Effects of age and photoperiod on reproduction and the spleen in the marsh rice rat (Oryzomys palustris)

2001 ◽  
Vol 280 (4) ◽  
pp. R1249-R1255 ◽  
Author(s):  
Kent E. Edmonds ◽  
Milton H. Stetson
Keyword(s):  
Adult Male ◽  
Reproductive Organ ◽  
Spleen Weight ◽  
Adult Males ◽  
Young Females ◽  
Reproductive Response ◽  
Body Weights ◽  
Marsh Rice Rat ◽  
Oryzomys Palustris ◽  
Older Males

To examine the interactions between age and photoperiod on reproduction and spleen weights, we exposed adult male and female rice rats of various ages to photoperiods of 16:8-h light-dark photoperiods (16L:8D) or 12L:12D. After 10 wk, animals were killed and the following data were recorded: weights of testes, seminal vesicles, uterus, ovaries, body, and spleen and, in addition, vaginal patency. Young adult males displayed a greater degree of testicular and seminal vesicle regression in short photoperiods than did older males; the testes of most older males did not regress in response to short photoperiods. Spleen weight was unresponsive to short photoperiods in all males, but was affected by age. Females, however, exhibited reproductive organ regression and decreased vaginal patency in response to short photoperiods at all ages examined. Body weights were affected by photoperiod in young females, and, as in males, photoperiod had no effect on spleen weights. These data suggest that the reproductive response to photoperiod in adult male rice rats declines with age, whereas in adult females it does not.

Effects of adults on survival and recruitment of Peromyscus leucopus

1987 ◽  
Vol 65 (10) ◽  
pp. 2519-2523
Author(s):  
Gregory H. Adler ◽  
Mark L. Wilson ◽  
Michael J. DeRosa
Keyword(s):  
Adult Female ◽  
Adult Male ◽  
Peromyscus Leucopus ◽  
Survival Rates ◽  
Adult Males ◽  
Control Grid ◽  
Young Males ◽  
Young Females ◽  
Breeding Seasons ◽  
And Control

A population of Peromyscus leucopus (white-footed mouse) in northeastern Massachusetts was manipulated for 3 years to determine the effects of adults on survival and recruitment. Two experimental grids were established, from which either all adult males or all adult females were removed continually. The effects of these two manipulations were compared with demography on a control grid. Manipulations had no apparent effect on breeding intensity of young, survival rates of adults, or residency rates of adults and young. Recruitment of adult males was higher on the adult male removal grid than on the control grid. Recruitment rates of adult males and of young males and young females were lower on the adult female removal grid than on the control grid. Survival rates of young males were higher on the adult female removal grid than on the control grid; this effect may have been due to either reduced adult female residency or adult male recruitment. All differences between experimental and control grids were noted only during breeding seasons. Adult males apparently limited recruitment of adult consexuals. The effects of manipulations on other measured parameters were inconclusive because of high immigration rates of adult males onto the adult male removal grid and reduced recruitment of adult males and decreased production of young on the adult female removal grid.

Breeding dispersions and site fidelity of American redstarts (Setophaga ruticilla)

1996 ◽  
Vol 74 (12) ◽  
pp. 2238-2247 ◽  
Author(s):  
R. E. Lemon ◽  
S. Perreault ◽  
G. A. Lozano
Keyword(s):  
Site Fidelity ◽  
Adult Males ◽  
Male Population ◽  
Setophaga Ruticilla ◽  
Young Females ◽  
Breeding Territory ◽  
American Redstarts ◽  
Plumage Maturation ◽  
One Year ◽  
Older Males

We relate features of the breeding dispersions and site fidelity of American redstarts (Setophaga ruticilla) to breeding success and interpret the findings in terms of sexual selection. One-year-old male redstarts show delayed plumage maturation, making male dispersions particularly easy to appreciate. In our study site in New Brunswick, Canada, older males usually arrived early each breeding season and gathered in contiguous territories or neighborhoods, while subadult males arrived later and settled peripherally to the adults. Subadult males constituted about 40% of the male population, on average, yet only 5% of banded nestlings returned to the natal breeding ground. Also, newly adult males, 2 years old or more, constituted about 15% of all males. Nearly 50% of adult males returned, twice the return rate of subadults. Among returns, older males returned more often to the same territory than did those that were subadult the previous year. Regardless of age, returns of males in a subsequent year were predicted more by the duration of their stay on the breeding territory than reproductive success. Males outnumbered females. Females returned less often than their mates, but more often if they had fledged young. Females rarely returned to the same mate or territory, but often returned to the same vicinity. The subadult males seem to represent a special dispersive phase of the life history. The evidence indicates strong competition among males for territories and females, older males being more often successful in both circumstances.

HAPTEN-RADIOIMMUNOASSAY OF PLASMA OESTRADIOL

1973 ◽  
Vol 72 (2) ◽  
pp. 330-344 ◽  
Author(s):  
Peter Doerr
Keyword(s):  
Adult Male ◽  
Normal Values ◽  
Normal Adult ◽  
Adult Males ◽  
Reagent Blank ◽  
Keyhole Limpet Haemocyanin ◽  
Ether Extraction ◽  
The Mean ◽  
Assay Precision ◽  
Plasma Oestradiol

ABSTRACT A hapten-radioimmunoassay for plasma oestradiol is described and information about the reliability of the method is given in detail. Oestradiol-3-hemisuccinate coupled to keyhole limpet haemocyanin is used for immunization of rabbits. The antiserum utilized for the assay is characterized by its titer, affinity and specificity. Following ether extraction and NaOH-light petroleum partition oestradiol is separated from crossreacting oestrogens by TLC. Oxidation of oestradiol on the plate is prevented by mercaptoethanol. To separate free and antibody bound ligand 250 μg dextran-coated charcoal per tube is used in the presence of bovine serum gammaglobulin (1 mg/ml). The between-assay precision based on 15 different determinations of control samples from normal adult male plasma was 9.4% (C. V.). The mean reagent blank value of 31 determinations was equivalent to 0.3 pg oestradiol and the detection limit in terms of the 99% confidence limit for a single blank value, was equivalent to 4.3 pg oestradiol. A procedure for detecting plasma blanks is described. Plasma oestradiol is separated from approximately all concomitant substances originally present in the sample by enzymatic conversion into oestrone and a second TLC. No plasma blanks could be detected with respect to normal adult male plasma. Normal values for adult males based on 51 subjects were characterized by a median of 17.2 pg/ml and the 95 percentiles of 9.5–27.6.

Bonobo baby dominance: Did female defense of offspring lead to reduced male aggression?

2018 ◽  
Author(s):  
Kara Walker ◽  
Brian Hare
Keyword(s):  
Adult Male ◽  
Social System ◽  
Dominant Species ◽  
Potential Solution ◽  
Adult Males ◽  
Male Aggression ◽  
Dominance Style ◽  
The Social ◽  
Initial Support

The dominance style of bonobos presents an evolutionary puzzle. Bonobos are not male dominant but female bonobos do not show traits typical of female-dominant species. This chapter proposes the offspring dominance hypothesis (ODH) as a potential solution. ODH suggests the social system of bonobos evolved as a defence against infanticide and is not due to pressure to monopolize resources. Females that prevented aggression towards offspring and preferred mating with less aggressive males were most successful. Supporting ODH, during observations at Lola ya Bonobo Sanctuary it was found that: 1) adult male bonobos are rarely aggressive towards offspring with mothers, 2) some mother-reared juvenile bonobos attain rank higher than adult males and 3) mother-reared offspring often socially interact with adult males without their mothers nearby. These preliminary findings provide initial support that the bonobo social system evolved due to fitness advantages of effectively protecting offspring against consequences of male aggression. Le style de dominance des bonobos présente un puzzle évolutionnaire. Les bonobos ne sont pas dominés par les mâles mais les bonobos femelles ne montrent pas les traits caractéristiques d’une espèce dominée par femelles. On propose l’hypothèse de dominance de progéniture (ODH) comme une solution potentielle. La ODH suggère que le système social des bonobos a évolué en défense contre l’infanticide et pas sous pression pour la monopolisation des ressources. Les femelles qui préviennent l’agression vers leur progéniture et leur préférence d’accouplement avec des mâles moins agressives étaient très efficaces. À l’appui de la ODH on a trouvé pendant nos observations à Lola ya Bonobo Sanctuary que: 1) les mâles adultes bonobos agressent rarement vers les bébés avec mères, 2) quelques adolescents bonobos qui furent élevés par leurs mères atteignent un rang plus haut que les mâles adultes et 3) la progéniture élevée par la mère interagissent avec avec d’adultes mâles sans la présence de leur mère. Ces trouvailles préliminaires donnent appuie à l’hypothèse que le système social des bonobos a évolué par les avantages corporelles de la protection de la progéniture contre les conséquences de l’agression mâle.

scholarly journals Socio-ecology of the marsh rice rat (Oryzomys palustris) and the spatio-temporal distribution of Bayou virus in coastal Texas

2013 ◽  
Vol 7 (2) ◽  
pp. 289 ◽  
Author(s):  
Tyla S. Holsomback ◽  
Christopher J. Van Nice ◽  
Rachel N. Clark ◽  
Nancy E. McIntyre ◽  
Alisa A. Abuzeineh ◽  
...  
Keyword(s):  
Temporal Distribution ◽  
Spatio Temporal ◽  
Marsh Rice Rat ◽  
Oryzomys Palustris

scholarly journals Marsh Rice Rat, Oryzomys palustris, Predation on Forster's Tern, Sterna forsteri, Eggs in Coastal North Carolina

2003 ◽  
Vol 117 (4) ◽  
pp. 654
Author(s):  
John H. Brunjes ◽  
W. David Webster
Keyword(s):  
North Carolina ◽  
Stomach Contents ◽  
Nesting Success ◽  
Small Islands ◽  
Island Area ◽  
Harbor Island ◽  
Cedar Island ◽  
Marsh Rice Rat ◽  
Oryzomys Palustris

Nesting success of Forster’s Terns (Sterna forsteri) was examined on two small islands in the Cedar Island area of North Carolina. Forster’s Terns laid an average of 2.1 eggs per nest (n = 50) on Chainshot Island and 2.1 eggs per nest (n = 43) on Harbor Island in clutches that consisted of 1 to 3 eggs. On Chainshot Island every egg (n = 107) was lost to predation. On Harbor Island, 72 of 92 eggs were preyed upon. A trapping program, initiated on both islands, yielded 32 Marsh Rice Rats (Oryzomys palustris). Stomach contents of 23 rats were inspected, with 92.3% from Chainshot Island and 70% of the stomachs from Harbor Island containing yolk and feathers of Forster’s Terns.

scholarly journals Growth and body weight of free-range reindeer in western Alaska

Rangifer ◽  
2000 ◽  
Vol 20 (2-3) ◽  
pp. 221 ◽  
Author(s):  
Greg L. Finstad ◽  
Alexander K. Prichard
Keyword(s):  
Body Weight ◽  
Growth Rates ◽  
Total Body Weight ◽  
Growth Patterns ◽  
Spatial And Temporal Variation ◽  
Adult Males ◽  
Body Weights ◽  
Total Body ◽  
Reproductive Females ◽  
Average Body

Total body weight of 9749 reindeer calves and 4798 adult reindeer were measured from 1984 to 1999 on the Seward Peninsula, western Alaska, USA. Growth rates of male and female calves, and annual growth patterns of adults were determined. Male calves grew faster than female calves. Reproductive females were lighter than non-reproductive females during summer but there was no effect of reproduction on average body weights the following winter. Adult males age 3-5 were heavier during summer than winter. Castrated males weighed the same as uncastrated males in summer, but were significantly heavier in winter, and did not display the large annual fluctuations in weight typical of reproductive males and females. Growth rates were higher and body weights greater in this herd than many other cir-cumpolar reindeer populations. We suggest these kinds of physiological indices should be used to monitor the possible effects of spatial and temporal variation in population density and to evaluate changes in herding practices.

scholarly journals The development of affiliative and coercive reproductive tactics in male chimpanzees

2021 ◽  
Vol 288 (1942) ◽  
pp. 20202679
Author(s):  
Rachna B. Reddy ◽  
Kevin E. Langergraber ◽  
Aaron A. Sandel ◽  
Linda Vigilant ◽  
John C. Mitani
Keyword(s):  
Mating Success ◽  
Sexual Coercion ◽  
Adolescent And Young Adult ◽  
Adolescent Male ◽  
Male Mating ◽  
Adult Males ◽  
Reproductive Tactics ◽  
Males And Females ◽  
First Time ◽  
Older Males

Like many animals, adult male chimpanzees often compete for a limited number of mates. They fight other males as they strive for status that confers reproductive benefits and use aggression to coerce females to mate with them. Nevertheless, small-bodied, socially immature adolescent male chimpanzees, who cannot compete with older males for status nor intimidate females, father offspring. We investigated how they do so through a study of adolescent and young adult males at Ngogo in Kibale National Park, Uganda. Adolescent males mated with nulliparous females and reproduced primarily with these first-time mothers, who are not preferred as mating partners by older males. Two other factors, affiliation and aggression, also influenced mating success. Specifically, the strength of affiliative bonds that males formed with females and the amount of aggression males directed toward females predicted male mating success. The effect of male aggression toward females on mating success increased as males aged, especially when they directed it toward females with whom they shared affiliative bonds. These results mirror sexual coercion in humans, which occurs most often between males and females involved in close, affiliative relationships.

scholarly journals Low-frequency arterial pressure fluctuations do not reflect sympathetic outflow: gender and age differences

1998 ◽  
Vol 274 (4) ◽  
pp. H1194-H1201 ◽  
Author(s):  
J. Andrew Taylor ◽  
Todd D. Williams ◽  
Douglas R. Seals ◽  
Kevin P. Davy
Keyword(s):  
Arterial Pressure ◽  
Low Frequency ◽  
Total Activity ◽  
Sympathetic Outflow ◽  
Pressure Oscillations ◽  
Young Males ◽  
Young Females ◽  
Sympathetic Nervous ◽  
Mayer Wave ◽  
Older Males

Low-frequency arterial pressure oscillations (Mayer waves) have been proposed as an index of vascular sympathetic outflow. However, cross-sectional differences in these pressure oscillations may not reflect different levels of sympathetic nervous outflow in humans. Three groups of healthy subjects with characteristically different sympathetic nervous outflow were studied: young females ( n = 10, 18–28 yr), young males ( n = 11, 18–29 yr), and older males ( n = 13, 60–72 yr). Average R-R interval, arterial pressures, and systolic pressure variability at the Mayer wave frequency (0.05–0.15 Hz) did not differ among the three groups. Diastolic pressure Mayer wave variability was similar in young females vs. young males (39 ± 10 vs. 34 ± 5 mmHg2) and lower in older males vs. young males (14 ± 2 mmHg2; P < 0.05). In contrast, muscle sympathetic activity was lowest in young females (892 ± 249 total activity/min) and highest in older males (3,616 ± 528 total activity/min; both P < 0.05 vs. young males: 2,505 ± 285 total activity/min). Across the three groups, arterial pressure Mayer wave variability did not correlate with any index of sympathetic activity. Our results demonstrate that arterial pressure Mayer wave amplitude is not a surrogate measure of vascular sympathetic outflow.

New or little-known Diamesinae (Diptera: Chironomidae) from Oriental China

Zootaxa ◽  
2019 ◽  
Vol 4571 (4) ◽  
pp. 544
Author(s):  
BINGJIAO SUN ◽  
XIAOLONG LIN ◽  
XINHUA WANG ◽  
EUGENYI A. MAKARCHENKO
Keyword(s):  
New Species ◽  
Adult Male ◽  
Morphological Description ◽  
Adult Males ◽  
Oriental Region ◽  
A New Species

Morphological description for adult male of a new species Diamesa qiangi sp. nov. and redescription for adult males of the little-known species Linevitshia prima Makarchenko and Sasayusurika nigatana (Tokunaga) of subfamily Diamesinae from the Oriental Region of China are given. 

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