Behavioral thermoregulation in mammals and birds

Thermoregulation in homoiotherms is achieved by physiological and behavioural adjustments which involve the musculature, skin, sensory capacities, hypothalamus and endocrine glands. Under thermal stress animals exhibit anorexia, body extension, gasping, languor, lethargy, excessive drinking, bathing, decreased locomotor activities, group dispersion, and shade seeking. When exposed to cold, animals show body flexure, huddling, hyperphagia, extra locomotor activities, depressed respiration and nest building. Species and breed differences in the behavioural adjustments to unfavourable climates are related to habitat, morphological characteristics of body covering, degree of physiological adaptability, degree of physiological immaturity at birth or hatching, and the number of young.     

Behavioral and physiological flexibility are used by birds to manage energy and support investment in the early stages of reproduction

Interest in phenotypic flexibility has increased dramatically over the last decade, but flexibility during reproduction hasreceived relatively little attention from avian scientists, despite its possible impact on fitness. Because most avian species maintainatrophied reproductive organs when not active, reproduction in birds requires major tissue remodeling in preparation for breeding.Females undergo rapid (days) recrudescence and regression of their reproductive organs at each breeding attempt, while m...     

Behavioral and physiological correlates of ostracism

A model of social interaction is outlined and used to interpret behavioral and physiological correlates of ostracism. Reported findings suggest that several physiological systems contribute to behaviors that are associated with ostracism and that these as well as other systems are involved in responses to being ostracized. The ideas discussed in this article suggest that future research should (1) identify persons who may be genetically predisposed to engage in behaviors associated with ostracism, and (2) identify persons who are physiologically vulnerable to being ostracized.     

Behavioral correlates of physiological estrus in cheetahs

Historically, the cheetah (Acinonyx jubatus) has been known for its poor reproductive performance in captivity. Although breeding success has improved over the past decade, the percentage of breeders in the captive population is still low and successful propagation unpredictable. Estrus in this species has been reported as “silent” by some, therefore contributing to breeding problems by making appropriate timing of pair introductions difficult. To investigate whether any observable behavioral changes may be associated with estrus, we carried out quantitative behavioral observations and concomitant noninvasive monitoring of estradiol metabolites excreted in feces of 14 captive female cheetahs for periods of 5–22 consecutive weeks. We found that changes in fecal estradiol concentrations correlated significantly with variation in the occurrence of several types of behaviors, including rolling, rubbing, sniffing, vocalizing, and urine spraying. However, the number and types of correlated behaviors varied across females, revealing no single behavior indicative of estrus, but rather a constellation of behaviors that increased in frequency when estradiol concentrations were elevated. There was no significant difference in the overall average estradiol concentrations or peak values of the females that had previously mated and conceived compared to those of the females that had failed to breed. Successful breeders appeared to show significantly higher rates of rubbing and rolling than nonbreeders. However, rates of rubbing, rolling, and urine spraying also were found to increase with age, and older individuals were more likely to have bred. The results of this study indicate that estrus in the cheetah cannot be regarded as “silent” since the frequencies of some behaviors appear to covary with fluctuating estradiol levels. However, behavioral monitoring of estrus may nevertheless be difficult and time-consuming due to individual variation and subtle changes in behavioral frequencies rather than changes in the types of behaviors displayed. Zoo Biol 17:193–209, 1998. © 1998 Wiley-Liss, Inc.     

Behavioural and physiological mechanisms of polarized light sensitivity in birds

Polarized light (PL) sensitivity is relatively well studied in a large number of invertebrates and some fish species, but in most other vertebrate classes, including birds, the behavioural and physiological mechanism of PL sensitivity remains one of the big mysteries in sensory biology. Many organisms use the skylight polarization pattern as part of a sun compass for orientation, navigation and in spatial orientation tasks. In birds, the available evidence for an involvement of the skylight polarization pattern in sun-compass orientation is very weak. Instead, cue-conflict and cue-calibration experiments have shown that the skylight polarization pattern near the horizon at sunrise and sunset provides birds with a seasonally and latitudinally independent compass calibration reference. Despite convincing evidence that birds use PL cues for orientation, direct experimental evidence for PL sensitivity is still lacking. Avian double cones have been proposed as putative PL receptors, but detailed anatomical and physiological evidence will be needed to conclusively describe the avian PL receptor. Intriguing parallels between the functional and physiological properties of PL reception and light-dependent magnetoreception could point to a common receptor system.     

Behavioral and physiological effects of leukotriene C4

Leukotriene C4 (LTC4), a lipoxygenase metabolite of arachidonic acid, is a biological mediator of vasoregulation, pulmonary activity, shock, and inflammation, that has been demonstrated to have radioprotective efficacy. The effects of LTC4 on locomotor activity, rectal temperature and hematocrit were examined. Subcutaneous administration of doses of 1.0 micrograms LTC4/mouse or less did not affect locomotor activity. Doses of 5 or 10 micrograms LTC4/mouse, however, resulted in almost complete cessation of locomotion within 12-14 min following treatment. At these doses, activity was suppressed for 2 h with complete recovery by 3 h postinjection. While a dose as high as 10 micrograms LTC4 did not affect rectal temperature, 5 and 10 micrograms LTC4 resulted in hematocrit increases of 10% and 40% respectively. Hematocrit returned to baseline within 1 h after a 5 micrograms pretreatment of LTC4, and by 3 h following a 10 micrograms pretreatment. The duration of LTC4-induced locomotor suppression did not correlate with previously determined durations of LTC4-induced radioprotection.     

Behavioral and physiological suppression of fertility in subordinate marmoset monkeys

In laboratory groups of common marmosets (Callithrix jacchus jacchus), socially induced reproductive suppression among subordinates and offspring effectively maintained a monogamous breeding system. Male subordinates or male offspring were inhibited or restrained from showing sexual behavior, while similarly placed females could also suffer from complete ovarian failure. In well-established families, a familiarity or inbreeding taboo restricted reproduction among otherwise fertile offspring. However, only one daughter ovulated in any family, and in up to 50% of family groups, all daughters were inhibited from ovulating. This differential effect on daughters may have reflected a qualitative shift in the mother-daughter relationship: the ovulating daughter may have represented the next breeding female and may no longer have regarded the mother as an inhibitory influence. In newly established peer groups of pubertal and postpubertal offspring, one male and female dominated all others in each group and overtly inhibited sexual behavior in subordinates of their own sex. Ovulation was suppressed in all subordinate females because of inadequate gonadotrophin secretion. This was not related to increased secretion of cortisol or prolactin, but may have been related to hypothalamic inhibition of luteinizing hormone-releasing hormone (LHRH) secretion.     

Biochemical and physiological studies of long-term synaptic plasticity.

High frequency stimulation of fiber systems in the mammalian hippocampus produces a semipermanent increase in synaptic efficacy. This effect, long-term potentiation (LTP), has been of considerable interest as a potential substrate of memory due to its rapid onset and extreme persistence. Experiments are described that indicate that the locus of LTP is confined to the synaptic complex of the fibers stimulated; further, Ca2+ is shown to be essential for the initiation of LTP and may play a role in triggering this increase in synaptic efficiency. Data from biochemical analyses of LTP indicate that a 40,000 dalton synaptic membrane protein shows a highly reliable change in its endogenous phosphorylation following high frequency hippocampal stimulation. Phosphorylase kinase, a Ca2+ sensitive enzyme, is shown to specifically catalyse the phosphorylation of this 40,000 dalton protein. The data are discussed in terms of a working model in which the Ca2+ dependent phosphorylation of the 40,000 dalton protein produced by high frequency stimulation is a biochemical intermediate in the production of LTP.     

Comparative studies of social behavior in Callicebus and Saimiri: Behavioral and physiological responses of established pairs to unfamiliar pairs

The influences of cage size and novelty on the behavior of Galago senegalensis braccatus were examined in two captive groups (five adults and one immature per group) having similarly furnished but unequally sized cages. One group experienced expansion, and the other experienced contraction of space. Each group experienced the novelty of a new cage and return to its old cage. Exploration, nonsocial activity, and social sniffing behaviors were most frequent in both groups during the novelty phase independent of cage size. These behaviors remained elevated after return to the original cage. This pattern indicated that novelty, not space, was responsible for these behavioral changes. The increase in social sniffing indicated that group members may use olfactory cues to recognize each other, expecially when the setting is novel. In both groups, frequencies of displacements and chases were highest in the smaller space. Group differences in behavior prior to cage change also influenced a group's response to change.     

Stress in physiological studies

The review focuses on the concept of biological stress pioneered by Hans Selye, who demonstrated a key involvement of the pituitary-adrenocortical axis in the response to stress. It discusses the historic background of development of the stress concept and some aspects of modern physiological researches related to stress-induced activation of the hypothalamic-pituitary-adrenocortical axis. We focus mainly on the results demonstrating that stress-induced activation of the hypothalamic-pituitary-adrenocortical axis is a gastroprotective component of stress response.     

Behavioral and physiological responses of Diaeretiella rapae to semiochemicals

Diaeretiella rapae (M'Intosh) (Hymenoptera: Braconidae) parasitizes many aphid species, including cabbage aphids on cruciferous crops and Russian wheat aphids on cereal crops. We investigated the olfactory perception of D. rapae to semiochemicals that may be encountered in these two environments while searching for hosts or for mates. We conducted electroantennogram and flight-tunnel experiments on male and female D. rapae and found marked differences between sexes. Cruciferous volatiles elicited physiological and behavioral responses by females but not by males. Males and females responded similarly to (Z)-3-hexen-1-ol, a component of green-leaf volatiles, in both electroantennogram and flight-tunnel assays. Female wasps responded similarly regardless of prior oviposition experience or population origin. Likewise, mating history and aphid presence did not increase responsiveness toward these semiochemicals.     

Behavioral and physiological effects of RDX on adult zebrafish

1,3,5-Trinitroperhydro-1,3,5-triazine (RDX) is a nitroamine explosive, with common toxic effects including seizures. Here, we explore the behavioral effects of acute RDX exposure in adult zebrafish Danio rerio, a rapidly developing model in neuroscience and neurotoxicology research. Overall, a 30-min exposure to RDX low dose of 0.1 mM evoked behavioral activation in zebrafish, while a higher dose of 1 mM markedly reduced exploration, increased freezing and evoked seizure-like responses (i.e., bouts of hyperactivity, spasms, and corkscrew swimming). Likewise, whole-body cortisol levels were also significantly elevated in fish exposed to 1 mM (but not 0.1 mM) RDX. In line with clinical and animal data, our study demonstrates the dose-dependent behavioral activation and pro-convulsant effects of RDX in zebrafish-based models.