title: Physiological bases of genetic differences in cannibalism behavior of the confused flour beetle Tribolium confusum.
abstract: Physiological causes of genetic differences in cannibalism were examined to gain a better understanding of constraints on behavior evolution. Cannibalism has complex population level consequences in Tribolium confusum, including dramatic effects on population size. Laboratory strains with low and high cannibalism rates, obtained through inbreeding, have maintained distinct levels of cannibalism for over two decades even in the absence of artificial selection to maintain the differences. Why strains differ in their cannibalism rates was examined by measuring: (1) the nutritional benefit from cannibalism in both nutritionally good and poor environments, and (2) the possibility that eggs are an important source of water. How strains achieve differences in cannibalism was examined by testing for differences between strains in their ability to find eggs and in their tendency to eat eggs. Beetles from both strains survive equally well in a nutritionally good environment, but they accomplish this in different ways. The low cannibalism strain has high survivorship with and without cannibalism. The high cannibalism strain has low survivorship when not fed eggs and survivorship equivalent to the low cannibalism strain when fed eggs, suggesting it compensates for poor nutritional adaptation by eating eggs. The strains also differ in feeding behavior; beetles from the high cannibalism strain have a higher appetite for eggs. Beetles from the two strains did not differ in locomotor activity, search efficiency, or need for water. The observed behavioral and nutritional differences may contribute to the maintenance of different levels of cannibalism.
authors.affiliation: Department of Biology, University of Vermont, Burlington 05405, USA. tgiray@goliath.cnnet.clu.edu
authors.forename: T
authors.initials: T
authors.lastname: Giray
authors.forename: Y A
authors.initials: YA
authors.lastname: Luyten
authors.forename: M
authors.initials: M
authors.lastname: MacPherson
authors.forename: L
authors.initials: L
authors.lastname: Stevens
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D005075:Biological Evolution; D002190:Cannibalism; D005247:Feeding Behavior / Q000502:physiology; D005260:Female; D008124:Locomotion / Q000235:genetics / Q000502:physiology; D008297:Male; D014231:Tribolium / Q000235:genetics / Q000502:physiology*; D014867:Water / Q000502:physiology
chemical_list: D014867:Water