Metamorphic rate as a function of the light/dark cycle in Rana pipiens larvae

Wright, Mary L.; Blanchard, Linda S.; Jorey, Suzanne T.; Basso, Carolyn A.; Myers, Yvonne M; Paquette, Christine M

doi:10.1016/0300-9629(90)90068-4

Cited by 16 publications

(8 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…litsch and Caldwell 1982, Newman 1987, 1994, Berven and Chadra 1988, Scott 1990, and inter-and intraspecific chemical signaling (see Berven 1979, Werner 1986). Some abiotic factors that influence metamorphosis are water temperature (Smith-Gill and Berven 1979, Newman 1989), photoperiod (Wright et al 1990), and pond duration (reviewed by Newman 1992).…”

Section: Introductionmentioning

confidence: 99%

Adaptive Plasticity in Amphibian Metamorphosis: Response of Scaphiopus hammondii Tadpoles to Habitat Desiccation

Denver¹,

Mirhadi²,

Phillips³

1998

Ecology

171

251

View full text Add to dashboard Cite

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Ecological Society of America is collaborating with JSTOR to digitize, preserve and extend access to Ecology.Abstract. Amphibians exhibit extreme plasticity in the timing of metamorphosis, and several species have been shown to respond to water availability, accelerating metamorphosis when their ponds dry. In this study we analyzed the plasticity of the developmental response to water volume reduction in the western spadefoot toad, Scaphiopus hammondii. Also, we attempted to identify the environmental cue(s) that may signal a desiccating larval habitat. We spawned adults in the laboratory and raised tadpoles in aquaria in a controlled environmental chamber. Water levels of aquaria were gradually reduced by removing water at the rate of 0.5-1 L/d; water in control aquaria was similarly disturbed but not removed. Tadpoles subjected to water volume reduction showed significant acceleration of metamorphosis. The developmental acceleration depended on the rate of reduction of the water level; i.e., tadpoles exhibited a continuum of response. This developmental response did not result from thermal differences between treatments. Furthermore, the response was reversible in that refilling of the aquaria to the starting water level at various times following the onset of volume reduction resulted in restoration of body mass and a tendency to decelerate metamorphosis. Several lines of evidence suggest that the developmental response is due neither to the concentration of compounds in the water nor to chemical or physical interactions among conspecifics. Rather, the response appears to be related to the reduced swimming volume and perhaps the proximity to the water surface. When the water level is reduced, tadpoles reduce foraging, and food restriction of prometamorphic tadpoles maintained in a constant high water environment accelerated metamorphosis. Spadefoot toad tadpoles are a valuable model system for explaining both the proximate mechanisms (environmental cues and physiological responses) and the ultimate causes for adaptive phenotypic plasticity in amphibian metamorphosis. The lower and upper limitsto the length of the larval period and body size at metamorphosis are central amphibian life history traits (Wilbur and Collins 1973, Werner 1986, Smith 1987). Within these limits, larvae exhibit extreme plasticity in age and size at metamorphosis, which vary in relation to changes in both biotic and abiotic factors present in the larval habitat. For instance, biotic factors that influence amphibian development include, but are not limited to, food availability (D'Angelo et al. 1941, Travis 1984, Alford and interand intraspecific chemical signaling (see Smith-Gill and Berven 1979, Werner ...

show abstract

Section: Introductionmentioning

confidence: 99%

Adaptive Plasticity in Amphibian Metamorphosis: Response of Scaphiopus hammondii Tadpoles to Habitat Desiccation

Denver¹,

Mirhadi²,

Phillips³

1998

Ecology

171

251

View full text Add to dashboard Cite

show abstract

“…Through such mechanisms, no doubt, the LD regimen exerts influence on the rate of tadpole metamorphosis, which differs on each of the schedules studied (Wright et al, 1988a;Wright et al, 1990a), so that transformation is coordinated with external conditions favorable to survival of the juvenile frog. In this connection, it is relevant that the thyroid hormones induce metamorphosis and it has been recently shown in vitro that melatonin directly antagonizes the effect of thyroxine at the peripheral level (Wright et al, 1991).…”

Section: Discussionmentioning

confidence: 98%

“…In the present work, we studied the cell cycle in the hindlimb epidermis on circadian (6L:18D, 18L:6D) and noncircadian (12L:18D, 15L:15D) schedules, that had already been used in studies of metamorphic rate (Wright et al, 1988a;Wright et al, 1990a) and labeling and mitotic index rhythms (Wright et al, 1988b), to establish the influence of the LD regimen on specific cell cycle phases in a vertebrate. Since the influence of the LD schedule may be mediated through the pineal hormone, melatonin, we also studied the effect of melatonin on the labeling index rhythm in the hindlimb epidermis.…”

Section: Modulation Of Cell Cycle Phases By Various Circadian and Nonmentioning

confidence: 99%

Modulation of cell cycle phases by various circadian and noncircadian light/dark schedules and evidence implicating melatonin

Wright

Jorey

Blanchard

et al. 1993

Journal of Interdisiplinary Cycle Research

View full text Add to dashboard Cite

The influence of circadian (6L:18D, 18L:6D) and noncircadian (12L:18D, 15L:15D) light/dark (LD) schedules on the cell cycle was studied in the hindlimb epidermis of late premetamorphic tadpoles of the frog, Rana pipiens. Using tritiated thymidine autoradiography, percent labeled mitoses (PLM) curves were obtained for 3 cell cycle determinations on each LD schedule, starting at 0, 8, and 16 hr for the 24 hr, and at 0, 10, and 20 hr for the 30 hr LD regimens. From the PLM curves, the durations of the whole cycle (T), the DNA synthetic phase (S), and the pre-(G 1 +1/2M) and post-(G 2 +1/2M) synthetic gaps, which included mitotic time, were determined. The data were compared with previous work on 12L:12D. The shape of the PLM curves and the resulting phase durations were characteristic for each LD regimen. T was longer where L was less than D and shorter where L was greater than D. The relative duration of S decreased, while G 1 +1/2M increased, as L lengthened on the 24 hr regimens, whereas on the 30 hr regimens the opposite occurred. On both 24 and 30 hr schedules, as L lengthened the percentage of cell cycle time in G 2 +1/2M increased. The findings show the specific influence of a change in the LD schedule, including noncircadian regimens, on particular cell cycle phases in a vertebrate. In a separate experiment, the labeling index was studied over a 24 hr period in control tadpoles and in those treated with hydrocortisone or melatonin. Since only melatonin shifted the phase of the labeling index rhythm when injected during the light, this hormone may account for the effects of the LD schedule on the cell cycle.

show abstract

“…Photoperiodic phenomena could also affect the action of melatonin in vivo. When the length of the photophase was held constant while the LD cycle was progressively extended in Rana pipiens, metamorphic rate resonated (25), suggesting the occurrence of a circadian rhythm of photosensitivity in Amphibia as in other vertebrates (18). Metamorphic rate was rapid on some cycles with short photophases (e.g., 8L: 10D, 8L:28D) and slow on others (8L : 22D).…”

Section: In Vitro Experimentsmentioning

confidence: 99%

“…Since light stimulated thyroid gland activity in Rana catesbeiana (12), such inhibition might also exist in amphibians. However, the effects of light on metamorphic rate were basically the same during T4-induced and spontaneous metamorphosis (25,29), indicating that melatonin may affect T4 action at the peripheral level.…”

Section: Introductionmentioning

confidence: 98%

Influence of Melatonin on the Rate of Rana pipiens Tadpole Metamorphosis In Vivo and Regression of Thyroxine‐Treated Tail Tips In Vitro

Wright¹,

Cykowski²,

Mayrand³

et al. 1991

Dev Growth Differ

View full text Add to dashboard Cite

Metamorphosis of Rana pipiens tadpoles may be retarded when the light phase of the light/dark (LD) cycle is shortened or when thyroxine (T4) is given in the dark because melatonin peaks during the dark. Injection of premetamorphic tadpoles in spontaneous metamorphosis with melatonin (1 5 pg) retarded tail growth and hindlimb development on 18L:6D but had no significant effect on 6L: 18D. During induced metamorphosis (30 pg/liter T4), melatonin injections retarded tail resorption on 18L : 6D and accelerated it on 6L : 18D, but did not affect the hindlimb. When melatonin was injected during T4 immersion at different times in the photophase on 18L : 6D (L onset 0800 hr), tail regression was retarded by melatonin at 1430 or 2030 hr. At 0830 hr, shrinkage of tail length was accelerated whereas tail height was not affected. Tail tips in vifro induced to resorb by 0.2 pg/ml T4 in Niu-Twitty solution regressed more slowly in the presence of melatonin (10 or 15pg/ml) than with T4 alone on both 6L: 18D and 18L:6D. The findings implicate melatonin in LD cycle effects on tadpole metamorphic rate in vivo, show the importance of the time of melatonin injections, and indicate that melatonin antagonizes the metamorphic action of T4 at the tissue level.

show abstract

Metamorphic rate as a function of the light/dark cycle in Rana pipiens larvae

Cited by 16 publications

References 22 publications

Adaptive Plasticity in Amphibian Metamorphosis: Response of Scaphiopus hammondii Tadpoles to Habitat Desiccation

Adaptive Plasticity in Amphibian Metamorphosis: Response of Scaphiopus hammondii Tadpoles to Habitat Desiccation

Modulation of cell cycle phases by various circadian and noncircadian light/dark schedules and evidence implicating melatonin

Influence of Melatonin on the Rate of Rana pipiens Tadpole Metamorphosis In Vivo and Regression of Thyroxine‐Treated Tail Tips In Vitro

Contact Info

Product

Resources

About