Is death-feigning adaptive? Heritable variation in fitness difference of death-feigning behaviour.
The adaptation of death-feigning (thanatosis), a subject that has been overlooked in evolutionary biology, was inferred in a model prey-and-predator system. We studied phenotypic variation among individuals, fitness differences, and the inheritance of death-feigning behaviour in the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Two-way artificial selections for the duration of death-feigning, over 10 generations, showed a clear direct response in the trait and a correlated response in the frequency of death-feigning, thus indicating variation and inheritance of death-feigning behaviour. A comparison of the two selected strains with divergent frequencies of death-feigning showed a significant difference in the fitness for survival when a model predator, a female Adanson jumper spider, Hasarius adansoni Audouin (Araneomophae: Salticidae), was presented to the beetles. The frequency of predation was lower among beetles from strains selected for long-duration than among those for short-duration death-feigning. The results indicate the possibility of the evolution of death-feigning under natural selection.
Miyatake
Takahisa
T
Faculty of Agriculture, Okayama University, Okayama 700-8530, Japan. miyatake@cc.okayama-u.ac.jp
Katayama
Kohji
K
Takeda
Yukari
Y
Nakashima
Akiko
A
Sugita
Atsushi
A
Mizumoto
Makoto
M
D000220:Adaptation, Biological / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D003643:Death; D008192:Deception; D005260:Female; D008297:Male; D019370:Observation; D011235:Predatory Behavior / Q000502:physiology; D012641:Selection, Genetic; D013112:Spiders / Q000502:physiology; D014231:Tribolium / Q000502:physiology*