Does Crayfish Molting Affect Environmental DNA Detectability?

While previous studies have explored the impact of behavior and life history on environmental DNA (eDNA), little research has been conducted on the impact of molting on eDNA detectability and particle size for aquatic arthropods like crayfish. To address this knowledge gap, we conducted a study examining how molting affects eDNA detectability over a range of particle sizes using marbled crayfish (Procambarus virginalis Lyko, 2017). We collected water samples from aquariums at pre- and post-molt time intervals and filtered our samples using sequential filtration from large to small filter pore sizes. We found that molting had a weak negative effect on eDNA detectability, and P. virginalis eDNA was most detectable throughout the study at our largest filter pore size (5.0 µm) regardless of molt status. Additionally, time spent in aquariums had a strong, positive effect on eDNA detectability for P. virginalis. Given that molting had a weak effect on eDNA detectability for our study crayfish, we suggest that researchers align their sampling efforts with other seasonal life history events, like reproduction or egg extrusion, that have been demonstrated to improve eDNA detectability.