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Volume 24, Number 1
25
AN OBSERVATION ON THE USE OF COLOR FOR SPECIES-RECOGNITION IN HELICONIUS BESCKEI (NYMPHALIDAE)
Michael G. Emsley
George Mason College, U. of Virginia, Fairfax, Va.
Crane (1955) has shown red to be an important courtship releaser in Heliconius erato hydara Hewitson, and Swihart (1963, 1964) has confirmed the significance of red in that species by neurophysiological techniques.
During the course of genetical studies on Heliconius, living specimens of the mimetic pair, Heliconius erato phyllis (Fabricius) and H. besckei Menetries, from Rio de Janeiro, Brazil, were caged with specimens of H. melpomene melpomene (Linnaeus) from Trinidad. Both H. e. phyllis and H. besckei have red forewing bands and a yellow hindwing bar, but H. m. melpomene has only red forewing bands. All colors are on a black background.
It was observed that male erato phyllis and male melpomene would each fly towards members of either of the other two species in the cage, but presumably because secondary courtship releasers were lacking they would then disengage and fly off (all the females had already been mated). H. besckei, however, though appearing in good health, would only pursue the phyllis, not the melpomene. The color difference between these two is the lack of yellow in melpomene. The courtship releaser is known to be red in erato and is likely also to be red in melpomene. Possibly it is yellow in besckei.
Whether the courtship releaser in besckei is red or yellow is an important behavioral character which should be considered in deducing the course of the evolution of mimicry in Heliconius.
Literature Cited
Crane, J., 1955. Imaginal behavior of a Trinidad butterfly, Heliconius erato hydara
Hewitson, with special reference to the social use of color. Zoologica, N. Y., 40:
167-196. Swihart, S. L., 1963. The electroretinogram of Heliconius erato (Lepidoptera)
and its possible relation to established behavior patterns. Zoologica, N. Y., 48:
155-165. 1964. The nature of the electrorectinogram of a tropical butterfly. J. Insect
Physiol., 10: 547-562.