Mosquito spheres are large netting enclosures which prevent mosquitoes from entering from outside or escaping once released from inside the sphere. This unique facility provides an exceptional opportunity for field-oriented mosquito-borne diseases control research without exposure to infected vectors. Three mosquito spheres have been built at NIMR Amani Research Centre, at Ubwari area, Muheza, Tanga, Tanzania.
The mosquito sphere has a length of 12.2m, width of 8.2m, and a height of 5m, and it allows normal flow of air, temperature, relative humidity and rainfall in a similar way to outdoor environment. Therefore, mosquito spheres make a semi-field system which simulates real ecosystem of mosquito species; with simulated breeding sites, a residential hut and different types of plants.
The semi field environment has an advantage that it can be used for studying various behaviours of mosquitoes and exploit the findings to develop novel control strategies. Such behaviours includes: swarming and mating, host seeking, sugar seeking, resting, oviposition, dispersal etc. Within mosquito spheres, high through-put testing of mosquito traps, repellents and other control devices with infected colony reared mosquitoes can be conducted in a more realistic environment than that of the laboratory and a more controlled environment than that of the field.
Several tests have been conducted so far in mosquito spheres, these include; flight and dispersal studies such as mark and recapture of mosquito, oviposition behaviour in different substrates containing attractants and deterrents, testing of different traps using odour baits and evaluation of the efficacy of biolarvicides as well as botanical pesticides.
