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Dunbar, R. (2003). Evolution of the social brain. Science, 302(5648), 1160–1161.
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Ganswindt, A., Palme, R., Heistermann, M., Borragan, S., & Hodges, J. K. (2003). Non-invasive assessment of adrenocortical function in the male African elephant (Loxodonta africana) and its relation to musth. Gen Comp Endocrinol, 134(2), 156–166.
Abstract: Adult male elephants periodically show the phenomenon of musth, a condition associated with increased aggressiveness, restlessness, significant weight reduction and markedly elevated androgen levels. It has been suggested that musth-related behaviours are costly and that therefore musth may represent a form of physiological stress. In order to provide data on this largely unanswered question, the first aim of this study was to evaluate different assays for non-invasive assessment of adrenocortical function in the male African elephant by (i) characterizing the metabolism and excretion of [3H]cortisol (3H-C) and [14C]testosterone (14C-T) and (ii) using this information to evaluate the specificity of four antibodies for determination of excreted cortisol metabolites, particularly with respect to possible cross-reactions with androgen metabolites, and to assess their biological validity using an ACTH challenge test. Based on the methodology established, the second objective was to provide data on fecal cortisol metabolite concentrations in bulls during the musth and non-musth condition. 3H-C (1 mCi) and 14C-T (100 microCi) were injected simultaneously into a 16 year old male and all urine and feces collected for 30 and 86 h, respectively. The majority (82%) of cortisol metabolites was excreted into the urine, whereas testosterone metabolites were mainly (57%) excreted into the feces. Almost all radioactive metabolites recovered from urine were conjugated (86% 3H-C and 97% 14C-T). In contrast, 86% and >99% of the 3H-C and 14C-T metabolites recovered from feces consisted of unconjugated forms. HPLC separations indicated the presence of various metabolites of cortisol in both urine and feces, with cortisol being abundant in hydrolysed urine, but virtually absent in feces. Although all antibodies measured substantial amounts of immunoreactivity after HPLC separation of peak radioactive samples and detected an increase in glucocorticoid output following the ACTH challenge, only two (in feces against 3alpha,11-oxo-cortisol metabolites, measured by an 11-oxo-etiocholanolone-EIA and in urine against cortisol, measured by a cortisol-EIA) did not show substantial cross-reactivity with excreted 14C-T metabolites and could provide an acceptable degree of specificity for reliable assessment of glucocorticoid output from urine and feces. Based on these findings, concentrations of immunoreactive 3alpha,11-oxo-cortisol metabolites were determined in weekly fecal samples collected from four adult bulls over periods of 11-20 months to examine whether musth is associated with increased adrenal activity. Results showed that in each male levels of these cortisol metabolites were not elevated during periods of musth, suggesting that in the African elephant musth is generally not associated with marked elevations in glucocorticoid output. Given the complex nature of musth and the variety of factors that are likely to influence its manifestation, it is clear, however, that further studies, particularly on free-ranging animals, are needed before a possible relationship between musth and adrenal function can be resolved. This study also clearly illustrates the potential problems associated with cross-reacting metabolites of gonadal steroids in EIAs measuring glucocorticoid metabolites. This has to be taken into account when selecting assays and interpreting results of glucocorticoid metabolite analysis, not only for studies in the elephant but also in other species.
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Wilson, R. T. (2003). Biodiversity of Domestic Livestock in the Republic of Yemen. Tropical Animal Health and Production, 35(1), 27–46.
Abstract: Abstract This paper describes the domestic livestock of the Republic of Yemen and aspires to complement earlier sources listing or partially describing `breeds'. It attempts to cover all species and provide indications of production parameters through a literature review and via field observations made by the author in 1999. Information is provided on livestock numbers and the economic importance of animal production. Most animals are kept in sedentary mixed crop-livestock production systems; transhumant systems have the next greatest number of stock; with nomadic systems being of least and declining importance. Yemen's livestock appear to comprise at least 11 breeds of sheep, 5 breeds of goat, 2 breeds of cattle, 4 breeds of camel, 2 breeds of donkey and 1 breed of horse. There are no data on breeds of poultry but domestic fowl (where clearly considerable diversity exists) and pigeons are kept. There is little formal information on the history and relationships of most breeds. Some appear to be of ancient local origin, whereas others show affinities with those of neighbouring and other countries. None of the identified types is considered endangered, so conservation would be premature. A more formal and detailed genetic characterization, to add to the largely morphological and traditional classification, may, however, reveal such a need.
Keywords: Abstract This paper describes the domestic livestock of the Republic of Yemen and aspires to complement earlier sources listing or partially describing `breeds'. It attempts to cover all species and provide indications of production parameters through a literature review and via field observations made by the author in 1999. Information is provided on livestock numbers and the economic importance of animal production. Most animals are kept in sedentary mixed crop-livestock production systems; transhumant systems have the next greatest number of stock; with nomadic systems being of least and declining importance. Yemen's livestock appear to comprise at least 11 breeds of sheep, 5 breeds of goat, 2 breeds of cattle, 4 breeds of camel, 2 breeds of donkey and 1 breed of horse. There are no data on breeds of poultry but domestic fowl (where clearly considerable diversity exists) and pigeons are kept. There is little formal information on the history and relationships of most breeds. Some appear to be of ancient local origin, whereas others show affinities with those of neighbouring and other countries. None of the identified types is considered endangered, so conservation would be premature. A more formal and detailed genetic characterization, to add to the largely morphological and traditional classification, may, however, reveal such a need.
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Breuer, K., Hemsworth, P. H., & Coleman, G. J. (2003). The effect of positive or negative handling on the behavioural and physiological responses of nonlactating heifers. Appl. Anim. Behav. Sci., 84(1), 3–22.
Abstract: This experiment investigated the effects of positive and negative tactile handling on the stress physiology and behaviour of dairy heifers. Forty-eight 5-14-month-old nonlactating Holstein-Friesian heifers were allocated to one of two handling treatments, either positive or negative tactile handling, over four time replicates. Handling was imposed twice daily, 2-5 min per session and involved moving animals individually along a 64 m outdoor route. The negatively handled heifers took longer to approach within 1 and 2 m of a stimulus person in a standard test, than their positively handled counterparts (P<0.001) and had a greater flight distance to an approaching stimulus (P<0.001). The time taken by the heifers to approach within 1 and 2 m of a familiar person was similar to that taken to approach within 1 and 2 m of an unfamiliar person in the standard test (P<0.05). There was a tendency for heifers to have a greater flight distance from the approaching unfamiliar person than from the approaching familiar person (P=0.06). The negatively handled heifers had greater (P<0.05) increases in total cortisol concentrations 5, 10 and 15 min after exposure to a human and had higher (P<0.05) free cortisol concentrations in the afternoon than the positively handled heifers. It is concluded that the nature of the human contact affects the subsequent behavioural response of heifers to humans. This behavioural response may extend to other humans through the process of stimulus generalisation, although there was some evidence of moderate discrimination. Negative handling results in an acute stress response in the presence of humans and also leads to a chronic stress response. Further research into the effect of these stress responses on milk production and welfare in fearful cows in a commercial situation is suggested.
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Lee, R. D. (2003). Rethinking the evolutionary theory of aging: transfers, not births, shape senescence in social species. Proc Natl Acad Sci U S A, 100(16), 9637–9642.
Abstract: The classic evolutionary theory of aging explains why mortality rises with age: as individuals grow older, less lifetime fertility remains, so continued survival contributes less to reproductive fitness. However, successful reproduction often involves intergenerational transfers as well as fertility. In the formal theory offered here, age-specific selective pressure on mortality depends on a weighted average of remaining fertility (the classic effect) and remaining intergenerational transfers to be made to others. For species at the optimal quantity-investment tradeoff for offspring, only the transfer effect shapes mortality, explaining postreproductive survival and why juvenile mortality declines with age. It also explains the evolution of lower fertility, longer life, and increased investments in offspring.
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Cameron, E. Z. (2004). Facultative adjustment of mammalian sex ratios in support of the Trivers-Willard hypothesis: evidence for a mechanism. Proc Biol Sci, 271(1549), 1723–1728.
Abstract: Evolutionary theory predicts that mothers of different condition should adjust the birth sex ratio of their offspring in relation to future reproductive benefits. Published studies addressing variation in mammalian sex ratios have produced surprisingly contradictory results. Explaining the source of such variation has been a challenge for sex-ratio theory, not least because no mechanism for sex-ratio adjustment is known. I conducted a meta-analysis of previous mammalian sex-ratio studies to determine if there are any overall patterns in sex-ratio variation. The contradictory nature of previous results was confirmed. However, studies that investigated indices of condition around conception show almost unanimous support for the prediction that mothers in good condition bias their litters towards sons. Recent research on the role of glucose in reproductive functioning have shown that excess glucose favours the development of male blastocysts, providing a potential mechanism for sex-ratio variation in relation to maternal condition around conception. Furthermore, many of the conflicting results from studies on sex-ratio adjustment would be explained if glucose levels in utero during early cell division contributed to the determination of offspring sex ratios.
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Danchin, E., Giraldeau, L. - A., Valone, T. J., & Wagner, R. H. (2004). Public information: from nosy neighbors to cultural evolution. Science, 305(5683), 487–491.
Abstract: Psychologists, economists, and advertising moguls have long known that human decision-making is strongly influenced by the behavior of others. A rapidly accumulating body of evidence suggests that the same is true in animals. Individuals can use information arising from cues inadvertently produced by the behavior of other individuals with similar requirements. Many of these cues provide public information about the quality of alternatives. The use of public information is taxonomically widespread and can enhance fitness. Public information can lead to cultural evolution, which we suggest may then affect biological evolution.
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Moehlman, P. D. (2005). Endangered wild equids. Sci Am, 292(3), 74–81.
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Howard, R. W., & Blomquist, G. J. (2005). Ecological, behavioral, and biochemical aspects of insect hydrocarbons. Annu Rev Entomol, 50, 371–393.
Abstract: This review covers selected literature from 1982 to the present on some of the ecological, behavioral, and biochemical aspects of hydrocarbon use by insects and other arthropods. Major ecological and behavioral topics are species- and gender-recognition, nestmate recognition, task-specific cues, dominance and fertility cues, chemical mimicry, and primer pheromones. Major biochemical topics include chain length regulation, mechanism of hydrocarbon formation, timing of hydrocarbon synthesis and transport, and biosynthesis of volatile hydrocarbon pheromones of Lepidoptera and Coleoptera. In addition, a section is devoted to future research needs in this rapidly growing area of science.
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Rizhova, L. Y., & Kokorina, E. P. (2005). Behavioural asymmetry is involved in regulation of autonomic processes: Left side presentation of food improves reproduction and lactation in cows. Behav. Brain. Res., 161(1), 75–81.
Abstract: It is known that the right and left brain hemispheres differ in their ability to regulate autonomic processes in the organism. Direct unilateral stimulation of the brain provokes side-dependent endocrine, immune and other visceral reactions. Since brain hemispheres are mainly involved in the regulation of muscles and sensory organs on the contra lateral side of the body the activation of behavioural asymmetry stimulates the contra lateral half of the brain. The important theoretical and practical question of whether autonomic processes can be regulated via the behavioural asymmetry route remains unexplored. In this study, we report that the chronic presentation of an emotionally important stimulus--food--from the left side, improves reproductive performance in animals in a broad range of feeding conditions. The unilateral presentation of food can also influence lactation, but in this case the side-dependent effects are different under varying feeding conditions. This finding opens a simple practical approach to influence basic somatic functions in the organism.
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