population ◽  
Dry Season ◽  
Glossina Morsitans ◽  
Breeding Sites ◽  
Hot Dry Season ◽  
Breeding Distribution ◽  
Game Reserve ◽  
Transect Counts

A year-long survey of the breeding of Glossina morsitans Westw. in the Moremi Game Reserve, northern Botswana, was based on transect counts of pupae and empty puparial cases under logs. Levels of breeding were lowest during the hot dry months, and were similar in riverine woodland and mopane even when the latter was leafless: mopane contributed most pupae (65.7%) to the total population because of its greater area. Pupae to cases ratios decreased between February and November due to accumulation of cases, which apparently were largely destroyed in the rains. Comparison of holes, scattered sites and logs in a second survey showed that holes were important breeding sites during the hot dry season, possibly due to their higher humidity, but that at other times most breeding occurred in scattered sites. During the rains scattered sites contained the fewest dead pupae, and holes the most. There was a preference by G. morsitans for shaded sites. Breeding appeared to be depressed during the rains, possibly due to reduced availability of food hosts, particularly warthog.

Responses of Glossina morsitans morsitans Westwood and G. pallidipes Austen (Diptera: Glossinidae) to the skin secretions of oxen

1990 ◽  
Vol 80 (1) ◽  
pp. 91-97 ◽  
Author(s):  
M.L. Warnes
Keyword(s):  
Glossina Morsitans Morsitans ◽  
Active Components ◽  
Glossina Morsitans ◽  
Phenolic Fraction ◽  
Baited Traps ◽  
Landing Response ◽  
Acidic Fraction ◽  
Skin Secretions ◽  
Tsetse Attractants

AbstractIn Zimbabwe, catches of Glossina morsitans morsitans Westwood and G.pallidipes Austen at odour baited traps were increased in the presence of residues of a solution of the skin secretions of oxen (hereafter sebum) by 80% and 29% respectively, and catches at F3 traps were significantly increased when sebum was presented on adjacent screens. Testing of fractions of sebum revealed active components(s) in the phenolic and non-acidic fractions but not in the acidic fraction. Furthermore, the activity of the phenolic fraction could not be explained by the presence of the known phenolic tsetse attractants. The effect of sebum was to attract more flies to the target rather than to induce a landing response in a higher proportion of attracted flies. Whether or not tarsal contact responses are involved remains conjectural. However, targets that were electrified over only one quarter of the surface caught more than one quarter the catch of targets electrified over all the surface both with and without sebum, indicating that many tsetse habitually alight more than once on baited targets. Data on the catches of other Diptera are also presented

Seasonal variation in nutritional levels of male tsetse flies Glossina morsitans morsitans (Diptera: Glossinidae) caught using fly-rounds and electric screens

1999 ◽  
Vol 89 (4) ◽  
pp. 381-387 ◽  
Author(s):  
P. Van den Bossche ◽  
J.W. Hargrove
Keyword(s):  
Dry Weight ◽  
Glossina Morsitans Morsitans ◽  
Tsetse Flies ◽  
Feeding Rates ◽  
Cool Season ◽  
Glossina Morsitans ◽  
Wing Vein ◽  
Annual Cycles ◽  
Hot Dry Season ◽  
Highly Correlated

AbstractA total of 4420 male Glossina morsitans morsitans Westwood were captured on man fly-rounds in Katete District, Eastern Province, Zambia between February 1991 and December 1993. Of these flies, 1680 were captured before June 1992, during which period 989 flies were also captured on odour-baited electric screens operated in the same area. Non-teneral flies were analysed for fat, haematin and residual dry weight and their wing-vein length was measured. There were well marked annual cycles in wing length, fat and residual dry weight. Flies were biggest at the end of the rainy season, and smallest at the end of the hot dry season. Fat levels were lowest before the onset of the rains and highest in the cool season. Residual dry weight was a function of haematin content and the degree of wing-fray; these factors were used to correct the residual dry weight to zero haematin. Corrected residual dry weight and wing-vein lengths were most highly correlated with relative humidity in the month prior to capture (r > 0.8 and 0.6 respectively). Correlations with saturation deficit were weaker; temperature accounted for <20% of the variance. Fly-round flies had a consistently higher residual dry weight than those from the electric screen, but their fat levels were lower. The distributions of log haematin levels differed little between the two sampling methods and were adequately described by a model where capture and feeding rates increased exponentially after each meal. The increase in the feeding rate after each meal differed little with season and was closely similar to that estimated for female G. pallidipesAusten in Zimbabwe.

Wing fray inGlossina morsitans centralisMachado (Diptera: Glossinidae)

1985 ◽  
Vol 75 (1) ◽  
pp. 1-11 ◽  
Author(s):  
R. Allsopp
Keyword(s):  
Population Regulation ◽  
Dry Season ◽  
Tsetse Flies ◽  
Glossina Morsitans ◽  
Reliable Measure ◽  
Very Old ◽  
Glossina Morsitans Centralis ◽  
Hot Dry Season ◽  
The Relationship ◽  
Old Females

AbstractA study of wing fray and ovarian age in females ofGlossina morsitans centralisMachado in Botswana confirmed that although the relationship between the two was strong it varied from month to month. The rate of wing fray with age was greatest in the hot dry season, and in both very young and very old females it was affected by humidity. Both age and activity are manifested as fraying of the wings, but it is considered unlikely that wing fray could be used as a reliable measure of either. It is suggested that wing fray may impose a physiological limitation on the lifespan of tsetse flies and may consequently be a factor in population regulation.

A field trial of pyriproxyfen-treated targets as an alternative method for controlling tsetse (Diptera: Glossinidae)

1993 ◽  
Vol 83 (3) ◽  
pp. 361-368 ◽  
Author(s):  
J. W. Hargrove ◽  
P. A. Langley
Keyword(s):  
Chemical Analysis ◽  
Technical Problem ◽  
Glossina Morsitans Morsitans ◽  
Tsetse Flies ◽  
Research Station ◽  
Glossina Morsitans ◽  
Tsetse Control ◽  
Tsetse Population ◽  
Hot Dry Season ◽  
Juvenile Hormone Mimic

AbstractA juvenile hormone mimic (pyriproxyfen) was used with odour-baited targets to assess its suitability for controlling tsetse flies (Glossina spp.). In August 1991, 41 odour-baited targets identical to those used with insecticide in tsetse control operations, were each treated with 4 g of pyriproxyfen and deployed near Rekomitjie Research Station, Zambezi Valley, Zimbabwe, in a 12.3 km2 block of woodland habitat of Glossina morsitans morsitans Westwood and G. pallidipes Austen. After three months, emergence rates from puparia of the two species collected in the block fell to 34% and 20% of control levels; 50 and 70%, respectively, of puparia of the two species collected were found, on dissection, to show arrested development. Changes in mean ovarian age and wing-fray category in the tsetse population during the trial were due partially to the pyriproxyfen and partially to high mortality, in the larval/pupal stages and in young adult flies, which occurs each year in the hot/dry season. Chemical analysis of cloth samples indicated that after four months 68–85% of the pyriproxyfen had been lost, a large proportion apparently dripping off the bottom of the target. If the technical problem of persistence can be solved pyriproxyfen could substitute for pesticides in target-based tsetse control operations.

The dispersion of active Glossina morsitans morsitans Westwood and G. pallidipes Austen (Diptera: Glossinidae) near a large tree and an assessment of the capturing method used

1980 ◽  
Vol 70 (3) ◽  
pp. 455-466 ◽  
Author(s):  
R. J. Phelps ◽  
N. G. Chapman
Keyword(s):  
Glossina Pallidipes ◽  
Glossina Morsitans Morsitans ◽  
Diurnal Variations ◽  
Tsetse Flies ◽  
Glossina Morsitans ◽  
Late Afternoon ◽  
Large Tree ◽  
Hot Dry Season ◽  
Different Seasons ◽  
Representative Samples

AbstractLarge electrocuting nets were used at different seasons near a big tree in Zimbabwe to capture tsetse flies at different heights, distances from the bole and times of day. Some differences were found between species and sexes, but most flies were caught within 3·3 m of the ground and in the late afternoon. In the cool and wet seasons, Glossina pallidipes Aust. was less confined to lower levels than was G. morsitans morsitans Westw. Flies, especially fed males of G. pallidipes near the bole of the tree, were recorded in the greatest numbers in the midday period. Diurnal variations occurred in the relative proportions of females of the two species caught at different points. Releasing ox odour through an electrocuting net suspended at different heights confirmed that most flies were flying near the ground, especially in the hot dry season. Comparison of samples from the large electrocuting nets with those caught by other methods operated contemporaneously showed that the large nets gave samples which compared well with those from an electrocuting screen used in conjunction with a ventilated pit. Methods involving fly-capture by people gave very distorted results for all catch parameters examined. No method used gave consistently representative samples of replete flies or of newly emerged flies.

Prospects for autosterilisation of tsetse flies, Glossina spp. (Diptera: Glossinidae), using sex pheromone and bisazir in the field

1982 ◽  
Vol 72 (2) ◽  
pp. 319-327 ◽  
Author(s):  
P. A. Langley ◽  
T. W. Coates ◽  
D. A. Carlson ◽  
G. A. Vale ◽  
J. Marshall
Keyword(s):  
Carbon Dioxide ◽  
Average Duration ◽  
Laboratory Data ◽  
Response Duration ◽  
Glossina Morsitans Morsitans ◽  
Tsetse Flies ◽  
Glossina Morsitans ◽  
Stationary Model ◽  
Duration Of Copulation ◽  
Hot Dry Season

AbstractIn the presence of the odour of carbon dioxide and acetone, an electrified net adjacent to a stationary cylindrical black model in the Zambezi Valley, Zimbabwe, in the hot dry season caught more adults of Glossina morsitans morsitans Westw. and G. pallidipes Aust. than in the absence of odour. In the absence of odour, a moving model attracted more G. m. morsitans males than did a stationary model. Between 20 and 50% of males of G. m. morsitans but only 0 to 12% of males of G. pallidipes near a model were caught by electrified decoys (surrogate females) on the model. Hidden observers recorded the numbers of flies copulating with decoys baited with pheromone or pheromone plus bisazir (P, P-bis(1-aziridinyl)-N-methylphosphinothioic amide) on a stationary model with odour between 16.00 and 19.00 h daily. Males of G. m. morsitans contacted the decoys with much greater frequency than did males of G. pallidipes although the latter species was the more abundant. The numbers of copulatory attempts by G. m. morsitans males during each 10 min suggested that changes were a function of the total numbers of flies attracted to the model. At all times of the day, the average duration of copulation was 37–40 s. However, approximately 50% of responses were of 10 s duration or less and fewer than 10% endured for longer than 3 min. The presence of bisazir on the decoys did not influence the response duration or the total numbers of flies responding. A comparison with laboratory data suggested that further refinement of technique will allow pheromone-baited decoys to be used in the autosterilisation of G. m. morsitans males with bisazir in the field.

Growth of Bauhinia thonningii trees and saplings over a decade in a savanna in Zambia: interactions of climate, fire and source of regeneration

2008 ◽  
Vol 24 (4) ◽  
pp. 407-415 ◽  
Author(s):  
Emmanuel Ngulube Chidumayo
Keyword(s):  
Radial Growth ◽  
Plant Size ◽  
Height Growth ◽  
Dry Season ◽  
Tree Size ◽  
Maximum Temperature ◽  
Climate Factors ◽  
Growth Responses ◽  
Hot Dry Season ◽  
Cool Dry Season

AbstractThe present study investigated how climate and plant size affect the growth of Bauhinia thonningii and how fire and source of regeneration (grown from coppice versus seedlings) might modify the results. The study was conducted over a period of 10 y, from 1997 to 2007, at a savanna site in central Zambia. Trees were marked and monitored throughout the entire period; they showed a phase of declining growth (1998–2003) and a phase of low growth (2004–2007). During the phase of declining growth autocorrelation was high but either weakened or disappeared during the phase of low growth. After adjusting data for autocorrelation, climate factors and tree size accounted for between 14% and 35% of the variation in annual tree radial growth. However, the growth responses of trees to climate factors and tree size varied with the source of regeneration (i.e. coppice or seedling) and fire treatment. Trees of seedling origin were only affected by climate factors and tree size when exposed to annual burning whereas all trees of coppice origin were significantly affected by climate factors and tree size, regardless of the fire treatment. However, basal radial growth of saplings that were monitored for 4 y (2003–2007) was significantly influenced by maximum temperature and rainfall that accounted for 33–47% of the variance in annual radial growth under fire protection. Saplings recovered from shoot die-back during the cool dry season by resprouting in the hot dry season and this annual die-back slowed the height growth of B. thonningii saplings.

Relative humidity in the breeding sites of Glossina morsitans Westw. in northern Botswana

1971 ◽  
Vol 61 (2) ◽  
pp. 241-246 ◽  
Author(s):  
P. R. Atkinson
Keyword(s):  
Relative Humidity ◽  
Site Selection ◽  
Dry Season ◽  
Mortality Data ◽  
Glossina Morsitans ◽  
Breeding Sites ◽  
Hot Dry Season ◽  
Humidity Measurements ◽  
Tree Holes ◽  
Pupal Mortality

Humidity measurements in air spaces in the soil of Glossina morsitans Westw. breeding sites during the hot-dry season in northern Bostwana proved that ground holes were significantly more humid than tree holes, fallen logs or leaves. Site humidity decreased between September and October but did not differ significantly between riverine and mopane woodlands. Pupal mortality data demonstrated an apparent advantage in the dry season shift of breeding to holes. The evidence is only circumstantial that humidity is involved in site selection.

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