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

Ngowo, H. S. , Hape, E. E., Matthiopoulos, J. , Ferguson, H. M. and Okumu, F. O. (2021) Fitness characteristics of the malaria vector Anopheles funestus during an attempted laboratory colonization. Malaria Journal, 20, 148. (doi: 10.1186/s12936-021-03677-3) (PMID:33712003) (PMCID:PMC7955623)

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.

• Item Type: Articles
• Additional Information: This work was supported by Howard Hughes Medical Institute (HHMI) and Gates Foundation (Grants: OPP1099295) awarded to FOO and HMF. HSN and EEH are supported by HHMI Grant (OPP1099295) awarded to FOO.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Ngowo, Halfan and Okumu, Professor Fredros and Ferguson, Professor Heather and Matthiopoulos, Professor Jason
• Authors: Ngowo, H. S., Hape, E. E., Matthiopoulos, J., Ferguson, H. M., and Okumu, F. O.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Malaria Journal
• Publisher: BioMed Central
• ISSN: 1475-2875
• ISSN (Online): 1475-2875
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Malaria Journal 20: 148
• Publisher Policy: Reproduced under a Creative Commons License