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PubMed1995

A case-control study of human immunodeficiency virus type 1 seroconversion and risk-related behaviors in the Chicago MACS/CCS Cohort, 1984-1992. Multicenter AIDS Cohort Study. Coping and Change Study.

This paper focuses on 76 human immunodeficiency virus type 1 (HIV-1) seroconverters who concurrently participated in the Chicago, Illinois, component of the Multicenter AIDS Cohort Study (MACS) and the Coping and Change Study (CCS) of homosexual/bisexual men between 1984 and 1992. A nested case-control analysis was performed to assess the critical behavioral risk factors associated with incident HIV-1 infection and the consistency of these relations in early (1984-1988) versus later (1989-1992) phases of the study. Univariate results revealed strong early period associations between seroconversion and various measures of receptive anal intercourse (RAI) that became considerably weaker in the study's later period. The weaker associations reflected the overall decline in levels of RAI among the cohort during the 9 years of observation. In contrast, univariate results revealed stronger later period associations between seroconversion and measures of receptive oral intercourse and insertive anal intercourse. Subsequent multivariate testing did not support the hypothesis that receptive oral intercourse and/or insertive anal intercourse have replaced unprotected RAI as important risk behaviours in the homosexual transmission of HIV-1. In conditional logistic regression models combining intercourse measures with indices of drug and condom use, only the latter variables were consistently associated with HIV-1 seroconversion in both early and later study periods. Adjusted odds ratios (ORs) for nonuse of condoms during RAI were consistently significant throughout the study (ORs = 3.7-4.8), while adjusted odds ratios for recreational drug use variables rose dramatically during the latter half of the study (e.g., for use of cocaine, OR = 81.3 (95% confidence interval 8-824) [corrected], and for use of nitrite "poppers," OR = 9.1 (95% confidence interval 1.8-45.5)). The behavioral intervention applications of these findings, as well as their relation to data from other recent cohort studies of HIV-1 seroconversion among homosexual/bisexual men, are discussed.

Analysis of Variance↗

PubMed1978

Interactive effects of parity and early pup stress on the open field behavior of laboratory rats.

Pups of primiparous and multiparous Sprague Dawley rats received 0-, 2-, or 5-min cold stress on Days 2-6 postpartun. Stressed offspring of primiparous mothers had shorter latencies to move in an open field than did control offspring of primiparous mothers. However, stressed offspring of multiparous mothers had longer latencies than did the controls. The results suggest differences in maternal responsiveness immediately following return of stressed pups to the nest.

Animals↗

PubMed1985

The influence of multiple inseminations and multiple foundresses on social evolution.

The breeding biology of a population determines the way in which individuals are distributed within and between progeny groups and, thus, affects the genetic variation within and between these groups. The breeding biology of any organism can be characterized by the distribution of the numbers of mates of females, the apportionment of paternity among males, the distribution of the numbers of females reproducing in common nests, and the apportionment of total fecundity within a nest among founding females. In addition, the possibility of genetic correlations among mates or among founding females is an important consideration and will be addressed in a later paper. The influence of the breeding biology on social evolution was evaluated by deriving the necessary conditions for the spread of genes for social behaviors and the rate of spread of these genes for populations with different breeding biologies. The first step in this derivation is to demonstrate that selection for genes determining social behavior can be represented as the covariance between gene frequency and relative fitness. Secondly, it is shown that this covariance can be formally partitioned into within and between group components. Thirdly, each covariance component is shown to be equivalent to the product of a genetic variance and a coefficient of linear regression of relative fitness on gene frequency. Lastly, specific models for the genotype fitnesses and breeding biologies are assumed and the necessary conditions for the increase in the frequency of altruistic alleles are obtained. The theory illustrates that variation in the numbers of mates per female has less of an effect on the evolution of social behaviors than does variation in the numbers of reproductive females per nest. In addition, it points out that the harmonic mean number of mates per female or of females per nest is a more useful summary statistic for characterizing populations with respect to the expected degree of evolved sociality than is the arithmetic mean.

Alleles↗

PubMed1995

Early postnatal diazepam exposure facilitates maternal behavior in virgin female rats.

Virgin female rats do not display maternal behavior if they are not exposed to the pups during several days. This exposure is called induction. In this work we have studied the effects of early postnatal (PO-P16) diazepam (DZ) administration (1 and 2.5 mg/kg, SC) on the display of maternal behavior of virgin female rats when adults. Although we did not find statistically significant differences between P0-P16 DZ treated and control females with respect to the latency of retrieval, P0-P16 DZ administration resulted in a statistically significant increase of the percentage of female rats that became maternal, showing retrieval behavior. This early postnatal treatment with DZ also increased other variables that are currently measured in maternal behavior tests, such as: time of physical contacts, grooming, crouching, and nest building quality. No statistically significant differences were found in the body weight of treated versus control animals during development, nor during adulthood. Our results provide further evidence that the GABAA-BDZ-Cl- receptor complex is implicated in the development of maternal behavior in female rats.

Analysis of Variance↗

PubMed2006

Larval exposure to environmentally relevant mixtures of alkylphenolethoxylates reduces reproductive competence in male fathead minnows.

The ubiquitous presence of nonylphenolethoxylate/octylphenolethoxylate (NPE/OPE) compounds in aquatic environments adjacent to wastewater treatment plants (WWTP) warrants an assessment of the endocrine disrupting potential of these complex mixtures on aquatic vertebrates. In this study, fathead minnow larvae were exposed for 64 days to a mixture of NPE/OPE, which closely models the NPE/OPE composition of a major metropolitan WWTP effluent. Target exposure concentrations included a total NPE/OPE mixture load of 200% of the WWTP effluent concentration (148microg/L), 100% of the WWTP effluent concentration (74microg/L) and 50% of the WWTP effluent concentration (38microg/L). The NPE/OPE mixture contained 0.2% 4-t-octylphenol, 2.8% 4-nonylphenol, 5.1% 4-nonylphenolmonoethoxylate, 9.3% 4-nonylphenoldiethoxylate, 0.9% 4-t-octylphenolmonoethoxylate, 3.1% 4-t-octylphenoldiethoxylate, 33.8% 4-nonylphenolmonoethoxycarboxylate, and 44.8% 4-nonylphenoldiethoxycarboxylate. An additional exposure of 5microg/L 4-nonylphenol (nominal) was conducted. The exposure utilized a flow-through system supplied by ground water and designed to deliver consistent concentrations of applied chemicals. Following exposure, larvae were raised to maturity. Upon sexual maturation, exposed male fish were allowed to compete with control males in a competitive spawning assay. Nest holding ability of control and exposed fish was carefully monitored for 7 days. All male fish were then sacrificed and analyzed for plasma vitellogenin, developmental changes in gonadal tissues, alterations in the development of secondary sexual characters, morphometric changes, and changes to reproductive behavior. When exposed to the 200% NPE/OPE treatment most larvae died within the first 4 weeks of exposure. Both the 100% and 50% NPE/OPE exposures caused a significant decrease in reproductive behavior, as indicated by an inability of many of the previously exposed males to acquire and hold a nest site required for reproduction. In contrast, the 5microg/L 4-nonylphenol exposure resulted in significantly enhanced reproductive behavior compared to that of control males and a majority of the nesting sites were held by previously exposed males. No significant change in the development of gonadal tissues was observed. The 100% NPE/OPE exposure resulted in a significant reduction in the gonadal somatic index and in the prominence of secondary sexual characteristics of exposed larvae. This study indicates that NPE/OPE mixtures have an effect on the reproductive competence of previously exposed male fathead minnows. In addition, 4-nonylphenol concentrations utilized in all exposures were below regulatory guidelines, suggesting that evaluation of 4-nonylphenol alone may not be sufficient for identifying potentially adverse effects of this suite of compounds usually found as mixtures in the aquatic environment.

Animals↗

PubMed1988

Digging as tactics of escape in two bumblebee species with different nesting ecology: Bombus terrestris L. and B. pascuorum Scopoli.

Hymenoptera respond to confinement by vigorous and persistent escape behavior. In a field study, workers of two bumblebee species, Bombus terrestris L. and B. pascuorum Scop., were tested in glass tubes plugged by soil at the open end, and with their other, closed end oriented towards the-sunlight, so that the bees could alternate between two escape tactics: photopositive behavior and digging behavior. The bees of both species proved to be able to sdve such an escape task, i.e. to dig their way out of the tube almost without exceptions. However, as expected, workers of B. terrestris, a species nesting in underground cavities connected with the outside world by long tunnels, performed better than workers of B. pascuorum, a surface-nesting species. The workers of B. terrestris started to dig earlier, were digging more persistently and more efficiently, and, consequently, escaped out the test tubes earlier than the workers of B. pascuorum. High intraspecific variability in all parameters characterizing digging behavior of the bumblebees was also recorded.

Animals↗

PubMed1971

Interactions in Colonies of Primitively Social Bees: Artificial Colonies of Lasioglossum zephyrum.

Lasioglossum zephyrum usually lives in small colonies but is facultatively solitary. Lone bees and colonies produced from female pupae of the same generation were established in artificial indoor nests. Both the length of the prereproductive period and the number of cells produced per bee per day decreased with increasing colony size. In most colonies, ovarially and behaviorally recognized castes arose, a queen and workers, but with all intergradations. The mean size of queens was larger than that of workers. Nearly all queens mated although few workers did so in rooms with a few males, but mating had no effect on subsequent behavior or ovarian development. In groups of diverse age there was a tendency for the oldest bees to be queens; queens also were larger on the average than workers. In groups of equal age, the largest bee was most often queen. As would be expected for a scarcely social species, mechanisms of social integration (resulting in division of labor and differentiation of castes) mostly appear to involve behavioral features of the solitary ancestors and accidental results of joint occupancy of nests. There is no evidence of direct food or pheromone transfer among adult bees.

Journal Article↗

PubMed2004

Food-carrying behavior increased under risk-approaching signal in rats (Rattus norvegicus).

Food-carrying behavior in foraging rats has been assumed to have an advantage to avoid risks by shortening time spent outside their nests. However, there is no experimental evidence for this. In the present study, food-carrying behavior for four sizes of food pellets (45, 100, 200, and 1000 mg) was measured under the presentation of risk-approaching signal (shock-conditioned tone) to verify whether food-carrying behavior is related to risk avoidance or not. The results supported the hypothesis as a whole that food-carrying behavior has close relation to risk avoidance. Food-carrying behavior was increased by the signal for all food sizes, especially statistically significant in the 200 mg condition, while it decreased to the baseline at early stage of the test. These findings are discussed in relation to predatory risk.

Animals↗

PubMed2005

Orientation in the wandering albatross: interfering with magnetic perception does not affect orientation performance.

After making foraging flights of several thousands of kilometers, wandering albatrosses (Diomedea exulans) are able to pinpoint a specific remote island where their nests are located. This impressive navigation ability is highly precise but its nature is mysterious. Here we examined whether albatrosses rely on the perception of the Earth's magnetic field to accomplish this task. We disturbed the perception of the magnetic field using mobile magnets glued to the head of nine albatrosses and compared their performances with those of 11 control birds. We then used satellite telemetry to monitor their behavior. We found that the ability of birds to home specific nest sites was unimpaired by this manipulation. In particular, experimental and control birds did not show significant differences with respect to either foraging trip duration, or length, or with respect to homing straightness index. Our data suggest that wandering albatrosses do not require magnetic cues to navigate back to their nesting birds.

Animal Migration↗

PubMed1989

Effects of maternal hormones on 'timidity' and attraction to pup-related odors in female rats.

The present study was designed to determine whether changes in 'emotionality' and responses to odorants that occur in the postpartum rat are due to the same configuration of hormones that facilitate the expression of maternal behavior. Ovariectomized females were implanted with silastic capsules containing progesterone and estradiol or cholesterol for a 19-21 day period and were tested 1 or 7 days later for emergence behavior, ambulation in the open-field and responses to nesting-material containing different odorants. All females were given two tests in which clean nest-material was presented and two with lactating nest material. In comparison to cholesterol animals hormonally primed animals emerged more rapidly into the open-field, crossed more squares while in the field and spent more time around the odor stimulus. Moreover, hormonally primed animals crossed more squares in the region around the odor source when lactating nest odor was present than when it was not and, under the lactating nest odor condition, crossed more squares in the stimulus region than did any other group. This study suggests that the Bridges' regimen of progesterone and estradiol reduces general 'timidity,' reflected in open-field performance, and increases attraction to pup-related odors. These hormone-induced behavioral changes may well contribute to the heightened maternal responsiveness also produced by these hormones.

Animals↗

PubMed1995

Regulation of pigeon cropmilk secretion and parental behaviors by prolactin.

Prolactin stimulates the growth and development of specialized epithelial cells lining the cropsac of pigeons and doves (family Columbidae), leading to formation of "cropmilk," which is fed to the newly hatched squab. This system of milk feeding is unique among birds. To support the feeding of cropmilk, a complex array of behavioral adaptations are also supported by high levels of prolactin secretion in columbids during parenting. These specializations include elevated food intake (hyperphagia), nest attendance, and regurgitation feeding of the squab. Although prolactin is clearly important for these behavioral adaptations, the precise physiological and mechanistic bases for these behavioral effects remain controversial. The molecular mechanisms of prolactin action in the cropsac epithelium have been studied by cloning prolactin-induced genes, by cloning and expressing the pigeon prolactin receptor, and by analyzing the transcription factors that are activated after prolactin treatment. The avian (pigeon) prolactin receptor is a member of the cytokine receptor superfamily and uniquely contains a complete duplication of the extracellular ligand-binding domain. One of the early signal-transducing actions of prolactin in cropsac epithelium is the activation of signal transducer and activator of transcription (STAT) proteins via tyrosine phosphorylation. This fundamental signaling pathway is shared with mammalian prolactin target tissues. The convergent evolution of milk feeding and the behaviors that support parenting in columbids and mammals has depended on adaptation of both conserved mechanisms and divergent physiological processes.

Animals↗

PubMed2006

From social behavior to neural circuitry: steroid hormones rapidly modulate advertisement calling via a vocal pattern generator.

Across vertebrates, androgens are rapidly elevated within minutes in response to aggressive or reproductive stimuli, yet it is unclear what the causal relationship is between fast androgen elevation and the ongoing (minute-by-minute) expression of behavior. This study tested the hypothesis that rapid increases in plasma steroid levels induce similarly rapid increases in both vocal behavior and the neurophysiological output of a central pattern generator that governs vocal behavior. In Gulf toadfish (Opsanus beta), males call to attract females to their nesting sites, and both males and females vocalize in aggressive interactions. Previous field experiments with males showed that simulated territorial challenges produce rapid and concurrent elevations in ongoing calling behavior and circulating levels of the teleost-specific androgen 11-ketotestosterone (11kT), but not the glucocorticoid cortisol. The current field experiments showed that non-invasive (food) delivery of 11kT, but not cortisol, induced an elevation within 10 min in the ongoing calling behavior of males. Electrophysiological experiments revealed that intramuscular injections of either 11kT or cortisol, but neither testosterone nor 17-beta-estradiol, induced increases within 5 min in the output of the vocal pattern generator in males, whereas only cortisol had similarly fast effects in females. The field behavioral results support predictions generated by the challenge hypothesis and also parallel the 11kT-dependent modulation of the vocal pattern generator in males. The cortisol effect on the vocal pattern generator in both sexes predicts that glucocorticoids regulate vocalizations in non-advertisement contexts. Together, these experiments provide strong support for the hypothesis that surges in circulating steroid levels play a causal role in shaping rapid changes in social behavior (vocalizations) through non-genomic-like actions on neural (vocal motor) circuits that directly encode behavioral patterning.

Action Potentials↗

PubMed1990

Ventral somatosensory determinants of nursing behavior in Norway rats. I. Effects of variations in the quality and quantity of pup stimuli.

By varying the quality and quantity of tactile input that rat dams, between Days 2 and 14 postpartum, received from their pups, we found the following: a) After a 4-hr separation from their litter, mothers continuously display an array of activities, until the onset of nursing, in response to displaced pups and to pups gathered in the nest. b) While the dam hovers over the gathered pups, engaged in an activity such as pup-licking, the young gain access to the dam's ventrum and root for a nipple. c) Pups capable of effective rooting, nipple attachment, and suckling thereby stimulate the dam's immobility (i.e., inhibition of head and limb movements), assumption of the upright crouching posture, and milk ejections. d) Rat dams do not become immobile or crouch in response to pups that are inactive or that are active but incapable of rooting effectively or suckling. e) The likelihood and speed of assuming the quiescent nursing posture, as well as of having milk ejections subsequently, are directly related to the number of effective pups in the nest. We propose that the initiation, maintenance and termination of nursing behavior are related to the spatial and temporal summation of effective ventral somatosensory afferents.

Animals↗

PubMedDate not supplied

Maternal behavior is impaired by methamphetamine administered during pre-mating, gestation and lactation.

Previous studies demonstrated that stimulant drugs, such as cocaine or amphetamine, administered during gestation or lactation may attenuate maternal behavior in rats. The effect of methamphetamine (MA), a drug whose usage has increased lately, on maternal behavior has not yet been investigated. The present study tested the effect of MA (5 mg/kg daily) administered prior to, during and after gestation on maternal behavior. Regularity of the estrous cycle, the incidence of impregnation, and the weight gain was compared between groups (control, saline- and MA-treated). Maternal behavior was examined using two tests: Observation test (without disturbance of the mother and pups) and Retrieval test (with short separation of pups from the mother). All tests were conducted prior to dosing each day. In the Observation test, MA decreased the blanket position of active nursing, while increasing passive nursing. There were no MA-induced changes in other maternal activities such as mother being in the nest, in contact with pups, or grooming pups. MA increased some non-maternal activities, such as drinking, eating, and sleeping, while decreasing stereotypic behavior (sniffing and rearing) when compared to controls. In the Retrieval test, MA-treated mothers were slower in retrieving the first pup, returning the first pup into the nest, and returning all pups into the nest. Interestingly, there were differences in maternal behavior also in saline-treated mothers relative to controls. Saline-treated mothers spent more time in the nest and groomed pups more than controls or MA-treated mothers. In conclusion, the present study demonstrates a novel finding that MA administered during pre-mating, gestational and lactational periods has a negative effect on maternal behavior toward pups.

Animals↗

PubMed1994

Intracranial action of corticosterone facilitates the development of behavioral inhibition in the adrenalectomized preweanling rat.

We tested the hypothesis that in preweanling rats central administration of exogenous corticosterone (CORT) is sufficient to facilitate the development of behavioral inhibition. 28-gauge cannulae containing varying concentrations of CORT (0, 25, 50 and 100%) were implanted unilaterally into the lateral ventricles of 9-day-old rat pups. After a 24-h postoperative recovery period, pups were adrenalectomized. At 14 days of age, pups were tested for behavioral inhibition which consisted of removing the pup from the nest and exposing it to an unfamiliar adult male rat. Pups implanted with cannulae containing 0, 25 and 50% concentrations of CORT spent significantly less time in freezing postures than pups implanted with cannulae containing 100% CORT. These freezing pups also tended to emit fewer ultrasonic vocalizations than pups in the other three implant conditions, albeit the level obtained was not statistically significant. RIAs indicated that, in general, hormone-filled cannulae produced no detectable concentrations of plasma CORT on the day of the test or on days preceding testing. Results suggest that in the early postnatal period endogenous CORT acts centrally to facilitate the development of neural pathways involved in the ontogenetic expression of behavioral inhibition.

Adrenalectomy↗

PubMed1997

Characteristics of perceptual grouping in rats.

Parametric analysis was made of the characteristics by which proximity and alignment serve as cues for perceptual grouping in rats. Rats were initially conditioned to discriminate a series of horizontal lines from vertical lines. Following training, rats were presented with test stimuli that consisted of bistable arrays of disjunct dots. A grouping cue (greater proximity, greater alignment, or both) was randomly assigned to either the horizontal or vertical orientation. The effectiveness of the cues was based on behavioral responses to the cued orientation. Results indicated that proximity served as a cue for perceptual grouping. The effectiveness of the proximity cue was less for rats than found previously in humans and, unlike humans, diminished with increased stimulus scale. Rats did not respond to alignment cues when used in isolation, although alignment facilitated grouping when used in conjunction with proximity cues. Diminished effectiveness of grouping cues likely reduces object recognition abilities, particularly for complex visual stimuli.

Animals↗

PubMed2005

Influences of food type on food-carrying behavior in rats (Rattus norvegicus).

It is known that rats tend to eat a smaller/lighter piece of food at the food source but carry a larger/heavier one to the nest for consumption. This could be interpreted well in terms of the trade-off or motivational conflict between "feeding" and "risk avoidance", because eating food immediately satisfies feeding motivation while carrying food has an advantage to avoid predatory risk by keeping time spent outside the nest shorter. In the present study, influences of incentive factors of feeding motivation on food-carrying behavior were evaluated using three different kinds of food that were identical in weight. There was no significant difference in food-carrying tendency among the three kinds of food, though a significant preference was indicated among the food. The results suggest that food-carrying behavior is not influenced by food types.

Animals↗

PubMed1986

Effects of cage and floor pen management on behavior, production, and physiological stress responses of laying hens.

Behavior, physiology, health, egg production, and egg quality characteristics of laying hens housed either 1/1394-cm2 cage (S), 2/1394-cm2 cage (HD), 2/2788-cm2 cage (LD), or in floor pens (P), each containing 25 hens, were monitored in order to assess hen welfare in different management systems. Egg production was highest in P and S hens. There were no differences among treatment groups in feed efficiency, egg weight, or egg taste, although egg shell breaking strengths were lower in HD hens despite their relatively low egg production. Blood spots were most common in eggs from caged hens. With respect to behavior, penned hens locomoted more, spent less time in stationary exploration than caged birds, and utilized nest boxes for activities in addition to egg laying. The HD hens fed less frequently than did the LD, and HD cage pairs engaged less frequently in simultaneous feeding, drinking, and resting behavior than LD pairs. Plasma corticosterone levels were initially found to be higher in pens than cages; this difference disappeared when the use of trap-nesting to capture P birds for sampling was discontinued. Nighttime corticosterone levels were higher in HD hens. In contrast, primary and secondary hemagglutination titers to sheep erythrocyte (SRBC) antigen, heterophil to lymphocyte ratios, hepatic zinc metallothionein, serum zinc, and body weights did not differ among treatments. Mortality, however, was lower in pens. It was concluded that, although there were striking dissimilarities in behavior between the pen and cage environments, physiological and production data did not provide evidence of stress associated with cage housing per se. High density caging, however, may be a stressor; this is discussed with reference to other research.

Animals↗