Body size and agonistic experience affect dominance and mating success in male copperheads

Fighting behaviour in adult male copperheads, Agkistrodon contortrix (Serpentes, Viperidae), was investigated in the laboratory to assess the relative importance of body size and type of agonistic experience as determinants of dominance and mating success. Seven experiments were conducted. In each experiment, trials were run using two adult males and one female in a large arena. The first experiment tested the influence of body size. All males tested had no recent fighting experience for 6-12 months, and one male of each pair was 8-10% longer in snout-vent length and had greater mass. In all cases, larger males won fights and were first to locate, court and guard females; thus, larger snout-vent length was an important determinant of fighting success and priority of access to potential mates. Males with either winning or losing experience from the first experiment were used in six subsequent experiments on the relative importance of snout-vent length and agonistic experience in attaining dominance and mating success. Losing experience had a greater effect than snout-vent length on subsequent fighting success and gaining priority of access to females. Winning experience, in contrast, did not increase the probability of winning subsequent fights; however, winners appeared more excitable and none deferred from challenges of other males. The asymmetry in effects of single experiences of victory and defeat is consistent with studies on other vertebrates and supports the hypothesis that losing fights in males negatively affects behaviour directly related to their fitness.     

Success breeds success in mating male reed frogs (Hyperolius marmoratus)

Studies of the distribution of mating success among males in frog choruses typically seek to identify specific phenotypic attributes that confer a higher mating success on certain individual males. These attributes invariably relate to competition among males: either direct competition in the form of aggression, or competition to attract and be chosen by females. In this paper, we present evidence that an additional factor may operate in frog choruses. We show that individual males who mate on a given night enjoy a higher probability of being successful on the next night, and we suggest that this is because successful mating enables males to conserve energy.     

Individual variation in male vocal traits and female mating preferences in Bufo americanus

We investigated the amount of variation in mating behaviour between and within individual male and female American toads, because both sources of trait variation can influence the course of sexual selection. Males varied in all four call parameters investigated (dominant call frequency, pulse rate, call rate and call duration). Individual males lowered the dominant frequency of their call when they interacted vocally with nearby males. Dominant call frequency was more highly correlated with body size in vocally interacting males than in non-interacting males. Pulse rate of calls primarily varied with water temperature. Call rate and call duration showed the most variation of the four call properties, but this variation was unrelated to male morphology or social interactions. Females varied in three aspects of mating behaviour: two measures of pair formation and their preference for dominant frequency of male calls. The body size of paired males varied between females both in pairings initiated by either sex and in pairings initiated only by females. Males chosen by females were usually larger than average, although age and prior breeding experience of females did not affect mate choice. Playback experiments indicated that female preference for calls of low dominant frequency depended on the temporal patterning of alternative calls presented. Each of the four male vocal properties showed significant repeatability, but only one of the three aspects of female mating behaviour was repeatable. We discuss how different degrees of repeatability in sexual traits of males and females may influence the action and detection of sexual selection in this and other species. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.     

Postejaculatory quiescence in female and male rats: Consequences for sperm transport during group mating.

Studied the pattern of postejaculatory mating in the social context of a multimale–multifemale group of Sprague-Dawley rats (N?=?21), analyzing its timing and sequence from the females' as well as the males' perspective. During mating, females had a quiescent period following each ejaculation, which was comparable with the males' (a postejaculatory interval, PEI). The PEIs of both sexes were characterized by 3 behaviorally distinguishable phases: a stationary, an interactive, and a sexual phase. There was no significant sex difference in the total length of the PEI. Nonetheless, females began active sexual behavior and entered the sexual phase more quickly than males. The time course of each phase of the PEI is compared with the time course of sperm transport in the female, and the similarities and differences between the two sexes' reproductive strategies following an ejaculation are emphasized. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multivariate analysis of male and female professional career choice correlates.

Personality, aptitude, achievement, and social-demographic characteristics of graduate students in 4 professional degree programs were investigated in a comparative multivariate analysis of the correlates of professional career choice. 173 male and 175 female 1st-yr graduate students in 2 traditionally male fields (law and management) and 2 traditionally female fields (education and social work) completed an extensive questionnaire. Results confirmed the central hypothesis of the study: Differences across careers for each variable were greater than differences between the sexes within careers. In contrast to previous findings, no significant sex differences were found in assertiveness, locus of control, or Machiavellianism. Sex differences were primarily confined to the variables relating to psychological masculinity–femininity and sex role attitudes. The limitations of the current design are noted, and it is stressed that these findings are correlational in nature. Preexisting dispositions and attitudes may be the best predictors of professional career choice, although it is equally possible that these attitudes and attributes are adopted after people have made their career choices (i.e., during graduate school). (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correlates versus predictors of courtship success: courtship song in Drosophila silvestris and D. heteroneura

Males of the picture-winged flies Drosophila silvestris and D. heteroneura produce a sound during courtship wing vibration; successful courtships include more time spent in wing vibration. We clipped male wings to test whether this sound is a necessary signal for the success of male courtship. We tested females in no-choice tests and also in choice tests in which each female was provided with a clipped and normal male simultaneously. We found no differences in the probability of copulation for either species in no-choice tests, and no difference for the choice tests with D. heteroneuraSurprisingly, clipped males were significantly more successful than control males in the choice tests with D. silvestrisThe latencies to copulate did not differ by treatment in any tests. Consequently, the sound produced by courtship wing vibration does not influence male mating success and thus does not meet the most important criterion for being a sexual signal. We propose that the vibration of thoracic muscles, transmitted through the substrate or through the male's forelegs, could provide a sexual signal in these species.1997The Association for the Study of Animal Behaviour     

Perceiving the causes of success and failure of male and female performers.

Studied sex differences in attributions of ability, effort, task difficulty, or luck given by 320 Ss at 4 grade levels (5th, 8th, and 11th grades and college) to the outcomes of 4 masculine tasks performed by either male or female actors. Results suggest that differential perceptions of male and female performances appear to be well established in both boys and girls by the 5th grade. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential effects of courtship and mating on receptivity and brain metabolism in female red-sided garter snakes (Thamnophis sirtalis pareitalis).

In the female red-sided garter snake (Thamnophis sirtalis parietalis), the loss of receptivity following intromission during mating can be prevented by injection of a local anesthetic (tetracaine) in the cloacal region prior to courtship and mating. Females that were courted and then mated had significantly higher uptake of radio-labeled [1?C]2-fluoro-2-deoxyglucose (2-DG) in the preoptic area (25%) and significantly lower uptake in the ventromedial hypothalamus (-20%) compared with females that were courted but not mated. Tetracaine-treated females had accumulation patterns similar to courted but unmated females and to females exposed only to other females. These results suggest that in the female red-sided garter snake, sensory input from the cloaca during mating alters patterns of metabolism in those brain areas most often associated with female sexual behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimuli for male mouse (Mus musculus) ultrasonic courtship vocalizations: Presence of female chemosignals and/or absence of male chemosignals.

In research on animal chemocommunication, biological odors are sometimes presented by being applied to a "neutral" animal (e.g., castrated or ovariectomized conspecific). This technique is typically utilized when the behavioral response to the odor requires the presence of a conspecific. In 5 experiments, DBA/2J and 2 F? hybrid strains of mice that might be expected to be neutral stimuli were examined for their abilities to elicit ultrasonic courtship vocalizations from male mice. Paradoxically, adult castrated males, adult males that were neonatally castrated, hypophysectomized males, prepubertal females, and hypophysectomized females all elicited more vocalizations than would have been predicted from previous research in which their urine alone was used as the stimulus. These and previous results are consistent with courtship vocalizations being promoted by chemosignals from females and/or by an absence of cues from males. Thus, a truly neutral conspecific for presenting female sex odors may not exist in mice. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Issue importance and group choice shifts: A persuasive arguments approach.

Examined the ability of persuasive arguments theory to explain the effects of issue importance on group choice shifts. 75 female undergraduates completed 1 of 2 tasks (individual argument generation or small-group discussion) under conditions of either high or low issue importance. A. Vinocur and E. Burnstein's (see PA, Vols 52:5207 and 54:2992) persuasive arguments theory was then employed to predict the discussion-produced effects from the individually generated arguments. This model accurately forecasts both the direction and strength of the issue importance effects as well as the relative magnitude of the choice shifts. These results suggest that persuasive argumentation mediates the effects of issue importance on group choice shifts and help to establish the general validity of the theory. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Induction of female and male mating patterns in female rats by gonadal steroids: Effects of neonatal or adult olfactory bulbectomy.

Three experiments evaluated hormonally mediated sexual response patterns in Long-Evans female rats receiving olfactory bulb ablations neonatally (Day 2) or in adulthood. In a test of Ss' reactivity to a caged male in an open field, estrogen and progesterone treatments increased the number of squares entered and the number of cage contacts, but olfactory bulb removal had no effect on these measures. During mating tests, the feminine sexual behavior of Ss' bulbectomized on Day 2 was similar to that of control-operated Ss, whereas Ss bulbectomized as adults displayed enhanced levels of lordosis, darting, and ear wiggling. Lordosis varied with estrogen dose, whereas darting was progesterone-dependent. In tests of masculine copulatory behavior, the proportion of bulbectomized Ss (Day 2 and adult) that mounted was significantly lower than that of control-operated Ss. The effects of olfactory bulb removal, which vary with the age at ablation and the behavioral system investigated, are not mediated by a single neuroendocrine system and cannot be interpreted in terms of a unitary "arousal" construct. (54 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes in preferences for male and female counselors

Past studies have indicated a preference for male therapists among both client and nonclient samples. To test for possible changes in preferences since the time of these studies, 53 male and 76 female applicants for counseling and 140 male and 150 female nonclient undergraduates completed a university counseling service application form that included a question regarding preference for sex of therapist. Although more clients than nonclients expressed preferences, results from both groups indicate a decrease in male counselor preferences. (4 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assortative mating and female clutch investment in black grouse

Variation in female behaviour has only recently received attention in studies of sexual selection. It has been suggested that females may invest differentially in their offspring in relation to the quality of their mate. This may lead to females that mate with high-quality and/or attractive males laying larger clutches. Females may also differ in their ability to choose between males. For example, females in good physical condition may make better choices. If physical condition and clutch size are positively correlated, this hypothesis could also produce a relationship between male attractiveness and female clutch size. We found, in lekking black grouse, Tetrao tetrix, that females mated to the highest ranked males laid the largest clutches. Furthermore we found, regardless of female age, a positive relationship between a measure of female condition and male rank but not between female condition and her clutch size. In addition, females in good condition visited a larger number of different male territories, and old females produced the largest clutches. Our results suggest two mechanisms to explain our findings. First, females in good physical condition tend to mate with the top males, suggesting an assortative mating pattern. Second, females mating with the highest ranked males lay larger clutches as a consequence of their choice. In general, our result calls for caution in evaluating studies that look at the consequences of mate choice. It may be that differences in female quality produce effects that may be wrongly interpreted as male quality effects. (c) 1998 The Association for the Study of Animal Behaviour.     

Neural mediation of estrogen-dependent courtship behavior in female ring doves.

Investigated the role played by the preoptic-hypothalamic region in the mediation of female ring dove courtship behavior. In Exp I, 43 ovariectomized Ss were tested in response to estradiol benzoate (EB) injections both before and after preoptic area (POA), posterior medial hypothalamus (PMH), or sham lesions. Only the PMH group's behavior significantly declined following lesions. Exp II, with 46 Ss, examined whether intracranial EB implants would be effective in stimulating courtship behavior in ovariectomized Ss. Unilateral EB implants were placed throughout the hypothalamic region, including rostral to the anterior preoptic and caudal to the PMH. Implants in the PMH were most effective in stimulating behavior. Results indicate the importance of the PMH in mediation of estrogen-dependent courtship behavior and are analogous to recent findings concerning the role of the ventromedial hypothalamus in mammalian female sexual behavior. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Male-produced ultrasonic vocalizations and mating patterns in female rats.

Investigated the influence of male-produced 50-kHz vocalizations on mating behavior and choice of partner in estrous female rats. In Exp I, 17 estrous female Long-Evans rats were given a mating-choice test; 2 tethered males, one of which was devocalized, were used as incentives. Darting was directed toward the vocalizing male more frequently than toward the muted test partner, but ultrasonic vocalizations had no influence on visit rate or the amount of time that the females spent with each male. When 2 intact or 2 muted males were used as stimulus objects, the females' solicitation behavior was more evenly distributed between the 2 males. In Exp II, 16 estrous females were given a mating-choice test between 2 muted males; tape-recorded 50-kHz vocalizations or tape hiss was transmitted from a speaker located behind one of the males. Females spent equal amounts of time with the tethered males in both the vocalization and tape-hiss conditions; however, females directed more darting toward the males that were tethered in front of the speaker transmitting the ultrasonic vocalizations than toward the other muted tethered males. Findings demonstrate that the principal function of the male-produced ultrasounds is to facilitate and orient the solicitation behavior of the estrous female during mating. The vocalizations have little demonstrable effect in attracting the female to the immediate physical proximity of the male. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lordosis behaviour in male, female and androgenized female rats

Sex differences in the lordodis response of adult rats to ovarian hormones were studied in a series of experiments. Male rats were less sensitive to oestradiol benzoate (OB, a single injection of 10, 100 or 1000 mug/kg or seven daily injections of 2, 10, or 50mglkg)then were female rats. Oestradiol benzoate-primed (10 mglkg)female, but not male, rats showed dose-dependent responses to progesterone (0-4, 2-0 or 10-0 mg/kg/. male rats responded clearly to progesterone (2 mg/rat) only when primed with a high dose of OB (100 mug/rat). Display of the whole pattern of female sexual behaviour was induced in male rats by treatment with 100 mug OB and 2 mg progesterone. Female rats treated with 1 mg testosterone propionate (TP) on day 4 of life, ovariectomized as adults and tested under the same endocrine conditions as the rats described above, retained behavioural OB sensitivity but responded poorly to progesterone. Evidence is presented that ovarian secretions during development significantly modify the response of neonatally TP-treated and normal female rats to OB in adulthood.     

Forty generations of bidirectional selection for mating frequency in male Japanese quail

A bidirectional replicated selection experiment for high (H1 and H2) or low (L1 and L2) cumulative number of complete matings (CNCM) in male Japanese quail was conducted for 40 generations. In the S32 generation, a subline was taken from each selected line and selection was relaxed. In the randombred control line (C), CNCM and unselected traits changed significantly over generations. Means of the selected lines were adjusted each generation for deviations from the control means. After 40 generations of selection, there was a 21-fold difference in CNCM (59.4 vs 2.8) between Lines H1 and L1. Whereas means increased and variation decreased in the high lines, means decreased and variation increased in the low lines. Regressions of mean CNCM on generation of Lines H1, H2, L1, and L2 were 1.15 +/- 0.08, 0.61 +/- 0.08, -0.26 +/- 0.04, and -0.34 +/- 0.03, respectively. Although responses to selection were observed throughout the 40 generations in Line H1, the low lines appeared to have reached a limit to selection after the S30 generation. Relaxed lines provided supporting evidence for this conclusion. Mean CNCM decreased in the relaxed high lines to that of the control, whereas the low relaxed lines remained at the same level as their corresponding selected lines. Line H2 went into extinction in the 37th generation as a result of reduced fitness. Realized heritabilities of CNCM were 0.09, 0.07, 0.06, and -0.15 in Lines H1, H2, L1, and L2, respectively. As correlated responses to the selection, male quail in the high lines were heavier, exhibited greater relative aggressiveness, and had larger cloacal glands than those of the control and low lines.     

Operant investigation of mating preference in female rats.

Permitted 4 female Long-Evans hooded rats to indicate preferred mating partners by giving them operant control over the choice of a pair of sexually active males. Pressing 1 of 2 levers released 1 of the pair of male rats which was then allowed a single sexual contact. It was possible for a female to establish a preference in less than 10 estrous matings. No preference was apparent during diestrus tests, but preference returned when the female was again placed in estrus. When the males released by the levers were rotated in the apparatus, those females showing a preference altered their behavior accordingly. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Osteoporosis in male and female leprosy patients

We measured the bone mineral density (BMD) of 353 leprosy patients (197 males 50-89 years old, average age 70.2; and 156 females 53-90 years old, average age 72.9) and serum levels of free testosterone (FT) in 81 males. The BMD of the lumbar vertebrae (L2-L4), diaphysis of the radius (1/3 radius), and the neck of the femur (neck) was measured using DXA (QDR 4500). The BMD of -2.5 SD YAM (young adult mean) in Japanese men and women was used as the cutoff value for osteoporosis in the respective genders: BMD of L2-L4, 0.751 g/cm2 (male), 0.747 g/cm2 (female); 1/3 radius, 0.655 g/cm2 (male), 0.550 g/cm2 (female); neck, 0.581 g/cm2 (female). The percentages of males with osteoporosis were 31.3% in the 50th, 32.9% in the 60th, 44.9% in the 70th, and 40.7% in the 80th decade at L2-L4. Similarly, the percentages were 33.3%, 58.3%, 74.3%, and 75.0%, respectively, at 1/3 radius. Among females, the percentages were 22.2%, 41.3%, 44.9%, and 68.8%, respectively, at L2-L4; 0%, 42.9%, 89.5%, and 78.6%, respectively, at 1/3 radius; and 11.1%, 38.6%, 67.7%, and 84.6% respectively, at neck. FT in men ranged from almost 0 to normal at each decade and BMD levels were significantly correlated with FT in all three regions of the skeleton (P < 0.0001). More than 30% of osteoporosis was found at each decade and FT may be one of the main factors affecting BMD in male leprosy patients.     

Central DSP-4 treatment decreases norepinephrine levels and courtship behavior in male zebra finches

In zebra finches, gonadal steroids activate male courtship, including singing, and also strongly modulate norepinephrine (NE) levels and turnover in brain areas regulating courtship behavior. In a previous study, systemic administration of DSP-4 caused significant decreases in courtship singing. These behavioral decrements were correlated with the degree of NE depletion in several vocal control nuclei. In the present study, we attempted to further decrease brain NE levels while minimizing systemic effects by infusing DSP-4 directly into the third ventricle. DSP-4 treatment significantly reduced NE levels in three of six vocal control nuclei and both hypothalamic nuclei sampled without significantly altering dopamine or serotonin levels in any areas. DSP-4-treated males took longer to begin singing and performed fewer song bouts and courtship displays. Interestingly, behavioral deficits were limited to courtship song displays, other behavior patterns, including female-directed behaviors like approach and follow, were unaffected by DSP-4 treatment. DSP-4 treatment appeared to affect singing behavior by causing deficits in initial attentiveness to females and initiation of singing rather than by affecting song structure.