Environmental control of annual testicular cycles in the lizard <i>Anolis carolinensis</i>. III. Temperature thresholds for photoperiodism

Licht, Paul

doi:10.1002/jez.1401720306

Cited by 26 publications

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“…However, unlike rats, because lizards are ectothermic animals, it is important to point out here that maintenance of temperature levels suitable for activity in each phase of the experiments has been crucial to get meaningful results. We kept environmental chambers as well as the water of the maze at a temperature of 29±1.0°C, because it is comprised within the range of body temperatures best suited for activity in ruin lizards (Licht, 1969;Tosini et al, 1992). Ambient temperatures of 29±1.0°C were also used successfully to monitor locomotor activity of ruin lizards in previous laboratory experiments (Foà, 1991;Foà and Bertolucci, 2001).…”

Section: Discussionmentioning

confidence: 99%

Orientation of lizards in a Morris water-maze: roles of the sun compass and the parietal eye

Foà

Basaglia

Beltrami

et al. 2009

Journal of Experimental Biology

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Section: Discussionmentioning

confidence: 99%

Orientation of lizards in a Morris water-maze: roles of the sun compass and the parietal eye

Foà

Basaglia

Beltrami

et al. 2009

Journal of Experimental Biology

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Photoperiodic and thermoperiodic interaction affecting fat stores and reproductive indexes in the male green anole, Anolis carolinensis

Noeske

Meier

1977

J. Exp. Zool.

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Daily fluctuations in warm (30°C) and cold (20°C) temperatures have different effects on fat stores and gonad weights of male Anolis carolinensis than constant warm or cold temperatures; and the effects vary depending on the phase relations of the daily thermoperiod with a daily photoperiod. In addition there is a seasonal change in the thermoperiod-photoperiod interaction. For example an &hour interval of warm temperature beginning eight hours after the onset of a 6-hour daily photoperiod during July is more stimulatory for testicular weights than similar intervals of warm temperature beginning a t 0 or 16 hours after the onset of light, but it is less stimulatory in October. The results suggest that the interaction of thermoperiodic and photoperiodic cycles may have important roles in regulating the annual cycles of reproduction and lipid metabolism.The reproductive system of male green anoles is influenced by both temperature and daylength during the year. GonadaI regression in late summer is primarily dependent on decreasing daylengths. Daily photoperiods of less than 14 hours promote testis involution in late summer but not at other times during the year. In contrast, the regenerative period of the testicular annual cycle seems to depend primarily on temperature. Low constant temperatures (20°C or less) promote the initial stages of spermatogenesis and testis enlargement in late fall and winter independent of daily photoperiod. Higher temperatures approaching the "preferred" temperature of the anole (approximately 32°C) stimulate spermiation in the spring (Licht, '66, '67a,b, '69, '71).The manner in which temperature and daylength interact to influence the reproductive system is apparently complex. Some of the difficulty in interpretation of experimental data may result from the common practice of providing constant temperatures in the laboratories for ectothermic vertebrates including the green anole. However, under natural conditions, daily fluctuations in environmental temperatures (daily thermoperiods) are almost as predictable as the periodicity in light intensity. This study was undertaken to ex-J. EXP. ZOOL., 202: 97-102. plore possible influences on fat stores and reproductive indexes that daily thermoperiods may have when related temporally in different phases with respect to daily photoperiods a t different seasons of the year. MATERIALS AND METHODSAdult male green anoles (Anolis carolinensisl were collected in Baton Rouge, Louisiana, or purchased from a local biological supply house in southern Louisiana. Experimental groups of seven to ten animals were maintained in screen-covered plastic cages. Food (house crickets) and water were provided ad libitum. The cages were kept in incubators equipped with daylight fluorescent fixtures (150-200 lux at cage level) attached to a timer. The lizards were acclimated to the photoperiodic regimen for seven days before the experiments began. A 6L:18D daily schedule was used in all the experiments. This photoperiodic regimen inhibits the release of gona...

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The effect of temperature on the male reproductive system of the common water snake (Nerodia sipedon)

Weil

Aldridge

1979

J. Exp. Zool.

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The effect of various temperatures upon the male reproductive cycle of the common water snake fNerodia sipedon) was studied. Snakes were divided into five groups and kept a t five different temperature regimes and a OL:24D photoperiod for ten weeks. Those kept in Chamber 1 were a t 20°C the entire day while those kept in Chambers 2-5 were maintained a t 21.3, 23.3, 27.4 and 29.3"C for eight hours per day respectively and 20°C for the remaining 16 hours each day.Interstitial cell nuclear diameters, renal sexual segment tubule diameters and epithelial heights were found to be unrelated to increasing temperatures. Testicular growth was positively correlated to increasing temperatures. Seminiferous tubule diameters increased rapidly between 20 and 21.3"C with a Q l o = 39. Tubule diameters continued to increase, although a t a slower rate, with further increases in temperature, with a Q l o = 1.72 between 21.3 and 29.3"C. Spermatogenesis increased with increasing temperatures; the threshold temperature for initiation of spermatogenesis was between 20 and 21°C.Therefore, spermatogenesis and testicular recrudescence in Nerodia sipedon are temperature and not light dependent. Further, this report shows that weight of fat bodies does not affect normal spermatogenesis and testis growth in the presence of a sufficient food supply.

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Environmental control of annual testicular cycles in the lizard Anolis carolinensis. III. Temperature thresholds for photoperiodism

Cited by 26 publications

References 14 publications

Orientation of lizards in a Morris water-maze: roles of the sun compass and the parietal eye

Orientation of lizards in a Morris water-maze: roles of the sun compass and the parietal eye

Photoperiodic and thermoperiodic interaction affecting fat stores and reproductive indexes in the male green anole, Anolis carolinensis

The effect of temperature on the male reproductive system of the common water snake (Nerodia sipedon)

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