Journal of Chemical Ecology

, Volume 17, Issue 11, pp 2063-2075

First online:

Chemical basis of egg cannibalism in a caterpillar (Utetheisa ornatrix)

  • Franz BognerAffiliated withSection of Neurobiology and Behavior, Cornell University
  • , Thomas EisnerAffiliated withSection of Neurobiology and Behavior, Cornell University

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Larvae of the mothUtetheisa ornatrix are shown to cannibalize eggs in the laboratory. They proved most cannibalistic if they were systemically deficient in pyrrolizidine alkaloid (PA), the defensive agent that protectsUtetheisa at all stages of development against predation, and whichUtetheisa acquire as larvae from their food plant. In exercising cannibalistic choice,Utetheisa larvae feed preferentially on eggs that are PA-Iaden rather than PA-free. Egg cannibalism can therefore provideUtetheisa with a supplemental means of PA procurement. Moreover, presence of PA in the egg, while providing the egg with defense against predation, can increase its vulnerability to cannibalism. Although evidence is presented thatUtetheisa larvae cannibalize eggs in nature, it is argued that such feeding may occur only opportunistically in the wild, rather than as a matter of course.

Key Words

Utetheisa ornatrix Lepidoptera Arctiidae pyrrolizidine alkaloid egg cannibalism acquired defense phagostimulant specific hunger