Fitness characteristics of the malaria vector Anopheles funestus during an attempted laboratory colonization

Abstract Background The malaria vector Anopheles funestus is increasingly recognized as a dominant vector of residual transmission in many African settings. Efforts to better understand its biology and control are significantly impeded by the difficulties of colonizing it under laboratory conditions...

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Main Authors: Halfan S. Ngowo, Emmanuel E. Hape, Jason Matthiopoulos, Heather M. Ferguson, Fredros O. Okumu
Format: Article
Language:English
Published: BMC 2021-03-01
Series:Malaria Journal
Online Access:https://doi.org/10.1186/s12936-021-03677-3
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author Halfan S. Ngowo
Emmanuel E. Hape
Jason Matthiopoulos
Heather M. Ferguson
Fredros O. Okumu
author_facet Halfan S. Ngowo
Emmanuel E. Hape
Jason Matthiopoulos
Heather M. Ferguson
Fredros O. Okumu
author_sort Halfan S. Ngowo
collection DOAJ
description Abstract Background The malaria vector Anopheles funestus is increasingly recognized as a dominant vector of residual transmission in many African settings. Efforts to better understand its biology and control are significantly impeded by the difficulties of colonizing it under laboratory conditions. To identify key bottlenecks in colonization, this study compared the development and fitness characteristics of wild An. funestus from Tanzania (FUTAZ) and their F1 offspring during colonization attempts. The demography and reproductive success of wild FUTAZ offspring were compared to that of individuals from one of the only An. funestus strains that has been successfully colonized (FUMOZ, from Mozambique) under similar laboratory conditions. Methods Wild An. funestus (FUTAZ) were collected from three Tanzanian villages and maintained inside an insectary at 70–85% RH, 25–27 °C and 12 h:12 h photoperiod. Eggs from these females were used to establish three replicate F1 laboratory generations. Larval development, survival, fecundity, mating success, percentage pupation and wing length were measured in the F1 -FUTAZ offspring and compared with wild FUTAZ and FUMOZ mosquitoes. Results Wild FUTAZ laid fewer eggs (64.1; 95% CI [63.2, 65.0]) than FUMOZ females (76.1; 95% CI [73.3, 79.1]). Survival of F1-FUTAZ larvae under laboratory conditions was low, with an egg-to-pupae conversion rate of only 5.9% compared to 27.4% in FUMOZ. The median lifespan of F1-FUTAZ females (32 days) and males (33 days) was lower than FUMOZ (52 and 49 for females and males respectively). The proportion of female F1-FUTAZ inseminated under laboratory conditions (9%) was considerably lower than either FUMOZ (72%) or wild-caught FUTAZ females (92%). This resulted in nearly zero viable F2-FUTAZ eggs produced. Wild FUTAZ wings appear to be larger compared to the lab reared F1-FUTAZ and FUMOZ. Conclusions This study indicates that poor larval survival, mating success, low fecundity and shorter survival under laboratory conditions all contribute to difficulties in colonizing of An. funestus. Future studies should focus on enhancing these aspects of An. funestus fitness in the laboratory, with the biggest barrier likely to be poor mating.
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spelling doaj.art-3d2276ddaad943f896ba7407b3e853a62022-12-21T23:41:19ZengBMCMalaria Journal1475-28752021-03-0120111310.1186/s12936-021-03677-3Fitness characteristics of the malaria vector Anopheles funestus during an attempted laboratory colonizationHalfan S. Ngowo0Emmanuel E. Hape1Jason Matthiopoulos2Heather M. Ferguson3Fredros O. Okumu4Department of Environmental Health and Ecological Sciences, Ifakara Health InstituteDepartment of Environmental Health and Ecological Sciences, Ifakara Health InstituteInstitute of Biodiversity, Animal Health and Comparative Medicine, University of GlasgowDepartment of Environmental Health and Ecological Sciences, Ifakara Health InstituteDepartment of Environmental Health and Ecological Sciences, Ifakara Health InstituteAbstract Background The malaria vector Anopheles funestus is increasingly recognized as a dominant vector of residual transmission in many African settings. Efforts to better understand its biology and control are significantly impeded by the difficulties of colonizing it under laboratory conditions. To identify key bottlenecks in colonization, this study compared the development and fitness characteristics of wild An. funestus from Tanzania (FUTAZ) and their F1 offspring during colonization attempts. The demography and reproductive success of wild FUTAZ offspring were compared to that of individuals from one of the only An. funestus strains that has been successfully colonized (FUMOZ, from Mozambique) under similar laboratory conditions. Methods Wild An. funestus (FUTAZ) were collected from three Tanzanian villages and maintained inside an insectary at 70–85% RH, 25–27 °C and 12 h:12 h photoperiod. Eggs from these females were used to establish three replicate F1 laboratory generations. Larval development, survival, fecundity, mating success, percentage pupation and wing length were measured in the F1 -FUTAZ offspring and compared with wild FUTAZ and FUMOZ mosquitoes. Results Wild FUTAZ laid fewer eggs (64.1; 95% CI [63.2, 65.0]) than FUMOZ females (76.1; 95% CI [73.3, 79.1]). Survival of F1-FUTAZ larvae under laboratory conditions was low, with an egg-to-pupae conversion rate of only 5.9% compared to 27.4% in FUMOZ. The median lifespan of F1-FUTAZ females (32 days) and males (33 days) was lower than FUMOZ (52 and 49 for females and males respectively). The proportion of female F1-FUTAZ inseminated under laboratory conditions (9%) was considerably lower than either FUMOZ (72%) or wild-caught FUTAZ females (92%). This resulted in nearly zero viable F2-FUTAZ eggs produced. Wild FUTAZ wings appear to be larger compared to the lab reared F1-FUTAZ and FUMOZ. Conclusions This study indicates that poor larval survival, mating success, low fecundity and shorter survival under laboratory conditions all contribute to difficulties in colonizing of An. funestus. Future studies should focus on enhancing these aspects of An. funestus fitness in the laboratory, with the biggest barrier likely to be poor mating.https://doi.org/10.1186/s12936-021-03677-3
spellingShingle Halfan S. Ngowo
Emmanuel E. Hape
Jason Matthiopoulos
Heather M. Ferguson
Fredros O. Okumu
Fitness characteristics of the malaria vector Anopheles funestus during an attempted laboratory colonization
Malaria Journal
title Fitness characteristics of the malaria vector Anopheles funestus during an attempted laboratory colonization
title_full Fitness characteristics of the malaria vector Anopheles funestus during an attempted laboratory colonization
title_fullStr Fitness characteristics of the malaria vector Anopheles funestus during an attempted laboratory colonization
title_full_unstemmed Fitness characteristics of the malaria vector Anopheles funestus during an attempted laboratory colonization
title_short Fitness characteristics of the malaria vector Anopheles funestus during an attempted laboratory colonization
title_sort fitness characteristics of the malaria vector anopheles funestus during an attempted laboratory colonization
url https://doi.org/10.1186/s12936-021-03677-3
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