Accumulation of Lactate by Frozen Painted Turtles (Chrysemys picta) and Its Relationship to Freeze Tolerance

2004 ◽  
Vol 77 (3) ◽  
pp. 433-439 ◽  
Author(s):  
Mary J. Packard ◽  
Gary C. Packard
1992 ◽  
Vol 262 (3) ◽  
pp. R530-R537 ◽  
Author(s):  
T. A. Churchill ◽  
K. B. Storey

Hatchlings of both the Midland (Chrysemys picta marginata) and Western (C. picta bellii) subspecies of the painted turtle tolerate the freezing of extracellular body fluids while overwintering in terrestrial nests. Fall-collected hatchlings survived 3 days of continuous freezing at -2.5 degrees C, with ice contents of 43.5 +/- 1.0% of total body water (SE; n = 24) for C. picta marginata and 46.5 +/- 0.8% (n = 32) for C. picta bellii. Survival times dropped to 4-5 h when temperature was lowered to -4 degrees C, correlated with ice contents of greater than or equal to 50%. However, C. picta marginata tested immediately after excavation from nests in the spring showed greater freeze tolerance, with survival extending to 11 days at -2.5 degrees C and a higher mean ice content of 50.2 +/- 1.2% (n = 6). Spring hatchlings also had high supercooling points, -1.07 +/- 0.13 degrees C (n = 8), that dropped within 3 days to -4.83 +/- 0.83 degrees C (n = 4), suggesting a breakdown of endogenous ice-nucleating agents when hibernation ended. A search for possible cryoprotectants showed that both subspecies accumulated glucose and lactate in liver during freezing (net increase = 3-13 mumols/g wet wt); both also maintained large free amino acid pools in organs, with taurine making up 21-47% of the total.


1989 ◽  
Vol 67 (4) ◽  
pp. 1082-1084 ◽  
Author(s):  
Gary L. Paukstis ◽  
Robert D. Shuman ◽  
Fredric J. Janzen

Hatchling painted turtles, (Chrysemys picta) in north central Nebraska overwinter terrestrially within the nest cavity. Nest temperatures as low as −2.1 °C were recorded during January 1982 within nests from which hatchlings survived. Under laboratory conditions, nine turtles survived a cooling cycle (0 to −8.0 to 0 °C) over a 29-h period. Four of these turtles exhibited the ability to supercool to temperatures as low as −8.9 °C at which point freezing occurred. Partial freeze tolerance was exhibited by one individual. The ability of hatchling painted turtles to supercool and to survive subfreezing temperatures may be an important factor in the northern distribution of this species.


2000 ◽  
Vol 78 (2) ◽  
pp. 226-233 ◽  
Author(s):  
Roy D Nagle ◽  
Owen M Kinney ◽  
Justin D Congdon ◽  
Christopher W Beck

Hatchling painted turtles (Chrysemys picta) often exhibit delayed emergence by remaining in shallow sub- terranean nest cavities throughout winter. As a result, those at northern latitudes are sometimes exposed to lethal subzero temperatures. Our field study compared survivorship of hatchling C. picta during a winter in which low subzero temperatures coincided with the absence of insulating snow cover (1995-1996) with survivorship during the following three winters (1996-1997, 1997-1998, and 1998-1999), which were characterized by more moderate conditions. Ambient-air and soil temperatures were monitored at a weather station located within ~1 km of all nests. During the first winter of our study (1995-1996), minimum ambient-air temperature reached -25.6°C on 2 February, concomitantly with the complete absence of snow cover, and soil temperatures fell to between -7 and -9°C. Resultant over-winter hatchling mortality was 45%. Because some hatchlings survived temperatures well below the lethal limits described for freeze tolerance (-1 to -4°C), it is likely that hatchlings in Michigan sometimes survive by supercooling. During the following three winters, soil temperatures remained above -2°C, except during brief periods when they fell to -4°C in the absence of snow cover. Over-winter hatchling mortality was <3% during each of these last 3 years. Our study highlights the importance of insulating snow cover to survival of hatchling C. picta. Air temperature and snowfall data from southeastern Michigan over the past 33 years indicate that conditions associated with substantial winter mortality occurred in 3 out of 33 years (9.1%). We demonstrate that the impact of substantial over-winter mortality on hatchling recruitment is dependent on nest survivorship during the preceding nesting season.


1993 ◽  
Vol 130 (2) ◽  
pp. 314 ◽  
Author(s):  
Nat B. Frazer ◽  
Judith L. Greene ◽  
J. Whitfield Gibbons

1979 ◽  
Vol 57 (5) ◽  
pp. 1046-1051 ◽  
Author(s):  
Shannon F. Timmers ◽  
Paul D. Lewis Jr.

One new monogenean is described and 11 other helminths are reported from painted turtles from eastern Manitoba. Polystomoides pauli sp.n. from the host's oral mucosa most closely resembles P. coronatum (Leidy) and P. oris Paul. It differs from the former in having more and larger genital coronet spines, and possession of anterior cecal diverticula, and from the latter in size, larger number of genital coronet spines, and possession of great hooks with entire, not bifid, roots. Price's emendation of P. coronatum to include five species he held to be its synonyms is rejected; and the five species, P. opacum Stunkard, P. megacotyle Stunkard, P. microcotyle Stunkard, P. albicollis MacCallum, and P. digitatum MacCallum are designated species inquirendae. Polystomoides coronatum is restricted to the redescription given for it by Stunkard. The trematodes Crepidostomum sp., Eustomos chelydrae, Microphallus opacus, Protenes angustus, Spirorchis parvus, S. scripta, Telorchis attenuatus, and T. corti, the cestode Proteocephalus sp., and the nematodes Serpinema trispinosa and Spiroxys contortus are reported from Chrysemys picta belli. Except for P. angustus, all represent first reports from turtles in Canada. This is the first report of E. chelydrae from the host stomach, and the second report of M. opacus from naturally infected turtles.


1981 ◽  
Vol 54 (1) ◽  
pp. 165-178 ◽  
Author(s):  
Gary C. Packard ◽  
Mary J. Packard ◽  
Thomas J. Boardman

2006 ◽  
Vol 84 (8) ◽  
pp. 1129-1137 ◽  
Author(s):  
I.R. Caldwell ◽  
V.O. Nams

Orientation mechanisms allow animals to spend minimal time in hostile areas while reaching needed resources. Identification of the specific mechanism used by an animal can be difficult, but examining an animal's path in familiar and unfamiliar areas can provide clues to the type of mechanism in use. Semiaquatic turtles are known to use a homing mechanism in familiar territory to locate their home lake while on land, but little is known about their ability to locate habitat in unfamiliar territory. We tested the tortuosity and orientation of 60 eastern painted turtles ( Chrysemys picta picta (Schneider, 1783)). We released turtles at 20 release points located at five distances and in two directions from two unfamiliar lakes. Turtle trails were quite straight (fractal dimension between 1.1 and 1.025) but were not oriented towards water from any distance (V-test; u < 0.72; P > 0.1). Turtles maintained their initially chosen direction but either could not detect water or were not motivated to reach it. Furthermore, paths were straighter at larger spatial scales than at smaller spatial scales, which could not have occurred if the turtles had been using a correlated random walk. Turtles must therefore be using a reference stimulus for navigation even in unfamiliar areas.


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