Predator and prey behaviors were observed during a
continuous 60-min period. Foraging behaviors (searching and
handling prey) for both starved and satiated predators were
quantified. Handling time per prey was calculated as the total
time taken to manipulate a single prey item, from encounter to
the end of consumption. Encounters between predators and prey,and the outcomes of the encounters, were also quantified. The
encounter rate was calculated as the total number of encounters
divided by predator search time (no./min). Encounters with prey
could result in attacking, pre-capture, avoidance or consumption
of prey. Each trial involved introducing an individual Odonata
nymph into the experimental glass aquaria filled with clear pond
water (to facilitate observation) and containing 10 live snails of
one of the three different snail's sizes.