QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by JOHN-ALDER, H. B. Articles by BENNETT, A. F. Search for Related Content PubMed Articles by JOHN-ALDER, H. B. Articles by BENNETT, A. F.

Journal of Experimental Biology 142,357-372 (1989)
Published by Company of Biologists 1989

Thermal Sensitivity of Swimming Performance and Muscle Contraction in Northern and Southern Populations of Tree Frogs (Hyla Crucifer)

HENRY B. JOHN-ALDER ¹, M. CHRISTOPHER BARNHART ², and ALBERT F. BENNETT ²

¹ Rutgers University, Department of Biological Sciences, Nelson Biological Laboratory Piscataway, NJ 08855-1059, USA
² University of California-Irvine, Department of Developmental and Cell Biology Irvine, CA 92715, USA

The effects of temperature on sprint swimming ability and muscle contractile properties were examined in northern and southern populations of the holarctic tree frog, Hyla crucifer Wied-Neuwied, acclimated to 20-23°C. Maximal swimming velocities of 29 (southern) and 32 (northern) cms^-1 and stroke frequencies of 4.1 (southern) and 5.5 (northern) strokes s^-1 were attained at 30°C, and maximal stroke lengths (i.e. distance moved per stroke) of 8.0 (southern) and 7.4 (northern) cm at 20°C. The thermal dependence of swimming velocity decreases with increasing temperature (e.g. Q₁₀ = 4.0 from 6 to 10°C, 1.2 from 20 to 30°C), as reported for locomotion in other ectothermic vertebrates. Over a temperature range of l.5-30°C, velocity increases by a factor of 5.5, frequency by a factor of 4, and length by a factor of 1.7. Thus, increased velocity at higher temperatures can be attributed mostly to increased stroke frequency; increments in stroke length contribute less. Muscle contractile properties have similar thermal dependencies to those of other vertebrates: rate processes [including twitch time-to-peak tension (TPT), twitch half-relaxation time (RT), maximal rate of tetanic tension development and isotonic shortening velocity] are much more sensitive to temperature than is force generation (twitch and tetanic tension). Below 8°C, stroke frequency is limited by twitch contraction time (TPT + RT), and leg extension in a swimming stroke by TPT. At higher temperatures, the thermal dependence of stroke time is lower than that of contraction time. Neither locomotor nor muscle contractile properties are different between the two populations (except for twitch tension at low temperatures). Inflexibility in the thermal dependence of muscle contraction and locomotion in this species may help to explain differences in breeding phenologies between northern and southern populations.

Key words: amphibian, locomotion, muscle, temperature-dependence, hylidae, population, anuran

Accepted on October 18, 1988

This article has been cited by other articles:

				I. A. Johnston and G. K. Temple Thermal plasticity of skeletal muscle phenotype in ectothermic vertebrates and its significance for locomotory behaviour J. Exp. Biol., August 1, 2002; 205(15): 2305 - 2322. [Abstract] [Full Text] [PDF]

				R. S. Wilson Geographic variation in thermal sensitivity of jumping performance in the frog Limnodynastes peronii J. Exp. Biol., March 14, 2002; 204(24): 4227 - 4236. [Abstract] [Full Text] [PDF]