Drop or fly? Negative genetic correlation between death-feigning intensity and flying ability as alternative anti-predator strategies.
A prey animal may have the alternative of flying away or feigning death when it encounters predators. These alternatives have a genetic base as anti-predator strategies in the adzuki bean beetle, Callosobruchus chinensis. A negative genetic correlation between death-feigning intensity and flying ability was found in C. chinensis, i.e. lower flying ability is genetically connected to escaping by dropping from a perch and then feigning death, whereas higher flying ability does not correspond to death-feigning behaviour. Two bidirectional artificial selections for death-feigning duration and flying ability were conducted independently in C. chinensis. The strains selected for shorter (longer) duration of death-feigning had higher (lower) flying ability, while the strains selected for lower (higher) flying ability showed longer (shorter) duration of death-feigning. When the two traits were compared in 21 populations of C. chinensis derived from different geographical regions, a significant negative correlation was found between death-feigning intensity and flying ability. Based on these results, the choice between alternative escaping behaviours in animals is discussed from two points of view: phenotypic plasticity, an individual with two tactics; and pleiotropic genetic correlation, different individuals with opposite strategies.
Ohno
Tatsunori
T
Laboratory of Evolutionary Ecology, Graduate School of Environmental Science, Okayama University, Tsushima-naka 111, Okayama 700-8530, Japan.
Miyatake
Takahisa
T
D000818:Animals; D001517:Coleoptera / Q000235:genetics / Q000502:physiology*; D005426:Flight, Animal; D046353:Immobility Response, Tonic; D011235:Predatory Behavior