Diel activity and thermoregulatory behavior of a fully aquatic frog: Xenopus laevis

Ten adult Xenopus laevis were tested individually for 48-hr periods, following an initial 24-hr introductory period, in electronic shuttleboxes which allowed them to control water temperatures without operant conditioning. Locomotor activity was recorded via photocell-monitored light beams. The frogs were nocturnal, being nearly twice as active at night as during the day. The mean preferred temperature was 22.4°C, with no significant difference between night (22.5°C) and day (22.3°C), although the modal preferendum shifted from 24°C by day to 22°C at night, with a corresponding change in skewness. The range of voluntarily occupied temperatures was 14–32°C by day and 14–29°C at night. The median thermal preferendum was 22°C both day and night.     

Thermoregulatory behavior of brown trout,Salmo trutta

Brown trout, Salmo trutta, were allowed to thermoregulate individually in an electronic shuttlebox. Pooled data for 6 fish showed a diel pattern of preferred temperature, with a diurnal minimum of 10.3°C, an early nocturnal maximum of 13.7°C, a less pronounced mid-scotophase minimum of 11.7°C, and a secondary dawn maximum of 12.8°C, in a somewhat crepuscular pattern. The 24-hour mean preferendum was 12.2°C.     

Thermal preference and activity thresholds in populations of Argia vivida (Odonata: Coenagrionidae) from habitats with different thermal regimes

The hypothesis was tested that isolated populations of Argia vivida Hagen living in habitats with different thermal regimes would show similar larval temperature preferenda, similar distributions in a temperature gradient, similar larval upper temperature acitivity thresholds, and similar adult minimum temperature flight thresholds. The hypothesis was supported in all cases, except for distribution within the gradient, where there were significantly fewer observations below 22°C in a population from a habitat with a fluctuating diel and annual temperature regime than in a population from a more thermally stable habitat. Larval modal temperature preferendum was 28°C; escape temperature (EST) was 35.4–36.4°C, critical thermal maximum (CTM) was 39.1–41.0°C, and upper lethal temperature (ULT) was 44.4–46.0°C. While technical difficulties affected the estimates of flight thresholds, there was no difference between the field estimates from different sites. Minimum body temperature for flight appears to be about 25°C, apparently higher than for several other zygopterans, while larval activity thresholds and 96 hr LD50 of 36.8°C are similar to those recorded for other odonates.     

Thermoregulatory behavior of a tropical marine fish: Canthigaster jactator (Jenkins)

Ten Canthigaster, jactator, tropical marine puffers from Hawaii, were tested individually for 3-day periods in electronic shuttle-boxes (Ichthyotrons) to determine their ability to thermoregulate behaviorally. These fish thermoregulated with a degree of precision comparable to that of temperate freshwater fishes: range 23–31°C, S.D. 1.8–2.4°C, S.E. 0.3–0.5° C. The modal final thermal preferendum was 27°C, comparable to temperate warmwater fishes. The mean preferred temperature did not differ significantly between night (26.5°C) and day (26.9°C); the 24-hr mean was 26.7°C. Apparently at least some tropical marine fishes are capable of thermoregulatory behavior similar to that of temperate freshwater fishes.     

Thermoregulatory activity in the Tecopa pupfish,Cyprindon nevadensis amargosae,an inhabitant of a thermal spring

Synopsis The final thermal preferendum of Tecopa pupfish Cyprinodon nevadensis amargosae collected from a thermal spring was determined in the laboratory in spatial and temporal thermal gradients. Temperatures chosen centred around 30°C — a value close to those reported for other warmwater species in the literature. Upper limits to final preferenda and thermal tolerance in all species of fish are proposed.     

Behavioral thermoregulation in the spiny lobster Panulirus Argus (latreille)

Ten spiny lobsters (Panulirus argus) were allowed to thermoregulate individually for 3-day periods in an electronic thermoregulatory shuttlebox which allowed them to control water temperatures (and thereby their own body temperatures) by their movements. The range of preferred (voluntarily occupied) temperatures was 25–35°C (mean 29.9°C; mode 30.0°C; median 30.0°C; midpoint 30.0°C; S_k (skewness, Pearson's coefficient) –0.04; s.e.m. 0.19°C; S.D. 2.32°C). The final thermal preferendum (by the gravitation method) in this species is 30°C.     

Influence of acclimation temperature and season on acute temperature preference of adult mountain whitefish,Prosopium williamsoni

Synopsis Temperatures preferred by four groups of adult mountain whitefish, Prosopium williamsoni, collected in October before spawning, in December after spawning, in late winter, and in spring were determined in the laboratory in a horizontal gradient. Acute temperature preference based on fish tested soon after capture and final preferendum estimates were 12.8 and 17.7°C, respectively (pre-spawning), 9.6 and 11.9°C (post-spawning), 10.8 and 9.9°C (winter), and 16.4 and 16.3°C (spring). Seasonal influence on temperature preference was evident on the basis of differences in final preferenda, covariance analysis of responses of laboratory-acclimated fish, and temperature preference of fish held at ambient river temperatures. Fish of the post-spawning and winter groups preferred lower temperatures than did those of pre-spawning and spring groups. Temperatures preferred by pre-spawning fish were too high for embryo survival. Caution is necessary in predicting thermal preference on the basis of a sample collected at one time of year or stage of sexual development.     

Thermoregulatory behavior of juvenile cromileptes altivelis (serranidae), a tropical marine fish

Ten juvenile Cromileptes altivelis were tested individually for 3-day periods in electronic shuttleboxes to measure their thermoregulatory behavior. The fish voluntarily occupied a 21–27°C span, out of a potentially available 0–50°C range. The mean final thermal preferendum was 24.5°C for all individuals. The thermoregulatory performance of this species is similar to that of cool temperate freshwater fishes.     

Thermal preference,tolerance and oxygen consumption of adult white shrimp Litopenaeus vannamei (Boone) exposed to different acclimation temperatures

Final temperature preferendum of white shrimp adults were determined with acute and gravitation methods. The final preferendum was similar, independent of method (26.2–25.6 °C). A direct relationship was determined between the critical thermal maxima values and the acclimation temperatures (P<0.05). The end point of Critical Thermal Maxima (CTMax) for adults was defined as the loss of righting response (LRR). The acclimation response ratio (ARR) for adults of white shrimp had an interval of 0.36–0.76, values that agreed with others obtained for crustaceans from tropical and subtropical climates. The oxygen consumption rates increased significantly (P<0.05) from 39.6 up to 90.0 mg O₂ kg⁻¹ h⁻¹ wet weight (w.w.) as the acclimation temperature increased from 20 to 32 °C. The range of temperature coefficient (Q₁₀) of the white shrimp between 23 and 26 °C was the lower 1.60. The results obtained in this work are discussed in relation to the species importance in the reproductive scope and maintenance of breeders.     

Behavioral thermoregulation, temperature tolerance and oxygen consumption in the Mexican bullseye puffer fish, Sphoeroides annulatus Jenyns (1842), acclimated to different temperatures

An inverse and unusual relationship was found between preferred temperature and acclimation temperature in the bullseye puffer, Sphoeroides annulatus. The final preferendum temperature (PT) was 26.8 °C. The critical thermal maxima (CTMax) were 37.7, 38.8, 40.0, 40.8 and 41.3 °C where the temperatures of acclimation were 19, 22, 25, 28 and 31 °C±1 °C, respectively, and the endpoint of CTMax was loss of the righting response. The acclimation response ratio presented an interval of 0.22-0.38; these values are in agreement with results for other subtropical and tropical fishes. The temperature significantly affected the oxygen consumption of bullseye puffer juveniles. The oxygen consumption rate (OCR) increased significantly with an increment in the temperature from 19 to 31 °C. The range of the temperature coefficient Q₁₀ in bullseye puffer individuals was lowest between 25 and 28 °C, at 1.37. The optimal temperature for growth was 26 °C. The results of this study will be useful for optimizing the culture of bullseye puffer juveniles in controlled conditions.     

Comments on a study of the thermal behaviour of the American eel (Anguilla rostrata) and some statistical suggestions for temperature preference studies

Some suggestions are made concerning methods and statistical evaluation of results in temperature preference studies. The use of regression analysis is advocated rather than graphical methods for evaluating results from acute temperature preference studies and a method of assessing the final preferendum and its confidence interval is demonstrated. This method is applied to a previously published study of the acutely preferred temperature of the American eel (Barila & Stauffer, 1980). The final preferendum and its 95% confidence interval is shown to be 17.4° ± 2.0 °C. In direct contrast to conclusions there drawn, the preferred temperature is shown to depend on the acclimated temperature. Some critical comments are also made concerning other parts of the study.     

Behavioral response of the New England dog whelk,Nassarius trivittatus,to a temperature gradient

Thirty New England dog whelks (Mollusca: Gastropoda: Nassariidae), Nassarius trivittatus, were tested as a group for 3 days in a long linear gradient trough encompassing a thermal gradient ranging from 5°C to 45°C. The modal thermal preferendum of the snails lay between 30°C and 35°C. The lowest temperature interval voluntarily occupied by the snails was 15–20°C, the highest 35–40°C. W e believe this to be the first published study of temperature preference and avoidance behavior of gastropod molluscs.     

Observations on the thermoregulatory behaviour of juvenile spotted grunter, Pomadasys commersonnii (Haemulidae: Pisces)

The thermal preference of juvenile spotted grunter, Pomadasys commersonnii (Haemulidae), was determined in a horizontal thermal gradient. Temperature preference was tested over a range of 17–31°C at three salinities. The modal temperature preferenda at 5, 12 and 35 ppt were 25°C, 24.5°C and 25°C, respectively. They were not significantly different. The thermal preferendum of this species was found to be between 24°C and 25°C. Supplementary experiments were conducted to test the stability of the final thermal preferendum. Initial observation of the behaviour of juvenile spotted grunter indicated the presence of a strong circadian rhythm. However, diel variation in activity did not influence temperature preference. These data are important for the development of a culture protocol for this euryhaline species.     

Influence of freezing temperatures on a cactus,Coryphantha vivipara

Summary Coryphantha vivipara (Nutt.) Britton & Rose var. deserti (Engelm.) W.T. Marshall (Cactaceae) survived snow and tissue temperatures of-12°C in southern Nevada. However, the freezing point depression of the cell sap was only about 0.9°C. When the nocturnal air temperature in the laboratory was reduced from 10°C to-10°C for one night, the optimum temperature for CO₂ uptake shifted from 10°C to 6°C and uptake was reduced 70%, but full recovery to the original values occurred in 4 days. Nocturnal temperatures of-15°C killed 2 out of 5 plants and-20°C killed 5 out of 5, as judged by lack of net CO₂ uptake at night over a 2-month observation period. when the stems were cooled at 2° C/h, supercooling to about-6°C occurred followed by an exothermic reaction that presumably represented the freezing of extracellular water. When the subzero temperature was lowered further, no other exothermic reaction was observed and the cells became progressively dehydrated. Freezing-induced tissue death was ascribed to this cellular dehydration, which led to about 94% loss of intracellular water at-15°C. when the tissue temperature was lowered, the ability of chlorenchyma cells to plasmolyze and to take up a stain decreased, both being nearly 70% inhibited at-15°C and completely abolished at-20°C. Some cold-bardening occurred, since lowering the air temperature from 30° to-10°C in 10°C increments at weekly intervals caused the subzero temperature for 50% inhibition of staining to decrease from-10°C to-17°C. Extension of the range of C. vivipara to regions with wintertime freezing apparently reflects the tolerance of considerable freeze dehydration by its protoplasts.     

Spring behavioral patterns of the apple blossom weevil

Individual pairs of overwintered adult apple blossom weevils, Anthonomus pomorum (L.), confined with apple twigs under different ambient temperatures in the laboratory and on apple trees in the field, were observed through day and night for their spring activities. Flight behavior in relation to ambient temperature was also investigated under laboratory conditions using flight stands. Both sexes displayed predominantly nocturnal behavior patterns in both the laboratory and the field. Feeding, crawling, and mating activities increased following sunset in the field or onset of scotophase in the laboratory while resting occurred most frequently during daylight hours. Results of the laboratory experiments showed that temperature affected significantly the activity patterns. The diel pattern of activities became less distinctive at higher temperatures (above 15°C), and total activities in crawling, feeding, and mating were suppressed significantly at lower temperatures (below 5°C). Over 97% of the test weevils initiated take-off response from flight stands at 20°C within the 30 min trial period; however, flight initiation rarely occurred at temperatures 12°C or below. Overall, results of the laboratory and field experiments indicate that A. pomorum is a remarkably cold-adapted insect with ability to crawl, feed, and mate at a few degrees above freezing, a physiological attribute necessary for the exploitation of early stages of apple bud development in the cold early spring.     

Behavioral thermoregulation by Ammocoete larvae of the sea lamprey (Petromyzon marinus) in an electronic shuttlebox

Ammocoete larvae of the sea lamprey Petromyzon marinus, a member of the primitive vertebrate class Agnatha, were tested for thermoregulatory behavior in an electronic shuttlebox (ichthyotron). The final preferendum derived from pooled data for 24 individually tested ammocoetes was characterized by a mean of 13.6 ± 0.17 (s.e.m.)°C, a mode and median of 140°C, and a range of voluntarily occupied temperatures from 10–19°C over a 3-day period.     

Is locomotor performance optimised at preferred body temperature? A study of Liolaemus pictus argentinus from northern Patagonia, Argentina

We studied the relationship between locomotor performance and temperature in Liolaemus pictus argentinus, from the Andean-Patagonian forest, Argentina. We determined the running speed in long and sprint runs at four different body temperatures, the panting threshold, and minimum critical temperature. The results are discussed in relation to body temperature in the field and thermal preference in the laboratory (T_pref). L. p. argentinus achieved higher speed in sprint runs than in long runs at all temperatures. In order to know if pregnancy constrains performance in this viviparous species, the differences between pregnant females and the other adults were analysed. Pregnant females were at a disadvantage when running long distances, but in sprint runs they were able to run as efficiently as the rest of the individuals, suggesting that they mainly use sprint runs and this may explain their conspicuous more-withdrawn behaviour. In long runs, the performance optimal temperature for L. p. argentinus (T_o=30.7 °C) was below the 25th percentile for all body temperatures selected in the laboratory (set-point range of T_pref=34.6-37.9 °C), but similar to the mean field body temperature (32.1 °C). However, in sprint runs the T_o (36.3 °C) was within the set-point range of T_pref. The mean panting threshold (42.8 °C) and the mean minimum critical temperature (6.9 °C) were similar to those of other liolaemids. The results are evidence that L. p. argentinus is well-adapted to the temperatures available in their environment and that the species has a T_pref that allows the achievement of maximal locomotor performance in the most frequently used and probably the most important run type, the sprint run.     

Body temperature and behaviour of golden hamsters (Mesocricetus auratus) and ground squirrels (Spermophilus tridecemlineatus) in a thermal gradient

Golden hamsters and thirteen-lined ground squirrels were maintained individually in a thermal gradient (14°C to 33°C) for several weeks under a 14L: 10D light-dark cycle. Animals of both species showed robust daily rhythms of body temperature and locomotor activity with acrophases consistent with the habits of the species (diurnal acrophases in the diurnal squirrels and nocturnal acrophases in the nocturnal hamsters). Hamsters showed a robust daily rhythm of temperature selection 180° out of phase with the rhythms of body temperature and locomotor activity. Squirrels did not show a daily rhythm of temperature selection. These results raise the hypothesis that a daily rhythm of temperature selection is exhibited by nocturnal but not by diurnal endotherms.     

Thermoregulatory behavior of the triggerfish Balistes fuscus in an electronic shuttlebox

Ten blue triggerfish,Balistes fuscus, were tested individually for 3 days each in Ichthyotron electronic shuttleboxes to measure their thermoregulatory behavior. The modal thermal preferendum, a species-specific measure of temperature preference which is independent of prior thermal acclimation, was 25 °C. The triggerfish voluntarily occupied a 16–27 °C range of temperature, out of a potentially available range of 0–50 °C. There was no significant difference in preferred temperature between night and day, indicating lack of a thermoregulatory rhythm in this species. The preferred temperature range of this tropical marine reef species is similar to that of cool temperate freshwater and marine fishes; many warm temperate species prefer higher temperatures.