Effect of Removal from the Family Group on Feeding Behavior by Captive Callithrix jacchus

Common marmosets are omnivorous primates with a highly diversified diet. There is no study describing if and how the diet is learned. Infants get their first bits of solid food from other monkeys in the group, which suggests that they may need an introduction to food items by older individuals before including them in their diet. We assessed the acceptance of novel and familiar food items by common marmosets, both isolated and in their family groups. We tested adult, subadults and juveniles from 5 captive families while isolated and in their family groups. The test consisted of presenting for 10 min novel and familiar food items to isolated individuals or to the whole family. We recorded the latency to start eating and the number of food items ingested. When isolated, adults ate more novel and familiar food items than juveniles did. They also started eating sooner than juveniles did. When tested alone, all juveniles, except one, never tasted novel food, and juveniles ingested fewer familiar food items than adults did. When tested in their family groups, juveniles ingested more familiar and novel food than when they were isolated. Our results suggest that: 1. juvenile common marmosets show more food neophobia than adults do, especially when alone; 2. the family group may facilitate the acceptance of novel food items by juveniles; 3. the family group, besides promoting the acceptance of novel food, may also increase its ingestion; and 4. dietary acquisition in Callithrix jacchus involves social facilitation.     

Compensatory behaviors: Suggestion for a common basis from deficits in hamsters

Unlike all other animals tested, golden hamsters ($\text{Mesocricetus auratus}$) do not increase their consumption of food, ethanol or saccharin solution after deprivation of these substances. They also fail to compensate for water deprivation and fail to show spontaneous alternation in a T-maze. This suggests that a common factor may be involved in producing these compensatory behaviors in other animals.     

Experimental analysis of the social value of flocking by starlings (Sturnus vulgaris) in relation to predation and foraging

In groups of ten, indidual starlings, Sturnus vulgaris, spent significantly less time in surveillance than did individuals in smaller groups and responded more quickly than single birds to a flying model hawk. Captive starlings in flocks reduce their individual surveillance efforts, but their combined efforts still enable them to be more effective than single birds in the detection of predators. Foraging behaviour of flocks was observed by placing single starlings with groups of tricoloured blackbirds, Agelaius tricolor; the starlings reduced the time they devoted to surveillance at the same rate as if they were with other starlings.     

Does dehydration contribute to retarded fetal growth in rats exposed to alcohol during gestation?

An earlier study showed that pregnant rats given ethanol in drinking water exhibited a significant degree of dehydration. The objective of the present study was to determine whether dehydration alone contributes to fetal growth retardation in alcohol treated rats. Female Sprague-Dawley rats were divided into 4 dietary groups. Group 1 (alcohol) received 20% ethanol in drinking water for four weeks prior to mating and 30% alcohol in drinking water throughout pregnancy and a stock diet $\text{ad libitum}$. Group 2 (pair-fed) was given an amount of food equal to that consumed by the alcohol group with the alcohol isocalorically substituted by corn starch. Water was available $\text{ad libitum}$. Group 3 (pair-water) was given an amount of food and water equal to that consumed by the alcohol animals. Group 4 ($\text{ad libitum}$) was given food and water $\text{ad libitum}$. On day 21 of gestation body weights of the alcohol exposed fetuses were significantly lower than those of the other three treatment groups. The difference in fetal body weights between the pair-fed and pair-water groups was not significant. Placentas were significantly heavier in the alcohol group than in the pair-fed and pair-water groups. Maternal plasma osmolality was significantly higher in the alcohol treated rats when compared to the pair-fed and $\text{ad libitum}$ controls but not the pair-water group. No significant differences were seen in fetal plasma osmolality among the four treatment groups. It is concluded that dehydration does not contribute significantly to retarded fetal growth in rats given alcohol in drinking water as the sole source of fluid prior to and during gestation.     

Studies on the activity of brown adipose tissue in suckling,pre-obese, obob mice

The properties and activity of brown adipose tissue have been investigated in suckling, pre-obese, $\text{ob}\text{ob}$ mice in order to determine whether decreased thermogenesis in the tissue precedes the development of obesity in this mutant. At 14 days of age there was no difference between the $\text{ob}\text{ob}$ and normal animals in the total amount of interscapular brown adipose tissue, and the DNA content, protein content, and cytochrome oxidase activity of the tissue were similar in the two groups of mice. Respiration rates of brown adipose tissue mitochondria in the presence of albumin were, however, greater in the normal than the $\text{ob}\text{ob}$ animals, although after the addition of GDP to recouple the mitochondria there was no difference between the two groups. The mitochondrial membrane potential, measured with [³H]methyltriphenylphosphonium, was less affected by exogenous GDP in $\text{ob}\text{ob}$ mice than in normal animals. GDP binding to brown adipose tissue mitochondria, an index of the proton conductance pathway, was much greater in normal than in $\text{ob}\text{ob}$ mice at both 10 and 14 days of age; the decreased GDP binding in the mutant animals was found to result from a reduction in the number of binding sites. It is concluded that brown adipose tissue mitochondria of pre-obese $\text{ob}\text{ob}$ mice are more tightly coupled than those of normal siblings, and that the activity of the ‘thermogenic’ proton conductance pathway is lower in the mutant animals. A decrease in thermogenesis in brown adipose tissue is therefore an early event in the development of the $\text{ob}\text{ob}$ mouse and precedes the appearance of obesity.     

Probing the micelle/water interface by rapid laser-induced proton pulse

The laser-induced pH jump (Gutman, M. and Huppert, D.J. (1979) Biochem. Biophys. Methods 1, 9–19) has a time resolution capable of measuring the diffusion-controlled rate constant of proton binding. In the present study we employed this technique for measuring the kinetics of protonation-deprotonation of surface groups of macromolecules.The heterogeneous surface of proteins excludes them from serving as a simple model, therefore we used micelles of a neutral detergent (Brij 58) as a high molecular weight structure. The charge was varied by the addition of a low concentration of sodium dodecyl sulfate and the surface group with which the protons react was an adsorbed pH indicator (bromocresol green or neutral red).The dissociation of a proton from adsorbed bromocresol green is slower than that from free indicator. This effect is attributed to the enhanced stabilization of the acid form of the indicator in the pallisade region of the micelle. The $\text{p}\text{K}$ shift of bromocresol green adsorbed on neutral micelles is thus quantitatively accounted for by the decreased rate of proton dissociation. Indicators such as neutral red, which are more lipid soluble in their alkaline form, do not exhibit such decelerated proton dissociation in their adsorbed state nor a $\text{p}\text{K}$ shift on adsorption to neutral micelles.The protonation of an indicator is a diffusion-controlled reaction, whether it is free in solution or adsorbed on micelles. By varying the electric charge of the micelle this rate can be accelerated or decelerated depending on the total charge of the micelle. The micellar charge calculated from this method was corroborated by other measurements which rely only on equilibrium parameters.The high time resulation of the pH jump is exemplified by the ability to estimate the diffusion coefficient of protons through the hydrated shell of the micelle.     

Social learning directs feeding preferences in the zebra finch, Taeniopygia guttata

We tested sexually mature zebra finches to see whether social learning influenced their feeding preferences, in particular whether they followed the preference of a male or a female demonstrator, of a red-ringed or a green-ringed male, and of a familiar or an unfamiliar male. Each observer was exposed to two demonstrators feeding at different-coloured hoppers, and then tested with a choice of hoppers to see which of the two colours they preferred. Males showed no preference between male and female demonstrators when choosing from which colour of food hopper to feed, but females preferred to feed from the hopper colour the male demonstrator had used. Both males and females exposed to male demonstrators wearing red or green leg rings fed preferentially from the same colour hopper as the red-ringed demonstrators had used. Finally, male birds exposed to familiar and unfamiliar demonstrators, preferred the food hopper from which the familiar demonstrator had fed. We interpret the results as indicating differences between the demonstrators in the amount of attention they attracted from observers.Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.     

Photoperiodism in the common coturnix (Coturnix c. japonica) male

Testicular growth of young and mature coturnix ($\text{Coturnix c.}$$\text{japonica}$) on intermittent light was observed. Five experiments were designed to determine if intermittent symmetrical photoperiods were more effective when they occurred during the photosensitive phase. A brief review of night interruption and resonance experiments with male birds is also given.All birds received a total of 12 hours of light per day. The number of light cycles per 24 hours and hours of light and dark per cycle were as follows: 1(LD12:12), 2(LD6:6), 3(LD4:4) and 4(LD3:3). Testicular growth differed among groups depending on the number of photoperiods received. The most effective light treatment was the 4(LD3:3) and least effective was 1(LD12:12). These results are interpreted on the basis of a circadian rhythm in photosensitivity.     

Fuel, fasting, fear: routine metabolic rate and food deprivation exert synergistic effects on risk-taking in individual juvenile European sea bass

1. Individuals of the same species often exhibit consistent differences in metabolic rate, but the effects of such differences on ecologically important behaviours remain largely unknown. In particular, it is unclear whether there is a cause-and-effect relationship between metabolic rate and the tendency to take risks while foraging. Individuals with higher metabolic rates may need to take greater risks while foraging to obtain the additional food required to satisfy their energy requirements. Such a relationship could be exacerbated by food deprivation if a higher metabolic demand also causes greater mass loss and hunger. 2. We investigated relationships among metabolic rate, risk-taking and tolerance of food deprivation in juvenile European sea bass. Individual fish were tested for risk-taking behaviours following a simulated predator attack, both before and after a 7-day period of food deprivation. The results were then related to their routine metabolic rate (RMR), which was measured throughout the period of food deprivation. 3. The amount of risk displayed by individual fish before food deprivation showed no relationship with RMR. After food deprivation, however, the amount of risk among individuals was positively correlated with RMR. In general, most fish showed an increase in risk-taking after food deprivation, and the magnitude of the increase in risk-taking was correlated with the rate of individual mass loss during food deprivation, which was itself strongly correlated with RMR. 4. The observation that RMR was related to risk-taking behaviour after food deprivation, but not before, suggests that although RMR can influence risk-taking, the strength of the relationship is flexible and context dependent. The effects of RMR on risk-taking may be subtle or non-existent in regularly feeding animals, but may lead to variability in risk-taking among individuals when food is scarce or supply is unpredictable. This synergistic relationship between RMR and food deprivation could lead to an increased likelihood of being predated for individuals with a relatively high intrinsic energy demand during times when food is scarce.     

Capacity of adult steel (SI/SId) and dominant spotting (W/Wv) mouse skin to support melanogenesis.

Utilizing skin grafting techniques, melanocytes were incorporated into adult steel ($\text{Sl}\text{Sl}{}^{\mathrm{d}}$) and dominant spotting ($\text{W}\text{W}{}^{\mathrm{v}}$) hair follicles, where they survived and pigmented a number of hair generations. Previous investigations have indicated that the steel alleles act on the embryonic skin to prevent the survival of melanocytes. The present study suggests that this gene action mechanism may be temporary and does not continue into adult life. In addition, the study demonstrates that some hair bulb melanocytes can pigment more than one hair generation.     

Habitat selection by dispersing yellow-headed blackbirds: evidence of prospecting and the use of public information

In migratory birds individuals may prospect for potential breeding sites months before they attempt to breed and should use the cues most predictive of future reproductive success when selecting a breeding site. However, what cues individuals use when prospecting and which cues are used in selecting a breeding site are unknown for most species. I investigated whether yellow-headed blackbirds (Xanthocephalus xanthocephalus) prospect for future breeding sites and whether they select breeding habitats based on food availability, male or female density, or the average number of young produced per female in the previous year. Although it is often assumed that migratory birds prospect for potential breeding sites at the end of the breeding season, I investigated this by recording all visits to sites early and late in the breeding season. I found that males and females who visited sites other than the site at which they bred were more likely to disperse than individuals only observed at the site where they bred, and that males and females were more likely to prospect late in the breeding season. Both food availability and density in year ^x were not predictive of the number of young per female in year ^x+1; however, the number of young produced per female at a site in year ^x was predictive of the number of young per female in year ^x+1. As expected, dispersers used the most informative cue, the number of young per female and moved to sites with a relatively high number of young per female. This study suggests that individuals prospect for potential breeding sites late in the breeding season when they can use information gathered from the reproductive success of other individuals (i.e., public information) to select a breeding site.     

Do kleptoparasites reduce their own foraging effort in order to detect kleptoparasitic opportunities?: An empirical test of a key assumption of kleptoparasitic models

Determining if, or when, individuals trade off time spent personally feeding against time spent monitoring others for kleptoparasitism opportunities is essential to an understanding of the evolution of scrounging and usurpation behaviours. We provide a first field test of whether kleptoparasites reduce their personal foraging effort in situations where the frequency and rewards of kleptoparasitism increase. We provided experimental food patches for wild European blackbirds that varied in the distribution of prey and that had a potentially high rate of kleptoparasitism within pairs of blackbirds feeding in them. Although individuals differed in their rate of kleptoparasitism, they did not vary in the size of the reward that they gained from kleptoparasitism. As prey became more clumped, kleptoparasitism rate and its reward per incident increased on average. There was, however, no evidence that individuals that were kleptoparasitising more quickly and/or at a higher frequency had lower personal foraging effort. In contrast, foraging effort increased in both birds compared to when they were foraging alone, independent of dominance, kleptoparasitic opportunity or reward. Our evidence suggests that in some circumstances a kleptoparasite can detect kleptoparasitic opportunities without compromising its own personal foraging rate.     

Thermogenic and anorectic effects of ephedrine and congeners in mice and rats

(?)-Ephedrine has been shown to increase energy expenditure and cause the loss of body fat in rats and mice. The present study compares the effects of (?)- and (+)-ephedrine, (?)- and (+)- pseudoephedrine, (±)- and (+)-norephedrine and (?)- and (+)-norpseudoephedrine on food intake, energy expenditure and body composition in $\text{ob}$/$\text{ob}$ and normal mice and food intake in rats. The most potent anorectic and thermogenic compounds had the S configuration at the C-2 position but the orders of potencies for the compounds for anorexia and thermogenesis were not identical. The potencies of the compounds in reducing body lipid content correlated better with their thermogenic than their anorectic potencies.     

Ephedrine reduces weight of viable yellow obese mice (Avy/a)

Ephedrine administered subcutaneously or in the diet reduces the weight of viable yellow obese mice ($\text{A}{}^{\mathrm{vy}}$/$\text{a}$) and normal mice. The compound has some appetite-suppression activity; however, reduced food consumption could not account for all of the weight loss. Ephedrine did not affect lipogenesis or lipolysis acutely. The major portion of the weight loss was due to the loss of triacylglycerol. The rectal temperature of long-term treated $\text{A}{}^{\mathrm{vy}}$/$\text{a}$ mice was elevated suggesting that ephedrine may alter energy metabolism.     

Turkey feeding regimes with different ages of introduction of a choice of foods

An experiment was carried out to investigate five feeding regimes for the turkey which involve introducing a choice of wheat grain and a higher-protein food at 1, 14, 28, 56 and 77 days of age. Broken wheat grains were used from days 1 to 14, and whole grains thereafter. Protein intakes per bird, calculated from standard tables of feed composition, were 39.1, 43.0, 41.8, 35.5 and 36.0 g/day, respectively, from 14 to 98 days. Further groups of birds on a complete diet regime consumed a significantly lower 33.3 g/day. Only two comparisons were significantly different for body weight at 98 days: birds which received the choice at 14 days had a significantly higher weight (5.7 kg/bird) than those which received the choice at 56 days (5.5 kg) and than those on the complete diet regime (5.5 kg). $\text{P}$resentation of the wheat and higher-protein food during the period of protein over-consumption, according to a fixed ratio schedule, might reduce protein intake.     

Prostaglandin levels in preovulatory follicles from rabbit ovaries perfused invitro

Prostaglandin (PG) levels in follicular fluid from preovulatory follicles of rabbit ovaries perfused $\text{in}$$\text{vitro}$ were measured in order to compare PG changes in this model system with those that occur $\text{in}$$\text{vivo}$ and in isolated, LH-treated follicles $\text{in}$$\text{barvitro}$. One ovary from each rabbit was perfused without further treatment (control). The other ovary was exposed to LH (0.1 or 1 ug/ml) beginning 1 hour (h) after initiation of perfusion. Samples of perfusion medium were taken at frequent intervals for measurement of PGE, PGF, progesterone and estradiol 17β. The perfusions were terminated when the first ovulation occurred or appeared imminent as judged by changes in the size and shape of the follicles. Follicular fluid was then rapidly aspirated from all large follicles on both ovaries for PGE and PGF measurement.Ovulations occurred only in the LH-treated ovaries. Progesterone and estradiol levels were significantly elevated in the perfusion medium within 1 h of LH treatment in comparison to controls. PG levels in perfusion medium from the control and LH-treated ovaries were not different throughout perfusion and increased in both groups. In contrast, PG levels measured in follicular fluid from LH-treated ovaries were 4- to 5-fold greater than in fluid from control ovaries. It is concluded that ovulation induced by LH in this experimental model is accompanied by an increase in follicular PG levels similar to that seen in other $\text{in}$$\text{vivo}$ and $\text{in}$$\text{vitro}$ models. This difference in follicular PG levels between the LH-treated and control ovaries is, however, not reflected in the perfusion medium.     

Enzymatic removal of O6-methylguanine from DNA by mammalian cell extracts

Extracts from various rat tissues were incubated with [³H]methylated DNA or chromatin in order to compare their abilities to catalyze the removal of labeled $\text{O}{}^6$-methylguanine from acid precipitable DNA. Liver extracts had the greatest activity. Kidney extracts had about 35% of the activity in liver and extracts from lung, colon, small intestine and brain were much less active. The enzyme responsible for this reaction does not appear to be an $\text{N}$-glycosidase because no labeled $\text{O}{}^6$-methylguanine could be detected in the supernatant fraction even though more than 50% of this base was lost from the DNA. The released radioactivity was present as methanol which is consistent with the possibility that the reaction may involve a demethylase action on either the DNA substrate or an oligonucleotide derived from it.     

Effects of a series of substituted benzamides on rat prolactin secretion and 3H-spiperone binding to bovine anterior pituitary membranes

The potency of seven substituted benzamine drugs (AHR-5531B, AHR-5645B, AHR-6092, AHR-8764, bromopride, sultopride and tiapride) to stimulate rat prolactin (PRL) secretion $\text{in vivo}$ was found to be three orders of magnitude greater than that of non-benzamide neuroleptic drugs relative to their respective abilities to inhibit ³H-spiperone binding to bovine anterior pituitary membranes. Nevertheless, the IC₅₀ values for the inhibition of ³H-spiperone binding by the seven substituted benzamide drugs was significantly correlated with their high potency to stimulate rat PRL secretion $\text{in vivo}$. Further, the slope of the regression line for these substituted benzamides paralleled that of a series of butyrophenone, phenothiazine, morphanthridine and dibenzodiazepine neuroleptic drugs. Two benzamide (sulpiride and metoclopramide) and three non-benzamide neuroleptic drugs gave intermediate results. This data suggests that blockade of different subgroups of dopamine receptors in the anterior pituitary gland labeled by ³H-spiperone may be responsible for the $\text{in vivo}$ stimulation of PRL secretion by the benzamide and non-benzamide neuroleptioc drugs.     

Social Learning of a Novel Foraging Skill by White-throated Magpie-jays (Calocitta formosa,Corvidae): a Field Experiment

The cooperatively breeding white-throated magpie-jay (Calocitta formosa) uses a variety of foraging tactics to find, harvest, and process food. Members of territorial groups forage together and may gain information about how to acquire food by observing each other. A field experiment was performed to determine whether a novel skill, door opening to gain access to food, was more rapidly acquired by members of groups in which a trained individual performed the skill. A higher proportion of jays in groups with behavioural ‘models’ (trained birds that opened doors in the presence of group members) acquired the door-opening skill than those groups without models. Young birds acquired the behaviour more frequently than older individuals. Aggressive behaviour at feeders may have affected the spread of the behaviour by reducing the likelihood that individuals performed the behaviour in the presence of other group members but may also have encouraged subordinate individuals to attempt door opening rather than ‘scrounge’.