Studies on the flight of black-flies (Diptera:Simuliidae). II. Flight performance of three cytospecies in the complex of Simulium damnosum Theobald

1983 ◽  
Vol 73 (2) ◽  
pp. 275-288 ◽  
Author(s):  
R. J. Cooter
Keyword(s):  
Sucrose Solution ◽  
West African ◽  
Flight Performance ◽  
Black Flies ◽  
Flight Duration ◽  
Frequency Distributions ◽  
Simulium Damnosum ◽  
Long Duration ◽  
Migration Potential ◽  
Access To Water

AbstractThe flight performance of three cytospecies from the West African complex of Simulium damnosum Theo. was tested under controlled laboratory conditions. A total of 293 individuals (174 of S. squamosum (End.), 65 of a new form of the subgroup of S. soubrense Vajime & Dunbar and S. sanctipauli Vajime & Dunbar and 54 of S. sirbanum Vajime & Dunbar) was tested on 526 occasions, of which 380 involved sucrose-fed insects, 65 water-only-fed insects, of both sexes, from laboratory-emerged stock and 81 blood-fed, wild-caught females. A high percentage of tests resulted in flights. Frequency distributions of both flight duration and distance flown were skewed, more flights being of short than of long duration. Sucrose-fed females and females caught wild at human bait generally flew well. Insects given access to water only made short flights, but S. sirbanum flew fairly well under these conditions. The recorded maximum flight durations and distances were 262 min (in a male) and 5·25 km (in a female) in S. squamosum, 282 min (in a male) and 6·15 km (in a male) in S. soubrense/sanctipauli, and 186 min (in a female) and 5 27 km (in a female) in S. sirbanum, all from sucrose-fed groups. Some insects were flown on several days up to 11 days after emergence. Some insects made long flights on one day but not on others. Further long flights could be induced on the same day if the insect was allowed access to sucrose solution prior to retesting. These results are discussed in relation to previous findings from S. ornatum Mg. s.l. and to the migration potential of the important vectors of onchocerciasis in West Africa.

Studies on the flight of black-flies (Diptera: Simuliidae). I. Flight performance ofSimulium ornatumMeigen

1982 ◽  
Vol 72 (2) ◽  
pp. 303-317 ◽  
Author(s):  
R. J. Cooter
Keyword(s):  
Sucrose Solution ◽  
Maximum Speed ◽  
Absolute Maximum ◽  
Flight Performance ◽  
Black Flies ◽  
Flight Duration ◽  
Average Speed ◽  
Maximum Duration ◽  
High Level ◽  
Age Range

AbstractThe flight performance ofSimulium ornatumMg. s.l. was measured under laboratory conditions using a simple flight mill. Males and unmated females were flown and the duration, distance and average speed of flight were recorded for adults fed on water only, sucrose, blood & water, or blood & sucrose. On 91% of all test occasions sucrose-fed insects flew but 25% of those on water only did not fly. Feeding flies on 10% sucrose solution markedly improved both willingness to fly and flight performance, and under these conditions maximum duration, distance and average speed recorded were 4.9 h, 4·2 km and 2·84 km/h, respectively. The ratio of average to maximum speed was 0·631 for females and 0·610 for males, with absolute maximum speeds of 3·19 and 2·99 km/h, respectively. Duration and distance flown were well-correlated, speed being the least variable aspect of flight performance measured. The distributions of flight duration and distance flown were skewed such that few insects made long flights. Mean flight performance at different ages was measured; unmated females appeared to retain a high level of willingness to fly throughout the age-range tested (up to 33 days). The longest recorded flight (5·3 h) was made by a female during an overnight experiment. The implications for long-range flight movements by simuliids are discussed.

Displacements of Simulium damnosum and strategy of control against onchocerciasis

1979 ◽  
Vol 287 (1022) ◽  
pp. 277-288 ◽  
Keyword(s):  
Sensu Stricto ◽  
Control Programme ◽  
West African ◽  
Simulium Damnosum ◽  
Logistic Problem ◽  
Degree Of Control ◽  
High Degree ◽  
Onchocerciasis Control ◽  
Upper Volta ◽  
West African Savannah

Regular aerial treatment of 14000 km of watercourses has achieved and maintained, over an area of 700000 km 2 of West African savannah, a very high degree of control of the larvae of Simulium damnosum sensu stricto and S. sibanum , the vectors of onchocerciasis in this area. However, particular and relatively restricted parts of this area, mainly in northern Ivory Coast and neighbouring parts of Upper Volta, experience regular and prolonged reinvasions by parous female vectors, which have already taken bloodmeals (and many of them carrying the parasites) and arrive from unknown sources probably hundreds of kilometres away, from directions probably between southwest and north. This reinvasion, now experienced in three successive years, represents the outstanding scientific, epidemiological and logistic problem still facing the WHO Onchocerciasis Control Programme. An outline is presented of the multidisciplinary investigations being undertaken to find a solution.

scholarly journals An entomological study of onchocerciasis vectors, Simulium damnosum s.l., in Kinshasa, Democratic Republic of Congo

2021 ◽  
Author(s):  
Jean-Claude MAKENGA BOF ◽  
Paul MANSIANGI ◽  
Josué ZANGA ◽  
Félicien ILUNGA ◽  
Yves COPPIETERS
Keyword(s):  
Aquatic Plants ◽  
Democratic Republic Of Congo ◽  
Abundant Species ◽  
Host Population ◽  
Black Flies ◽  
River Blindness ◽  
Transmission Potential ◽  
Simulium Damnosum ◽  
Plastic Bags ◽  
Biting Rate

Abstract Background Onchocerciasis, a parasitic disease caused by the filarial worm Onchocerca volvulus transmitted through the bite of Simulium (black flies), is a cause of global concern, with the African population being majorly affected. This study focused on the bite rates, bite cycle, and transmission potential of Simulium damnosum s.l. in two sites with river blindness outbreaks in Kinshasa, DRC: Gombe (S1) and Mont-Ngafula at Kimwenza (S2). Methods From August 1, 2019, to July 31, 2020, we captured adult female black flies near breeding sites along the Congo River at S1 and Lukaya Valley at S2. Collections using human baits at the two sites were conducted for five days/month. Results A total of 6082 black flies of species Simulium squamosum (classified based on other entomological surveys) were captured during the study period. The daily cycle of aggression revealed two peaks: one between 8 and 9 a.m. and the other between 4 and 5 p.m. Low bite rates were observed between 11 a.m. and 1 p.m. The annual biting rate/person reached 13,463 in S1 and 23,638 in S2, with a total of 37,101 bites/person. The average daily biting rate, 37 ± 10 and 69 ± 23 bites/day/person in S1 and S2, respectively, did not differ significantly (P = 0.8901). The high density of the host population can disrupt the transmission of vector-borne diseases by diluting the transmission indices. There was no evidence of onchocerciasis transmission at the study sites because of inadequate laboratory facilities in the DRC. Various larval supports have been identified: at Gombe: aquatic plants, plastic bags, dead leaves, and rocks; at Kimwenza: Ledermaniella ledermanii (the most abundant species at the site), plastic bags, artificial waste, and aquatic plants. Conclusions The study provides further evidence for the need for alternative strategies to eliminate the parasite in the formerly hyper-endemic foci.

scholarly journals The long duration cryogenic system of the OLIMPO balloon–borne experiment: Design and in–flight performance

Cryogenics ◽  
2020 ◽  
Vol 110 ◽  
pp. 103129
Author(s):  
A. Coppolecchia ◽  
L. Lamagna ◽  
S. Masi ◽  
P.A.R. Ade ◽  
G. Amico ◽  
...  
Keyword(s):  
Experiment Design ◽  
Cryogenic System ◽  
Flight Performance ◽  
Long Duration

Age and growth of the squid Todaropsis eblanae (Cephalopoda: Ommastrephidae) on the north-west African shelf

2000 ◽  
Vol 80 (4) ◽  
pp. 747-748 ◽  
Author(s):  
Alexander I. Arkhipkin ◽  
Vladimir V. Laptikhovsky
Keyword(s):  
High Growth ◽  
West African ◽  
Age And Growth ◽  
Length Frequency ◽  
Annual Life Cycle ◽  
Frequency Distributions ◽  
North West ◽  
The North ◽  
West African Coast ◽  
African Coast

Length composition, maturation and growth of the ommastrephid squid Todaropsis eblanae were studied using length–frequency distributions (LFDs) and statoliths of squid caught off the north-west African coast. Length–frequency distributions were quite similar in all seasons studied, indicating all year round spawning. However, both high proportions of mature squid in the winter and the hatching peak of squid from our sample in spring suggested the winter–spring peak of spawning. Immature and maturing squid had rather high growth rates, attaining 140—150 mm of dorsal mantle length (ML) by the age of 160—170 d. Todaropsis eblanae is likely to have an annual life cycle on the north-west African shelf.

scholarly journals Onchocerca volvulus transmission in the Mbam valley of Cameroon following 16 years of annual community-directed treatment with ivermectin, and the description of a new cytotype of Simulium squamosum

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Adam Hendy ◽  
Meryam Krit ◽  
Kenneth Pfarr ◽  
Christine Laemmer ◽  
Jacobus De Witte ◽  
...  
Keyword(s):  
Dry Season ◽  
Onchocerca Volvulus ◽  
Black Flies ◽  
Infection Rates ◽  
Transmission Rates ◽  
Pool Screening ◽  
Simulium Damnosum ◽  
First Time

Abstract Background The onchocerciasis focus surrounding the lower Mbam and Sanaga rivers, where Onchocerca volvulus is transmitted by Simulium damnosum s.l. (Diptera: Simuliidae), was historically the largest in the southern regions of Cameroon. Annual community-directed treatment with ivermectin (CDTI) has been taking place since 2000, but recent studies have shown that new infections are occurring in children. We aimed to investigate blackfly biting and O. volvulus transmission rates along the lower Mbam river 16 years after the formal onset of annual CDTI. Methods Black flies were collected for three consecutive days each month between July 2016 and June 2017 at two riverside villages and two inland sites situated 4.9 km and 7.9 km from the riverside. Specimens collected at each site were dissected on one of the three collection days each month to estimate parity rates and O. volvulus infection rates, while the remaining samples were preserved for pool screening. Results In total, 93,573 S. damnosum s.l. black flies were recorded biting humans and 9281 were dissected. Annual biting rates of up to 606,370 were estimated at the riverside, decreasing to 20,540 at 7.9 km, while, based on dissections, annual transmission potentials of up to 4488 were estimated at the riverside, decreasing to 102 and 0 at 4.9 km and 7.9 km, respectively. However, pool screening showed evidence of infection in black flies at the furthest distance from the river. Results of both methods demonstrated the percentage of infective flies to be relatively low (0.10–0.36%), but above the WHO threshold for interruption of transmission. In addition, a small number of larvae collected during the dry season revealed the presence of Simulium squamosum E. This is the first time S. squamosum E has been found east of Lake Volta in Ghana, but our material was chromosomally distinctive, and we call it S. squamosum E2. Conclusions Relatively low O. volvulus infection rates appear to be offset by extremely high densities of biting black flies which are sustaining transmission along the banks of the lower Mbam river. Graphical Abstract

scholarly journals Metabolic reduction after long-duration flight is not related to fat-free mass loss or flight duration in a migratory passerine

2020 ◽  
Vol 223 (19) ◽  
pp. jeb215384
Author(s):  
Alexander R. Gerson ◽  
Joely G. DeSimone ◽  
Elizabeth C. Black ◽  
Morag F. Dick ◽  
Derrick J. Groom
Keyword(s):  
Metabolic Rate ◽  
Mass Loss ◽  
Body Mass ◽  
Lean Mass ◽  
Migratory Birds ◽  
Resting Metabolic Rate ◽  
Fat Free Mass ◽  
Flight Duration ◽  
Long Duration ◽  
Resting Metabolism

ABSTRACTMigratory birds catabolize large quantities of protein during long flights, resulting in dramatic reductions in organ and muscle mass. One of the many hypotheses to explain this phenomenon is that decrease in lean mass is associated with reduced resting metabolism, saving energy after flight during refueling. However, the relationship between lean body mass and resting metabolic rate remains unclear. Furthermore, the coupling of lean mass with resting metabolic rate and with peak metabolic rate before and after long-duration flight have not previously been explored. We flew migratory yellow-rumped warblers (Setophaga coronata) in a wind tunnel under one of two humidity regimes to manipulate the rate of lean mass loss in flight, decoupling flight duration from total lean mass loss. Before and after long-duration flights, we measured resting and peak metabolism, and also measured fat mass and lean body mass using quantitative magnetic resonance. Flight duration ranged from 28 min to 600 min, and birds flying under dehydrating conditions lost more fat-free mass than those flying under humid conditions. After flight, there was a 14% reduction in resting metabolism but no change in peak metabolism. Interestingly, the reduction in resting metabolism was unrelated to flight duration or to change in fat-free body mass, indicating that protein metabolism in flight is unlikely to have evolved as an energy-saving measure to aid stopover refueling, but metabolic reduction itself is likely to be beneficial to migratory birds arriving in novel habitats.

Midgut Endocrine Cells in the Mosouito, Aedes Aegypti

1985 ◽  
Vol 43 ◽  
pp. 500-501
Author(s):  
Mark R. Brown
Keyword(s):  
Endocrine Cells ◽  
Sucrose Solution ◽  
Secretory Process ◽  
Solution Ph ◽  
Thin Sections ◽  
Rabbit Igg ◽  
Access To Water ◽  
A Cell ◽  
Immuno Cytochemistry ◽  
Glucagon And Insulin

The ultrastructure of a cell type in the insect midgut resembles that of peptide hormonogenic cells in the vertebrate gut. Also, vertebrate-like peptides such as pancreatic polypeptide (PP), glucagon, and insulin have been detected by immunoassays in insect midguts. Research was initiated to characterize the endocrine cells in the mosquito midgut, determine their immunoreactivity to antisera against vertebrate peptide hormones, and to identify organelles related to secretion of the hormones.Female mosquitos had access to water or a sucrose solution for 7 days. Midguts from the insects were processed for TEM by routine methods. To assess the role of lysosomal enzymes in the secretory process, midguts were incubated in cerium-based medium for acid phosphatase histochemistry. For immuno-cytochemistry, midguts were fixed in a modified Bouin's solution (pH 7.6) and 156 glutaraldehyde for 1 hr and embedded in epon/araldite. Thin sections of midgut on nickel grids were sequencially emersed in filtered rabbit antisera to PP, 1:1000 in 0.05M Tris (pH 7.6); anti-rabbit IgG, 1:20; and PAP, 1:200.

Tethered flight and morphometric studies with Cicadulina storeyi and C. mbila leafhoppers (Hemiptera: Cicadellidae) vectors of maize streak virus in Uganda

1998 ◽  
Vol 88 (2) ◽  
pp. 117-125 ◽  
Author(s):  
M.C.A. Downham ◽  
R.J. Cooter
Keyword(s):  
Wing Length ◽  
Maize Streak Virus ◽  
Conclusive Evidence ◽  
Morphometric Parameters ◽  
Streak Virus ◽  
Environmental Constraints ◽  
Flight Duration ◽  
Migratory Flight ◽  
Long Duration ◽  
Tethered Flight

AbstractTethered flight studies, carried out in southern Uganda with the leafhoppers Cicadulina storeyi China and C. mbila Naudé, showed that depending on species, the factors of age, gender, gravid status and rearing on virus infected maize had significant effects on flight, whereas host plant species and mated status appeared unimportant. Distributions of wing length (WL), body length (BL) and the parameters WL/BL and WL-BL were mostly uni-modal, but in two cases very weakly bi-modal. Regressions of log-transformed flight duration against these morphometric parameters were all non-significant, except for very weak (r2 = 0.01–0.04) relations with wing length. There was no conclusive evidence for the existence of separate short- and long-duration flight morphs among the leafhoppers. It is proposed that differences between our results and those of an earlier study of Zimbabwean Cicadulina populations, particularly in respect of the effects of gravid status on flight, and the existence of distinct flight morphs, are explicable in terms of the different seasonal and environmental constraints experienced by Ugandan and Zimbabwean populations. These favour long-range migratory flight at certain times of the year in Zimbabwe, but not in Uganda.

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