Predator–prey interactions between Synbranchus marmoratus (Teleostei: Synbranchidae) and Hypsiboas pulchellus tadpoles (Amphibia: Hylidae): Importance of lateral line in nocturnal predation and effects of fenitrothion exposure.

JUNGES C. M; LAJMANOVICH R. C.; PELTZER P.M.; A. M. ATTADEMO; BASSÓ A

CHEMOSPHERE

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2010 vol. 81 p. 1233 - 1238

0045-6535

Environmental contaminants can disrupt interactions between aquatic species by altering communitystructure. We explored predator–prey interactions between marbled swamp juvenile eels (Synbranchusmarmoratus; predator) and anuran tadpoles (Hypsiboas pulchellus; prey) in relation to two aspects: theimportance of lateral line in the predator and whether the absence of light modifies predation rates;and the effect of a sub-lethal concentration of fenitrothion on both predator and prey. Eels were testedunder two sensory conditions (lateral line intact and lateral line blocked by cobalt chloride) in darkconditions. Predation rates were evaluated using different treatments that combined predator and preyexposed or not to insecticide. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activitieswere also measured in muscle samples of eels and tadpoles to explore whether fenitrothion affectspredator and prey differentially. Marbled swamp eels were more efficient in feeding on tadpoles duringthe night than during the day, showing that lateral line makes an important contribution to prey detectionand capture. Regarding pesticide effects, short-term (6 h) exposure to an ecologically relevant fenitrothiondose of 2.5 mg L1 altered the predator–prey relationship by changing prey behaviour,reducing prey detection and therefore increasing tadpole survival. At this concentration, the outcomeof the predator–prey relationship appears biased in favor of the exposed tadpoles, which were releasedfrom predation risk, despite their altered behaviour and the higher inhibition percentages of tail BChE(70%) and AChE (51%) than in control individuals. Our study involving these model species and agrochemicalsdemonstrates that fenitrothion affected the outcome of a predator–prey relationship. Furtherstudies are needed, in these species and other native amphibians, to investigate the nature of the mechanismsresponsible for the adverse effects of pesticides on antipredator behaviour and predationefficiency.