THE BREEDING BIOLOGY OF EQUATORIAL VERTEBRATES: REPRODUCTION OF THE LIZARD AGAMA AGAMA LIONOTUS BOULENGER AT LAT. 0·01′ N.

SUMMARY1 The equatorial lizard Agama agama Eionotus possesses a distinct breeding period which occurs during the peak of the seasonal harvest of protein animal food that follows the so‐called “long rains”. The males contain bunches of spermatozoa throughout the year. 2 As the proportion of ingested animal food increases, the sexual condition of the females heightens. There is a concurrent growth of large leaf‐shaped abdominal fat bodies. Widespread egg‐laying occurs during four months of the year (June‐September inclusive), the peak being in July and early in August. 3 During the height of reproduction three distinct phases of egg development can be seen macroscopically: 1, a layer of colourless ovarian eggs surmounted by 2, a series of yolked eggs and 3, a clutch of ten to twelve shelled oviducal eggs. This device enables quick and repeated ovulation during the period of the maximum insect harvest. 4 During the period of study one ovulation only was recorded after the so‐called “short rains”. This occurred in February and after unusually heavy precipitation during the, previous December. 5 Any possibility of the photoperiodic control of reproduction was eliminated by the choice of the collecting locality. It is suggested that the sexual cycle of Agama agama is timed not by rainfall but by the seasonal appearance of proteinous insect food. Vegetable food of various kinds seems to be relatively abundant throughout the year. It is not known whether widespread reproduction after the secondary “short rains” is inhibited by a relative lack of protein food or, perhaps more probably, by the comparatively low night temperatures that occur from December to February inclusive. 6 A. agama is almost omnivorous, feeding on grass, berries, seeds, flowers, caterpillars, beetles, spiders, ants, Hymenoptera and the eggs of smaller reptiles.