Meeting Abstract
The class Hydrozoa is the most diverse medusozoan class and includes species with a broad range of swimming and feeding mechanisms. When a medusa encounters prey, nematocysts distributed along the tentacles are directly responsible for prey capture. The goal of this study was to analyze whether variations in nematocyst distribution and density were related to the prey capture patterns of hydromedusae. High definition videos of the filter feeder Mitrocoma cellularia and the ambush predator Aglantha digitale feeding on Artemia salina larvae showed that capture locations along the tentacles were species-specific: in M. cellularia captures frequently occurred adjacent to the bell margin, but in A. digitale captures occurred further along the tentacle length. To determine the relationship between capture location and nematocyst density, we analyzed images of tentacles from both species taken with differential interference contrast microscopy. Overall, the nematocyst distribution in these two species was related to the different mechanisms for capturing and transferring prey from the tentacle toward the mouth. Gaining a better understanding of the mechanisms used by a predator to successfully capture food gives us a baseline for understanding prey selection patterns.
