Predation on Mosquitoes by Juveniles of Mesostoma spp. (Turbellaria)

Juveniles of several Mesostoma species (M. appia, M. timbunke, M. wanum and M. zariae) predatory on aquatic stages of mosquitoes were found to be able to attack and kill mosquito larvae of all stages. Tests were carried out in Petri dishes containing one freshly hatched Mesostoma and one mosquito larva of the following species: Aedes aegypti, Anopheles stephensi and Culiseta melanura. Efficiency of M. appia varied from 50-90% of third and fourth instar larvae killed in 24 h and depends on the mosquito species. Individuals of Aedes and Anopheles are more susceptable than those of Culiseta. Other species of Mesostoma are less efficient against late instars but always eliminated more than 50% of the second instar larvae in 24 h. Differences in efficiency of predation are attributed to different sizes of predator species and to behavioral characteristics of mosquito species.