On the Ecology of Hyla arborea var. meridionalis in Gran Canaria, with special reference to Predatory Habits considered in relation to the Protective Adaptations of Insects

1. The present paper is supplementary to an earlier publication (3), the purpose of which was to present a detailed investigation of the food‐habits of certain tree‐frogs–as indicated by the examination of food eaten under natural conditions–“(1) in order to test the efficiency of procryptic and warning colours and mimicry in defending insects from predatory attack; and (2) to indicate the part played by these batrachians as a factor in the production of adaptive coloration in insects,” additional support to the existing mass of evidence upon which the theory of warning colours rests, namely, that conspicuous colours in insects are typically associated with disagreeable or distasteful qualities, and that different insectivorous enemies discriminate in the choice of food, learning by experience in nature to recognize and to avoid unpalatable prey. 2. The general habits, habitat, and abundance of Hyla arborea var. meri‐dionalis in Gran Canaria are described. The frogs are considered in relation to their biological environment. A close parallelism as regards both habitat and food preferences between the present species and the Rhacophorid tree‐frog Hyperolius argus in Portuguese East Africa is discussed. Both frogs, in their respective environments, occupy the same ecological niche. 3. The stomach contents of 195 tree‐frogs are tabulated to show (1) the systematic distribution of prey, and (2) the number of frogs containing different groups of food‐animals. 1210 insects and other animals were obtained from 184 frogs containing recognizable material. 12 orders and at least 143 species are represented, as follows:–Hymenoptera, 58.18 per cent.; Coleoptera, 16.54; Diptera, 6.12; Araneee, 5.78; Isopoda, 3.88; Hemiptera, 3.55; Lepidoptera, 3–06; Orthoptera, 1.07; Acarina, 0.74; Chilopoda, 0.74; Neuroptera, 0.17; Amphipoda, 0.17. 4. The food‐animals have been classified according to colour, and the results are graphically shown for each of the following groups:–Orthoptera, Hemiptera, Coleoptera, Diptera, Hymenoptera, Araneæ. Of 617 specimens sufficiently well preserved for critical examination, only 6 (0.97 per cent.) belong to the typically aposematic group “AA.” These figures furnish additional support to the existing mass of evidence upon which the theory of warning colours rests, namely, that conspicuous colours in insects are typically associated with disagreeable or distasteful qualities, and that different insectivorous enemies discriminate in the choice of food, learning by experience in nature to recognize and to avoid unpalatable prey.