Swimming behavior of gregarious tadpoles in face of the alarm and environmental chemical signals

CUZZIOL BOCCIONI, ANA PAULA; CURI, LUCILA MARILÉN ; PELTZER, PAOLA M.; BASSÓ AGUSTIN; ATTADEMO MAXIMILIANO ANDRES; LEON EVELINA ; LAJMANOVICH RAFAEL CARLOS

Simposio; I International Symposium on Tadpoles Evolution; 2020

Universidad Federal do Paraná (Brasil)

Abstract. Tadpoles detect chemicals released from predators or conspecifics (other tadpoles) and those that occur in the environment to mediate behavioral responses. The alteration in the social behavior of gregarious tadpoles exposed to different chemical stressors has been little studied worldwide. This study aimed to evaluate the swimming activity of Rhinella fernandezae tadpoles exposed to different signals: a. Cues from the predator fish Synbranchus marmoratus (PC), and from injured conspecific (IC); b. Environment contaminant: sublethal concentration of the pesticide cypermethrin (10 µg/L; CY); c. Signal mixtures in additive form and, d. Control (dechlorinate water). Trials at individual (n=1) and interaction (n=3, 5, 7, and 10) tadpole´s levels were recorded and behavior parameters (total distance moved-DM, cm, average speed-AS, cm segˉ¹, global activity-GA, cm2, number of contacts between tadpoles-NC) were analyzed with video-tracking software SMART®. All the behavioral parameters decreased under exposure to PC, indicating a reduction of the encounter with predators and therefore reducing mortality or sublethal attacks. The DM and AS increased with one and three interacted tadpoles exposed to IC, whereas GA increased in all experiment trials, showing that gregarious tadpoles may be affected by conspecific alarm signals and disrupts its gregarious behavior. Individual CY or at mixtures (with PC or IC) stimulus increased swimming behavior parameters in all trial levels. In the mixture signals, the neurotoxic effect of CY altered ?scape and disaggregation? performances in presence of alarm cues (predator or injured tadpoles). Avoidance is the most commonly observed type of response to alarm cues, reinforcing the hypothesis that chemical alarm signaling has evolved primarily in social anuran genera. Moreover, behavior was altered by chemical contaminants, producing a disruption in the expected avoidance response.