Effects Of Structural Modifications Of Tsetse-Repellant Δ-Octalactone On The Responses Of Glossina Pallidipes And G. Morsitans Morsitans

ABSTRACT

Tsetse flies (Glossina spp.) are vectors of Animal African Trypanosomiasis and Human African Trypanosomiasis. Two approaches have been used to combat the diseases: parasite and vector control. Parasitic control by trypanocidal drugs has so far failed due to problems of availability, toxicity and resistance development. Vector control by use of insecticides is ineffective. Trapping using baits have been relatively successful, except among pastoralists. Integration of repellants and attractants to create push-pull strategy may provide an effective control tactic at individual farmer and pastoralist level. A previous study on waterbuck, led to the identification of a blend of 15 electrophysiologically active constituents: six C8-C13 methylketones, two phenolic compounds, six C5-C10 fatty acids and δ-octalactone that is repellant to savanna tsetse flies. δ-Octalactone has been shown to singly elicit allomonal responses, and a follow-up study has shown that its structural modification can bear both repellants and attractants. In the present study, the effects of some δ-octalactone analogues on two Glossina spp. were carried out to elucidate their activities. (RS)-3-propylcyclohexanone (15) and (RS)-δ-valerolactone (16) and were synthesized and their structures confirmed using spectroscopic techniques, while 2-propyloxane (14) and (RS)-3-propylcyclohex-2-enone (17) were acquired commercially. The responses of the two Glossina spp. to each of the four analogues were determined in a two-choice wind tunnel. Data collected were subjected to Analysis of Variance and means ranked using Student-Newman-Keuls test and the tsetse preferences were compared using t-Test. In the bioassays, it was noted that (RS)-δ-valerolactone (16) and (RS)-2-propyloxane (14) elicited avoidance; whereas (RS)-3-propylcyclohex-2-enone (17) and (RS)-3-propylcyclohexanone (15) elicited attraction. There was no significant difference between the repellency of (RS)-δ-valerolactone (16) and 2-propyloxane (14) (p > 0.05) to both Glossina spp. However, the repellency of both, (RS)-2-propyloxane and (RS)-δ-valerolactone, were significantly lower than that of δ-octalactone (5) (p < 0.05). When (RS)-δ-valerolactone (16) and (RS)-2-propyloxane (14) were blended it was noted that the repellency was comparable to that of δ-octalactone (5) (p > 0.05) when G. pallidipes were deployed, but there was no significant improvement in repellency against G. m. morsitans. The attractancy of (RS)-3-propylcyclohex-2-enone (17) and (RS)-3-propylcyclohexanone (15) to the two tsetse species were comparable (p > 0.05). Blending the two attractants did not lead to any change to both tsetse species (p > 0.05). The study identifies potent attractants and repellants on the two Glossina spp. and therefore lays a useful basis for the development of more effective behavioural control of the tsetse species.

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APA

OTONDI, R (2021). Effects Of Structural Modifications Of Tsetse-Repellant Δ-Octalactone On The Responses Of Glossina Pallidipes And G. Morsitans Morsitans. Afribary. Retrieved from https://afribary.com/works/effects-of-structural-modifications-of-tsetse-repellant-d-octalactone-on-the-responses-of-glossina-pallidipes-and-g-morsitans-morsitans

MLA 8th

OTONDI, RONALD "Effects Of Structural Modifications Of Tsetse-Repellant Δ-Octalactone On The Responses Of Glossina Pallidipes And G. Morsitans Morsitans" Afribary. Afribary, 01 Jun. 2021, https://afribary.com/works/effects-of-structural-modifications-of-tsetse-repellant-d-octalactone-on-the-responses-of-glossina-pallidipes-and-g-morsitans-morsitans. Accessed 26 May. 2024.

MLA7

OTONDI, RONALD . "Effects Of Structural Modifications Of Tsetse-Repellant Δ-Octalactone On The Responses Of Glossina Pallidipes And G. Morsitans Morsitans". Afribary, Afribary, 01 Jun. 2021. Web. 26 May. 2024. < https://afribary.com/works/effects-of-structural-modifications-of-tsetse-repellant-d-octalactone-on-the-responses-of-glossina-pallidipes-and-g-morsitans-morsitans >.

Chicago

OTONDI, RONALD . "Effects Of Structural Modifications Of Tsetse-Repellant Δ-Octalactone On The Responses Of Glossina Pallidipes And G. Morsitans Morsitans" Afribary (2021). Accessed May 26, 2024. https://afribary.com/works/effects-of-structural-modifications-of-tsetse-repellant-d-octalactone-on-the-responses-of-glossina-pallidipes-and-g-morsitans-morsitans