Abstract Many rodents exhibit inducible defenses when exposed to chemical cues from mammalian predators. These responses may include delays in sexual maturation, smaller adult body size and decreases in litter size an...Abstract Many rodents exhibit inducible defenses when exposed to chemical cues from mammalian predators. These responses may include delays in sexual maturation, smaller adult body size and decreases in litter size and pup weight. We exposed the hybrid juvenile offspring of field-caught and lab-descended house mice Mus musculus to the chemical cues of mouse-fed or chick-fed kingsnakes, Lampropeltis getula, for 20 days after weaning, to examine the effects of ophidian predator cues on prey development. We hypothesized that these cues would elicit inducible defenses such as alteration of growth rates, and/or the timing of reproductive development in mice. Once mature, the reproductive effort of the mice might also be impacted by producing smaller litter sizes or lighter pups or not reproducing at all. We found no effect of kingsnake cues on any of the measures. These findings support the hypothesis that inducible defenses may have evolved as a strategy to deal with specific predators.展开更多
Coral snakes and their mimics often have brightly colored banded patterns, generally associated with warning colora- tion or mimicry. However, such color patterns have also been hypothesized to aid snakes in escaping ...Coral snakes and their mimics often have brightly colored banded patterns, generally associated with warning colora- tion or mimicry. However, such color patterns have also been hypothesized to aid snakes in escaping predators through a ＂flicker-fusion＂ effect. According to this hypothesis, banded color patterns confuse potential predators when a snake transitions from resting to moving because its bands blur together to form a different color. To produce this motion blur, a moving snake＇s bands must transition faster than the critical flicker-fusion rate at which a predator＇s photoreceptors can refresh. It is unknown if coral snakes or their mimics meet this requirement. We tested this hypothesis by measuring the movement speed and color pat- terns of two coral snake mimics, Lampropeltis triangulum campbelli and L. elapsoides, and comparing the frequency of color transitions to the photoreceptor activity of the avian eye. We found that snakes often produced a motion blur, but moving snakes created a blurring effect more often in darker conditions, such as sunrise, sunset, and nighttime when these snakes are often active. Thus, at least two species of coral snake mimics are capable of achieving flicker-fusion, indicating that their color patterns may confer an additional defense aside from mimicry展开更多
文摘Abstract Many rodents exhibit inducible defenses when exposed to chemical cues from mammalian predators. These responses may include delays in sexual maturation, smaller adult body size and decreases in litter size and pup weight. We exposed the hybrid juvenile offspring of field-caught and lab-descended house mice Mus musculus to the chemical cues of mouse-fed or chick-fed kingsnakes, Lampropeltis getula, for 20 days after weaning, to examine the effects of ophidian predator cues on prey development. We hypothesized that these cues would elicit inducible defenses such as alteration of growth rates, and/or the timing of reproductive development in mice. Once mature, the reproductive effort of the mice might also be impacted by producing smaller litter sizes or lighter pups or not reproducing at all. We found no effect of kingsnake cues on any of the measures. These findings support the hypothesis that inducible defenses may have evolved as a strategy to deal with specific predators.
文摘Coral snakes and their mimics often have brightly colored banded patterns, generally associated with warning colora- tion or mimicry. However, such color patterns have also been hypothesized to aid snakes in escaping predators through a ＂flicker-fusion＂ effect. According to this hypothesis, banded color patterns confuse potential predators when a snake transitions from resting to moving because its bands blur together to form a different color. To produce this motion blur, a moving snake＇s bands must transition faster than the critical flicker-fusion rate at which a predator＇s photoreceptors can refresh. It is unknown if coral snakes or their mimics meet this requirement. We tested this hypothesis by measuring the movement speed and color pat- terns of two coral snake mimics, Lampropeltis triangulum campbelli and L. elapsoides, and comparing the frequency of color transitions to the photoreceptor activity of the avian eye. We found that snakes often produced a motion blur, but moving snakes created a blurring effect more often in darker conditions, such as sunrise, sunset, and nighttime when these snakes are often active. Thus, at least two species of coral snake mimics are capable of achieving flicker-fusion, indicating that their color patterns may confer an additional defense aside from mimicry
