Artificial-pool experiments were conducted to assess the effects of predatory dragonfly (Anax Imperator) nymphs on green toad (Bufo viridis) tadpoles. Six replicate pools were used for each of three treatment groups: (1) presence of free Anax nymphs (direct effects on mortality), (2) caged Anax (indirect effects on behavior, development, and individual growth rates), and (3) control (no Anax). Each pool consisted of 15 liters (10 cm depth) of water. After five days, 30 three-day-old tadpoles that had hatched from the same egg string were added. Caged Anax were fed with tadpoles three times a week. The experiments ran from 11 April through 4 August. Free Anax eliminated 90% of the tadpoles within two days and all of them within six days. Caged Anax had no effect on the spatial distribution of tadpoles. However, caged Anax caused tadpoles to metamorphose earlier and to a larger size (both statistically significant), and to attain a lighter color.
|Number of pages||1|
|Journal||Israel Journal of Zoology|
|State||Published - 1 Dec 2000|
ASJC Scopus subject areas
- Animal Science and Zoology