Shelter allocation of the Invasive Species Orconectes rusticus (Rusty Crayfish)

Abstract

Crayfish are a very destructive organism when they get introduce to an area or ecosystem they are not native to. In this paper and experiment I studied the intraspecific competition of the invasive species Orconectes rusticus, also known as Rusty crayfish, and their interactions with the native species Orconectes virilis and Orconectes propinquus, also known as Northern crayfish and Northern Clearwater crayfish respectively, trying to allocate or procure shelter resources to use as their personal home. There are many different advantages one Rusty Crayfish can have over another crayfish species in these competitions. Some of the advantages include but are not limited to their size; growth rate, strength, prior occupancy whether that be because of knowledge of the terrain or higher willingness to fight for a familiar shelter, and or any other characteristic that could help one Rusty Crayfish outcompete another crayfish. The results of my experiment show that when Rusty crayfish compete against native crayfish, in this case Northern crayfish, of the same size the Rusty crayfish will outcompete the native species 100% of the time. My results also show that small (<2 in) Rusty crayfish will allocate shelter about 50% of the time while competing against medium (2-3 in) and large (>3 in) Northern crayfish. Another thing my research shows is that medium (2-3 in) Rusty crayfish will allocate shelter resources about 73% of the time against all sizes of the Northern crayfish. Finally my results also show that large (>3 in) Rusty crayfish will out compete all Northern crayfish sizes, small medium and large (<2 in, 2-3 in, >3 in) for shelter resources about 90% of the time.