Interaction of predatory macroinvertebrate communities with malaria vectors in aquatic habitats of three climatic zones in Burkina Faso.

Background: In aquatic larval habitats, Anopheles larvae are subject to the predatory activity and competition of macroinvertebrates. These macroinvertebrates may play a key role in the Anopheles population's bioregulation in aquatic habitats and malaria control. There are few studies characterizing macroinvertebrate predators and other macroinvertebrates coexisting with Anopheles larvae in Burkina Faso. This study aimed at characterizing and evaluating the different interactions between anopheline mosquito larvae, predatory macroinvertebrates, and other co-habitants in aquatic habitats in the three climatic zones of Burkina Faso.

Methods: A larval survey was performed in the three climatic zones of Burkina Faso (Sahelian, Soudano-Sahelian, and Soudanian zones) from September to November 2022. Mosquito larvae and other macroinvertebrates were sampled using standard dippers or bucket, preserved in Falcon tubes containing 80% ethanol, and transported to the laboratory for morphological identification. Alpha diversity analysis was used to measure macroinvertebrate diversity according to climatic zones and correlation matrix analysis was performed to determine the different interactions between Anopheles and other macroinvertebrates in breeding sites.

Results: In the studied larval habitats, Anopheles were found with several aquatic macroinvertebrate predators and other cohabiting macroinvertebrates. The abundance and alpha diversity indices of macroinvertebrate predators and other coexisting macroinvertebrates varied significantly according to climatic zone (P = 0.01). Correlation analyses showed that in the Sahelian zone, Anopheles spp., Corixidae, and Notonectidae shared the same aquatic habitats. In the Soudano-Sahelian zone, Anopheles spp. occupied the same larval habitats with Belostomatidae, Notonectidae, and Achatinidae, and in the Soudanian zone, their presence in larval habitats was correlated with that of Beatidae.

Conclusions: This study showed a significant trophic association between Anopheles and predatory and other coexisting macroinvertebrates in larval habitats in Burkina Faso. Our study provides insights and thereby opens new avenues in terms of development of biological control against larvae of Anopheles populations in Burkina Faso.