Band Structure and Failures of Reproductive Suppression in a Cooperatively Breeding Carnivore, the Slender-Tailed Meerkat (Suricata Suricatta)

Behaviour ◽  
1997 ◽  
Vol 134 (11-12) ◽  
pp. 827-848 ◽  
Author(s):  
David W. Macdonald ◽  
Sean P. Doolan
Keyword(s):  
Band Structure ◽  
Adult Males ◽  
High Turnover ◽  
Reproductive Suppression ◽  
Suricata Suricatta ◽  
Adult Females ◽  
Reproductive Female ◽  
Band Size ◽  
Cooperatively Breeding ◽  
Reproductive Females

AbstractThe extent to which band structure influences the distribution of breeding activity is unknown for the slender-tailed meerkat Suricata suricatta, a cooperatively breeding mongoose. Here we present the residence histories of three focal bands monitored over ten band-years in the southwestern Kalahari, with less detailed data derived from non-focal bands for a further 20 band-years. Mean total band size early in the breeding season was 10, and mean size excluding juveniles was 6.7. Despite a tendency towards females among juveniles, and males among yearlings and adults, sex ratios within each age class did not significantly deviate from unity, but at the population level there were significantly more adult males than reproductive females. A large proportion (71.6%) of adult females bred, and failures of reproductive suppression occurred in 40% of band years. This incidence was high in all years and was not obviously related to environmental conditions. Bands with more than one reproductive female contained significantly more adults and adult females than bands with only a single reproductive female. There was a strong correlation between numbers of reproductive females and numbers of adult females in a band. Most (68%) subordinate females which bred were aged three years or more. Reproductive competition was strong and there was a negative correlation between numbers of adult females, breeding females or adult males and per capita juvenile production. Meerkat bands are unusual among cooperative breeders because many individuals were non-kin and the relative constancy in band size within and between years masked a high turnover of membership: all animals of known origin aged three years or older, were immigrants, although philopatry was commoner among younger animals. Our data show that meerkats employ a range of reproductive strategies: bands exhibiting a spectrum of reproductive suppression coexist, and individuals respond to the opportunities afforded by their social environments.

scholarly journals Reproductive skew in female common marmosets: what can proximate mechanisms tell us about ultimate causes?

2008 ◽  
Vol 276 (1656) ◽  
pp. 389-399 ◽  
Author(s):  
Wendy Saltzman ◽  
Leslie J Digby ◽  
David H Abbott
Keyword(s):  
Sexual Behaviour ◽  
Reproductive Skew ◽  
Reproductive Suppression ◽  
Free Living ◽  
Common Marmosets ◽  
Proximate Mechanisms ◽  
Adult Females ◽  
Cooperatively Breeding ◽  
Mating Interference

Common marmosets are cooperatively breeding monkeys that exhibit high reproductive skew: most subordinate females fail to reproduce, while others attempt to breed but produce very few surviving infants. An extensive dataset on the mechanisms limiting reproduction in laboratory-housed and free-living subordinate females provides unique insights into the causes of reproductive skew. Non-breeding adult females undergo suppression of ovulation and inhibition of sexual behaviour; however, they receive little or no aggression or mating interference by dominants and do not exhibit behavioural or physiological signs of stress. Breeding subordinate females receive comparable amounts of aggression to non-breeding females but are able to conceive, gestate and lactate normally. In groups containing two breeding females, however, both dominant and subordinate breeders kill one another's infants. These findings suggest that preconception reproductive suppression is not imposed on subordinate females by dominants, at a proximate level, but is instead self-imposed by most subordinates, consistent with restraint models of reproductive skew. In contrast to restraint models, however, this self-suppression probably evolved not in response to the threat of eviction by dominant females but in response to the threat of infanticide. Thus, reproductive skew in this species appears to be generated predominantly by subordinate self-restraint, in a proximate sense, but ultimately by dominant control over subordinates' reproductive attempts.

Is the Mahali mole-rat (Cryptomys hottentotus mahali) a spontaneous or induced ovulator?

2020 ◽  
Vol 98 (5) ◽  
pp. 299-305
Author(s):  
D.W. Hart ◽  
K. Medger ◽  
B. van Jaarsveld ◽  
N.C. Bennett
Keyword(s):  
Direct Contact ◽  
Physical Contact ◽  
Corpora Lutea ◽  
Reproductive Suppression ◽  
Subterranean Rodent ◽  
Breeding Female ◽  
Mole Rat ◽  
Cooperatively Breeding ◽  
Reproductive Females ◽  
Unrelated Male

The Mahali mole-rat (Cryptomys hottentotus mahali (Roberts, 1913)) is a social, cooperatively breeding subterranean rodent that breeds aseasonally. Only one female in a colony breeds and the remaining females are reproductively suppressed. When the opportunity arises, these non-reproductive females disperse from the natal colony to escape reproductive suppression and pair up with an unrelated male to start a new colony. This study set out to determine whether female Mahali mole-rats are induced or spontaneous ovulators once separated from the reproductive suppression of the breeding female. Fifteen separated females were subjected to three treatments: housed separately without a male (A), allowed chemical, but not physical, contact with a vasectomised male (NPC), and placed in direct contact with a vasectomised male (PC). Urine was collected from all females under each treatment every 2 days for 40 days. Only females housed in the PC treatment exhibited heightened progesterone concentrations and corpora lutea of ovulation in the ovaries. Furthermore, males possessed epidermal spines on the shaft of the penises that may be used to stimulate the cervix of the female during copulation. These findings suggest that the Mahali mole-rat is an induced ovulator.

Two new species and taxonomic notes on the Neotropical spiny orb-weaving spi-ders Micrathena and Chaetacis (Araneae: Araneidae), with remarks on the development of Micrathena excavata IVAN L. F. MAGALHÃES & ADALBERTO J. SANTOS (Brazil)

Zootaxa ◽  
2011 ◽  
Vol 2983 (1) ◽  
pp. 39 ◽  
Author(s):  
IVAN L. F. MAGALHÃES ◽  
ADALBERTO J. SANTOS
Keyword(s):  
New Species ◽  
Junior Synonym ◽  
Adult Males ◽  
Development Stages ◽  
Brazilian Amazonia ◽  
Central Brazil ◽  
Adult Females ◽  
Two New Species ◽  
Senior Synonym ◽  
First Time

In this paper, M. yanomami n. sp., from Brazilian Amazonia, Chaetacis bandeirante n. sp., from Central Brazil, and the males of M. gaujoni Simon, 1897 and M. ruschii (Mello-Leitão, 1945) n. comb. , respectively from Ecuador and Brazil, are described and illustrated for the first time. An ontogenetic series of the last development stages of both sexes of Micrathena excavata (C. L. Koch, 1836) is illustrated and briefly described. Adult females are larger and have longer legs and larger abdomens than adult males. Probably females undergo at least one additional moult before adulthood, compared to males. Micrathena ornata Mello-Leitão, 1932 is considered a junior synonym of M. plana (C. L. Koch, 1836), and M. mastonota Mello-Leitão 1940 is synonymized with M. horrida (Taczanowski, 1873). Acrosoma ruschii Mello-Leitão, 1945 is revalidated, transferred to Micrathena and considered a senior synonym of M. cicuta Gonzaga & Santos, 2004. Chaetacis necopinata (Chickering, 1960) is recorded for Brazil for the first time. Chaetacis incisa (Walckenaer, 1841) is considered a nomen dubium.

Spacing, movements, and habitat selection of the river otter in boreal Alberta

1994 ◽  
Vol 72 (7) ◽  
pp. 1314-1324 ◽  
Author(s):  
D. G. Reid ◽  
T. E. Code ◽  
A. C. H. Reid ◽  
S. M. Herrero
Keyword(s):  
Lontra Canadensis ◽  
Home Ranges ◽  
Adult Males ◽  
Movement Rates ◽  
River Otters ◽  
Aquatic Mammal ◽  
Adult Females ◽  
Two Factors ◽  
Bog Lakes ◽  
Selection Of

Seasonal spacing patterns, home ranges, and movements of river otters (Lontra canadensis) were studied in boreal Alberta by means of radiotelemetry. Adult males occupied significantly larger annual home ranges than adult females. Males' ranges overlapped those of females and also each other's. In winter, home ranges of males shrank and showed less overlap. Otters often associated in groups, the core members typically being adult females with young, or adult males. Otters tended to be more solitary in winter. In winter, movement rates of all sex and age classes were similar, and much reduced for males compared with those in other seasons. These data indicated a strong limiting effect of winter ice on behaviour and dispersion. We tested the hypothesis that otters select water bodies in winter on the basis of the suitability of shoreline substrate and morphology for dens with access both to air and to water under ice. Intensity of selection was greatest in winter, with avoidance of gradually sloping shorelines of sand or gravel. Adults selected bog lakes with banked shores containing semi-aquatic mammal burrows, and lakes with beaver lodges. Subadults selected beaver-impounded streams. Apart from human harvest, winter habitats and food availability in such habitats are likely the two factors most strongly limiting otter density in boreal Alberta.

scholarly journals Reproductive suppression in female cooperatively breeding cichlids

2008 ◽  
Vol 4 (6) ◽  
pp. 606-609 ◽  
Author(s):  
Dik Heg
Keyword(s):  
Clutch Size ◽  
Group Living ◽  
Egg Laying ◽  
Alloparental Care ◽  
Large Female ◽  
Egg Mass ◽  
Small Female ◽  
Reproductive Suppression ◽  
Cooperatively Breeding ◽  
Female Subordinate

Suppression by dominants of female subordinate reproduction has been found in many vertebrate social groups, but has rarely been shown experimentally. Here experimental evidence is provided for reproductive suppression in the group-living Lake Tanganyika cichlid Neolamprologus pulcher . Within groups of three unrelated females, suppression was due to medium- and small-sized females laying less frequently compared with large females, and compared with medium females in control pairs. Clutch size and average egg mass of all females depended on body size, but not on rank. In a second step, a large female was removed from the group and a very small female was added to keep the group size constant. The medium females immediately seized the dominant breeding position in the group and started to reproduce as frequently as control pairs, whereas clutch size and egg mass did not change. These results show that female subordinate cichlids are reproductively capable, but apparently suppressed with respect to egg laying. Nevertheless, some reproduction is tolerated, possibly to ensure continued alloparental care by subordinate females.

Time-Budgets of Camargue Horses Ii. Time-Budgets of Adult Horses and Weaned Sub-Adults

Behaviour ◽  
1980 ◽  
Vol 72 (1-2) ◽  
pp. 26-48 ◽  
Author(s):  
Patrick Duncan
Keyword(s):  
Social Structure ◽  
Social System ◽  
General Trend ◽  
Small Population ◽  
Time Budgets ◽  
Adult Males ◽  
Adult Females ◽  
Young Horses

AbstractTime-budgets of adult and weaned sub-adult horses were studied in a small population of Camargue horses living in semi-liberty. The categories of activities used were: Standing resting, Lying flat, Lying up, Standing alert, Walking, Trotting, Galloping, Rolling and Foraging. The main differences in time-budgets were related to age and to sex : young horses spent more time lying (sleeping), males spent more time standing alert and in rapid movements (trot, gallop), while usually foraging less than did the adult females. During the three years of the study the population increased from 20 to 54 horses and there were considerable changes in social structure as the number of adult males increased. Associated with these developments there were some changes between years in the time-budgets: the most striking of which was a general trend for all horses to spend less time lying. Nonetheless the time-budgets showed a considerable constancy across years and age/sex-classes, especially with regard to time spent foraging. This conclusion may provide a clue as to why horses have an unusual social system based on long term relationships between a male and the females of his harem.

Extrinsic Inter- and Intra-specific Competition in Parasitoid Wasps

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Paul J. Ode ◽  
Dhaval K. Vyas ◽  
Jeffrey A. Harvey
Keyword(s):  
Developmental Stages ◽  
Interference Competition ◽  
Apparent Competition ◽  
Annual Review ◽  
Publication Date ◽  
Natural Ecosystem ◽  
Adult Males ◽  
Alternate Host ◽  
Adult Females ◽  
Behavioral Mechanisms

The diverse ecology of parasitoids is shaped by extrinsic competition, i.e., exploitative or interference competition among adult females and males for hosts and mates. Adult females use an array of morphological, chemical, and behavioral mechanisms to engage in competition that may be either intra- or interspecific. Weaker competitors are often excluded or, if they persist, use alternate host habitats, host developmental stages, or host species. Competition among adult males for mates is almost exclusively intraspecific and involves visual displays, chemical signals, and even physical combat. Extrinsic competition influences community structure through its role in competitive displacement and apparent competition. Finally, anthropogenic changes such as habitat loss and fragmentation, invasive species, pollutants, and climate change result in phenological mismatches and range expansions within host–parasitoid communities with consequent changes to the strength of competitive interactions. Such changes have important ramifications not only for the success of managed agroecosystems, but also for natural ecosystem functioning. Expected final online publication date for the Annual Review of Entomology, Volume 67 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Filling in the holes: The reproductive biology of the understudied Mahali mole-rat (Cryptomys hottentotus mahali)

2021 ◽  
Vol 99 (9) ◽  
pp. 801-811 ◽  
Author(s):  
D.W. Hart ◽  
K. Medger ◽  
B. van Jaarsveld ◽  
N.C. Bennett
Keyword(s):  
Reproductive Tract ◽  
Breeding Strategy ◽  
Arid Environments ◽  
Reproductive Suppression ◽  
Mole Rat ◽  
Evolution Of Sociality ◽  
Great Insight ◽  
Cooperatively Breeding ◽  
Males And Females ◽  
Insight Into

African mole-rats have provided great insight into mammalian evolution of sociality and reproductive strategy. However, some species have not received attention, and these may provide further insights into these evolutionary questions. The cooperatively breeding Mahali mole-rat (Cryptomys hottentotus mahali (Roberts, 1913)) is one such species. Body mass, reproductive-tract morphometrics, gonad histology, and plasma reproductive hormone concentrations were studied for breeding and non-breeding males and females over 1 year. This study aimed to discern if this species exhibits a seasonal or aseasonal breeding pattern and whether there is a relaxation of reproductive suppression at any point in the year in non-breeding animals. The pattern of reproductive relaxation during the wetter months is similar to other African mole-rat species. Interestingly, births and pregnant breeding females were recorded throughout the year, thus indicating an aseasonal breeding strategy, despite inhabiting a region that experiences seasonal rainfall. However, there were periods of the year favouring increased reproduction to enable an increased likelihood of offspring survival. This suggests that the Mahali mole-rat may be an opportunistic breeder possibly brought about by the benefits of living in a cooperatively breeding group and potentially moving into more arid environments that were previously unexploited by the genus Cryptomys Gray, 1864.

Observations on social behaviour of Atlantic walruses (Odobenus rosmarus (L.)) during terrestrial haul-out

1980 ◽  
Vol 58 (3) ◽  
pp. 461-463 ◽  
Author(s):  
R. E. Salter
Keyword(s):  
Social Interactions ◽  
Social Behaviour ◽  
East Coast ◽  
Adult Males ◽  
Agonistic Interactions ◽  
Age Composition ◽  
Body Contact ◽  
Adult Females ◽  
Odobenus Rosmarus

Social interactions in walrus herds of mixed sex and age composition were recorded at a haul-out site on the east coast of Bathurst Island, N.W.T., during July–August 1977. Most walruses maintained body contact with at least one other walrus while hauled out on land; herds were usually circular in shape. Adult males, adult females, and immatures all displaced other walruses, and thus entered herds, by jabbing with the tusks. Dominance during agonistic interactions was related to relative tusk length and sex and age of interactants. Behaviour of walruses on land suggested an energetic advantage in mutual body contact, which would be maximized by occupation of interior positions within herds.

scholarly journals The Influence of Age, Sex, Pregnancy, Starvation, and Other Factors on the Cytoplasmic Ribonucleoproteins of Rat Liver

1958 ◽  
Vol 4 (6) ◽  
pp. 771-776 ◽  
Author(s):  
Mary L. Petermann ◽  
Mary G. Hamilton
Keyword(s):  
Body Weight ◽  
Rat Liver ◽  
Liver Tissue ◽  
Microsomal Protein ◽  
Male Rats ◽  
Differential Centrifugation ◽  
Adult Males ◽  
Analytical Ultracentrifuge ◽  
Total Rna ◽  
Adult Females

Rat liver was homogenized in 0.88 M sucrose. The DNA and total RNA were determined, and the homogenate was fractionated by differential centrifugation. The pellets obtained between 30 minutes at 20,000 g and 180 minutes at 105,000 g were analyzed for RNA and nitrogen. The ribonucleoproteins were determined in the analytical ultracentrifuge. The non-pellet RNA was calculated by difference. The results are reported as amounts per 6.7 x 10-9 mg. of DNA. In young, growing male rats the amounts of microsomal protein and ribonucleoprotein B (83S) increased with age. Non-pregnant adult females showed less non-pellet RNA and much more ribonucleoprotein C (63S) than did adult males. During pregnancy both of these cell constituents reverted to levels characteristic for male animals. Starvation for 5 days resulted in a reduction in the mass of liver tissue, the non-pellet RNA, the microsomal protein, and ribonucleoproteins B and C. During recovery from starvation the return of the liver to normal paralleled the rate at which body weight was restored. Treatment with cortisone, 25 mg. per rat per day for 5 days, caused an increase in microsomal protein and a decrease in ribonucleoprotein B. Treatment with 6-mercapto-purine, 50 mg. per kilo per day for 5 days, caused little change in liver composition in either males or females.

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