| dietary calcium content, calcium balance and mode of uptake in a subterranean mammal, the damara mole-rat. | calcium flux and mode of uptake were investigated in an underground dwelling mole-rat, cryptomys damarensis, fed diets of varying ca content. the amount of dietary ca positively influenced the amounts ingested, absorbed and retained. the linear relationship between ingested and absorbed ca was significantly (p less than 0.001) correlated, implying that this process is nonsaturable. when mole-rats were fed a diet low in ca, apparent fractional absorption of ca was high (85.88%). this increased st ... | 1992 | 1729458 |
| absence of calcitriol-mediated nongenomic actions in isolated intestinal cells of the damara mole-rat (cryptomys damarensis). | calcitriol [1,25(oh)2d3] actions on intestinal calcium transport involve genomic and nongenomic pathways. whether nongenomic 1,25(oh)2d3-mediated actions are employed was investigated using isolated intestinal epithelial cells of naturally vitamin d-deficient underground-dwelling damara mole-rats (cryptomys damarensis). 1,25(oh)2d3-mediated nongenomic pathways of intestinal calcium uptake, measured by opening of 1,25(oh)2d3-activated voltage-sensitive ca2+ channels (vscc), did not occur. rapid ( ... | 1994 | 7926652 |
| investigation of numbers and motility of spermatozoa in reproductively active and socially suppressed males of two eusocial african mole-rats, the naked mole-rat (heterocephalus glaber) and the damaraland mole-rat (cryptomys damarensis). | reproductive tracts and spermatozoa from reproductively active and reproductively suppressed non-breeding males from two species of eusocial african mole-rats cryptomys damarensis and heterocephalus glaber were examined. in two captive colonies of heterocephalus glaber, reproductive tracts from seven non-breeding males removed from their colonies, and housed singly for 5-6 weeks to cause reproductive activation, were compared with reproductive tracts from seven non-breeding males. the body weigh ... | 1994 | 8021857 |
| changes in food intake with ambient temperature alter hindgut fermentation in the damara mole-rat cryptomys damarensis. | 1. changes in food consumption and fermentation capacity were examined in mole-rats housed at 23 and 30 degrees c. 2. at both temperatures animals maintained body mass. food consumption was lower at the higher temperature and led to a similar decline in caecal mass. 3. caecal dry matter content and fermentation efficiency were unaffected by food intake. however, gas production per animal decreased markedly with the reduced food intake. 4. the drop in fermentation in response to decreased food in ... | 1993 | 8095886 |
| comparison of endothelial function, o2-* and h2o2 production, and vascular oxidative stress resistance between the longest-living rodent, the naked mole rat, and mice. | vascular aging is characterized by decreased nitric oxide (no) bioavailability, oxidative stress, and enhanced apoptotic cell death. we hypothesized that interspecies comparative assessment of vascular function among rodents with disparate longevity may offer insight into the mechanisms determining successful vascular aging. we focused on four rodents that show approximately an order of magnitude range in maximum longevity (ml). the naked mole rat (nmr; heterocephalus glaber) is the longest-livi ... | 2006 | 17090784 |
| the energetics of huddling in two species of mole-rat (rodentia: bathyergidae). | small rodents with a large surface-area-to-volume ratio and a high thermal conductance are likely to experience conditions where they have to expend large amounts of energy in order to maintain a constant body temperature at low ambient temperatures. the survival of small rodents is thus dependent on their ability to reduce heat loss and increase heat production at low ambient temperatures. two such animals are the social subterranean rodents cryptomys damarensis (the damaraland mole-rat) and cr ... | 2008 | 17928015 |
| neoplasia and granulomas surrounding microchip transponders in damaraland mole rats (cryptomys damarensis). | damaraland mole rats (cryptomys damarensis) are among the longest-living rodents, with a maximum longevity of approximately 16 years. as one of the few mammals termed eusocial, these animals have been used in behavioral, genetic, metabolic, and physiologic research at the university of connecticut since 1997. for individual identification at 3 to 4 months of age, mole rats were subcutaneously implanted with microchip transponders (11 mm in length) in the dorsal cervical region. in 2007, 2 of the ... | 2010 | 20724516 |
| social status and sex effects on neural morphology in damaraland mole-rats, fukomys damarensis. | we previously reported that in a eusocial rodent, the naked mole-rat (heterocephalus glaber), traditional neural sex differences were absent; instead, neural dimorphisms were associated with breeding status. here we examined the same neural regions previously studied in naked mole-rats in a second eusocial species, the damaraland mole-rat (fukomys damarensis). damaraland mole-rats live in social groups with breeding restricted to a small number of animals. however, colony sizes are much smaller ... | 2011 | 21701152 |
| low rates of hydrogen peroxide production by isolated heart mitochondria associate with long maximum lifespan in vertebrate homeotherms. | an inverse correlation between free radical production by isolated mitochondria and longevity in homeotherms has been reported, but previous comparative studies ignored possible confounding effects of body mass and phylogeny. we investigated this correlation by comparing rates of hydrogen peroxide (h(2)o(2)) production by heart mitochondria isolated from groups or pairs of species selected to have very different maximum lifespans but similar body masses (small mammals, medium-sized mammals, bird ... | 2007 | 17596208 |
| orexinergic neuron numbers in three species of african mole rats with rhythmic and arrhythmic chronotypes. | in the present study, orexinergic cell bodies within the brains of rhythmic and arrhythmic circadian chronotypes from three species of african mole rat (highveld mole rat-cryptomys hottentotus pretoriae, ansell's mole rat--fukomys anselli and the damaraland mole rat--fukomys damarensis) were identified using immunohistochemistry for orexin-a. immunopositive orexinergic (orx+) cell bodies were stereologically assessed and absolute numbers of orexinergic cell bodies were determined for the distinc ... | 2011 | 22056958 |
| energetics reveals physiologically distinct castes in a eusocial mammal. | eusociality, which occurs among mammals only in two species of african mole-rat, is characterized by division of labour between morphologically distinct 'castes'. in damaraland mole-rats (cryptomys damarensis), colony labour is divided between 'infrequent worker' and 'frequent worker' castes. frequent workers are active year-round and together perform more than 95% of the total work of the colony, whereas infrequent workers typically perform less than 5% of the total work. anecdotal evidence sug ... | 2006 | 16598257 |
| colony structure and parentage in wild colonies of co-operatively breeding damaraland mole-rats suggest incest avoidance alone may not maintain reproductive skew. | colonies of co-operatively breeding african mole-rats have traditionally been thought to be composed of a single breeding female, one or two breeding males, and their offspring. in the naked mole-rat (heterocephalus glaber), the occurrence of facultative inbreeding means incest avoidance cannot prevent reproduction in subordinate group members, and physiological suppression of reproductive function by the breeding female occurs in both sexes. in contrast, previous studies of captive colonies of ... | 2004 | 15245409 |
| a neuroanatomical and neuroendocrinological study into the relationship between social status and the gnrh system in cooperatively breeding female damaraland mole-rats, cryptomys damarensis. | the gonadotrophin-releasing hormone (gnrh) system in female damaraland mole-rats, cryptomys damarensis, has been investigated to map the distribution of gnrh-immunoreactive (gnrh-ir) structures in the brain of this species and to assess whether changes in this system may mediate the inhibitory effect of social cues on fertility. the distribution of gnrh-ir cell bodies and fibres was similar to that of other mammals, forming a loose continuum along a septo-preoptico-infundibular pathway. gnrh-ir ... | 2004 | 15056766 |
| circadian rhythms of locomotor activity in solitary and social species of african mole-rats (family: bathyergidae). | mole-rats are strictly subterranean and hardly, if ever, come into contact with external light. as a result, their classical visual system is severely regressed and the circadian system proportionally expanded. the family bathyergidae presents a unique opportunity to study the circadian system in the absence of the classical visual system in a range of species. daily patterns of activity were studied in the laboratory under constant temperature but variable lighting regimes in individually house ... | 2003 | 14667149 |
| eusociality in african mole-rats: new insights from patterns of genetic relatedness in the damaraland mole-rat (cryptomys damarensis). | after the discovery of eusociality in the naked mole-rat, it was proposed that inbreeding and high colony relatedness in this species were the major underlying factors driving cooperative breeding in african molerats. by contrast, field and laboratory studies of the eusocial damaraland mole-rat (cryptomys damarensis) have raised the possibility that this species is an obligate outbreeder, although the build-up of inbreeding over several generations could still occur. using microsatellite markers ... | 2002 | 12028759 |
| social suppression in nonreproductive female damaraland mole-rats, cryptomys damarensis: no apparent role for endogenous opioid peptides. | the role of endogenous opioid peptides (eops) on lh secretion was examined to investigate the neuronal mechanisms responsible for the inhibition of gnrh and the resultant infertility in nonreproductive female damaraland mole-rats, cryptomys damarensis. the endorphin antagonist naloxone was administered to five groups of females to determine its effect on plasma lh levels: grouping was determined by social status, social environment, and whether the females were ovariectomized. a single injection ... | 2002 | 11855897 |
| workforce effects and the evolution of complex sociality in wild damaraland mole rats. | explaining the evolution of eusocial and cooperatively breeding societies demands that we understand the effects of workforce size on the reproductive success of breeders. this challenge has yet to be addressed in the family that arguably exhibits the most extreme outcomes of vertebrate social evolution, the african mole rats (bathyergidae), leaving the ultimate causes of their many unusual adaptations open to debate. here we report-using a 14-year field study of wild damaraland mole rats, fukom ... | 2015 | 26655158 |
| a complete mitochondrial genome of the damaraland mole rat fukomys damarensis retrieved from the published genome of the brandt's bat myotis brandtii. | we reported the complete mitochondrial genome of the damaraland mole rat fukomys damarensis which was retrieved from the published genome of the brandt's bat myotis brandtii. the mitogenome of f. damarensis is 16 868 bp in length with a base composition of 33.81% a, 30.79% t, 22.20% c, and 13.20% g, and contains 22 trna, two rrna, 13 protein-coding genes, and a non-coding control region. the sequence of f. damarensis was verified by a phylogenetic analysis. our study suggests a caution when util ... | 2016 | 26370231 |
| ectoparasite burdens of the damaraland mole-rat (fukomys damarensis) from southern africa. | damaraland mole-rats (fukomys damarensis) of the family bathyergidae are widely distributed subterranean rodents in sub-saharan africa. no parasites have ever been reported for this species and only 1 ectoparasite is described for the entire genus. in the current study ectoparasites were collected from individuals captured at 3 localities in south africa and namibia to document the ectoparasite community of f. damarensis, investigate their aggregation patterns, and evaluate the influence of seas ... | 2015 | 26249137 |
| reproductive suppression in female damaraland mole-rats cryptomys damarensis: dominant control or self-restraint? | colonies of damaraland mole-rats cryptomys damarensis exhibit a high reproductive skew. typically one female breeds and the others are anovulatory. two models, the dominant control model (dcm) and the self-restraint model (srm), have been proposed to account for this reproductive suppression. the dcm proposes that suppression is under the control of the dominant breeder and is imposed by mechanisms such as aggression, pheromones and interference with copulation, whereas the srm does not involve ... | 2001 | 11370962 |
| anovulation in non-reproductive female damaraland mole-rats (cryptomys damarensis). | within colonies of damaraland mole-rats (cryptomys damarensis), anovulation in non-reproductive females is thought to play an important role in maintaining reproductive skew. pituitary sensitivity and ovarian structure were examined in three groups of females that differed with respect to their social environment and breeding status to determine whether anovulation is due to inhibitory social cues or is merely the result of a lack of copulatory stimulation. the contribution of gonadal steroid ne ... | 2000 | 10864811 |
| inbreeding avoidance and reproductive skew in a cooperative mammal. | in animal social groups, socially subordinate individuals frequently show low reproductive success or completely fail to breed. this suppression of subordinate reproduction is currently typically attributed to control by dominant individuals. however, subordinates in cooperative groups often lack access to unrelated mates, and an alternative possibility is that their reproduction is limited by inbreeding avoidance. using the eusocial damaraland mole-rat cryptomys damarensis, this paper provides ... | 2000 | 10819150 |
| ecological constraints drive social evolution in the african mole-rats. | the african mole-rats (family bathyergidae) are subterranean hystricomorph rodents occurring in a variety of habitats and displaying levels of sociality which range from solitary to eusocial, making them a unique mammalian taxonomic group to test ecological influences on sociality. here, we use an extensive dna-based phylogeny and comparative analysis to investigate the relationship between ecology, sociality and evolution within the family. mitochondrial cytochrome-b and 12s rrna trees reveal t ... | 1997 | 9404025 |
| lh responses to single doses of exogenous gnrh by freshly captured damaraland mole-rats, cryptomys damarensis. | pituitary function in reproductive and nonreproductive colony members of damaraland mole-rats, cryptomys damarensis, was investigated by measuring the lh responses to single doses of 2 micrograms exogenous gnrh and physiological saline in 29 females and 37 males (31 of these animals from two entire colonies). in females, basal lh concentrations were significantly greater in reproductive (n = 9) than in nonreproductive animals (n = 11): 7.6 +/- 1.0 versus 4.3 +/- 0.6 miu ml-1, respectively (p < 0 ... | 1993 | 8283457 |
| fibre utilization by kalahari dwelling subterranean damara mole-rats (cryptomys damarensis) when fed their natural diet of gemsbok cucumber tubers (acanthosicyos naudinianus). | kalahari dwelling damara mole-rats (cryptomys damarensis) naturally feed on a high fibre diet of underground gemsbok cucumber tubers, acanthosicyos naudinianus. we investigated the degree of fibre utilization and fermentation on this diet by measuring caecal characteristics (namely temperature, ph and weight) and in vitro rates of gas and short chain fatty acid (scfa) production in these underground dwelling hind-gut fermentors. rectal temperatures (33.8 +/- 0.6 degrees c) were consistently high ... | 1994 | 7956122 |
| vitamin d metabolism in the damara mole-rat is altered by exposure to sunlight yet mineral metabolism is unaffected. | vitamin d may be endogenously synthesized in the skin in the presence of sunlight or, alternatively, acquired from dietary sources. cryptomys damarensis appear to have a naturally impoverished vitamin d status with low plasma concentrations of both 25-hydroxyvitamin d (25(oh)d; < 5 ng/ml) and 1,25-dihydroxyvitamin d (1,25(oh)2d; < 20 pg/ml). we attribute this to their underground habitat and herbivorous habits. we questioned whether these subterranean mammals could utilize sunlight-mediated path ... | 1994 | 7829999 |
| the effect of dietary calcium content and oral vitamin d3 supplementation on mineral homeostasis in a subterranean mole-rat cryptomys damarensis. | the damara mole-rat, cryptomys damarensis, has no access to obvious dietary or endogenous sources of vitamin d. we tested the hypotheses that mineral metabolism in these animals is independent of vitamin d status but rather is affected by dietary calcium (ca) content. furthermore, we questioned whether bone and teeth assist in plasma mineral homeostasis. mole-rats increased ca intake when dietary ca content increased; however, mode of gastrointestinal uptake, vitamin d metabolite and plasma ca c ... | 1994 | 7711522 |
| intestinal calcium transport in mole-rats (cryptomys damarensis and heterocephalus glaber) is independent of both genomic and non-genomic vitamin d mediation. | the role of vitamin d in mineral uptake in the gastrointestinal tract (git) of mole-rats (heterocephalus glaber and cryptomys damarensis; family bathyergidae), animals with a naturally impoverished vitamin d status, was investigated. we measured relative rates of passage of radioactive markers, mode of calcium (ca) uptake, paracellular movement and the opening of voltage-sensitive ca channels (vsccs) along the git with and without oral vitamin d3 supplementation. the ratio of relative absorption ... | 1995 | 7576599 |
| effect of oral cholecalciferol supplementation at physiological and supraphysiological doses in naturally vitamin d3-deficient subterranean damara mole rats (cryptomys damarensis). | the damara mole rat, cryptomys damarensis, is a strictly subterranean dwelling herbivorous rodent that in its natural habitat has no access to any obvious source of cholecalciferol (d3). we examined the effects of d3 supplementation, at physiological and supraphysiological doses, on calcium metabolism, plasma concentrations of calcium and alkaline phosphatase (alp) and d3 metabolites. animals not receiving a d3 supplement maintained normal plasma calcium concentrations. in addition, they exhibit ... | 1991 | 1660517 |
| is vitamin d3 essential for mineral metabolism in the damara mole-rat (cryptomys damarensis)? | the damara mole-rat (cryptomys damarensis) leads a strictly subterranean existence in an extensive maze of plugged burrows and eats a strictly herbivorous diet. an obvious source of vitamin d3 (d3), an important hormone in mineral homeostasis, therefore is lacking in this mammal. the effects of orally ingested d3 on mineral balance were investigated. in the normal d' status group of mole-rats, the apparent fractional intestinal absorption of calcium (91.1%), magnesium (91.2%), and inorganic phos ... | 1991 | 1647351 |
| altered cochlear innervation in developing and mature naked and damaraland mole rats. | compared to many other rodent species, naked mole rats (heterocephalus glaber) have elevated auditory thresholds, poor frequency selectivity, and limited ability to localize sound. because the cochlea is responsible for encoding and relaying auditory signals to the brain, we used immunofluorescence and quantitative image analysis to examine cochlear innervation in mature and developing naked mole rats compared to mice (mus musculus), gerbils (meriones unguiculatus), and damaraland mole rats (fuk ... | 2019 | 30861124 |
| Body temperature patterns and rhythmicity in free-ranging subterranean Damaraland mole-rats, Fukomys damarensis. | Body temperature (T(b)) is an important physiological component that affects endotherms from the cellular to whole organism level, but measurements of T(b) in the field have been noticeably skewed towards heterothermic species and seasonal comparisons are largely lacking. Thus, we investigated patterns of T(b) patterns in a homeothermic, free-ranging small mammal, the Damaraland mole-rat (Fukomys damarensis) during both the summer and winter. Variation in T(b) was significantly greater during wi ... | 2011 | 22028861 |
| Teasing apart socially-induced infertility in non-reproductive female Damaraland mole-rats, Fukomys damarensis (Rodentia: Bathyergidae). | The Damaraland mole-rat is a subterranean mammal exhibiting extreme reproductive skew with a single reproductive female in each colony responsible for procreation. Non-reproductive female colony members are physiologically suppressed while in the colony, exhibiting reduced concentrations of plasma luteinizing hormone (LH) and a decreased response of the pituitary, as measured by the release of bioactive LH, to an exogenous dose of gonadotrophin releasing hormone (GnRH). Removal of the reproducti ... | 2011 | 22182323 |
| morphological divergence of breeders and helpers in wild damaraland mole-rat societies. | the specialization of body shape to an individual's role within society represents a pinnacle of social evolution. although commonplace among social insects, divergence in the body shapes of breeders and helpers has to date been documented in just one social vertebrate, the naked mole-rat, heterocephalus glaber; an extraordinary species in which large colony size and frequent inbreeding may have favored the evolution of such specialization. here, we present new evidence of morphological divergen ... | 2010 | 20561049 |
| physiological suppression eases in damaraland mole-rat societies when ecological constraints on dispersal are relaxed. | in many vertebrate societies, subordinate females exhibit down-regulated reproductive physiologies relative to those of dominants, a condition commonly termed physiological suppression. research into the causes of physiological suppression has focused principally on the role of the subordinate's social environment (typically the presence of the dominant female and/or an absence of unrelated males within the group), while few studies have considered the additional role that the physical environme ... | 2010 | 19900456 |
| spatial learning and memory in african mole-rats: the role of sociality and sex. | spatial learning and memory is an important skill for the survival and fitness and may vary between the sexes depending on differences in space use. this is particularly true for animals that explore the subterranean niche as it is associated with high travelling costs. in subterranean rodents the complexity of burrow systems varies with differing degrees of sociality possibly posing stronger selective pressures regarding spatial abilities on species with more complex burrow structures. this cou ... | 2009 | 18824187 |
| parentage analysis of ansell's mole-rat family groups indicates a high reproductive skew despite relatively relaxed ecological constraints on dispersal. | to better understand evolutionary pathways leading to eusociality, interspecific comparisons are needed, which would use a common axis, such as that of reproductive skew, to array species. african mole-rats (bathyergidae, rodentia) provide an outstanding model of social evolution because of a wide range of social organizations within a single family; however, their reproductive skew is difficult to estimate, due to their cryptic lifestyle. a maximum skew could theoretically be reached in groups ... | 2013 | 23992451 |
| reproductive status and testosterone among females in cooperative mole-rat societies. | sexual selection acts on traits that increase reproductive success. variation in reproductive success is often higher among males than females. consequently, sexual selection has been studied extensively in males while its possible role in females has only recently attracted considerable attention. in some cooperatively breeding species females compete intensely for reproductive opportunities and may thereby have evolved 'male-like' traits such as increased intra-sexual aggression and exaggerate ... | 2013 | 23583770 |
| do dispersing non-reproductive female damaraland mole-rats, cryptomys damarensis (rodentia: bathyergidae) exhibit spontaneous or induced ovulation? | the damaraland mole-rat is a eusocial, subterranean rodent that exhibits a seasonal breeding. non-reproductive females show physiological suppression of reproduction whilst in the confines of the natal colony. this study set out to investigate whether dispersing female damaraland mole-rats exhibit induced or spontaneous ovulation. fifteen non-reproductive females were removed from their natal colonies and housed individually for a period of 6 weeks. during this period urine was collected from al ... | 2006 | 16209879 |
| plasticity and constraints on social evolution in african mole-rats: ultimate and proximate factors. | here, we review comparative studies of african mole-rats (family bathyergidae) to explain how constraints acting at the ultimate (environmental) and proximate (organismal) levels have led to convergent gains and losses of sociality within this extensive adaptive radiation of subterranean rodents endemic to sub-saharan africa. at the ultimate level, living in environments that range from mesic through to arid has led to both variation and flexibility in social organization among species, culminat ... | 2013 | 23569295 |
| specific paucity of unmyelinated c-fibers in cutaneous peripheral nerves of the african naked-mole rat: comparative analysis using six species of bathyergidae. | in mammalian peripheral nerves, unmyelinated c-fibers usually outnumber myelinated a-fibers. by using transmission electron microscopy, we recently showed that the saphenous nerve of the naked mole-rat (heterocephalus glaber) has a c-fiber deficit manifested as a substantially lower c:a-fiber ratio compared with other mammals. here we determined the uniqueness of this c-fiber deficit by performing a quantitative anatomical analysis of several peripheral nerves in five further members of the bath ... | 2012 | 22528859 |
| gnrh mrna expression in the brain of cooperatively breeding female damaraland mole-rats. | the damaraland mole-rat (fukomys damarensis) is a eusocial, subterranean rodent, in which breeding is limited to a single reproductive pair within each colony. non-reproductive females, while in the confines of the colony, exhibit socially induced infertility. anovulation is thought to be caused by a disruption in the normal gonadotropin-releasing hormone (gnrh) secretion from the hypothalamus. to assess whether social suppression is associated with altered gnrh mrna expression in the brain, we ... | 2017 | 28104824 |
| differences in cooperative behavior among damaraland mole rats are consequences of an age-related polyethism. | in many cooperative breeders, the contributions of helpers to cooperative activities change with age, resulting in age-related polyethisms. in contrast, some studies of social mole rats (including naked mole rats, heterocephalus glaber, and damaraland mole rats, fukomys damarensis) suggest that individual differences in cooperative behavior are the result of divergent developmental pathways, leading to discrete and permanent functional categories of helpers that resemble the caste systems found ... | 2016 | 27588902 |
| naked but not hairless: the pitfalls of analyses of molecular adaptation based on few genome sequence comparisons. | the naked mole-rat (heterocephalus glaber) is the only rodent species that naturally lacks fur. genome sequencing of this atypical rodent species recently shed light on a number of its morphological and physiological adaptations. more specifically, its hairless phenotype has been traced back to a single amino acid change (c397w) in the hair growth associated (hr) protein (or hairless). by considering the available species diversity, we show that this specific position is in fact variable across ... | 2015 | 25714745 |
| adaptations to a subterranean environment and longevity revealed by the analysis of mole rat genomes. | subterranean mammals spend their lives in dark, unventilated environments that are rich in carbon dioxide and ammonia and low in oxygen. many of these animals are also long-lived and exhibit reduced aging-associated diseases, such as neurodegenerative disorders and cancer. we sequenced the genome of the damaraland mole rat (dmr, fukomys damarensis) and improved the genome assembly of the naked mole rat (nmr, heterocephalus glaber). comparative genome analyses, along with the transcriptomes of re ... | 2014 | 25176646 |
| reproduction is associated with a tissue-dependent reduction of oxidative stress in eusocial female damaraland mole-rats (fukomys damarensis). | oxidative stress has been implicated as both a physiological cost of reproduction and a driving force on an animal's lifespan. since increased reproductive effort is generally linked with a reduction in survival, it has been proposed that oxidative stress may influence this relationship. support for this hypothesis is inconsistent, but this may, in part, be due to the type of tissues that have been analyzed. in damaraland mole-rats the sole reproducing female in the colony is also the longest li ... | 2014 | 25068591 |
| breeding status and social environment differentially affect the expression of sex steroid receptor and aromatase mrna in the brain of female damaraland mole-rats. | the damaraland mole-rat (fukomys damarensis) is a eusocial, subterranean mammal, which exhibits an extreme reproductive skew with a single female (queen) monopolizing reproduction in each colony. non-reproductive females in the presence of the queen are physiologically suppressed to the extent that they are anovulatory. this blockade is thought to be caused by a disruption in the normal gonadotropin-releasing hormone (gnrh) secretion from the hypothalamus. in order to understand the underlying p ... | 2014 | 24839456 |
| social cues elicit sexual behavior in subordinate damaraland mole-rats independent of gonadal status. | damaraland mole-rats (fukomys damarensis) are among a small number of eusocial mammals. eusociality is a social system where only a few individuals within a colony engage in direct reproduction, while remaining subordinate members are non-breeders and support reproductive efforts of breeding individuals. inbreeding avoidance precludes mating between subordinate siblings and between offspring and parents. interestingly, non-breeders readily attempt to mate with unrelated opposite-sex individuals. ... | 2014 | 24246377 |
| reproductive suppression in subordinate, non-breeding female damaraland mole-rats: two components to a lifetime of socially induced infertility. | the damaraland mole-rat cryptomys damarensis exhibits an extreme reproductive division of labour. reproduction in the colony is restricted to a single breeding pair, resulting from a two-fold control: (i) a reduced pituitary synthesis and/or secretion of luteinizing hormone leading to a block to ovulation in non-reproductive females; and (ii) a strong inhibition to breeding with familiar kin. circulating basal concentrations of luteinizing hormone as well as luteinizing hormone levels measured i ... | 1996 | 8952096 |
| intra-sexual selection in cooperative mammals and birds: why are females not bigger and better armed? | in cooperatively breeding mammals and birds, intra-sexual reproductive competition among females may often render variance in reproductive success higher among females than males, leading to the prediction that intra-sexual selection in such species may have yielded the differential exaggeration of competitive traits among females. however, evidence to date suggests that female-biased reproductive variance in such species is rarely accompanied by female-biased sexual dimorphisms. we illustrate t ... | 2013 | 24167305 |
| thermoregulatory differences in african mole-rat species from disparate habitats: responses and limitations. | individuals and populations possess physiological adaptations to survive local environmental conditions. to occur in different regions where ambient temperature varies, animals must adopt appropriate thermoregulatory mechanisms. failure to adjust to environmental challenges may result in species distributional range shifts or decreased viability. african mole-rats (bathyergidae) occupy various habitats in sub-saharan africa from deserts to montane regions to mesic coastal areas. we examined ther ... | 2020 | 32125983 |
| is the mole rat vomeronasal organ functional? | the colonial naked mole rat heterocephalus glaber is a subterranean, eusocial rodent. the h. glaber vomeronasal organ neuroepithelium (vne) displays little postnatal growth. however, the vne remains neuronal in contrast to some mammals that possess nonfunctional vomeronasal organ remnants, for example, catarrhine primates and some bats. here, we describe the vomeronasal organ (vno) microanatomy in the naked mole rat and we make preliminary observations to determine if h. glaber shares its minima ... | 2020 | 30614661 |
| growth affects dispersal success in social mole-rats, but not the duration of philopatry. | in naked mole-rats (heterocephalus glaber), some non-breeding males show faster growth and are more likely to disperse than others. these differences have been suggested to be the result of a specialized developmental strategy leading to shorter philopatry and independent breeding, as opposed to extended philopatry as non-reproductive helpers. however, it is unclear whether fast-growing males disperse sooner than slow-growing males. an alternative explanation is that variation in quality between ... | 2018 | 29467175 |
| no task specialization among helpers in damaraland mole-rats. | the specialization of individuals in specific behavioural tasks is often attributed either to irreversible differences in development, which generate functionally divergent cooperative phenotypes, or to age-related changes in the relative frequency with which individuals perform different cooperative activities; both of which are common in many insect caste systems. however, contrasts in cooperative behaviour can take other forms and, to date, few studies of cooperative behaviour in vertebrates ... | 2018 | 30245525 |
| breeders are less active foragers than non-breeders in wild damaraland mole-rats. | eusocial societies are characterized by a clear division of labour between non-breeding workers and breeding queens, and queens often do not contribute to foraging, defence and other maintenance tasks. it has been suggested that the structure and organization of social mole-rat groups resembles that of eusocial insect societies. however, the division of labour has rarely been investigated in wild mole-rats, and it is unknown whether breeders show decreased foraging activity compared with non-bre ... | 2020 | 33023382 |
| oxidative costs of cooperation in cooperatively breeding damaraland mole-rats. | within cooperatively breeding societies, individuals adjust cooperative contributions to maximize indirect fitness and minimize direct fitness costs. yet, little is known about the physiological costs of cooperation, which may be detrimental to direct fitness. oxidative stress, the imbalance between reactive oxygen species (by-products of energy production) and antioxidant protection, may represent such a cost when cooperative behaviours are energetically demanding. oxidative stress can lead to ... | 2020 | 32900314 |
| ovulation mitigates fatty liver associated with reproductive suppression and oxidative stress in damaraland mole-rats (fukomys damarensis). | oxidative damage is often linked to reproduction; however, reproducing female damaraland mole-rats (fukomys damarensis) exhibit a reduction in oxidative damage relative to their non-reproductive, anovulatory, cohorts. specifically, liver concentrations of malondialdehyde, a biomarker for lipid peroxidation, are significantly lower in reproducing females. we examined liver histology in reproductive, anovulatory and recently ovulating non-reproductive females, demonstrating an accumulation of lipi ... | 2020 | 32586422 |
| food availability and foraging by wild colonies of damaraland mole-rats (cryptomys damarensis): implications for sociality. | we investigated some of the ecological determinants of sociality in the damaraland mole-rat, including the spatial distribution and biomass of resources (geophytes) available to foraging damaraland mole-rats in partly vegetated sand dunes in the kalahari and in grasslands near dordabis, namibia, and the foraging behaviour and residency characteristics of colonies at dordabis. in both study areas, the geophytes had a clumped distribution, but the highest coefficients of dispersion and mean biomas ... | 1998 | 28308209 |
| the metabolism of social subterranean rodents: adaptation to aridity. | the social damara mole-rat cryptomys damarensis (124 g), has a mean (±sd) resting metabolic rate of 0.57±0.09 cm(3) o2 g(-1) h(-1), within a thermoneutral zone of 27-31° c. this rate of metabolism is 43% lower than that predicted by the curve for rodents, and 29% lower than that predicted by the subterranean rodent curve. these data support the hypothesis that the resting metabolic rates of social and solitary subterranean rodents are lower than those of solitary species inhabiting mesic habitat ... | 1986 | 28311614 |
| reproductive status-dependent kisspeptin and rfamide-related peptide (rfrp) gene expression in female damaraland mole-rats. | damaraland mole rats (fukomys damarensis) are cooperatively breeding, subterranean mammals, which exhibit high reproductive skew. reproduction is monopolized by the dominant female of the group while subordinates are physiologically suppressed to the extent that they are anovulatory. it is thought that in these latter animals normal gnrh secretion from the hypothalamus is disrupted. the rfamide peptides kisspeptin (kiss1) and rfamid-related peptide-3 (rfrp-3) are considered potent regulators of ... | 2018 | 29345030 |
| genome-wide adaptive evolution to underground stresses in subterranean mammals: hypoxia adaption, immunity promotion, and sensory specialization. | life underground has provided remarkable examples of adaptive evolution in subterranean mammals; however, genome-wide adaptive evolution to underground stresses still needs further research. there are approximately 250 species of subterranean mammals across three suborders and six families. these species not only inhabit hypoxic and dark burrows but also exhibit evolved adaptation to hypoxia, cancer resistance, and specialized sensory systems, making them an excellent model of evolution. the ada ... | 2020 | 32760535 |
| evidence for contrasting roles for prolactin in eusocial naked mole-rats, heterocephalus glaber and damaraland mole-rats, fukomys damarensis. | elevated prolactin (prl) has been associated with the expression of social and cooperative behaviours in a number of vertebrate species, as well as suppression of reproduction. as social mole-rats exhibit both of these traits, prl is a prime candidate in mediating their social phenotype. while naked and damaraland mole-rats (nmrs and dmrs) have evolved eusociality independently within their family, both species exhibit an extreme skew in lifetime reproductive success, with breeding restricted to ... | 2018 | 29794008 |
| the hypoxia tolerance of eight related african mole-rat species rivals that of naked mole-rats, despite divergent ventilatory and metabolic strategies in severe hypoxia. | burrowing mammals tend to be more hypoxia tolerant than non-burrowing mammals and rely less on increases in ventilation and more on decreases in metabolic rate to tolerate hypoxia. naked mole-rats (heterocephalus glaber, nmrs), eusocial mammals that live in large colonies, are among the most hypoxia-tolerant mammals, and rely almost solely on decreases in metabolism with little change in ventilation during hypoxia. we hypothesized that the remarkable hypoxia tolerance of nmrs is an evolutionaril ... | 2020 | 31885213 |
| exploratory behaviour, memory and neurogenesis in the social damaraland mole-rat (fukomys damarensis). | both exploratory behaviour and spatial memory are important for survival in dispersing animals. exploratory behaviour is triggered by novel environments and having a better spatial memory of the surroundings provides an adaptive advantage to the animals. spatial challenges can also affect neurogenesis in the hippocampus by increasing cell proliferation and enhancing survival of young neurons. in social damaraland mole-rat colonies, the social hierarchy is largely based on body size. individuals ... | 2020 | 32532860 |
| reproductive status-dependent dynorphin and neurokinin b gene expression in female damaraland mole-rats. | damaraland mole rats (fukomys damarensis) are cooperatively breeding, subterranean mammals, which exhibit high reproductive skew. reproduction is monopolized by the dominant female of the group, while subordinates are physiologically suppressed. the blockade of reproduction results from an inhibition of ovulation, which is caused by inadequate secretion of luteinizing hormone (lh) from the pituitary, which in turn might be brought about by a disruption of the normal gnrh secretion from the hypot ... | 2019 | 31669432 |
| fossorial damaraland mole rats do not exhibit a blunted hypercapnic ventilatory response. | damaraland mole rats (dmrs, fukomys damarensis) are a eusocial fossorial species that spend the majority of their life in densely populated underground burrows, in which they likely experience intermittent periods of elevated co2 (i.e. hypercapnia). the primary physiological response to hypercapnia in most mammals is to increase depth and rate of breathing (i.e. hyperpnoea), but this response is often blunted in species that inhabit hypercapnic environments. in their natural habitat, dmrs putati ... | 2019 | 30862308 |
| reproductive status affects the expression of prolactin receptor mrna in the brain of female damaraland mole-rats. | the eusocial damaraland mole-rat (fukomys damarensis) represents an extreme example of reproductive skew, in that reproduction is completely blocked in female subordinate group members. it is thought that in these animals normal gnrh secretion from the hypothalamus is disrupted. prolactin, a peptide hormone secreted from the anterior pituitary gland, has been implicated in a wide variety of functions. well documented in rodents is its role in mediating lactational infertility. elevated circulati ... | 2018 | 30118754 |
| reproduction triggers adaptive increases in body size in female mole-rats. | in social mole-rats, breeding females are larger and more elongated than non-breeding female helpers. this status-related morphological divergence is thought to arise from modifications of skeletal growth following the death or removal of the previous breeder and the transition of their successors from a non-breeding to a breeding role. however, it is not clear what changes in growth are involved, whether they are stimulated by the relaxation of reproductive suppression or by changes in breeding ... | 2018 | 29875307 |
| non-invasive assessment of glucocorticoid and androgen metabolite levels in cooperatively breeding damaraland mole-rats (fukomys damarensis). | dominant females of cooperative breeding species often use aggression to suppress reproduction of subordinate females, resulting in subordinates experiencing stress-related increases in glucocorticoid levels, which may cause reproductive down-regulation. this would suggest a general pattern with higher glucocorticoid levels in subordinate compared to dominant individuals; however, the opposite was found in a number of cooperatively breeding species. furthermore, breeding females of the cooperati ... | 2018 | 29782838 |
| allo-parental care in damaraland mole-rats is female biased and age dependent, though independent of testosterone levels. | in damaraland mole-rats (fukomys damarensis), non-breeding subordinates contribute to the care of offspring born to the breeding pair in their group by carrying and retrieving young to the nest. in social mole-rats and some cooperative breeders, dominant females show unusually high testosterone levels and it has been suggested that high testosterone levels may increase reproductive and aggressive behavior and reduce investment in allo-parental and parental care, generating age and state-dependen ... | 2018 | 29730030 |