Direct and indirect effects of dragonfly (Anax imperator) nymphs on green toad (Bufo viridis) tadpoles

• Published in: Hydrobiologia Vol. 579; no. 1; pp. 85 - 93
• Main Authors: Stav, Gil, Kotler, Burt P, Blaustein, Leon
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Kluwer Academic Publishers 01-03-2007; Springer; Springer Nature B.V
• Subjects: Amphibia; Anax; Anax imperator; Animal and plant ecology; Animal, plant and microbial ecology; Aquatic insects; Artificial ponds; Biological and medical sciences; Bufo; Bufo viridis; Distribution; Food resources; Freshwater; Frogs; Fundamental and applied biological sciences. Psychology; General aspects; Insecta; Invertebrates; Odonata; Organic matter; Ponds; predation; Predators; Risk of predation; Synecology; Toads; Insecta; Amphibia; Salientia; Bufo viridis; Artificial ponds; Risk of predation; Aquatic environment; Vertebrata; Pond; Hydrobiology; Larva; Arthropoda; Distribution; Nymph; Odonata; Predation; Invertebrata; Predation risk
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1007/s10750-006-0388-5

We conducted an artificial pond experiment to assess the direct and indirect effects of predation on Bufo viridis tadpoles. We ran three treatments: free Anax (unrestrained predatory dragonfly nymph Anax imperator), caged Anax (non-consumptive effects), and control (no Anax). Anax showed both strong consumptive and non-consumptive effects on Bufo tadpoles. Free Anax eliminated all of the tadpoles within six days. Tadpoles preferred the shady side of the ponds. Caged Anax caused tadpoles to increase their spatial preferences. Tadpoles avoided the center of the pond, and in the presence of the caged predator, they were found in the center even less. Tadpoles also showed a strong preference for crowding together, and in the presence of a caged Anax, they tended to crowd more. Moreover, Bufo metamorphosed earlier and at a larger size in the caged Anax ponds, possibly by providing extra food resources due to the extra organic matter excreted by the predators.