Skip to main content
U.S. flag

An official website of the United States government

Native amphibian toxin reduces invasive crayfish feeding with potential benefits to stream biodiversity

September 13, 2023


Biodiversity is generally reduced when non-native species invade an ecosystem. Invasive crayfish, Procambarus clarkii, populate California freshwater streams, and in the Santa Monica Mountains (Los Angeles, USA), their introduction has led to trophic cascades due to omnivorous feeding behavior and a rapid rate of population growth. The native California newt, Taricha torosa, possesses a neurotoxin, tetrodotoxin (TTX), that affects freshwater animal behavior. Given P. clarkii has a limited evolutionary history with TTX, we hypothesized that TTX may affect crayfish feeding behaviors. To determine if TTX affects P. clarkii behavior, we measured cumulative movement and various feeding behaviors of P. clarkii exposed to (i) waterborne, ecologically realistic concentrations of TTX (~ 3.0 × 10− 8 moles/L), (ii) an anuran chemical cue to account for intraguild cues, or (iii) a T. torosa chemical cue with quantitated TTX in it (~ 6.2 × 10− 8 moles/L).


We found that the presence of TTX in any form significantly reduced crayfish movement and decreased the amount of food consumed over time. Crayfish responses to the anuran treatment did not significantly differ from controls.


Our laboratory results show that naturally occurring neurotoxin from native California newts limits invasive crayfish foraging and feeding rates, which may play a role in preserving local stream ecosystems by limiting invasive crayfish behaviors that are detrimental to biodiversity.

Publication Year 2023
Title Native amphibian toxin reduces invasive crayfish feeding with potential benefits to stream biodiversity
DOI 10.1186/s12862-023-02162-6
Authors Gary M. Bucciarelli, Sierra J. Smith, Justin J. Choe, Phoebe D. Shin, Robert N. Fisher, Lee B. Kats
Publication Type Article
Publication Subtype Journal Article
Series Title BMC Ecological Evolution
Index ID 70248743
Record Source USGS Publications Warehouse
USGS Organization Western Ecological Research Center