Fitness benefits of egg cannibalism in the Colorado potato beetle, Leptinotarsa decemlineata

Neonates of the Colorado potato beetle, Leptinotarsa decemlineata, commonly cannibalize other eggs within their own clutch.  Because these eggs are siblings, such cannibalism reduces the inclusive fitness of the cannibal.  For evolution to select for cannibalism in this species, such a fitness loss must be balanced or outweighed by a fitness gain.  Neonates were fed 0, 1, or 2 eggs upon hatching in addition to potato foliage.  Individuals were weighed daily, their time in each developmental stage was monitored, and mortality for each group in each life stage was calculated.  Additionally, all eggs laid by females during their first two weeks of reproduction were counted.  Preliminary studies suggest that, while overall growth rates and mortality do not differ between groups, individuals fed two eggs molt to second-instar larvae more rapidly than the other treatments.  Also, maximum weight for adult females increases with the number of eggs consumed as neonates, and, while not significant, the number of eggs laid by females also increases with eggs consumed.  The results of follow-up work will also be discussed.