The Cost of Reproduction in a Cooperatively Breeding Mammal: Consequences of Seasonal Variation in Rainfall, Reproduction, and Reproductive Suppression

Biological investments, such as reproduction, are influenced by both biotic and abiotic factors and their interactions. The trade-off between reproduction and survival has been well established. Seasonally breeding species, therefore, may exhibit variations in these trade-offs, but there is a dearth of knowledge concerning this. This study investigated the physiological cost of reproduction (measured through oxidative stress) across seasons in the cooperatively breeding highveld mole-rat (Cryptomys hottentotus pretoriae), one of the few seasonal breeding mole-rats. Oxidative stress indicates elevated reactive oxygen species (ROS) levels, which can overwhelm antioxidant defences resulting in damaged proteins, lipids and DNA, which overall can reduce longevity and compromise reproduction. Oxidative markers such as total oxidant status (TOS-measure of total peroxides present), total antioxidant capacity (TAC), oxidative stress index (OSI), and malondialdehyde (MDA) are utilised to measure oxidative stress. In this study, breeding and non-breeding male (NBM) and female mole-rats were captured during the dry season (breeding period) and wet season (non-breeding period). There was an apparent cost of reproduction in the highveld mole-rat; however, the seasonality pattern to the cost of reproduction varied between the sexes. Breeding females (BFs) had significantly higher MDA during the breeding period/dry season in comparison to the non-breeding period/wet season; this is possibly a consequence of bearing and nursing offspring. Contrastingly, breeding males (BMs) showed increased oxidative damage in the non-breeding/wet season compared to the breeding/dry season, possibly due to increased activities of protecting their mating rights for the next breeding/dry season, but this was not significant. Interestingly, during the non-breeding period/wet season, non-breeding females (NBFs) are released from their reproductive suppression, which resulted in increases in TOS and OSI, which again indicated that just the mere ability to be able to breed results in a cost (oxidative stress). Therefore we can speculate that highveld mole-rats exhibited seasonal variation in redox balance brought about by variation in abiotic variables (e.g., rainfall), physiology and behaviour. We conclude that physiological changes associated with reproduction are sufficient to induce significant acute oxidative stress in the plasma of female highveld mole-rats, which become alleviated following transition to the non-breeding season/wet period suggesting a possible hormetic effect.

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

Canadian Journal of Zoology ◽

10.1139/cjz-2020-0158 ◽

2021 ◽

Vol 99 (9) ◽

pp. 801-811 ◽

Cited By ~ 1

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.

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The cost of reproduction in women: Reproductive effort and oxidative stress in premenopausal and postmenopausal American women

American Journal of Human Biology ◽

10.1002/ajhb.23069 ◽

2017 ◽

Vol 30 (1) ◽

pp. e23069 ◽

Cited By ~ 7

Author(s):

Anna Ziomkiewicz ◽

Amara Frumkin ◽

Yawei Zhang ◽

Amelia Sancilio ◽

Richard G. Bribiescas

Keyword(s):

Oxidative Stress ◽

Reproductive Effort ◽

Cost Of Reproduction ◽

American Women ◽

The Cost ◽

And Oxidative Stress

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Evidence for the Cost of Reproduction in Humans: High Lifetime Reproductive Effort Is Associated with Greater Oxidative Stress in Post-Menopausal Women

PLoS ONE ◽

10.1371/journal.pone.0145753 ◽

2016 ◽

Vol 11 (1) ◽

pp. e0145753 ◽

Cited By ~ 35

Author(s):

Anna Ziomkiewicz ◽

Amelia Sancilio ◽

Andrzej Galbarczyk ◽

Magdalena Klimek ◽

Grazyna Jasienska ◽

...

Keyword(s):

Oxidative Stress ◽

Reproductive Effort ◽

Cost Of Reproduction ◽

Menopausal Women ◽

Post Menopausal ◽

The Cost

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Seasonal variation in quality of Louhajong river water, Tangail

Bangladesh Journal of Scientific Research ◽

10.3329/bjsr.v28i1.26239 ◽

2016 ◽

Vol 28 (1) ◽

pp. 9-16

Author(s):

Md Rakib Hasan Sarker ◽

Asadul Islam ◽

Ariful Islam ◽

Md Mahbubul Hoque ◽

Shimul Roy

Keyword(s):

Seasonal Variation ◽

River Water ◽

Water Samples ◽

Dry Season ◽

Fish Culture ◽

Chemical Parameters ◽

Wet Season ◽

Physico Chemical ◽

Standard Level

Water samples were collected from three points of Louhajong river (Dighulia, Kagmari Bridge and Oloa) to see the seasonal variation in physico-chemical parameters. The results revealed that some of the parameters such as TDS, alkalinity and acidity have exceeded the standard level in dry season in all of the points, which are unsuitable for different purposes including fish culture. During dry and wet seasons the highest concentrations of BOD was recorded as 2.0 and 0.8 ppm at Kagmari Bridge (point-2) respectively. DO ranged from 1.4 to 3.1 and 2.4 to 3.8 ppm during dry and wet seasons. Maximum and minimum EC was recorded as 890 and 130 ?s/cm at Dighulia (point-1) during dry and wet seasons. The results suggest that at wet season Louhajong river may be suitable for fish culture and other purposes.Bangladesh J. Sci. Res. 28(1): 9-16, June-2015

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THE EFFECT OF SEASONAL VARIATION ON PERFORMANCE OF EGG TYPE POULTRY: A Case Study of Mitchell Farms, Mosogar, Delta State, Nigeria

Nigerian Journal of Animal Production ◽

10.51791/njap.v24i2.2306 ◽

2021 ◽

Vol 24 (2) ◽

pp. 101-105

Author(s):

E. E. Guobadia

Keyword(s):

Seasonal Variation ◽

Feed Intake ◽

Egg Production ◽

Management Practices ◽

Secondary Data ◽

Dry Season ◽

Wet Season ◽

Egg Hatchability ◽

Significant Difference

The study was designed to find out the effect of seasonal variation on poultry in Delta State of Nigeria. The variables considered were mortality rate, feed intake, egg production and egg hatchability in the wet and dry seasons of the year. Secondary data were also collected from records kept in the farm. Sites 4AHI-BLK,5AKI-BLK, 9H/BF and 10H/BF were used for the study with each having an average of 2,500-3,500 birds of the same breed and sex aged 1-9 weeks and 21-52weeks. The records were grouped into dry season (October-March) and wet season (April-September) covering three years, 1991-1994. The analysis of the result showed that seasonal variation does not have any significant effect (P < 0.05) on mortality and feed intake in the two seasons. However percentage egg production and egg hatchability revealed a significant difference (P < 0.05) between the two seasons, with a mean % egg production and hatchability of 74±.03 and 80.6 in the wet season and 53.67±0.01 and 55.9 respectively in the dry season. Recommendation is therefore made for proper planning which ensures the utilization of wet and dry season management practices to reduce the effect of high humidity and embient temperature on production.

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Seasonal variation in foraging behaviour of plains zebra (Equus quagga) may alter contact with the anthrax bacterium (Bacillus anthracis)

Canadian Journal of Zoology ◽

10.1139/cjz-2013-0186 ◽

2014 ◽

Vol 92 (4) ◽

pp. 331-337 ◽

Cited By ~ 12

Author(s):

Zepee Havarua ◽

Wendy C. Turner ◽

John K.E. Mfune

Keyword(s):

Seasonal Variation ◽

Bacillus Anthracis ◽

Foraging Behaviour ◽

Dry Season ◽

Wet Season ◽

Contact Rates ◽

Bacterium Bacillus ◽

Environmental Pathogens ◽

Host Foraging ◽

Plains Zebra

Pathogens transmitted via the environment are often aggregated in space, and seasonal variation in wildlife foraging behaviour may alter contact rates with environmental pathogens. The soil-borne bacterium Bacillus anthracis Cohn, 1872 causes anthrax, and herbivores acquire gastrointestinal anthrax by ingesting spores. Therefore host foraging behaviour could be a fundamental component of anthrax epidemiology. This study investigated seasonal changes in bite density and diet of plains zebras (Equus quagga Boddaert, 1785) in relation to anthrax seasonality in Etosha National Park, Namibia, where most zebra anthrax cases are observed in wet seasons. The diet of zebras shifted from more short grasses during the wet season to more tall grasses in the dry season, suggesting a greater potential for soil ingestion in wet seasons. Zebras also foraged most intensively in the wet season with the number of bites/step declining through the dry season. This higher bite density in wet seasons may lead individuals to ingest greater concentrations of the pathogen if foraging in a localized infectious area. Although sex and reproductive state affected bite density, no sex difference in anthrax occurrence was observed. This study demonstrates how considering variation in host foraging behaviour may enhance our understanding of disease seasonality for pathogens with foraging-dependent transmission.

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Seasonal Variation and Ecological Risk Assessment of Heavy Metal in an Estuarine Mangrove Wetland

Water ◽

10.3390/w13152064 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2064

Author(s):

Hualong Hong ◽

Binghuang Zhang ◽

Haoliang Lu

Keyword(s):

Risk Assessment ◽

Seasonal Variation ◽

Metal Pollution ◽

Toxic Metal ◽

Dry Season ◽

Wet Season ◽

Mangrove Wetland ◽

Mangrove Wetlands ◽

Zn And Cu In ◽

Potential Toxic Metals

Potential toxic metal pollution in mangroves has attracted extensive attention globally; however, the seasonal variation of potential toxic metals in mangrove wetlands is still poorly understood. Herein, we investigated the variation of content as well as chemical speciation of typical metals (Pb, Cr, Zn and Cu) in the sediments from the Zhangjiang Estuary mangrove wetland, China. The potential risk of metal contamination was also investigated. Compared to the wet season, we found that sediment metal content was higher in the dry season. Mangrove sites show accumulated significant metals than does the mudflat both in wet and dry seasons. Geo-accumulation (Igeo) shows moderate pollution, probably because of the dilution as result of runoff and tidal hydrodynamics in the wet season. Increased concentrations of all metals in the acid-soluble fraction and decreased metal contents in the residue fraction were found in the dry season. Risk assessment indicated that the concentrations of Pb poses a higher environmental risk in the dry season. These results can increase awareness of metal pollution in the dry season and provide information for potential toxic metal management in mangrove wetlands.

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Ecogeography of group size suggests differences in drivers of sociality among cooperatively breeding fairywrens

10.32942/osf.io/729be ◽

2022 ◽

Author(s):

Allison E. Johnson ◽

Joseph F. Welklin ◽

Ian R. Hoppe ◽

Daizaburo Shizuka

Keyword(s):

Social Systems ◽

Group Living ◽

Cost Of Reproduction ◽

Harsh Environments ◽

Costs And Benefits ◽

Resource Defense ◽

Social Variation ◽

Cooperatively Breeding ◽

The Cost ◽

Insight Into

Cooperatively breeding species exhibit a range of social behaviors associated with different costs and benefits to group-living, often in association with different environmental conditions. For example, species in which collective-care of offspring reduces the cost of reproduction are more common in harsh environments (true cooperative breeding), while species that collectively defend resources are present in benign environments (family-living). Here, we examine whether environment also shapes sociality within cooperatively-breeding species. We illustrate that Purple-backed Fairywrens, which primarily gain intrinsic, or collective-care benefits, have larger groups in hot, dry environments and smaller groups in cool, wet environments, whereas Superb Fairywrens which primarily gain extrinsic, or resource defense benefits, exhibit the opposite trend. We suggest differences in the costs and benefits of sociality contribute to these opposing ecogeographic patterns, demonstrating that comparisons of intraspecific patterns of social variation across species can provide insight into how ecology shapes transitions between social systems.

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Manakins (Pipridae) in Second-Growth and Old-Growth Forests: Patterns of Habitat Use, Movement, and Survival

The Auk ◽

10.1093/auk/119.1.132 ◽

2002 ◽

Vol 119 (1) ◽

pp. 132-148 ◽

Cited By ~ 6

Author(s):

John G. Blake ◽

Bette A. Loiselle

Keyword(s):

Seasonal Variation ◽

Habitat Use ◽

Survival Rates ◽

Dry Season ◽

Wet Season ◽

Old Growth ◽

Old Growth Forest ◽

Second Growth ◽

Old Growth Forests ◽

Capture Rates

AbstractWe used capture and recapture data (1985 to 1994) to examine seasonal variation in habitat use, movements within and among habitats, and survival rates of manakins (Manacus candei, Corapipo altera, Pipra mentalis, P. pipra) in northeastern Costa Rica. Manakins were captured in young and old second-growth woodlands in the lowlands and in old-growth forest at approximately 50, 500, and 1,000 m. Manakin species differed in their use of habitats, with old-growth forest species showing large and predictable seasonal variation in capture rates. Corapipo capture rates in lowland (nonbreeding) habitats were greater during the wet season than during the dry season and were greater in old-growth forest than in second growth. Capture rates at 500 m were higher in the dry season. Pipra mentalis capture rates were high in second growth and old growth. Capture rates were higher in the wet season and were correlated with capture rates of Corapipo, indicating that at least some individual P. mentalis migrate along the elevational gradient. P. pipra capture rates were highest at 1,000 m; few individuals descended to lowlands in the wet season. Manacus capture rates were highest in young second growth and did not vary between wet and dry seasons. Use of second-growth habitats by species typically associated with old-growth forests illustrates the value of maintaining a mosaic of habitats to accommodate seasonal changes in use of habitats. Contrary to expectations based on lek mating systems, there was little evidence that movements within habitats (i.e. recapture distances) varied between sexes. Yet, recapture percentages were higher in all species for adult females than males. Adult survival rates were ∼0.75 for Manacus in young second growth, 0.62 for Corapipo in old-growth forest at 50 m and 0.66 at 500 m, and 0.70 for Pipra mentalis in lowland old-growth forest. Results support the suggestion that geographic variation in survival rates may be common in the tropics and illustrate the need for examining survival rates separately by age and sex.

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

Canadian Journal of Zoology ◽

10.1139/cjz-2019-0112 ◽

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.

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