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Visually guided avoidance in the chameleon (Chamaeleo chameleon): response patterns and lateralization.

Lustig A, Ketter-Katz H, Katzir G - PLoS ONE (2012)

Bottom Line: We found two equal-sized sub-groups, each displaying lateralization of motor responses to a given direction of stimulus approach.Such an anti-symmetrical distribution of lateralization in a population may be indicative of situations in which organisms are regularly exposed to crucial stimuli from all spatial directions.This is because a bimodal distribution of responses to threat in a natural population will reduce the spatial advantage of predators.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology and Ethology, University of Haifa, Haifa, Israel. Lustigavi@gmail.com

ABSTRACT
The common chameleon, Chamaeleo chameleon, is an arboreal lizard with highly independent, large-amplitude eye movements. In response to a moving threat, a chameleon on a perch responds with distinct avoidance movements that are expressed in its continuous positioning on the side of the perch distal to the threat. We analyzed body-exposure patterns during threat avoidance for evidence of lateralization, that is, asymmetry at the functional/behavioral levels. Chameleons were exposed to a threat approaching horizontally from the left or right, as they held onto a vertical pole that was either wider or narrower than the width of their head, providing, respectively, monocular or binocular viewing of the threat. We found two equal-sized sub-groups, each displaying lateralization of motor responses to a given direction of stimulus approach. Such an anti-symmetrical distribution of lateralization in a population may be indicative of situations in which organisms are regularly exposed to crucial stimuli from all spatial directions. This is because a bimodal distribution of responses to threat in a natural population will reduce the spatial advantage of predators.

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Related in: MedlinePlus

Latency of response as a function of pole width or threat-approach direction.The latency to final exposure on a narrow or wide pole, under a right- or left-approaching threat (N  = 17).
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pone-0037875-g009: Latency of response as a function of pole width or threat-approach direction.The latency to final exposure on a narrow or wide pole, under a right- or left-approaching threat (N  = 17).

Mentions: A repeated measures MANOVA, with pole width and direction of threat approach as the main effects (Figs. 7, 8), revealed significantly lower exposure in tests on wide poles than in tests on narrow poles, for Initial exposure (F(1,16)  = 34.276, p<0.001), End of rotation exposure (F(1,16)  = 38.509, p<0.001), and Final exposure (F(1,16)  = 25.809, p<0.001). The latency to final exposure in tests on wide poles did not differ from the latency in tests on narrow poles (F(1,16)  = 1.704, p  = 0.210). The direction of threat approach did not have a significant effect on the Initial exposure (F(1,16)  = 3.39, p  = 0.084) or on the End of rotation exposure (F(1,16)  = 1.501, p  = 0.238). The Final exposure during tests with a right-approaching threat was significantly lower than the Final exposure with a left-approaching threat (F(1,16)  = 6.233, p  = 0.024). The latency to final exposure (Fig. 9) in tests with right-approaching threats did not differ from the latency in tests with left-approaching threats (F(1,16)  = 1.182, p  = 0.293). The interaction between the main effects of pole width and direction of threat approach was not significant (F(1,16)  = 0.392, p  = 0.540).


Visually guided avoidance in the chameleon (Chamaeleo chameleon): response patterns and lateralization.

Lustig A, Ketter-Katz H, Katzir G - PLoS ONE (2012)

Latency of response as a function of pole width or threat-approach direction.The latency to final exposure on a narrow or wide pole, under a right- or left-approaching threat (N  = 17).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3369868&req=5

pone-0037875-g009: Latency of response as a function of pole width or threat-approach direction.The latency to final exposure on a narrow or wide pole, under a right- or left-approaching threat (N  = 17).
Mentions: A repeated measures MANOVA, with pole width and direction of threat approach as the main effects (Figs. 7, 8), revealed significantly lower exposure in tests on wide poles than in tests on narrow poles, for Initial exposure (F(1,16)  = 34.276, p<0.001), End of rotation exposure (F(1,16)  = 38.509, p<0.001), and Final exposure (F(1,16)  = 25.809, p<0.001). The latency to final exposure in tests on wide poles did not differ from the latency in tests on narrow poles (F(1,16)  = 1.704, p  = 0.210). The direction of threat approach did not have a significant effect on the Initial exposure (F(1,16)  = 3.39, p  = 0.084) or on the End of rotation exposure (F(1,16)  = 1.501, p  = 0.238). The Final exposure during tests with a right-approaching threat was significantly lower than the Final exposure with a left-approaching threat (F(1,16)  = 6.233, p  = 0.024). The latency to final exposure (Fig. 9) in tests with right-approaching threats did not differ from the latency in tests with left-approaching threats (F(1,16)  = 1.182, p  = 0.293). The interaction between the main effects of pole width and direction of threat approach was not significant (F(1,16)  = 0.392, p  = 0.540).

Bottom Line: We found two equal-sized sub-groups, each displaying lateralization of motor responses to a given direction of stimulus approach.Such an anti-symmetrical distribution of lateralization in a population may be indicative of situations in which organisms are regularly exposed to crucial stimuli from all spatial directions.This is because a bimodal distribution of responses to threat in a natural population will reduce the spatial advantage of predators.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology and Ethology, University of Haifa, Haifa, Israel. Lustigavi@gmail.com

ABSTRACT
The common chameleon, Chamaeleo chameleon, is an arboreal lizard with highly independent, large-amplitude eye movements. In response to a moving threat, a chameleon on a perch responds with distinct avoidance movements that are expressed in its continuous positioning on the side of the perch distal to the threat. We analyzed body-exposure patterns during threat avoidance for evidence of lateralization, that is, asymmetry at the functional/behavioral levels. Chameleons were exposed to a threat approaching horizontally from the left or right, as they held onto a vertical pole that was either wider or narrower than the width of their head, providing, respectively, monocular or binocular viewing of the threat. We found two equal-sized sub-groups, each displaying lateralization of motor responses to a given direction of stimulus approach. Such an anti-symmetrical distribution of lateralization in a population may be indicative of situations in which organisms are regularly exposed to crucial stimuli from all spatial directions. This is because a bimodal distribution of responses to threat in a natural population will reduce the spatial advantage of predators.

Show MeSH
Related in: MedlinePlus