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

Abstract

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

Comparing the effects of introduced signal crayfish and native noble crayfish on the littoral invertebrate assemblages of boreal lakes

“…A meta-analysis by Twardochleb et al (2013) showed consistently negative effects of crayfish on Gastropoda abundance and suggested a tendency for effects of nonnative species to be stronger than that of native species. However, the abundance and species richness of Sphaeriidae and Gastropoda did not differ between signal and noble crayfish lakes, and recent direct experimental comparisons indicate that effects can be either similar or different between species independent of species origin (Nyström et al 1999, Olden et al 2009, Haddaway et al 2012, Dorn 2013, Jackson et al 2014. Limited data are available on effects of crayfish on small Bivalvia in general (e.g., they were not included in the meta-analysis by Twardochleb et al 2013), but Klocker and Strayer (2004) found that the invasive species Orconectes rusticus and the native crayfish Orconectes limosus both fed readily and to the same extent on native bivalves (Sphaeriidae) in a laboratory experiment.…”

A Model Approach for Estimating Colony Size, Trends, and Habitat Associations of Burrow-Nesting Seabirds

“…These snails were introduced 40 years ago and are now broadly distributed in hundreds of lakes that historically supported relatively few native snails (Olden et al 2009). The Chinese mystery snail has now become a food source for both the native and invasive species of crayfish.…”

“…The Chinese mystery snail has now become a food source for both the native and invasive species of crayfish. Interestingly, the native crayfish is able to consistently handle and consume the snails at a faster pace, outcompeting both species of invasive crayfish for this novel food source (Olden et al 2009). Even so, the invasive red swamp crayfish still outnumbers the native signal crayfish by more than 2 to 1 where both species co-occur (Mueller 2007).…”

The State of Crayfish in the Pacific Northwest

“…Mueller and Bodensteiner (2009) did not find competitive dominance of P. clarkii over native P. leniusculus under field conditions in a Washington lake. Olden et al (2009b) observed that P. clarkii was less predatory on an invasive snail common to Washington than P. leniusculus. More work on the distribution and impacts of this invader in the Pacific Northwest is needed.…”