Common predators and factors influencing their abundance inAnopheles funestusaquatic habitats in rural south-eastern Tanzania

Abstract

AbstractBackgroundThe role that larval predators play in regulating the population of malaria vectors remains relatively unknown. This study aimed to investigate the common predators that co-exist withAnopheles funestusgroup larvae and evaluate factors that influence their abundance in rural south-eastern Tanzania.MethodsMosquito larvae and predators were sampled concurrently using standard dipper (350 ml) or 10 L bucket in nine villages in southern Tanzania. Predators were identified using standard identification keys. All positive habitats were geo-located and their physical features characterized. Water physicochemical parameters such as dissolved oxygen (DO), pH, electrical conductivity (EC), total dissolved solids (TDS) and temperature were also recorded.ResultsA total of 85 previously identifiedAn. funestusaquatic habitats were sampled for larvae and potential predators. A total of 8,295 predators were sampled. Of these Coenagrionidae 57.7% (n=4785), Corixidae 12.8% (n=1,060), Notonectidae 9.9% (n=822), Aeshnidae 4.9% (n=405), Amphibian 4.5% (n=370), Dytiscidae 3.8% (n=313) were common. A total of 5,260 mosquito larvae were sampled, wherebyAnopheles funestusgroup were 60.3% (n= 3,170),Culexspp. 24.3% (n= 1,279),An. gambie s.l. 8.3% (n= 438) and other anophelines 7.1% (n= 373). Permanent and aquatic habitats larger than 100m2were positively associated withAn. funestusgroup larvae (P<0.05) and predator abundance (P<0.05). Habitats with submerged vegetation were negative associated withAn. funestusgroup larvae (P<0.05). Only dissolved oxygen (DO) was positively and significantly affect the abundance ofAn. funestusgroup larvae (P<0.05). While predators abundance were not impacted by all physicochemical parameters.ConclusionSix potential predator families were common in aquatic habitats ofAn. funestuslarvae group. Additional studies are needed to demonstrate the efficacy of different predators on larval density and adult fitness traits. Interventions leveraging the interaction between mosquitoes and predators can be established to disrupt the transmission potential and survival of theAn. funestusmosquitoes.