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PubMed2002

Different colors reveal different information: how nutritional stress affects the expression of melanin- and structurally based ornamental plumage.

Avian plumage colors have emerged recently as model systems for investigating the types of information that can be signaled by showy sexual displays in animals. In many species, the brightness of carotenoid-based plumage reflects the health and condition of individuals and is used in mate selection. The information contained in melanin-based and structurally based ornamental colors in birds is less well resolved, however. We subjected male house sparrows Passer domesticus and brown-headed cowbirds Molothrus ater to stressful nutritional conditions during molt to test the hypothesis that melanin- and structurally based plumage colors are nutritionally condition-dependent. We restricted food access for treatment males during randomized 6 h periods on 4 days per week, while allowing control birds access to food ad libitum throughout the course of the molt. We found that the size and brightness of the melanin-based throat badges in male house sparrows were not affected by nutritional stress. Similarly, there were no differences between treatment and control male cowbirds in the size or brightness of the melanin-based brown hood. However, the structurally based iridescent plumage of cowbirds was indicative of the nutritional condition of males during molt. Nutritionally stressed cowbirds grew significantly less colorful plumage than did males with access to food ad libitum. These results are consistent with observations in other avian species that different types of plumage color communicate different sets of information. Melanin ornaments are less sensitive to nutritional conditions during molt and instead may reflect the hormonal status and/or competitive ability of males, whereas structural coloration appears to be an accurate signal of health and condition.

Animal Nutritional Physiological Phenomena↗
PubMed2005

Evolutionary neurobiology and aesthetics.

If aesthetics is a human universal, it should have a neurobiological basis. Although use of all the senses is, as Aristotle noted, pleasurable, the distance senses are primarily involved in aesthetics. The aesthetic response emerges from the central processing of sensory input. This occurs very rapidly, beneath the level of consciousness, and only the feeling of pleasure emerges into the conscious mind. This is exemplified by landscape appreciation, where it is suggested that a computation built into the nervous system during Paleolithic hunter-gathering is at work. Another inbuilt computation leading to an aesthetic response is the part-whole relationship. This, it is argued, may be traced to the predator-prey "arms races" of evolutionary history. Mate selection also may be responsible for part of our response to landscape and visual art. Aesthetics lies at the core of human mentality, and its study is consequently of importance not only to philosophers and art critics but also to neurobiologists.

Animals↗
PubMed2003

Size of the vomeronasal organ in wild Microtus with different mating strategies.

Most studies on mammalian vomeronasal organ (VNO) have been on laboratory-bred animals. Our present study examines the VNO in wild-caught meadow voles (Microtus pennsylvanicus: n=16) and prairie voles (M. ochrogaster: n=15). These species vary in their mating strategies and degree of parental care by males. M. ochrogaster exhibits pair bonding and more paternal care compared to M. pennsylvanicus, a promiscuous species. We hypothesize that sexual dimorphism will occur in the promiscuous species based on previous studies which suggest that those who exhibit more aggressive or masculine behavior have larger VNOs. Our results support our original finding that VNOs are not different in size in wild Microtus spp. that vary in male parental tendencies. However, the present study also indicates that M. pennsylvanicus, the species exhibiting more disparate parental tendencies, exhibited larger VNOs in females than males. This is the reverse of previous findings on rats, and we hypothesize that this difference may be due to mate selectivity and/or maternal aggression.

Analysis of Variance↗
PubMed1982

Influence of olfactory signals on the reproductive behaviour of social groups of rhesus monkeys (Macaca mulatta).

Olfactory influences are important in the control of reproductive function in many mammalian species including primates. Previous studies have shown that a mixture of volatile aliphatic acids (copulins), normally present in the vaginal secretions of rhesus monkeys, can exert a stimulatory effect on the sexual behaviour of males when pairs are tested in small cages. The present study deals with the role of these substances when tested in social groups of rhesus monkeys housed in a large testing arena, the purpose being to assess the effectiveness of olfactory signals under more nearly naturalistic conditions. Each group consisted of one male with four long-term ovariectomized females from which the male could choose. A counter-balanced experimental design was used in which each female of a testosterone-treated pair was given applications to the sexual skin of either copulins or control ether immediately before each 1-h behaviour test. After 16 tests, the procedure was repeated with the previously untreated pair in each group, and nine groups were separately studied. Testosterone was used here simply to enhance female proceptivity. The results showed that females received significantly more ejaculations (P less than 0.05), mounting attempts (P less than 0.01) and mounts (P less than 0.05) when bearing copulins than when bearing control ether. There were positive responses to copulins in 12 of the 36 males-females pairs, involving all males, and positive responses to ether in five of 36 pairs, involving four males. Copulins resulted in a change in the choice of sexual partner in five males, but there were no changes in the choice of partner with ether. Social factors, such as dominance, could override the responses to olfactory signals, and there was a significant treatment order effect, but this was eliminated by the counter-balanced design. These findings indicate a significant role for olfactory communication in mate selection in a socially living higher primate.

Animals↗
PubMed1998

Estimation of the dominance variance for postweaning gain in the U.S. Limousin population.

The objective of this study was to estimate the dominance variance for postweaning gain in Limousin cattle. Data included 215,326 records of postweaning gain from 205 to 365 d, provided by the North American Limousin Foundation. Parental dominance subclasses were formed and related using the method of Hoeschele and VanRaden. Variance components were estimated using Method R based on six samples of 50%. Fixed effects in the model included contemporary group and covariates for inbreeding and breed composition (percentage Limousin). Heterozygosity was negatively correlated with breed composition (< -.99) and was therefore not included in the model. Two types of contemporary groups used as original groups from the National Cattle Evaluation were partially based on breed composition. Original contemporary groups that were too homogeneous for breed composition were replaced by herd-year-sex classes. Two models were used with the two data sets. Model 1 contained the fixed effects described above and an additive genetic effect. Model 2 included a dominance effect in addition to the effects contained in Model 1. In total, four combinations of contemporary group x model were used. Dominance variance was computed as being four times the estimated parental subclass variance. Estimates for inbreeding depression and breed composition (percentage Limousin) were all small and not greatly affected by inclusion of dominance effects or changes in contemporary groups. Estimates of the additive variance (expressed as percentage of the phenotypic variance) were only slightly affected, with values between 20 and 21%. Dominance estimates were highly affected when passing from original (10%) and to alternative contemporary groups (18%). Such large values may indicate that dominance is important for postweaning gain. Results showed the advantage of an individual dominance approach based on sire-dam combinations; therefore, expected gains through the use of specific combination ability as a part of the mating selection criteria for growth might be high.

Animals↗
PubMed1997

Biology of chromosome 6.

The major histocompatibility (HLA) complex on the short arm of human chromosome 6 has attracted many scientists over the last three decades. It is the purpose of this brief review to point out that the remaining large regions of chromosome 6 contain genes involved in several interesting biological phenomena as well. Focus will be particularly on genes affecting behavioural features and sensory perception. The likely involvement of HLA and closely linked olfactory receptor loci in mate selection and their possible role in favouring heterozygosity among the offspring will also be discussed.

Animals↗
PubMed1985

The influence of staining techniques and examiners on evaluation of the morphology of fowl spermatozoa.

A total of 53 dwarf Single Comb White Leghorn males from the relaxed selection mating of low and high body weight lines and a randombred control line were used to determine the influence of technique (eosin-nigrosin smears or collection of spermatozoa on membrane filters) and examiner on the assessment of sperm morphology. There were significant (P less than .05) line, technique, examiner, and technique X examiner interactions for sperm abnormalities. Total abnormal spermatozoa were higher in the high line than in the other two lines, and this was associated with increased midpiece defects and twisted spermatozoa. Eosin-nigrosin smears showed almost twice the percentage of abnormal spermatozoa compared to stained membrane filters.

Animals↗
PubMed2003

[Oligodontia and its inheritance in Kerry blue terrier].

Defects of the premolar tooth formula (oligodontia, tooth number reduction) were studied in dogs of the Kerry blue terrier breed. For this purpose, a database including 480 individuals of 96 litters was constructed. The occurrence of oligodontia was investigated in pedigree groups with inbred and outbred crosses. No selective mating choice for the anomaly under study was found in the sample. The results indicate that oligodontia is inherited, which requires comprehensive study of its genetic control and search for corresponding genes.

Animals↗
PubMed2003

Molecular basis for ultraviolet vision in invertebrates.

Invertebrates are sensitive to a broad spectrum of light that ranges from UV to red. Color sensitivity in the UV plays an important role in foraging, navigation, and mate selection in both flying and terrestrial invertebrate animals. Here, we show that a single amino acid polymorphism is responsible for invertebrate UV vision. This residue (UV: lysine vs blue:asparagine or glutamate) corresponds to amino acid position glycine 90 (G90) in bovine rhodopsin, a site affected in autosomal dominant human congenital night blindness. Introduction of the positively charged lysine in invertebrates is likely to deprotonate the Schiff base chromophore and produce an UV visual pigment. This same position is responsible for regulating UV versus blue sensitivity in several bird species, suggesting that UV vision has arisen independently in invertebrate and vertebrate lineages by a similar molecular mechanism.

Amino Acid Substitution↗
PubMed2004

Surgical enhancement of facial beauty and its psychological significance.

Facial beauty is easier to recognize than to define. It is widely agreed that beauty is an evolutionary adoption for ensuring the survival of the species, because physical attractiveness is rated as more vital in mate selection. It includes a combination of qualities, starting from the grace of form to the charm of the colours that delight the sight and other senses. It does not have any norms however individual or societal assessment of attractiveness is greatly influenced by cultural standards. Several soft and hard tissue surgical procedures are therefore performed around the world each year. In this 12 years study from 1992 to 2004 the types of orthognathic surgical procedures performed and their psychological impact on the patients' well-being have been evaluated. By carefully structured interviews and psychosomatic evaluations It has been clinically demonstrated that psychological analysis is as important as soft and hard tissue parameters for patients undergoing surgical procedures to enhance facial beauty.

Adolescent↗
PubMed1991

Gender and changing generational relations: spouse choice in Indonesia.

Many Asian societies are undergoing a nuptiality transition that is not only tied integrally to other aspects of family organization, but is also often more complex than standard studies of female age at marriage can reveal. To comprehend some of this complexity, we focus on the patterns of spouse choice for both men and women in central Java. The extent of parental control over mate selection is examined for change over time, gender differences, and likely determinants, including family class, education, premarital work, and residence. It is argued that the current marriage transition in Indonesia reflects both gender and generational hierarchies in the Javanese family system. The analysis is conducted using a multinomial logit model; in general, it yields results strongly supportive of the argument that the determinants of spouse selection differ by gender. The results also show that although there is a dramatic shift towards self-choice marriages, it is occurring within the context of historical and institutional factors specific to Javanese society.

Adult↗
PubMed1986

Premarital sex: attitudes and behavior by dating stage.

Using data gathered from a sixty-three item dating and mate-selection questionnaire completed by two hundred and eighty student and nonstudent respondents, this study investigates the differences between what people believe is proper premarital sexual behavior, what they do and what they think others are doing at five stages of dating. It was found that persons are most restrictive in what they believe is proper conduct, more permissive in their reported behavior, and most permissive in their perception of what others are doing. During the early stages of dating, males and females differ widely in their outlook as to what is proper behavior and also in their reported behavior. Other studies which failed to take dating stage into consideration may have missed important gender differences in the early period of dating.

Adolescent↗
PubMed1982

Diverse xenotropic virus expressions in two NZB mouse breeding lines that differ in chromosome breakage.

Two breeding lines of the NZB/BI mouse strain, which was originated from Bielschowsky's stock and maintained as a conventional inbred colony since 1963, were developed by selective matings according to chromosome breakage incidence in bone marrow cells. These breeding lines were used because they represent an interesting experimental model, since they differ in the manifestations of the autoimmune process and the incidence of lymphomas. The present study showed that embryos from both breeding lines differed in the expression of the xenotropic type C RNA virus, characteristic of NZB mice. All 17 cultures initiated with embryos from the line showing high chromosome breakage (HB) had positive reverse transcriptase (RT) reactions after cocultivation with an indicator cell line (SIRC). On the contrary, only 3 of the 22 embryos from the line showing low chromosome breakage (LB) had RT activity at late passages (7-10). The chromosome studies done on these embryo cultures showed highly significant differences in the chromosome breakage incidence for the 2 breeding lines [10.6 and 20.5% of cells with aberrations for LB and HB embryos, respectively (P less than 0.001)].

Animals↗
PubMed1983

Immunologic and enzymatic studies of two breeding lines of NZB mice that differ in chromosome breakage.

Two sublines of NZB/BI mice were developed by selective matings according to chromosome breakage frequencies. These sublines--HB, a line with high chromosome breakages, and LB, a line with low or normal breakage rates--were studied in regard to the age of the animals as it related to two different aspects. The first aspect was immunologic: A decreased response to T-cell mitogens was found in old NZB mice, but this response was more pronounced in HB mice. The response to the B-cell mitogen (lipopolysaccharide) was increased in both sublines as compared to that in BALB/c mice. The percentages of IgG-positive and theta-positive spleen cells were evaluated in both sublines: Some increase in IgG-positive cells was observed in the spleens of 2- to 8-month-old NZB mice and a slight decrease was seen after age 8 months. The percentage of theta-positive cells diminished according to the age of the mice, and the decrease occurred earlier in HB than in LB mice. The second aspect studied was enzymatic and concerned the levels of DNA alpha- and beta-polymerases and terminal DNA nucleotidyltransferase in the thymuses and spleens of these animals. The major finding noted was an augmentation of 100-200% in the terminal DNA nucleotidyltransferase levels in HB thymuses by comparison with LB thymuses. The levels of both polymerases were increased in spleen cells of HB mice as compared to those of LB mice.

Age Factors↗
PubMed1978

[Psychodynamic aspects of marriages of schizophrenics (author's transl)].

20 couples, each of which with one spouse suffering from schizophrenia, are investigated with clinical and psychological (individual and consensus Rorschach, Freiburg personality inventory) methods. Married schizophrenics seem to be less schizoid than passive dependent, infantile or stormy in their premorbid personality. Regarding our results their spouses don't differ in their mental health from the average population. Behaviour disorders of the non-schizophrenic spouses rather have to be seen as reactions caused secondarily by the patient's schizophrenic symptoms than as characteristics of their primary personality, because they only arise in the exploration of both spouses together. The schizophrenics appear less disturbed in the interaction with their spouses than in the situation of the single exploration. The "interacting personality" of the non-schizophrenic spouses, however, seems to be more disturbed than their "individual personality". Special factors, which are connected with premorbid personality of the later schizophrenic, are important in the mate selection. Very often first manifestation and the course of schizophrenic syndrome on the one hand and the marital dynamics on the other hand are closely related. Describing the attitude of the spouses to each other the non-schizophrenic shows three characteristic patterns, which are seen in the interaction of the couple: acceptation, emotional distance and ambivalence. Further the question of indication and prospect of marital therapy is discussed.

Adult↗
PubMed2000

Estimating sexual selection and sexual isolation effects from mating frequencies.

Sexual selection (defined as the change in genotypic or phenotypic frequencies of mated versus total population frequencies) and sexual isolation (defined as the deviation from random mating in mated individuals) show different evolutionary consequences and partially confounded causes. Traditionally, the cross-product estimator has been used to quantify sexual selection, whereas a variety of indexes, such as Yule V, Yule Q, YA, joint I, and others have been used to quantify sexual isolation. Because the two types of estimators use different scales, the effects of both processes cannot be monitored simultaneously. We describe three new related statistics that quantify both sexual selection (PSS) and sexual isolation (PSI) effects for every mating pair combination in polymorphic traits, as well as measure their combined effects (PTI = PSI x PSS). The new statistics have the advantage of providing information on every mating pair combination, quantifying the effects of sexual selection and isolation in the same units, and detecting asymmetry in sexual isolation. The ability of the new statistics to ascertain the biological causes of sexual selection and sexual isolation are investigated under different models involving distinct marginal frequencies, mate propensity, and mate choice coefficients. We also studied the use of classical isolation indexes applied on PSI coefficients, instead of on raw data. The use of the classical indexes applied to PSI coefficients considerably reduces the statistical bias of the estimates, revealing the good estimation properties of the new statistics.

Animals↗