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Flexibility is everything: prey capture throughout the seasonal habitat switches in the smooth newt Lissotriton vulgaris.

Heiss E, Aerts P, Van Wassenbergh S - Org. Divers. Evol. (2014)

Bottom Line: Due to the different biophysical demands on the whole organism in water and air, such transitions require major changes of many physiological functions, including feeding.Accordingly, the capability to modulate the pre-programmed chain of prey-capture movements might be essential to maintain performance in a new environment.Our results indicate that newts exhibit a high degree of seasonal flexibility of the prey-capture behavior.

View Article: PubMed Central - PubMed

Affiliation: Institute of Systematic Zoology and Evolutionary Biology, Friedrich-Schiller-University Jena, Erbertstr. 1, 07743 Jena, Germany ; Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium ; Department of Integrative Zoology, University of Vienna, Althanstr. 14, 1090 Vienna, Austria.

ABSTRACT

Transitions between aquatic and terrestrial habitats are significant steps in vertebrate evolution. Due to the different biophysical demands on the whole organism in water and air, such transitions require major changes of many physiological functions, including feeding. Accordingly, the capability to modulate the pre-programmed chain of prey-capture movements might be essential to maintain performance in a new environment. Newts are of special interest in this regard as they show a multiphasic lifestyle where adults change seasonally between an aquatic and a terrestrial stage. For instance, the Alpine newt is capable of using tongue prehension to feed on land only when in the terrestrial stage, but still manages to suction feed if immersed whilst in terrestrial stage. During the aquatic stage, terrestrial feeding always involved grasping prey by the jaws. Here, we show that this seasonal shift in feeding behavior is also present in a species with a shorter terrestrial stage, the smooth newt Lissotriton vulgaris. Behavioral variability increases when animals change from aquatic to terrestrial strikes in the aquatic stage, but prey-capture movements seem to be generally well-coordinated across the feeding modes. Only suction feeding in the terrestrial stage was seldom performed and appeared uncoordinated. Our results indicate that newts exhibit a high degree of seasonal flexibility of the prey-capture behavior. The similarity between movement patterns of suction feeding and terrestrial feeding suggests that only relatively subtle neuromotoric adjustments to the ancestral, suction-feeding motor program are required to successfully feed in the new environment.

No MeSH data available.


Related in: MedlinePlus

Kinematic profiles of the four feeding modes. Kinematic means (dark and bold curves) ± SD (pale and slim curves) of gape (blue), hyoid (green), head rotation (orange), and tongue movement (gray, only shown in d). The time scale on the x axes is normalized as percentages of total gape cycle, but see Table 2 for absolute values
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Fig3: Kinematic profiles of the four feeding modes. Kinematic means (dark and bold curves) ± SD (pale and slim curves) of gape (blue), hyoid (green), head rotation (orange), and tongue movement (gray, only shown in d). The time scale on the x axes is normalized as percentages of total gape cycle, but see Table 2 for absolute values

Mentions: When capturing prey underwater in the aquatic stage, L. vulgaris approached prey and then sucked it up by an anterior to posterior oropharyngeal expansion wave (Figs. 2a and 3a). The strike at the prey started with mouth opening, achieved by dorsal head rotation and lower jaw depression. The gape reached its peak of 4.5 ± 0.8 mm (mean ± SD) 30 ± 6 ms after the onset of mouth opening, immediately after which the mouth started closing. Hyoid depression started with a short delay of 9.4 ± 5.0 ms after the onset of mouth opening and reached its ventral depression peak of 4.0 ± 0.9 mm after 25 ± 6 ms, almost simultaneously with the peak gape (see section on correlations below). Prey was sucked in before jaw closing started (Figs. 2a and 3a). The angle of the skull relative to the longitudinal body axis was smaller after jaws were closed (end of gape cycle) than before jaw opening started (start of gape cycle). The whole gape cycle was described by a bell-shaped curve and lasted 51.4 ± 7.5 ms (Table 2; Figs. 2a and 3a).Fig. 2


Flexibility is everything: prey capture throughout the seasonal habitat switches in the smooth newt Lissotriton vulgaris.

Heiss E, Aerts P, Van Wassenbergh S - Org. Divers. Evol. (2014)

Kinematic profiles of the four feeding modes. Kinematic means (dark and bold curves) ± SD (pale and slim curves) of gape (blue), hyoid (green), head rotation (orange), and tongue movement (gray, only shown in d). The time scale on the x axes is normalized as percentages of total gape cycle, but see Table 2 for absolute values
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4470538&req=5

Fig3: Kinematic profiles of the four feeding modes. Kinematic means (dark and bold curves) ± SD (pale and slim curves) of gape (blue), hyoid (green), head rotation (orange), and tongue movement (gray, only shown in d). The time scale on the x axes is normalized as percentages of total gape cycle, but see Table 2 for absolute values
Mentions: When capturing prey underwater in the aquatic stage, L. vulgaris approached prey and then sucked it up by an anterior to posterior oropharyngeal expansion wave (Figs. 2a and 3a). The strike at the prey started with mouth opening, achieved by dorsal head rotation and lower jaw depression. The gape reached its peak of 4.5 ± 0.8 mm (mean ± SD) 30 ± 6 ms after the onset of mouth opening, immediately after which the mouth started closing. Hyoid depression started with a short delay of 9.4 ± 5.0 ms after the onset of mouth opening and reached its ventral depression peak of 4.0 ± 0.9 mm after 25 ± 6 ms, almost simultaneously with the peak gape (see section on correlations below). Prey was sucked in before jaw closing started (Figs. 2a and 3a). The angle of the skull relative to the longitudinal body axis was smaller after jaws were closed (end of gape cycle) than before jaw opening started (start of gape cycle). The whole gape cycle was described by a bell-shaped curve and lasted 51.4 ± 7.5 ms (Table 2; Figs. 2a and 3a).Fig. 2

Bottom Line: Due to the different biophysical demands on the whole organism in water and air, such transitions require major changes of many physiological functions, including feeding.Accordingly, the capability to modulate the pre-programmed chain of prey-capture movements might be essential to maintain performance in a new environment.Our results indicate that newts exhibit a high degree of seasonal flexibility of the prey-capture behavior.

View Article: PubMed Central - PubMed

Affiliation: Institute of Systematic Zoology and Evolutionary Biology, Friedrich-Schiller-University Jena, Erbertstr. 1, 07743 Jena, Germany ; Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium ; Department of Integrative Zoology, University of Vienna, Althanstr. 14, 1090 Vienna, Austria.

ABSTRACT

Transitions between aquatic and terrestrial habitats are significant steps in vertebrate evolution. Due to the different biophysical demands on the whole organism in water and air, such transitions require major changes of many physiological functions, including feeding. Accordingly, the capability to modulate the pre-programmed chain of prey-capture movements might be essential to maintain performance in a new environment. Newts are of special interest in this regard as they show a multiphasic lifestyle where adults change seasonally between an aquatic and a terrestrial stage. For instance, the Alpine newt is capable of using tongue prehension to feed on land only when in the terrestrial stage, but still manages to suction feed if immersed whilst in terrestrial stage. During the aquatic stage, terrestrial feeding always involved grasping prey by the jaws. Here, we show that this seasonal shift in feeding behavior is also present in a species with a shorter terrestrial stage, the smooth newt Lissotriton vulgaris. Behavioral variability increases when animals change from aquatic to terrestrial strikes in the aquatic stage, but prey-capture movements seem to be generally well-coordinated across the feeding modes. Only suction feeding in the terrestrial stage was seldom performed and appeared uncoordinated. Our results indicate that newts exhibit a high degree of seasonal flexibility of the prey-capture behavior. The similarity between movement patterns of suction feeding and terrestrial feeding suggests that only relatively subtle neuromotoric adjustments to the ancestral, suction-feeding motor program are required to successfully feed in the new environment.

No MeSH data available.


Related in: MedlinePlus