Metriocnemus knabi provides guardianship resulting in an exclusive habitat for Wyeomyia smithii within the pitchers of Sarracenia purpurea.

The leaves of the carnivorous pitcher plant provide a unique habitat for obligate insects. Wyeomyia smithii mosquito larvae are found along with the pitcher plant midge, Metriocnemus knabi, while no other mosquito species has been reported to colonize this habitat. We tested whether the midge larvae is responsible for the elimination of other potential mosquito species through predation. We introduced one foreign Eastern tree hole mosquito larva, Aedes triseriatus, into 90 different pitchers. After 45 to 75 minutes water was extracted and counts of mosquito larvae and midge larvae were made. Although Wy. smithii were found in 98% of pitchers, 61 of the introduced mosquito larvae were not found and assumed to have been consumed . Of the 29 surviving treehole larvae, 13 were found in pitchers that had no midge larvae present. A Whitney-Mann Rank Sum Test (t = 988; p = <0.001) shows that the presence of the midge larvae is a controlling factor for presence of mosquito larvae other than Wy. smithii. The results of this study indicate adaptations by Wy. smithii to complete their life cycle in the leaves of pitcher plants containing predaceous midge larvae.