Postmating barriers to gene flow among species and subspecies of tsetse flies (Diptera: Glossinidae)

1990 ◽  
Vol 68 (8) ◽  
pp. 1727-1734 ◽  
Author(s):  
R. H. Gooding

Postmating barriers to gene flow between closely related species and subspecies of tsetse flies include (i) reduced fecundity of hybridized and hybrid females and (ii) sterility of hybrid and backcross males, owing mainly to incompatibility between X and Y chromosomes from two different taxa or, possibly, incompatibility between the X from one taxon and autosomes from the other. There are also maternally inherited factors that confer unidirectional sterility upon males; these factors may influence the direction of gene flow. When Glossina morsitans morsitans and Glossina morsitans centralis are crossed, these factors appear to be unstable and lose their effectiveness as barriers to gene flow when hybrid females, from several consecutive generations, are backcrossed to G. m. centralis. In hybrid females of the morsitans group, intrachromosomal recombination is suppressed in the X chromosomes, but it may occur at near normal levels in at least part of linkage group II. Some backcross flies with chromosomes composed of segments from two different taxa are fertile. Naturally occurring hybrids have been found, but it appears that hybridization zones are narrow. It remains to be determined whether introgression of genes plays a significant role in the evolution of tsetse flies.

1989 ◽  
Vol 67 (4) ◽  
pp. 869-871 ◽  
Author(s):  
R. H. Gooding

In hybrid females of Glossina morsitans morsitans Westwood and Glossina morsitans centralis Machado that carried four well-separated marker genes, suppression of intrachromosomal recombination occurred between the loci for glucose-6-phosphate dehydrogenase (G6pd) and arginine phosphokinase (Apk) on the X chromosome. Fertility of backcross females was not influenced by whether they mated with G. m. morsitans or G. m. centralis, but it was higher in females that received both of their X chromosomes from G. m. morsitans than it was in females that received one X chromosome from G. m. morsitans and the other from G. m. centralis.


1988 ◽  
Vol 78 (2) ◽  
pp. 293-300 ◽  
Author(s):  
G. A. Vale ◽  
D. R. Hall ◽  
A. J. E. Gough

AbstractIn Zimbabwe, catches of Glossina morsitans morsitans Westwood and G. pallidipes Austen in traps baited with acetone and 1-octen-3-ol were increased by the addition of the synthetic mixture of eight phenols found in cattle urine to a level equal to or greater than those with natural urine. The addition of natural urine to the synthetic mixture did not increase catches further, indicating that the phenols account for essentially all the attractiveness of cattle urine. 4-Methylphenol and 3-n-propylphenol were shown to be the naturally-occurring components essential for attractiveness, and 2-methoxyphenol was found to reduce attractiveness. 4-Methylphenol alone was slightly attractive to both species, but only for males, increasing catches by approximately 30%. Catches of both species were increased by approximately 50% by 3-n-propylphenol. The addition of 4-methylphenol increased catches of G. pallidipes by up to a further four times, but catches of G. m. morsitans were decreased. Of 14 other phenols tested, phenol, 3-methylphenol and 4-ethylphenol increased the attractiveness of 3-n-propylphenol to G. pallidipes without decreasing the attractiveness to G. m. morsitans; (E)- and (Z)-3-(1-propenyl)phenol, potential contaminants in 3-n- propylphenol, did not reduce the attractiveness of mixtures of 3-n-propylphenol and 4-methylphenol, and the E and, to a lesser extent, the Z isomer could substitute for 3-n-pro-pylphenol in these mixtures. Mixtures of phenols which increased the attractiveness of traps to tsetse showed similar effects with targets but at a slightly reduced level.


1988 ◽  
Vol 66 (6) ◽  
pp. 1289-1292 ◽  
Author(s):  
R. H. Gooding

A significant proportion of post-teneral male Glossina morsitans morsitans Westwood and post-teneral male and female Glossina morsitans centralis Machado develop mature infections of Trypanosoma brucei brucei Plimmer and Bradford without being starved before feeding upon infected rabbits.


2021 ◽  
Vol 15 (7) ◽  
pp. e0009620
Author(s):  
Jackson Muyobela ◽  
Christian W. W. Pirk ◽  
Abdullahi A. Yusuf ◽  
Njelembo J. Mbewe ◽  
Catherine L. Sole

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.


1985 ◽  
Vol 63 (11) ◽  
pp. 2694-2702 ◽  
Author(s):  
R. H. Gooding

Two colonies of Glossina morsitans morsitans Westwood, two colonies of Glossina morsitans submorsitans Newstead, and one colony of Glossina morsitans centralis Machado, each originating from a different geographic location, were compared genetically and by their ability to hybridize. There were marked asymmetries in results of intersubspecific hybridization. Most F1 males were sterile but most F1 females were fertile. Nei's mean genetic identity (based on 12 loci) and four hybridization indices (based upon proportion of females fertilized, puparia produced per fertilized female, F1 adults per fertilized female, and proportion of females fertilized in backcross experiments) yielded the same results: intrasubspecific similarities are greater than intersubspecific similarities, and G. m. centralis is more similar to G. m. morsitans than it is to G. m. submorsitans. Evidence is presented indicating that a phenogram based upon allele frequencies is as good as phenograms based upon hybridization as a means of representing relationships among tsetse flies.


1987 ◽  
Vol 65 (3) ◽  
pp. 640-646 ◽  
Author(s):  
R. H. Gooding

Glossina morsitans morsitans Westwood and Glossina morsitans centralis Machado carrying from one to three marker genes on each chromosome were hybridized. F1 females were backcrossed and the resulting backcross males were tested for their ability to inseminate and to fertilize both G. m. morsitans and G. m. centralis; these abilities were then related to the genetic constitution of each male. Hybrid males having an X chromosome from one subspecies and a Y chromosome from the other were sterile, as were about half the males having X and Y chromosomes from the same subspecies. There is weak evidence for autosomal involvement in hybrid sterility but this involvement is not through genetical recombination between the loci Ao and Xo, nor does it depend upon the number of autosomes from the same taxon as the sex chromosomes. Hybrid males descending from G. m. morsitans females could not fertilize G. m. centralis although they could inseminate them. F1 hybrid females had lower than expected intrachromosomal recombination in the X chromosome and in linkage group II, and hybrid females tended to use autosomes of G. m. centralis origin more frequently than chromosomes from G. m. morsitans. Models for evolution of the maternally inherited sterility factor(s) suggest that G. m. centralis is ancestral to G. m. morsitans. Use of hybrid males descending from female G. m. morsitans for genetic control of G. m. centralis is proposed.


1988 ◽  
Vol 78 (2) ◽  
pp. 281-291 ◽  
Author(s):  
E. Bursell ◽  
A. J. E. Gough ◽  
P. S. Beevor ◽  
A. Cork ◽  
D. R. Hall ◽  
...  

AbstractThe attractiveness of cattle urine to Glossina morsitans morsitans Westwood and G. pallidipes Austen was shown to be entirely attributable to the phenolic components which it contains. Four of the eight naturally occurring phenol derivatives (3- and 4-methylphenol, 3-ethylphenol and 3-n-propylphenol) were electroantennographically active, induced upwind flight in wind-tunnel bioassays and increased trap catches in field tests in Zimbabwe. One of the minor components, 2-methoxyphenol, had little antennographic activity but induced upwind flight in the wind-tunnel and appeared to be repellent in field tests.


1953 ◽  
Vol 44 (4) ◽  
pp. 627-640 ◽  
Author(s):  
K. S. Hocking ◽  
H. C. M. Parr ◽  
D. Yeo ◽  
D. Anstey

Attempts have been made to eradicate the tsetse flies G. morsitans and G. swynnertoni from two blocks of savannah woodland situated in the Central Province of Tanganyika.The insecticides were applied from aircraft. Coarse aerosols were used, with mass median diameters of approximately 90 microns; droplet diameters varied from 4 microns to 250 microns approximately.Eight applications of insecticides were made at intervals of two weeks. Each application was carried out at a nominal dosage of 0·25 gallons per acre, which was equivalent to 0·20 1b. per acre of the p, p'isomer of DDT or 0·03 lb. per acre of the γ isomer of BHC.In the area treated with DDT it is possible that both species of flies were eradicated for a short period, but small populations were re-established there by immigrant flies. In the other block the reduction was not so great, but it is not considered that this was due to a lesser effectiveness of the BHC, but to a combination of circumstances that led to less effective applications.Some general observations are made upon the use of aircraft for this sort of work, particularly in connection with the effect of meteorological conditions.


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