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101.
The penile morphology and bacular structure of five species of African mole rat are described in relation to the method of ovulation, degree of sociality and polygynandry. We predicted that, with an increase in sociality, and a concomitant decrease in polygynandry and sperm competition, there would be a decrease in penis ornamentation (spinosity) and baculum size. In solitary species of African mole rat with marked seasonal reproduction and induced ovulation ( Bathyergus suillus and Georychus capensis ), males have numerous epidermal spines on the penis. Social, seasonally breeding, induced ovulating mole rats Cryptomys hottentotus natalensis possess less elaborate ornamentation in the form of small protrusions that are rounded at the apex. Two aseasonally breeding eusocial species with spontaneous ovulation Cryptomys damarensis and Heterocephalus glaber have ridges on the penis but lack any elaborate ornamentation. Baculae, however, showed a trend to become proportionally smaller in the solitary species. Our prediction that, with an increase in sociality and a move from induced to spontaneous ovulation, the amount and degree of penile ornamentation declines was, therefore, generally supported.  相似文献   
102.
To investigate possible anatomical and endocrine differences between breeding and non-breeding male naked mole-rats, 113 animals from 24 captive and 4 wild colonies were studied. While breeding males had larger reproductive tract masses compared to non-breeders relative to body mass (P less than 0.01), spermatogenesis was active in all of the non-breeding males examined histologically (n = 9) and spermatozoa were present in the epididymides. Compared with non-breeders, breeding males had significantly higher urinary testosterone concentrations (mean +/- s.e.m.: 23.8 +/- 2.3 vs 5.2 +/- 1.4 ng/mg Cr respectively; P less than 0.001), and plasma LH (10.7 +/- 1.7 vs 5.0 +/- 0.8 mi.u./ml respectively; P less than 0.01). Single doses of 0.1, 0.5 or 1.0 microgram GnRH produced a significant rise in plasma LH concentrations 20 min after s.c. injection in breeding and non-breeding males at all doses (P less than 0.001). However, there were differences in the magnitude of the LH response following administration of GnRH between breeding and non-breeding males, with non-breeding males showing a dose-response and having lower plasma LH concentrations 20 min after a single injection of 0.1 or 0.5 microgram (P less than 0.05), but not 1.0 microgram, GnRH. This apparent lack of pituitary sensitivity of non-breeding males to single doses of exogenous GnRH was reversed by 4 consecutive injections of 0.5 microgram GnRH at hourly intervals, suggesting that the reduced sensitivity may be the result of insufficient priming of the pituitary by endogenous GnRH. These results indicate that, despite the fact that non-breeding males were apparently producing mature gametes, clear endocrine deficiencies existed in male naked mole-rats.  相似文献   
103.
Eight male naked mole-rats, from three colonies were studied in captivity. When non-breeding male naked mole-rats were removed from their colonies and paired with a non-breeding female, or removed and housed singly for 6 weeks before pairing with a female, concentrations of urinary testosterone and plasma luteinizing hormone (LH) increased significantly (P less than 0.05). Concentration of these hormones were highest while the males were singly housed: urinary testosterone (mean +/- s.e.m.) increased from 8.2 +/- 1.3 ng/mg urinary creatinine (Cr) in a non-breeder in a colony to 49.1 +/- 5.5 ng/mg Cr when singly housed and 21.8 +/- 2.5 ng/mg Cr when paired with a female. Plasma LH concentrations increased from 4.7 +/- 1.0 miu/ml when a non-breeder in a colony to 19.8 +/- 4.0 miu/ml when singly housed and 9.9 +/- 1.1 miu/ml when paired with a female. After pairing with a female, the pattern of urinary testosterone secretion in the male was synchronized with the ovarian cycle of the female mate, such that urinary testosterone concentrations were significantly higher during the early follicular phase of the female's cycle (P less than 0.05). These results suggest that active suppression of reproductive physiology by social cues occurs in non-breeding male naked mole-rats, and that this is readily reversible if social cues are removed and males are housed singly. When a male was subsequently paired with a female, endocrine suppression was partially reimposed on the reproductively active males, such that urinary testosterone concentrations were suppressed to values similar to those in non-breeding males, except for periods prior to mating.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
104.
The study investigated the role of odor cues from two naked mole-rat colonies, in conjunction with behavioral cues from nonbreeding colony members, in maintaining suppression of ovulation in subordinate female naked mole-rats isolated from the two parent colonies. Four high ranking nonbreeding female naked mole-rats were removed from their respective parent colonies and singly housed in separate burrow systems. For a 64-day period, the removed females were maintained in daily odor contact with their parent colony by daily rotating soiled bedding material between the parent colony and the burrow systems of removed females. In addition, subsets of nonbreeding animals from the respective parent colony were regularly moved into the burrow systems of removed females for 2-day periods during this 64-day period. Removed females were therefore in continual social contact with subsets of parent colony animals except for the breeding pair. All four removed females exhibited raised levels of urinary progesterone (< 2 ng/mg Cr) indicative of the onset of ovarian function within 3 days of being separated from the parent colony. Removed females exhibited a normal ovulatory cycle with levels of progesterone remaining elevated for 25–35 days (mean concentration of progesterone ± SEM; 16.2 ± 2 ng/mg Cr). Initiation of aggression and sexual behavior by removed females increased significantly when they were isolated from the parent colony. The results demonstrated that odor cues from the complete colony in conjunction with behavioral / tactile / vocal cues from the nonbreeding colony members were not the major cues maintaining reproductive suppression in nonbreeding female naked mole-rats. Instead, our results suggest that female reproductive suppression in naked mole-rats is caused by a dominance-related behavioral mechanism requiring direct contact with the breeding female.  相似文献   
105.
Naked mole-rat colonies exhibit a high reproductive skew, breeding being typically restricted to one female (the ''queen'') and one to three males. Other colony members are reproductively suppressed, although this suppression can be reversed following the removal or death of the queen. We examined dominance and queen succession within captive colonies to investigate the relationship between urinary testosterone and cortisol, dominance rank and reproductive status; and to determine if behavioural and/or physiological parameters can be used as predictors of queen succession. Social structure was characterized by a linear dominance hierarchy before and after queen removal. Prior to queen removal, dominance rank was negatively correlated with body weight and urinary testosterone and cortisol titres in males and females. Queen removal results in social instability and aggression between high ranking individuals. Dominance rank appears to be a good predictor of reproductive status: queens are the highest ranking colony females and are succeeded by the next highest ranking females. The intense dominance-related aggression that accompanies reproductive succession in naked mole-rats provides empirical support for optimal skew theory.  相似文献   
106.
107.
Naked mole-rat colonies are societies with a high reproductive skew, breeding being restricted to one dominant female (the ''queen'') and 1-3 males. Other colony members of both sexes are reproductively suppressed. Experimental removal of breeding males allowed us to investigate the relationship between urinary testosterone and cortisol, dominance rank, and male reproductive status. Dominance rank was strongly correlated with body weight, age, and urinary testosterone titres in males. No relationship between urinary cortisol levels and male reproductive status or dominance was found. Breeding males were among the highest-ranking, heaviest and oldest males in their respective colonies, and were succeeded by other high-ranking, large, old colony males. In contrast to females, no evidence of competition over breeding status was observed among males. Male-male agonism was low both before and after removal of breeders and mate guarding was not observed. The lower reproductive skew for males compared with female skew or queen control over male reproduction may explain why males compete less strongly than females over breeding status after removal of same-sexed breeders.  相似文献   
108.
This article reports the results of an 18-month study of immune system and psychological changes in stage 1 breast cancer patients provided with relaxation, guided imagery, and biofeedback training. Thirteen lymph node negative patients who had recovered from a modified radical mastectomy were randomly assigned to either an immediate treatment or a delayed treatment control group. Multiple pre-post psychological measures were performed. Significant effects were found in natural killer cell (NK) activity (p<.017), mixed lymphocyte responsiveness (MLR) (p<.001), concanavalin A (Con-A) responsiveness (p<.001), and the number of peripheral blood lymphocytes (PBL) (p<.01). No significant psychological changes were detected; however, reductions were seen in psychological inventory scales measuring anxiety. The results show that behavioral interventions can be correlated with immune system measures, thereby replicating the results of an earlier pilot study from our Center. Discussion is provided on differential T-cell and B-cell responsiveness to behavioral interventions.We wish to thank Douglas B. Coulson, Ph.D. for his expertise on the statistical analysis of the data. We would also like to thank Clay Steiner, M.D.; Janelle Oliver, M.S.; Maureen O'Grady, Ph.D.; and Rena Goetz, Ph.D., for their contribution to the performance of the assays. Finally, we thank both Sandy Bangham, R. N., and the medical laboratory staff at The Washington Clinic, Washington, D.C. for their services in performing phlebotomy.  相似文献   
109.
We have isolated 14 polymorphic greater horseshoe bat, Rhinolophus ferrumequinum microsatellite loci. The number of alleles varied from two to 12 in 58 individuals. These loci will be used to assign paternity in order to characterize patterns of breeding and reproductive success in a wild R. ferrumequinum population. Loci were also tested in 17 other bat species. Twelve loci cross‐amplified in other species and three loci were polymorphic in all eight Rhinolophus species tested.  相似文献   
110.
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