Phenotypic plasticity in the common snapping turtle (Chelydra serpentina): long-term physiological effects of chronic hypoxia during embryonic development

Studies of embryonic and hatchling reptiles have revealed marked plasticity in morphology, metabolism, and cardiovascular function following chronic hypoxic incubation. However, the long-term effects of chronic hypoxia have not yet been investigated in these animals. The aim of this study was to determine growth and postprandial O2 consumption (V̇o2), heart rate ( fH), and mean arterial pressure ( Pm, in kPa) of common snapping turtles ( Chelydra serpentina) that were incubated as embryos in chronic hypoxia (10% O2, H10) or normoxia (21% O2, N21). We hypothesized that hypoxic development would modify posthatching body mass, metabolic rate, and cardiovascular physiology in juvenile snapping turtles. Yearling H10 turtles were significantly smaller than yearling N21 turtles, both of which were raised posthatching in normoxic, common garden conditions. Measurement of postprandial cardiovascular parameters and O2 consumption were conducted in size-matched three-year-old H10 and N21 turtles. Both before and 12 h after feeding, H10 turtles had a significantly lower fH compared with N21 turtles. In addition, V̇o2 was significantly elevated in H10 animals compared with N21 animals 12 h after feeding, and peak postprandial V̇o2 occurred earlier in H10 animals. Pm of three-year-old turtles was not affected by feeding or hypoxic embryonic incubation. Our findings demonstrate that physiological impacts of developmental hypoxia on embryonic reptiles continue into juvenile life.

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CHEMICAL SIGNALS IN VERTEBRATE PREDATOR-PREY SYSTEMS INVOLVING COMMON MUSK TURTLES, STERNOTHERUS ODORATUS, AND THEIR PREDATORS

Journal of North American Herpetology ◽

10.17161/jnah.vi1.11896 ◽

2014 ◽

pp. 69-75

Author(s):

Don Moll ◽

Neil Dazet

Keyword(s):

Field Experiments ◽

Experimental Studies ◽

Chelydra Serpentina ◽

Agkistrodon Piscivorus ◽

Predator Prey ◽

Snapping Turtle ◽

Snapping Turtles ◽

Sternotherus Odoratus ◽

The Common ◽

And Control

Rathke’s gland secretions (RGS) of Common Musk Turtles have a variety of proposed functions including predator deterrence and attraction, but experimental studies testing these hypotheses are lacking. This study used laboratory and field experiments to test whether RGS had attraction or repellent effects on two natural predators, the Cottonmouth (Agkistrodon piscivorus), and the Common Snapping Turtle (Chelydra serpentina). In a laboratory experiment, we examined latency to feed and consumption times for Cottonmouths offered RGS-treated minnows and control minnows. In a field study, we investigated the ratio of snapping turtles appearing in traps with and without RGS-treated bait. The latency to feed times for Cottonmouths offered RGS-treated minnows were not significantly different from those offered control minnows. However, prey consumption times for Cottonmouths feeding on RGS-treated minnows were significantly greater than those feeding on control minnows. These results suggest that the RGS may lengthen the time of a predation sequence, possibly allowing the turtle more time to escape from the predator. The number of snapping turtles appearing in traps with RGS-treated bait was significantly greater than the number of snapping turtles in traps without RGS-treated bait. These results support the predator attraction hypothesis, where the signal may attract additional predators that interfere with a predation event, providing an opportunity for the prey to escape.

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