Individual Behavioral Responses Research Articles

Hydroquinone: a general phagostimulating pheromone in termites.

The organization of termite societies depends predominantly on intraspecific chemical signals (pheromones) produced by exocrine glands, which induce and modulate individual behavioral responses. Here, the saliva-producing labial glands of termites were investigated with respect to their pheromonal role in communal food exploitation of termite colonies. From these glands, we identified for the first time hydroquinone (1,4-dihydroxybenzene) as a phagostimulating pheromone in the Australian termite species Mastotermes darwiniensis. Hydroquinone is released from the labial glands of termite workers and applied onto the food. It stimulates nestmates to feed at the spot of application and is, thus, employed to mark feeding sites. No synergistic effect with other identified labial gland compounds, such as glucose, inositol, and arbutin, was evident. Significantly, we show that termite species from all over the world, irrespective of taxonomic position and biological traits, produce and employ hydroquinone as phagostimulating signal. The use of the same chemical signal throughout an order is a unique phenomenon, not reported before in animals. Its possible biosynthetic pathway, ecological significance, and evolution are discussed.

Female‐biased density‐dependent dispersal of a tephritid fly in a fragmented habitat and its implications for population regulation

The aim of this study was to quantify the rate of dispersal as a response to density in the specialist tephritid fly Paroxyna plantaginis (the main seed predator on its patchily distributed host plant, Tripolium vulgare, Asteraceae). Marked flies were released at three different fly densities in artificial host patches. The individual histories of recaptures were recorded as well as migration between patches and invasion by unmarked flies. The loss of marked flies relative to initial density was analysed using maximum likelihood estimation. Females generally had the highest loss rate. When comparing a density‐independent model with a density‐dependent model of the loss rate, the density‐dependent model won four times out of six for the females but not a single time for the males. A stronger immigration rate of females relative to males supported the suggested female‐biased dispersal. This indicates a sit‐and‐wait strategy for the territorial males and a pre‐emptive competition strategy for egg‐laying substrates for the females. These results may be of general importance for non‐frugivorous tephritid systems with unpredictable and almost ephemeral accessibility to host plants and with a dynamics characterised by a high turnover rate and high attack levels. The study presents a method for measuring the propensity of individuals to leave an area as a response to local density. It is further an example of the consequences individual behavioural responses may have on the population dynamics of a patchy population.

Short-Term Effects of Timber Harvest on Abundance, Territory Characteristics, and Pairing Success of Ovenbirds in Riparian Buffer Strips

AbstractIn managed forests, riparian buffer strips typically are maintained to protect water quality. If properly designed, buffer strips also may act as wildlife reserves. However, forest managers have lacked the information to develop standards for buffer strips to maximize benefits for wildlife species. We assessed the conservation potential of 20-, 100-, and 200-m wide buffers for an area-sensitive songbird in boreal mixed-wood forest in Alberta. We measured abundance, territory characteristics, and pairing success of Ovenbirds (Seiurus aurocapillus) at treatment and control lakes one year before and after upland timber harvest. After harvest, Ovenbirds were absent from 20-m buffer strips. Harvesting did not significantly influence abundance or territory size in 100-m or 200-m buffers, although territories generally became narrower. Postharvest territory position did not change in 200-m buffers, but territories in 100-m strips shifted lakeward and included more habitat adjacent to the riparian edge than before harvest. Despite this shift in territory position, males that occupied 100-m strips successfully attracted mates. High availability of regional forest cover may have muted the more pronounced effects of habitat alteration observed in other studies. Our research is among the first to evaluate individual behavioral responses to the creation of forest edges. Our data indicate that 20-m buffer strips do not support breeding Ovenbirds, whereas 100- and 200-m buffers retain Ovenbirds during the year following harvest. Long-term harvest effects may differ from those we monitored and require study, particularly as timber extraction increases in the boreal mixed-wood ecoregion.

Antenatal glucocorticoids and programming of the developing CNS.

Glucocorticoids (GCs) are essential for many aspects of normal brain development. However, there is growing evidence from a number of species that exposure of the fetal brain to excess GC, at critical stages of development, can have life-long effects on behavior and neuroendocrine function. The hypothalamo-pituitary-adrenal axis, which is central to the integration of the individual's endocrine and behavioral response to stress, appears highly sensitive to excess GC exposure during development. A number of animal studies have shown that exposure to synthetic GCs in utero results in adult offspring that exhibit hyperactivity of the hypothalamo-pituitary-adrenal axis. This will have a long-term impact on health, inasmuch as increased life-long exposure to endogenous GC has been linked to the premature onset of diseases associated with aging. The mechanisms involved in the permanent programming of hypothalamo-pituitary-adrenal function and behavior are not well understood. Synthetic GCs are used extensively to promote pulmonary maturation in fetuses at risk of being delivered before term. Therefore, it is important that we understand the potential long-term consequences of prenatal GC exposure on brain development as well as the underlying mechanisms involved. This review will explore the current state of knowledge in this rapidly expanding field.

Polymorphisms in the APO E gene in gerontopsychiatric patients

Capture and temporary confinement of wild birds are integral parts of wildlife management practice and research used, for example, during translocation or reintroduction initiatives. We report here on the behavioural and stress hormone (corticosterone) responses of wild blackbirds (Turdus merula) to capture and short-term confinement, partly consistent with some translocation protocols. We examine also the relationship between behaviour and plasma corticosterone concentrations. Acute capture induced responses in corticosterone concentration, integrated over 60 min, at the commencement and conclusion of a 22-day confinement in aviaries were similar at 669.1 ± 66.6 (mean ± 1S.E.) and 678.2 ± 115.8 ng/mL/min respectively. However, base levels of corticosterone were higher at final release than at initial capture (6.8 and 2.2 ng/mL respectively, P < 0.001). This may reflect that the 3-week period of confinement is a chronic stressor. There was an increased propensity for locomotory behaviours (P = 0.001), maintenance behaviours (P = 0.032) and alarm vocalisations (P = 0.04) over the period of captivity. The frequency of alert behaviours (P < 0.001) decreased, probably related to habituation to captivity and possibly an associated decrease in perceived predation or starvation risk. Individual behavioural responses were generally repeatable across all observation days, with locomotory behaviours showing the highest repeatability (Repeatability = 0.592 ± 0.084, P < 0.0001). Significant repeatabilities were also detected for corticosterone concentrations measured at 60 min after capture (Repeatability = 0.619 ± 0.166, P = 0.0007) and corrected integrated corticosterone (Repeatability = 0.368 ± 0.166, P = 0.039) measured on initial capture and on release. We used principle component analysis to generate a composite measure of locomotory, alert and vocalisation behaviours. This measure was positively correlated with corrected integrated corticosterone response at release (P = 0.019) when behaviour was summed across all observation days. Corrected integrated corticosterone response at initial capture (P = 0.049) was also correlated with this behavioural measure at 20 days after capture. This, in combination with the consistency in the behavioural and corticosterone responses across the period of captivity, may reflect individual differences in coping abilities to confinement that may ultimately predict post-translocation survival.

Evaluation and selection of maskers and other devices used in the treatment of tinnitus and hyperacusis.

For more than two decades there has been a significant increase in the number and quality of studies investigating the phenomenon of subjective tinnitus. We mention subjective tinnitus because it is, by far, the most prevalent. Subjective tinnitus may be defined as the perception of an acoustic-like sensation for which there is no external generation. Objective tinnitus (vibratory tinnitus), on the other hand, is an acoustic-like sensation that can be heard by others and lends itself to physical measurement. Chronic myoclonus (chronic spasm of a muscle or of a group of muscles) involving the tensor tympani, stapedius and palatine muscles (referring to the palate), blood flow turbulence, and movement involved in the opening of the Eustachian tube are conditions that can cause objective tinnitus. Perhaps, one may include otoacoustic emissions as a form of objective tinnitus. This review will concern itself primarily with the rationale underlying the use of masker devices, hearing aids and other noise generating systems used in the treatment of subjective tinnitus. We review not only the phenomenon of tinnitus masking, but also discuss the use of controlled levels of noise in the treatment of hyperacusis, an exaggerated or abnormal intolerance to ordinary sounds in one's acoustic environment. In so doing, the emphasis is placed on the reader's understanding of each of the disorders, not only in terms of an applied external, acoustic stimulus but also of the individual's behavioral response to his or her malady. There are four messages for those contemplating the provision of clinical service to patients with subjective tinnitus. First, there is no consensus regarding the etiology of this perplexing disorder. Second, there is no known “cure” for subjective tinnitus. Third, there is no single therapeutic modality sufficiently compelling to warrant its use above all others. We are not suggesting individuals cannot be helped with some form of therapeutic intervention, including masker devices, but rather that there is much to be learned about the neurophysiological generation of subjective tinnitus and the psychodynamics of those who are suffering from it. Fourth, there is enough intellectual and clinical challenge in the treatment of subjective tinnitus to warrant the interest and active involvement of audiologists. Those working with the tinnitus patient deal with the symptoms of the disorder. The clinician can control to some extent the patient's awareness of the ongoing tinnitus through the use of masker or noise generating instrument(s), but can do nothing to affect a cure. To cure this perplexing problem, a way must be found to suppress the tinnitus generator(s), whatever it (they) may be, and thereby alter the abnormal neural activity which gives rise to its perception. The understanding of tinnitus and its treatment has advanced to that point where it is no longer necessary, or prudent, for the physician or any other health practitioner to advise the patient to “learn to live with it.” We say this, because there are a number of therapeutic approaches which have proven of significant benefit to the tinnitus patient, including masker and noise generating devices. Our task here is to review therapeutic practices and patient management strategies related to the use of masker devices and other noise generating systems. This review will include not only traditional masking, wherein the intent is to cover an aversive sound with a neutral one, but it will also discuss the use of combination hearing aid-masker instruments and masking tinnitus with hearing aids. Finally, it will consider retraining therapy, which has the intent not of covering the sound but rather of retraining the brain to ignore the sound so that it is no longer an issue in the patient's life.

Group size structure affects patterns of aggression in larval salamanders

The potential importance of intrapopulation phenotypic variability to population-level ecology has been demonstrated in both theoretical and field studies. One way to connect individuals to the dynamics of populations they compose is to study behavioral response (an individual-level characteristic) to variability in conspecific phenotypes (a population-level characteristic). We examined effects of variation in size of individuals on patterns of aggression in larval tiger salamanders (Ambystoma tigrmum nebulosum) by observing aggressive behavior in groups of three larvae in a laboratory experiment. We assessed effects of variability in size of conspecdfics independently of mean larval size and larval density. Overall levels of aggression were generally higher in groups in which all individuals were similarly sized than in groups of variably sized individuals. Medium-sized individuals exhibited significantly higher levels of aggression and were attacked significantly more often when in groups consisting only of similarly sized larvae as compared to groups composed of larvae representing a wider range of body sizes. Activity levels of larvae were also generally lower when all individuals were the same size, resulting in a negative correlation between activity and levels of aggression. These results suggest that groups of similarly sized individuals experience a more aggressive social environment than groups of variably sized individuals, and they suggest a promising avenue of research for connecting individual behavioral and physiological responses to size structure (phenotypic variability) with population dynamics.

Predator‐Induced Behavioral Indirect Effects: Consequences to Competitive Interactions in Anuran Larvae

This study examines the non—lethal effects of an odonate predator (Anax junius) on the competitive interactions among several size classes of anuran larvae. In an outdoor experiment using cattle watering tanks, we estimated the effects of both large and small bullfrogs (Rana catesbeiana) on themselves, on each other, and on small green frogs (R. clamitans) in the absence and non—lethal (caged) presence of Anax. The presence of Anax depressed both growth and survivorship of small bullfrogs and green frogs. In contrast, the presence of Anax had positive effects on growth rates and size at metamorphosis of the large bullfrogs. Increasing density of competitors also decreased survivorship of small classes, and growth rates of all classes. The per—unit—biomass competitive effects of the small bullfrogs on target classes were much greater than those of large bullfrogs. The presence of Anax significantly altered the per—unit—biomass competitive effects of small bullfrogs but not large bullfrogs, presumably because individuals in the small class reduced their activity rates in the presence of Anax. Overall production of new tadpole biomass was quite similar across experimental units, with decreases in production of small size classes in the presence of Anax compensated for by increases in production of the large size class. Thus the non—lethal presence of Anax had substantial effects on the nature of competitive interactions in this system, and we discuss the implications of such behavioral indirect effects in the study of ecological communities. Our results also illustrate the futility of attempting to partition the effects of competitors and predators, as both competitors and the non—lethal presence of predators significantly affected growth rates and death by starvation of small larvae. Finally, our results illustrate how individual behavioral responses may be translated to community and ecosystem properties.

Serum prolactin levels and behavior in infants

This study examined the relationship between serum prolactin levels and behavior in infants and toddlers who experienced two potentially stressful experiences (developmental testing and venipuncture). Serum prolactin levels showed considerable consistency over a 3-month period (r = 0.64 between study entry and three months, p < 0.001, n = 50). There was also stability in having either a normal or a high value (> or = 25 ng/ml). Among children who had a normal value on initial testing, 97% also has a normal value after 3 months; 55% of those with initial high values continued to have high values (chi 2 = 19.26, p < 0.001). Children with high serum prolactin levels were more likely to be rated as unusually hesitant and unhappy during developmental testing. Overall, 53% of the children with serum prolactin levels > or = 25 ng/ml were considered abnormal in affect, compared to 20% of those with lower serum prolactin values (total n = 138, chi 2 = 13.56, p < 0.001). These results suggest that, even in early life, serum prolactin levels may reflect characteristic individual behavioral and neuroendocrine responses to stress.

Social Inequalities and Health

Social Inequalities and Health

Behavioral responses of Daphnia pulex exposed to carbaryl and Chaoborus kairomone

AbstractAn analysis of digitized three‐dimensional video records of free‐swimming Daphnia pulex identified six measurements of swimming behavior that can be used to quantify individual behavioral responses to pesticides or natural chemical signals. Protocols are given for measuring the parameters that showed statistically significant changes in pesticide treatments. The most efficient experimental design would involve observing as many animals as possible, with one observation per animal. Parameters most likely to be useful in future studies are velocity, turning angle, upward and downward angles during hops, variance in vertical position, and hopping frequency. The parameters varied in usefulness, defined as the ratio of within‐treatment to among‐treatment variance (F ratios). Velocity was the most useful (i.e., had the highest F ratio); hopping frequency was the least useful. Daphnia exhibited three kinds of swimming behavior, as defined by eight parameters: (a) “spinning” (extreme and continuous escape response) to acutely toxic levels of Carbaryl (40 ppb); (b) “irritation” (an increase in escape‐like behavior) to low levels of Carbaryl (1 ppb); and (c) “null” behavioral responses to Chaoborus‐conditioned water, in which there was no detectable change in any measurement of swimming behavior. In predation trials, bluegill sunfish preferentially selected individuals showing “spinning” behavior. Results from this and other studies of Daphnia swimming behavior suggest a conservative‐swimming hypothesis for understanding constraints on Daphnia swimming behavior.

Stress and the Individual

This article presents a new formulation of the relationship between stress and the processes leading to disease. It emphasizes the hidden cost of chronic stress to the body over long time periods, which act as a predisposing factor for the effects of acute, stressful life events. It also presents a model showing how individual differences in the susceptibility to stress are tied to individual behavioral responses to environmental challenges that are coupled to physiologic and pathophysiologic responses. Published original articles from human and animal studies and selected reviews. Literature was surveyed using MEDLINE. Independent extraction and cross-referencing by us. Stress is frequently seen as a significant contributor to disease, and clinical evidence is mounting for specific effects of stress on immune and cardiovascular systems. Yet, until recently, aspects of stress that precipitate disease have been obscure. The concept of homeostasis has failed to help us understand the hidden toll of chronic stress on the body. Rather than maintaining constancy, the physiologic systems within the body fluctuate to meet demands from external forces, a state termed allostasis. In this article, we extend the concept of allostasis over the dimension of time and we define allostatic load as the cost of chronic exposure to fluctuating or heightened neural or neuroendocrine response resulting from repeated or chronic environmental challenge that an individual reacts to as being particularly stressful. This new formulation emphasizes the cascading relationships, beginning early in life, between environmental factors and genetic predispositions that lead to large individual differences in susceptibility to stress and, in some cases, to disease. There are now empirical studies based on this formulation, as well as new insights into mechanisms involving specific changes in neural, neuroendocrine, and immune systems. The practical implications of this formulation for clinical practice and further research are discussed.

Information Processing and the Evolutionary Ecology of Cognitive Architecture

The individual's behavioral response to the environment is a consequence of three processes. Information from the environment must be encoded into a form that can be manipulated and stored in the nervous system. Encoded information is then subject to computational operations that lead to a representation of the environment that forms the basis for decisions and actions. The design of information-processing schemes acts as both a constraint on behavioral response and an aspect of the organism's phenotype that may be subject to natural selection. My experiments with bumblebees suggest that individual workers process information about floral rewards according to expected utility theory. Utility is here defined by a biomechanical function relating floral reward sizes to rates of net energetic gain. This model also suggests that bees process information from successive visits so as to maximize expected short-term (rather than long-term) energetic gain. Short-term computational algorithms may prove advantageous when environments are spatially or temporally autocorrelated or when individuals are subject to short-term memory constraints. Short-term computational algorithms may lead to perceptual biases, for example, underestimation of low-probability events. Observations on the computational rules employed by individuals may reveal aspects of nervous system organization and operation. At the same time, the floral preferences that result from individual decision making may have profound consequences for the evolution of pollinator-plant interactions and ecological community organization.

Individual and social behavioral responses to injury in wild toque macaques (Macaca sinica)

Individual and social behavioral responses to injury in wild toque macaques (Macaca sinica)

Equity and Efficiency Consequences of Unemployment Insurance Reform in Canada: The Importance of Sensitivity Analyses

This paper conducts an evaluation of the equity and efficiency consequences of proposals for the reform of the Canadian Unemployment Insurance program. The sensitivity of results to the measure of welfare chosen and to the model employed to simulate individual behavioral responses is illustrated. Copyright 1991 by The London School of Economics and Political Science.

Behavioral and immunological consequences of brief mother‐infant separation: A species comparison

The immediate behavioral and immunological consequences of a single 2-week maternal separation experience were studied in socially housed 7-month old bonnet and pigtail macaques. Maternal separation was associated with species dependent behavioral changes. Both species showed significant increases in ingestive behaviors associated with separation. Separated and matched controls showed an increase in disturbance behaviors (vocalization, startles, shaking, temper-tantrums) that subsided after 24-36 hours in control subjects, but continued, albeit with species-dependent patterns, in the separated monkeys. Allomaternal care of the separated bonnet infants but not the pigtail infants was associated with a progressive reduction of these disturbance behaviors during the separation period. Following a period of agitation, pigtail infants showed a depressive phase characterized by slouched, withdrawn postures and reduced motor activity. As a group, the separated infants of both species were not different from controls with respect to lymphocyte activation by mitogens, a measure of immunocompetence. However, when individual behavioral responses were considered, the change in lymphocyte activation during separation was significantly related to behavioral responses which reflected disturbance, such that the change in lymphocyte activation following in vitro stimulation with the mitogens phytohemagglutinin and Concanavalin A (markers of the immunocompetence of T lymphocytes) was related to levels of vocalization and time spent in slouched postures. The activation of B lymphocytes by pokeweed mitogen was not influenced by the separation experience nor was it associated with specific behavioral responses to separation. The importance of assessing the affective consequences of stressor is discussed.

Individual and social behavioral responses to injury in wild toque macaques (Macaca Sinica)

Toque macaques (Macaca sinica),inhabiting natural forest at Polonnaruwa, Sri Lanka, are frequently injured in fights with conspecifics. The behavior of known individuals when they were injured was compared to that after they had recovered their health. Thus, injured animals rested and alloand autogroomed more, but they foraged less and initiated fewer aggressive episodes. They spent most time being sedentary in the safety of arboreal refuges and reduced acrobatic movements by locomoting more often terrestrially. Other group members showed no special tolerance (or altruism) toward injury victims during the costly and highly competitive activity of foraging for food. In fact, some injured animals received more aggression, or lost dominance rank, and thereby had their competitive abilities further impaired. Care for the injured was manifest mostly by grooming and wound cleaning. All hair in the area surrounding a wound, as well as dirt, scabs, and fly larvae, were removed, and saliva was applied by licking the wound (wounds so treated healed with no obvious signs of infection). (1) Injured macaques sought and received significantly more grooming (owing to wound care); (2) the amount so received increased with the severity of the injury; and (3) the initiative of other group members often compensated for a victim’s inability to solicit care. Juvenile males were especially attentive to injured adult males, suggesting that they were investing in a social bond with these adults, which might reciprocate altruism toward their juvenile caregivers in the future. Injured juvenile females received most care from their mothers.

Individual behavioral and neuroendocrine differences in responsiveness to audiogenic stress

A relatively wide range of individual differences in neuroendocrine, immune and behavioral components of the audiogenic stress response has been found. In this study, an analysis of the association between the physiological and behavioral measures revealed that the degree of noise-induced suppression of both general activity and ingestive behaviors was significantly correlated with activation of adrenal steroid secretion following both acute and repeated noise exposures. Splenic natural killer cytotoxicity was not correlated with the behavioral measures of the stress response. Characterization of individual behavioral response profiles may be needed to evaluate accurately the neuroendocrine effects of stress.

An overview of health effects on noise

Although noise can damage the inner ear and cause other pathological changes, its most common negative effects are non-somatic, such as a perception of noisiness and disturbance of daily activities. According to the definition of health by WHO, this should be considered as a health hazard. These health effects of noise can be classified into the following three categories: (I) hearing loss, perception of noisiness and masking are produced along the auditory pathway and are thus direct and specific effects of noise; (II) interference with performance, rest and sleep, a feeling of discomfort and some physiological effects are produced as indirect and non-specific effects via reticular formation of the midbrain; (III) annoyance is not merely a feeling of unpleasantness but the feeling of being bothered or troubled, and includes the development of a particular attitude toward the noise source. Individual or group behavioral responses will be evoked when annoyance develops. Annoyance and behavioral response are integrated and composite effects. The health effects of noise are modified by many factors related to both the noise and the individual. Noise level, frequency spectrum, duration and impulsiveness modify the effects. Sex, age, health status and mental character also have an influence on the effects. Direct effects of noise are most dependent on the physical nature of the noise and least dependent on human factors. Indirect effects are more dependent, and integrated effects most dependent, on human factors.

Budget Deficits, Inflation Accounting, and Macroeconomic Policy: A Skeptical Note

ABSTRACTThis paper challenges the mechanical application of inflation accounting to public sector deficits as it has been suggested in recent years. Although the theoretical considerations underlying the proposed adjustment for the inflation premium of interest payments are well taken, the new approach has fundamentally focused on measurement issues with little attention paid to the behavioral aspects of microeconomic adjustment. This paper, therefore, raises skepticism about the usefulness of inflation accounting, if such a correction is not accompanied by a conceptual model that links behavioral responses of individuals to balance sheets and other stock variables. In a departure from previous investigations, the paper also points out the possibility that inflation accounting might have more relevant implications for public, rather than private, spending.