An electrically heated membrane blood-feeding device for mosquito colony maintenance.

The maintenance of most mosquito species in the laboratory requires periodic feedingof blooc to females. The expense and inconvenience of maintaining laboratory animals for this purpose has led to the development of methods fbr feeding preserved blood through various natural and artificial membrane materials (Tarshis 19b8. Bailey et al. 1978, Wirtz and Rutledge 19g0. Savage et al. 1980, Thomas et al. 198b). The resulting convenience and cost reduction can more than compensate for the reduced egg production reported by some of these workers. especially in laboratories where mass rearing is done. In our mosquito rearing facility, wliere production demands are usually low, this technique proved to be worthwhile. To decrease handling time, devices for holding and filling the membrane, and for maintaining a constant blood temperature were constructed. Initially, a coiled glass tube was inserted into the blood-filled condom, and 40'C tap water circulated through it. This device required proximity of hot and cold running water and, due to unpredictable changes in hot water temperature, needed constant adjustment. Aquarium heaters have been used to maintain the temperature of a water bath for a specialized membrane bloodfeeding device described by Tarshis (19b8), and for directly warming blood held in a condom (D. A. Dame, personal communication). In the latter case, use of the heater was discontinued because it frequently malfunctioned; however. we recently have obtained satisfactory results from an electric heater that was modified as described below. As a base for holding both the condom and the heater, four disks were cut from acrvlic sheet (LuciterN{, DuPont Co., Methacrylate Products Division, Wilmington, DE 19898) and laminated with methylene chloride to the configuration shown in Fig. 1. Three holes were drilled through the resulting stack: a 2.54 cm (1 in.) diam. hole through the center to hold the heater tube and two 5 mm (3/16 in.) diam. holes on opposite sides of the center hole for filling and draining the device. The resulting collar has a groove formed by the 6 x 36 mm diam. disc in which