Methods in Anopheles Research - MR4

Chapter 1 : Insectary Operation1.1 Equipping and Operating an InsectaryPage 1 of 4Chapter 1: Insectary Operation1.1 Equipping and Operating an InsectaryMark BenedictIntroductionMosquito insectaries vary widely in their sophistication and cost. Fortunately, the requirements for goodmosquito culture are easily met and can be achieved by both simple (inexpensive) and complex(expensive) means. In the following section, I will present very personal prejudices and experiences toguide you. My objective is to convey approaches that are sufficiently useful, safe, and - where possible -inexpensive. Additional ideas can be found in Gerberg (1994), and many of those below are also found inBenedict (1997).TemperatureConstant temperature is the most important environmental criterion. Immature mosquitoes are typicallycultured at a water temperature of 27°C. There are several ways in which this can be accomplished.• Standalone incubators. These are a good choice particularly where temperature experiments areplanned or space cannot be dedicated to a mosquito insectary. Care should be given to the shelfspacing and sizes so that the space can be occupied efficiently with the trays you plan to use formosquito culture. The disadvantage is that floor space is not efficiently used relative to someother systems, and the probability of equipment failures multiplies with each additional unit. Thisapproach does provide a good way to divide work spaces for different individuals, stocks orspecies.• Walk-in incubators are often used for larger facilities. These are usually equipped with rustresistantshelving giving greater flexibility for space use. They also allow entry of carts totransport materials and should not have raised thresholds.• Air-conditioned rooms. Dedicated rooms for mosquito culture require a commitment of the spacesfor this activity. Ideally they are designed with water-resistant wall- and floor-coverings such astile or a monolithic material. These provide the greatest flexibility but often mean that all insectaryactivities will be performed in the hot humid environment. They often contain screened enclosuresto separate activities or stocks.• Heater tapes (Dame et al. 1978) and shelves. Means have been devised to heat trays of larvaeby placing heating elements under the trays or shelves. This is a flexible method that providescomfort for personnel. However, the equipment must be devised on an ad hoc basis, and traysmust be covered to prevent water loss and evaporative cooling if the room is not humidified.Relative HumidityIn all of the designs listed under temperature above, humidity is necessary only for adults. 80% relativehumidity to maintain adults is an often-mentioned value that possibly requires more experimental support.None-the-less, one should plan on being able to reach this level. Excessively high humidity is harmful toadult mosquitoes and must be prevented. The only benefit of high humidity to immatures is to preventwater loss and evaporative cooling, both of which can be prevented by covering containers with animpermeable cover. In rough order of descending space capacity, means to generate humidity are:• Steam injection into the central ventilation• Greenhouse-type misting humidifiers• Centrifugal room humidifiers