Development of PVC Dispensers for Long-Lasting Release of Attractants for the Control of Invasive Crayfish Populations

Invasive alien species (IAS) are considered one of the major threats to biodiversity worldwide, thus requiring severe control strategies. Based on the promising results obtained in the field of insect pest management with polyvinyl chloride (PVC) for long-lasting release of attractants, the main aim of this study was to ascertain the efficacy of PVC/attractant dispensers also in the aquatic environment. Therefore, we developed PVC/food dispensers and evaluated their attractiveness, by means of behavioural bioassays on whole animals, over a 60-day period of continuous use towards the red swamp crayfish Procambarus clarkii, one of the top 100 worst IAS. The attractiveness in PVC of trehalose, leucine and taurocholic acid was also tested. Our results show that the PVC dispensers release the food and are strongly attractive for crayfish over a prolonged time, even if their effectiveness depends on the storage conditions: From 18 days when stored underwater at 23 °C up to 50 days when stored out of the water at -20 °C. Besides, trehalose, leucine and taurocholic acid in PVC resulted in reliable attractants for P. clarkii. The development of PVC dispensers for long-lasting release of attractants may help improve the efficiency of mass trapping strategies in the management and control of invasive crayfish.