Journal Article 1 Mention
Effects of the removal or reduction in density of the malaria mosquito, Anopheles gambiae s.l ., on interacting predators and competitors in local ecosystems
C. Matilda Collins2018
J. A. S. BondsM. Megan Quinlan
Top 3% · 97th Percentile
80 citations · Public Health, Environmental and Occupational Health
Open Access

TLDR

Getting rid of malaria mosquitoes is unlikely to harm other animals or upset local ecosystems, because many other insects can take their place as food for predators.

Summary

1 Study Aim

The paper aims to review and summarize existing scientific literature on how reducing or removing populations of the malaria mosquito Anopheles gambiae sensu lato (s.l.) might affect other species in local ecosystems, especially predators that eat these mosquitoes and other mosquito species that compete with them. The authors want to clarify whether targeting this mosquito with new genetic control methods could have unintended ecological consequences. The study looks at whether removing malaria mosquitoes would hurt other animals or change the balance of local species.

2 Study Design

The authors conducted a literature review, searching peer-reviewed articles, internal reports, and web-based resources for studies on the ecological interactions of Anopheles gambiae s.l. with its predators and competitors. They included studies using a range of methods, from laboratory experiments to field observations, and considered both direct and indirect effects on other species. The review focused on natural habitats and included evidence from previous mosquito control interventions to assess potential ecosystem impacts. The researchers gathered and analyzed published studies to see how malaria mosquitoes interact with other animals in their environment.

3 Findings

The review demonstrates that most predators of Anopheles gambiae s.l., such as fish, spiders, and insects, are generalists (species that eat a wide variety of prey) and do not rely solely on these mosquitoes for food. Only one predator, the jumping spider Evarcha culicivora, shows some preference for blood-fed mosquitoes, but it can also eat other mosquito species. When Anopheles gambiae numbers drop, other mosquito species often increase, filling the ecological gap and maintaining the food supply for predators. The authors argue that previous mosquito control efforts show that while the types and numbers of mosquito species may change, the total amount of insect food available to predators stays about the same. They conclude that removing or reducing Anopheles gambiae s.l. is unlikely to cause major disruptions to local ecosystems or harm predator populations. The study finds that getting rid of malaria mosquitoes probably won't hurt other animals, because other insects will take their place as food.

Abstract

New genetic control methods for mosquitoes may reduce vector species without direct effects on other species or the physical environment common with insecticides or drainage. Effects on predators and competitors could, however, be a concern as Anopheles gambiae s.l. is preyed upon in all life stages. We overview the literature and assess the strength of the ecological interactions identified. Most predators identified consume many other insect species and there is no evidence that any species preys exclusively on any anopheline mosquito. There is one predatory species with a specialisation on blood-fed mosquitoes including An. gambiae s.l.. Evarcha culicivora is a jumping spider, known as the vampire spider, found around Lake Victoria. There is no evidence that these salticids require Anopheles mosquitoes and will readily consume blood-fed Culex. Interspecific competition studies focus on other mosquitoes of larval habitats. Many of these take place in artificial cosms and give contrasting results to semi-field studies. This may limit their extrapolation regarding the potential impact of reduced An. gambiae numbers. Previous mosquito control interventions are informative and identify competitive release and niche opportunism; so while the identity and relative abundance of the species present may change, the biomass available to predators may not.

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