Predator-avoidance of larval black-bellied salamanders (Desmognathus quadramaculatus) in response to cues from native and nonnative salmonids

Abstract

Fish are significant predators of amphibian larvae in streams and larvae can detect these predators through both visual and olfactory cues. The ability to effectively recognize these cues may depend on the evolutionary history of predator and prey such that recently introduced predators may not be recognized as readily as those that have consistently coexisted with the prey species. As such, the relatively recent introduction of rainbow trout (Oncorhynchus mykiss) into Southern Appalachian headwater streams where the black-bellied salamander (Desmognathus quadramaculatus) and brook trout (Salvelinus fontinalis) naturally coexist has raised concern. The objective of this study was to determine whether black-bellied salamander larvae respond to cues from introduced rainbow trout. To evaluate this, salamander activity metrics (general activity and number of movements) were recorded before and after exposure to either native trout predator cue (brook), introduced trout predator cue (rainbow), or conditioned tap water (control). Larvae were collected from different stream reaches based on their cooccurrence with brook trout only, rainbow trout only, rainbow and brook trout, or no trout predators. Larvae that co-occur with trout reduced their activity when exposed to brook trout predator cue, but their response to rainbow trout predator cue depended on their previous co-occurrence. A follow-up test to determine the influence of alarm cue on predator response indicated that the alarm cue enhanced the response to the rainbow trout predator.

KEY WORDS:

• Desmognathus
• predator-avoidance
• predator cue
• trout
• nonnative predator

HIGHLIGHTS

• Larvae responded to rainbow trout predator cue based on their previous co-occurrence with that predator.

• Larvae did not show the capacity to learn to identify a novel predator as dangerous, although consecutive exposure events may be required.

• Predation risk and experience likely play a role in predator recognition and predator generalization for larval salamanders in this system.

ACKNOWLEDGEMENTS

The authors are thankful to the anonymous reviewers for their valuable comments and feedback on an earlier draft of the manuscript. We also thank Trevor Chapman for help with experimental design and statistical advice. Special thanks to Celeste Gallardo and Anna Grizzard for help with field collections. Additionally, we would like to thank the Tennessee Wildlife Resource Agency (TWRA) and Tennessee Department of Environment and Conservation (TDEC) for permitting the collection of larvae and a special thank you to Jim Habera of the TWRA for all the help he provided in collecting trout. Lastly, we would like to thank East Tennessee State University’s Institutional Animal Care and Use Committee (IACUC) for permitting this study.

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by East Tennessee State University’s College of Graduate Studies under grant number [E85077].