Filial Egg-Cannibalism in the Brook Stickleback, Culaea Inconstans (Kirtland)

Abstract

Filial cannibalism was directly verified in the laboratory. All test males (n = 43) ate some or all of their own 125I labelled eggs. Eight males successfully reared some eggs to hatching. This success rate is comparable to those in the literature for other Gasterosteid species. Parental males and their nests were removed individually from a dugout. Differences in the importance of eggs in diet and the frequency of egg-consumption between trap-caught fish and parental males offered indirect evidence for the occurrence of filial cannibalism. Of 22 egg-guarding males which cannibalized eggs, 21 contained eggs at the same stage as eggs in their nest. In cases where the nearest neighbouring nest contained eggs of a different age, filial cannibalism (rather than egg-robbery) could be assumed in at least seven of 13 parental males which ate eggs.