scholarly journals Male reproductive suppression in the cooperatively breeding fish Neolamprologus pulcher

2005 ◽  
Vol 17 (1) ◽  
pp. 25-33 ◽  
Author(s):  
J.L. Fitzpatrick ◽  
J.K. Desjardins ◽  
K.A. Stiver ◽  
R. Montgomerie ◽  
S. Balshine
Keyword(s):  
Reproductive Suppression ◽  
Neolamprologus Pulcher ◽  
Cooperatively Breeding

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.

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.

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 Pregnancy is detected via odour in a wild cooperative breeder

2017 ◽  
Vol 13 (11) ◽  
pp. 20170441 ◽  
Author(s):  
J. Mitchell ◽  
M. A. Cant ◽  
H. J. Nichols
Keyword(s):  
Scent Marking ◽  
Alloparental Care ◽  
Scent Mark ◽  
Reproductive State ◽  
Reproductive Suppression ◽  
Pregnant Females ◽  
Direct Demonstration ◽  
Cooperatively Breeding ◽  
Banded Mongoose ◽  
Mungos Mungo

Among mammals, scent has long been known to encode oestrus; however, in many species, detecting pregnancy may also be important in terms of both competition and mate-choice. Here, we show, through odour presentation experiments, that pregnancy is discernible via scent by both sexes in the cooperatively breeding banded mongoose, Mungos mungo . Males spent more time investigating and were more likely to scent mark the odours of non-pregnant females, compared to pregnant females. Females showed increased levels of scent marking when odours were of the same reproductive state as themselves. These results present the first direct demonstration that pregnancy is detectable via scent in wild cooperative breeders. Detecting pregnancy may be particularly important in cooperative breeders as, in addition to the competition between males for receptive mates, there is also intense competition between females for access to alloparental care. Consequently, dominant females benefit from targeting reproductive suppression towards subordinates that represent direct threats, such as pregnant females.

scholarly journals Stress hormones and sociality: integrating social and environmental stressors

2007 ◽  
Vol 274 (1612) ◽  
pp. 967-975 ◽  
Author(s):  
Dustin R Rubenstein
Keyword(s):  
Environmental Factors ◽  
Social Interactions ◽  
Social Factors ◽  
Stress Hormones ◽  
Environmental Stressors ◽  
Reproductive Decisions ◽  
Reproductive Suppression ◽  
Cooperatively Breeding ◽  
Maximal Stress ◽  
Plural Breeding

In cooperatively breeding species, reproductive decisions and breeding roles may be influenced by environmental (food resources) or social factors (reproductive suppression of subordinates by dominants). Studies of glucocorticoid stress hormones in cooperatively breeding species suggest that breeding roles and hormone levels are related to the relative costs of dominance and subordination, which are driven primarily by social interactions. Few studies, however, have considered how environmental factors affect glucocorticoid levels and breeding roles in cooperative breeders, even though environmental stressors modulate seasonal glucocorticoid release and often influence breeding roles. I examined baseline and stress-induced levels of the glucocorticoid corticosterone (CORT) across 4 years in the plural breeding superb starling, Lamprotornis superbus , to determine whether (i) environmental factors (namely rainfall) directly influence breeding roles or (ii) environmental factors influence social interactions, which in turn drive breeding roles. Chronic baseline and maximal stress-induced CORT changed significantly across years as a function of pre-breeding rainfall, but dominant and subordinate individuals responded differently. Pre-breeding rainfall was also correlated directly with breeding roles. The results are most consistent with the hypothesis that environmental conditions influenced the relative costs of dominance and subordination, which in turn affected the degree and intensity of social interactions and ultimately reproductive decisions and breeding roles.

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

2021 ◽  
Vol 12 ◽  
Author(s):  
Paul Juan Jacobs ◽  
Daniel William Hart ◽  
Tobias Suess ◽  
Andries Koch Janse van Vuuren ◽  
Nigel Charles Bennett
Keyword(s):  
Oxidative Stress ◽  
Seasonal Variation ◽  
Cost Of Reproduction ◽  
Dry Season ◽  
Breeding Period ◽  
Wet Season ◽  
Reproductive Suppression ◽  
Mole Rat ◽  
Cooperatively Breeding ◽  
The Cost

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.

scholarly journals Simulating more realistic predation threat using attack playbacks

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8149
Author(s):  
Mukta Watve ◽  
Sebastian Prati ◽  
Barbara Taborsky
Keyword(s):  
Chemical Cues ◽  
Induced Responses ◽  
Neolamprologus Pulcher ◽  
Predation Threat ◽  
Predator Cues ◽  
Experimental Animals ◽  
Cooperatively Breeding ◽  
Visual Predator ◽  
Predator Odour ◽  
Predator Behaviour

Use of virtual proxies of live animals are rapidly gaining ground in studies of animal behaviour. Such proxies help to reduce the number of live experimental animals needed to stimulate the behaviour of experimental individuals and to increase standardisation. However, using too simplistic proxies may fail to induce a desired effect and/or lead to quick habituation. For instance, in a predation context, prey often employ multimodal cues to detect predators or use specific aspects of predator behaviour to assess threat. In a live interaction, predator and prey often show behaviours directed towards each other, which are absent in virtual proxies. Here we compared the effectiveness of chemical and visual predator cues in the cooperatively breeding cichlid Neolamprologus pulcher, a species in which predation pressure has been the evolutionary driver of its sociality. We created playbacks of predators simulating an attack and tested their effectiveness in comparison to a playback showing regular activity and to a live predator. We further compared the effectiveness of predator odour and conspecific skin extracts on behaviours directed towards a predator playback. Regular playbacks of calmly swimming predators were less effective than live predators in stimulating a focal individual’s aggression and attention. However, playbacks mimicking an attacking predator induced responses much like a live predator. Chemical cues did not affect predator directed behaviour.

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