Home-field advantage: native signal crayfish (Pacifastacus leniusculus) out consume newly introduced crayfishes for invasive Chinese mystery snail (Bellamya chinensis)

摘要: The introduction of non-indigenous plants, animals and pathogens is one today’s most pressing environmental challenges. Freshwater ecologists are challenged to predict the potential consequences species invasions because many ecosystems increasingly support novel assemblages native non-native that likely interact in complex ways. In this study we evaluated how signal crayfish (Pacifastacus leniusculus) red swamp (Procambarus clarkii) northern (Orconectes virilis) utilize a prey resource: Chinese mystery snail (Bellamya chinensis). All widespread United States, as well globally, recent surveys have discovered them co-occurring lakes Washington State. A series mesocosm experiments revealed able consume B. chinensis, despite snail’s large size, thick outer shell trapdoor defense behaviour. Crayfish exhibited size-selective predation whereby consumption levels decreased with increasing size; common pattern among decapod predators. Comparison profitability curves—defined yield food (weight tissue) per second feeding time (the taken crack contents)—suggests small very snails may represent profitable choice. By contrast, previous studies reported opposite for on thin-shelled snails. For all size classes, found P. leniusculus invasive O. virilis consumed greater numbers than clarkii. Moreover, consistently handled at faster pace compared both crayfishes across range sizes examined our study. These results suggest not only chinensis suitable source crayfish, but also ultimately out-consume new resource.