The impact of the presence of the crayfish Faxonius virilis on the excavating behavior of Faxonius propinquus, Michigan, 2025

Faxonius propinquus are native crayfish to the Upper Midwest. They are burrowing crayfish that work the sediment and make small burrows with numerous openings. These crayfish are imperiled by Faxonius virilis which overlap in niche structure. We were interested in the impact of the chemical cues emanating from F. virilis on the sediment and burrowing nature of F. propinquus. We conducted a study at the University of Michigan's Biological Station using F. propinquus caught in nearby Douglas Lake. In addition, we collected marl substrate from where these animals are found. We created flow through mesocosms and placed F. propinquus in the mesocosm with marl substrate. Then upstream of this, we placed a F. virilis in a flow through container to allow chemical cues from F. virilis to reach F. propinquus. We did a 48 hour study where 24 hours were with a competitor chemical cue and 24 were without. This 48 cycle was repeated to provide discrete 48 hour replicates. We monitored sediment working behavior at night and during the day.