The inheritance of pheromone production in the sulphur butterflies Colias eurytheme and C. Philodice

Absence of dosage compensation for a sex-linked enzyme in butterflies (Heliconius)

“…As both these styles of gene action seem quite likely, roughly 50 per cent of male-limited characters in butterflies (and just possibly in birds like ducks and pheasants) should turn out to be X-linked. This is exactly what has been found in the only investigation so far made of the repertoire of secondary sexual characters in a male butterfly; on hybridising the closely related species Colias eurytheme and C. philodice, it was found that both ultraviolet reflectance and hydrocarbon pheromones (the secondary male characters of eurytheme) were X-linked, and that the n-hexyl esters which are the male pheromones of philodice were controlled by autosomal genes (Silberglied and Taylor, 1973;Grula and Taylor, 1979).…”

“…Thus the linkage of the pheromone and reflectance genes on the X chromosome is not necessarily evidence for the evolution of a supergene (as suggested by Grula and Taylor, 1979), but is an outcome of Stehr's hypothesis that sex-limitation in lepidoptera results from the interaction of autosomal genes and uncompensated X-linked genes. Female-limited characters will be predominantly autosomal, and of the genes controlling male-limited characters, roughly half will be scattered among the autosomes and the rest will be linked together on the X chromosome.…”

“…The scarcity of information on sex-linked genes has prevented an evaluation of the prevalence of dosage compensation in groups other than mammals, birds (which lack compensation), and Drosophila (Cock, 1964). Indeed, 6PGD in Heliconius is only the third example of an X-linked locus in butterflies (Silberglied and Taylor, 1973;Grula and Taylor, 1979), and only the second X-linked enzyme in a lepidopteran (May, Leonard and Vadas, 1977). The approximately two-fold difference in 6PGD activities of males and females is a clear case of the absence of dosage compensation.…”

Localization of pheromonal sexual dimorphism in Drosophila melanogaster and its effect on sexual isolation.

“…These serve several functions, including protection against desiccation and stimulation of male courtship (1). Recent work has concentrated on the pheromonal function of these compounds and the genetic bases of intraspecific polymorphisms and interspecific differences (2)(3)(4)(5)(6). In several species of Drosophila, large cuticular hydrocarbons act as female contact pheromones detected by the male's tapping or licking of the female during courtship (7,8).…”

Sexual Communication with Pheromones

“…The occurrence of an insect's pheromone trait on the X-chromosome (in the Lepidoptera the female is the heterogametic sex) has been demonstrated for the major 'species-recognition' pheromone in Colias eurytheme, sulfer butterfly, by Grula and Taylor (1979). Another signal used by males in courtship is the ultraviolet reflection pattern of the wing, which is also transmitted on the X-chromosome.…”