William W. Reynolds

Responses of Young Gulf Grunion, Leuresthes sardina, to Gradients of Temperature, Light, Turbulence and Oxygen

. 1955. Field experiments on the biology and genetic relationships of the California species of Triturus. Ibid. 129:129-148. . 1961a. Experiments of homing behavior and speciation in Taricha, p. 415-459. In: Vertebrate Speciation. W. F. Blair, ed. Univ. Texas Press, Austin. . 1961b. Second-generation hybrids of the species of Taricha. Proc. Nat. Acad. Sci. 47:1461-1486. 1964. Fertility of Taricha specieshybrids and viability of their offspring. Ibid. 51:156-161. . 1966. Of Scientists and Salamanders. W. H. Freeman and Co., San Francisco. WHITE, M. J. D. 1946. The spermatogenesis of hybrids between Triturus cristatus and T. marmoratus (Urodela). J. Exp. Zool. 102:179205. YANG, S. Y., L. L. WHEELER AND I. R. BOCK. 1972. Isozyme variations and phylogenetic relationships in the Drosophila bipectinata species complex. Studies in Genetics VII. Univ. of Texas. Publ. no. 7213:213-227.

Body temperatures of behaviorally thermoregulating largemouth blackbass (Micropterus salmoides)

Abstract 1. 1. Five largemouth blackbass, ranging from 50 to 460 g body weight, were allowed to behaviorally thermoregulate in an electronic device which permitted them to regulate the water temperature. 2. 2. Mean gut temperatures over a 12-hr period did not differ significantly from mean occupied temperatures or from mean water temperatures.

Diel patterns of preferred temperature and locomotor activity in the goldfish Carassius auratus

Abstract 1. 1. Goldfish thermoregulating in an electronic shuttlebox device exhibited a bimodal (crepuscular) rhythm of locomotor activity (peaks at the beginning and end of the dark period) and a unimodal (nocturnal) peak of preferred temperature during the latter half of the dark period. 2. 2. There was no direct relationship between temperature and activity level within the preferred-temperature range of 26–30°C. 3. 3. The preferred temperature peak (29.7°C) occurred at a time (“pre-dawn”) most conducive to increase in body weight and gonosomatic index in goldfish subjected to an exogenously cycled thermal regime.

Behavioral thermoregulation and activity in Homarus americanus

Abstract 1. 1. American lobsters thermoregulated precisely for 6 days in an electronic shuttlebox (mode 16°C; range 15–21°C), with no significant difference in mean preferred temperature between night (17.1°C ± 0.15 SE) and day (17.2°C ± 0.18 SE), although mean hourly activity was 1.3 times as great at night as during the day. 2. 2. The preferred temperature falls within a zone (15–20°C) in which activity decreases with increasing temperature, while activity generally increases with temperature over the range 10–30°C; this may have implications for the adaptive value, if not the mechanism, of thermoregulatory behavior. 3. 3. During the second 6 days, thermoregulatory precision declined markedly (range 10–29°C; modes at 14°C and 26°C), perhaps representing a shift from preference to avoidance behavior, while the nocturnal activity pattern remained stable; the frequency distribution of occupied temperatures became nearly congruent with the temperature-activity relationship and complementary to the temperature distribution during the first 6 days.

Bahavioral fever in crayfish

Crayfish (Cambarus bartoni) were tested individually in an electronic shuttlebox thermoregulatory device which allowed them to control water temperature, and thereby their body temperature, by their movements.Crayfish which initially selected 22.1°C water increased their preferred temperature by 1.8°C following injection of killed bacteria (Aeromonas hydrophila) into the gill cavity.This ‘behavioral fever’ appears similar to that of vertebrates, and may enhance host defense reactions against pathogens.

Ontogenetic change in preferred temperature and diel activity of the yellow bullhead, Ictalurus natalis

Abstract 1. 1. In an electronic thermoregulatory shuttlebox, the (24 hr) mean preferred temperature of 12 adult yellow bullheads was 27.6°C, while that of 12 juveniles was 28.8°C; the mean for all ages was 28.4°C (final preferenda). 2. 2. Mean preferred temperatures differed by no more than 0.4°C between photophase (day) and scotophase (night) of the light cycle. 3. 3. Adult bullheads were nocturnal (most active during the central 8 hr of the scotophase), while juveniles were more crepuscular (most active during the two 4-hr “dusk” periods centered about the light-dark and dark-light transitions).

Fever and antipyresis in the bluegill sunfish, Lepomis Macrochirus

1. 1. Bluegills develop a behavioral fever (increase in preferred temperature) of about 3°C when injected with killed gram-negative bacteria, Aeromonas hydrophila. 2. 2. The antipyretic drug acetaminophen, when dissolved in the ambient water, counteracts the febrile response to bacterial pyrogen. 3. 3. Injection of sterile pyrogen-free saline, or dissolution of acetaminophen in the ambient water of afebrile thermoregulating bluegills, does not significantly affect their preferred temperature.

Aspects of habitat selection in the mosquitofish gambusia affinis

Laboratory experiments were performed to determine behavioral preferences of Gambusia affinis for habitat variables in partitioned aquaria. The fish preferred calm water, dark-colored substrates and subsurface vegetation providing lateral concealment. Floating cover, which obstructed access to the surface, was avoided. Lack of preference for real over plastic plant cover indicates that visual rather than chemical cues are involved. These laboratory preferences correspond to the reported microhabitat distribution of G. affinis in nature and indicate the presence of an active habitat preference, as opposed to passive habitat correlation, in this species. Species-specific habitat preferences, which may be narrower where a species occurs sympatrically with its congeners, probably form part of a reproductive isolating mechanism.

Activity Rhythms and Light Intensity Preferences of Micropterus salmoides and M. dolomieui

Abstract Activity rhythms and light intensity preferences of largemouth (Micropterus salmoides) and smallmouth (M. dolomieui) black basses were investigated in laboratory experiments designed to elucidate aspects of niche separation between these sympatric congeners. Both species exhibited crepuscular activity, but M. salmoides also showed a mid-day activity peak. M. dolomieui avoided bright light, and their peak activity periods occurred at the beginning and end of the dark periods. Activity of M. salmoides was much more depressed during the dark periods, and rose sharply at the onset of light periods. Activity records in constant light conditions showed these activity rhythms to be endogenous.

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.