# Crayfish Lab - The Effects of Snail Size on their...

• Lab Report
• 4

This preview shows page 1 - 2 out of 4 pages.

The Effects of Snail Size on their Consumption by Crayfish, Orconectes rusticusBreanna AndersonMarch 22nd, 2019Introduction:The rusty crayfish, Orconectes rusticus, is an omnivore. This means that it eats an array of organisms, ranging from plant life to other, smaller animals. Though crayfish clearly have an abundance of possible food sources, they are still effective predators of snails. They are effective to the point that they have a significant impact on the population size of snails (Wilson et al.,2004). Crayfish also will affect the size of the snail in their environment based on what size they choose to eat. In one study, it was found that after being placed in a habitat near crayfish, the snail shell sizes were typically above 14mm, while snails in a habitat without crayfish had shells around 4mm (Dorn, 2013). Crayfish are also optimal foragers, meaning that they will choose to feed when it maximizes their overall energy intake. In an experiment similar to this one, crayfish were found to prefer smaller sized snails to larger ones. This is because smaller snails tend to have thinner shells and therefore take less energy and time to feed on (Nyström et al., 1998). Thus, it was hypothesized that the crayfish O. rusticus will choose snails of a