The origin of phenolic tsetse attractants from host urine: Studies on the pro-attractants and microbes involved

Okech, Matilda A.; Hassanali, Ahmed

doi:10.1017/s1742758400012789

Cited by 20 publications

(21 citation statements)

References 8 publications

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“…Evidently this was associated with ageing of the urine. This is what might have been expected if the urine had not been refrigerated, as under natural conditions the phenolic component of fresh urine is low, with some days of microbial activity required for the phenols to be formed (Okech & Hassanali, 1990). Madunbunyi et al .…”

Section: Discussionmentioning

confidence: 92%

Field studies on efficacy of host odour baits for the biting midge Culicoides impunctatus in Scotland

Bhasin

Luntz

Mordue

2001

Medical Vet Entomology

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The efficacy of some putative attractants for the biting midge Culicoides impunctatus (Goetghebuer) (Diptera: Ceratopogonidae) was assessed using odour-baited 'delta traps' and suction traps. 1-octen-3-ol was confirmed as a potent olfactory attractant for C. impunctatus when released at 0.06mg/h. Acetone (23mg/h) and a mix of six phenolic compounds (phenol, 3-ethylphenol, 4-ethylphenol, 3-methylphenol, 4-methylphenol and 4-propylphenol), at undetermined release rate, also significantly increased delta trap catches compared to unbaited controls. When tested in combination, there was evidence of synergism between CO2 (0.2L/min) and acetone, 1-octen-3-ol or cow urine, trap catches being, respectively, 4.7, 6.2 and 9.3-fold greater than for CO2 alone. Highest catches were obtained with triple bait combinations comprising cow urine + acetone + CO2 or cow urine + 1-octen-3-ol+CO2, which increased trap catches by X 22 and X 24, respectively, compared to CO2 alone. Culicoides impunctatus was found to be extremely sensitive to CO2 and responses, gauged over two field seasons, showed a significant dose-dependent increase in catch across the entire range of release rates (0.2-2.5 L/min). Responses to these release rates, ranging from small to large mammal equivalents, emphasized the important role of CO2 in host location by C. impunctatus. Uses of olfactory attractants for monitoring and control of Culicoides are reviewed on the basis of these results.

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Section: Discussionmentioning

confidence: 92%

Field studies on efficacy of host odour baits for the biting midge Culicoides impunctatus in Scotland

Bhasin

Luntz

Mordue

2001

Medical Vet Entomology

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“…Reducing the ring size to five membered ring (γ-heptalactone) was found to significantly (P < 0.05) reduce repellency to both tsetse species. However, increasing the ring to seven members (ε-nonalactone) transformed the molecule to an attractant of comparable potency with the phenolic blend of fermented cow urine (Okech and Hassanali, 1990). Reduction of the alkyl side chain of δ-octalactone from a 3-carbon to a 2-carbon (CH 3 CH 2 ) ethyl unit gave a structure (δ-heptalactone) with reduced repellency (P < 0.05).…”

Section: 0 Discussionmentioning

confidence: 99%

Responses of Glossina pallidipes and Glossina morsitans morsitans tsetse flies to analogues of δ-octalactone and selected blends

et al. 2016

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Previous studies have shown that δ-octalactone is an important component of the tsetse-refractory waterbuck (Kobus defassa) repellent odour blend. In the present study, structure-activity comparison was undertaken to determine the effects of the length of the side chain and ring size of the lactone on adult Glossina pallidipes and Glossina morsitans morsitans. The responses of the flies to each compound were studied in a two-choice wind tunnel. Increasing the chain length from C3 (δ-octalactone) to C4 (δ-nonalactone) enhanced repellency to both species (G. pallidipes from 60.0 to 72.0 %, and G. m. morsitans from 61.3 to 72.6 %), while increasing the ring size from six (δ-octalactone) to seven members (ε-nonalactone) changed the activity from repellency to attraction that was comparable to that of the phenolic blend associated with fermented cow urine (p > 0.05). Blending δ-nonalactone with 4-methylguaiacol (known tsetse repellent) significantly (p < 0.05) raised repellency to 86.7 and 91.7 % against G. pallidipes and G. m. morsitans respectively. Follow-up Latin Square Designed field studies (Shimba hills in coastal areas in Kenya) with G. pallidipes populations confirmed the higher repellence of δ-nonalactone (with/without 4-methylguaiacol) compared to δ-octalactone (also, with/without 4-methylguaiacol). The results show that subtle structural changes of olfactory signals can significantly change their interactions with olfactory receptor neurons, and either shift their potency, or change their activity from repellence to attraction. Our results also lay down useful groundwork in the development of more effective control of tsetse by ‘push’, ‘pull’ and ‘push-pull’ tsetse control tactics.

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“…In the field, the attractiveness of the three types of urine was quite similar despite some differences in the catch index. Aged urine gradually accumulates phenolic attractants as a result of microbial activity (Okech & Hassanali, 1990) and probably many other active chemicals that may have indifferent or repellent effects. Mammal urines and their phenol constituents (3‐methylphenol, 4‐methylphenol, 3‐ n ‐propylphenol) have been tested in outdoor experiments in tabanids with contrasting results (Gibson & Torr, 1999; Mihok & Mulye, 2010).…”

Section: Discussionmentioning

confidence: 99%

Behavioural and electrophysiological responses of females of two species of tabanid to volatiles in urine of different mammals

Baldacchino

Cadier

Porciani

et al. 2012

Medical Vet Entomology

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Urine volatiles from different ungulates (cows, horses and sheep) were tested as bait for tabanids in southeastern France using Nzi traps during the early summer of 2011. Tabanus bromius Linnaeus, 1758 and Atylotus quadrifarius (Loew, 1874) (both: Diptera: Tabanidae) were the most captured species, respectively representing 57% and 41% of all tabanids collected (all of which were female). Horse urine significantly increased catches of T. bromius (1.6-fold) and A. quadrifarius (3.5-fold), and sheep urine significantly increased catches of A. quadrifarius (2.5-fold). In parallel, an electroantennogram (EAG) study was conducted for the first time on these two species, in which EAGs were recorded using 1-octen-3-ol and extracts of the same urine samples used in the field. For T. bromius, the EAG response to 1-octen-3-ol increased quasi-sigmoidally with dose, with a maximum response at ≥100 µg on filter paper. For both species of tabanid, cow and horse urine elicited larger EAGs than did sheep urine. The behavioural implications in host-seeking and feeding habits are discussed.

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The origin of phenolic tsetse attractants from host urine: Studies on the pro-attractants and microbes involved

Cited by 20 publications

References 8 publications

Field studies on efficacy of host odour baits for the biting midge Culicoides impunctatus in Scotland

Field studies on efficacy of host odour baits for the biting midge Culicoides impunctatus in Scotland

Responses of Glossina pallidipes and Glossina morsitans morsitans tsetse flies to analogues of δ-octalactone and selected blends

Behavioural and electrophysiological responses of females of two species of tabanid to volatiles in urine of different mammals

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