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Grenfell KL, Jacobs PJ, Bennett NC, Hart DW. The role of ambient temperature and light as cues in the control of circadian rhythms of Damaraland mole-rat. Chronobiol Int 2024; 41:356-368. [PMID: 38444071 DOI: 10.1080/07420528.2024.2325649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 02/27/2024] [Indexed: 03/07/2024]
Abstract
Light is considered the primary entrainer for mammalian biological rhythms, including locomotor activity (LA). However, mammals experience different environmental and light conditions, which include those predominantly devoid of light stimuli, such as those experienced in subterranean environments. In this study, we investigated what environmental cue (light or ambient temperature (Ta)) is the strongest modulator of circadian rhythms, by using LA as a proxy, in mammals that experience a lifestyle devoid of light stimuli. To address this question, this study exposed a subterranean African mole-rat species, the Damaraland mole-rat (Fukomys damarensis), to six light and Ta cycles in different combinations. Contrary to previous literature, when provided with a reliable light cue, Damaraland mole rats exhibited nocturnal, diurnal, or arrhythmic LA patterns under constant Ta. While under constant darkness and a 24-hour Ta cycle mimicking the burrow environment, all mole-rats were most active during the coolest 12-hour period. This finding suggests that in a subterranean environment, which receives no reliable photic cue, the limited heat dissipation and energy constraints during digging activity experienced by Damaraland mole-rats make Ta a reliable and consistent "time-keeping" variable. More so, when providing a reliable light cue (12 light: 12 dark) to Damaraland mole-rats under a 24-hour Ta cycle, this study presents the first evidence that cycles of Ta affect the LA rhythm of a subterranean mammal more strongly than cycles of light and darkness. Once again, Damaraland mole-rats were more active during the coolest 12-hour period regardless of whether this fell during the light or dark phase. However, conclusive differentiation of entrainment to Ta from that of masking was not achieved in this study, and as such, we have recommended future research avenues to do so.
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Affiliation(s)
- Kerryn L Grenfell
- Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Paul J Jacobs
- Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Nigel C Bennett
- Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Daniel W Hart
- Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
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2
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Perioral secretions enable complex social signaling in African mole-rats (genus Fukomys). Sci Rep 2022; 12:22366. [PMID: 36572727 PMCID: PMC9792591 DOI: 10.1038/s41598-022-26351-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 12/13/2022] [Indexed: 12/28/2022] Open
Abstract
Subterranean common mole-rats of the genus Fukomys (family Bathyergidae) live in large, cooperatively-breeding families. Odor cues have been hypothesized to play an important role in mediating social behaviors in the underground ecotope, but only little is known about the role of olfactory signaling in burrowing mammals. Here we characterize the so far neglected perioral glands of Fukomys and other African mole-rats as an important source of olfactory social information. Histology demonstrates these structures to be derived sebaceous glands that are developed regardless of sex and reproductive status. However, gland activity is higher in Fukomys males, leading to sexually dimorphic patterns of stain and clotting of the facial pelage. Behavioral assays revealed that conspecifics prefer male but not female perioral swabs over scent samples from the back fur and that male sebum causes similar attraction as anogenital scent, a known source of social information in Fukomys. Finally, we assessed volatile compounds in the perioral sebum of the giant mole-rat (Fukomys mechowii) via GCxGC-MS-based metabolomic profiling. Volatiles display pronounced sex-specific signatures but also allow to differentiate between intrasexual reproductive status groups. These different lines of evidence suggest that mole-rat perioral glands provide complex odor signals which play a crucial role in social communication.
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3
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Vavrušková Z, Okrouhlík J, Šumbera R. Together or alone? Huddling energetic savings in three social mole-rat species of genus Fukomys. A dispersal perspective. J Therm Biol 2022; 110:103385. [DOI: 10.1016/j.jtherbio.2022.103385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/11/2022] [Accepted: 10/26/2022] [Indexed: 11/06/2022]
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4
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Dammann P, Šaffa G, Šumbera R. Longevity of a solitary mole-rat species and its implications for the assumed link between sociality and longevity in African mole-rats (Bathyergidae). Biol Lett 2022; 18:20220243. [PMID: 36416033 PMCID: PMC9682431 DOI: 10.1098/rsbl.2022.0243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 10/26/2022] [Indexed: 08/27/2023] Open
Abstract
Sociality and cooperative breeding are associated with enhanced longevity in insects and birds, but whether this is also true for mammals is still subject to debate. African mole-rats (Bathyergidae) have recently been claimed to be the only mammalian family in which such an association may exist because cooperatively breeding bathyergids seem to be substantially longer lived than solitary bathyergids. However, although ample longevity data are available for several social bathyergids, almost nothing is known about mortality distribution and lifespan in solitary bathyergids. Here we present robust long-term data on the longevity of a solitary African mole-rat, the silvery mole-rat Heliophobius argenteocinereus. Our findings show that this species is much longer-lived than previously believed. Nonetheless, our comparative analysis suggests that sociality has indeed a positive effect on longevity in this family. We argue that the extreme longevity seen particularly in social bathyergids is probably caused by a combination of subterranean lifestyle and cooperative breeding.
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Affiliation(s)
- P. Dammann
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Germany
- Central Animal Laboratory, Faculty of Medicine, University of Duisburg-Essen, Germany
| | - G. Šaffa
- Faculty of Science, University of Southern Bohemia, České Budějovice, Czech Republic
| | - R. Šumbera
- Faculty of Science, University of Southern Bohemia, České Budějovice, Czech Republic
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5
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Zöttl M, Bensch HM, Finn KT, Hart DW, Thorley J, Bennett NC, Braude S. Capture Order Across Social Bathyergids Indicates Similarities in Division of Labour and Spatial Organisation. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.877221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The social mole-rats of the family Bathyergidae show elaborate social organisation that may include division of labour between breeders and non-breeders as well as across non-breeders within their groups. However, comparative behavioural data across the taxa are rare and contrasts and similarities between species are poorly understood. Field studies of social bathyergids usually involve capturing all group members until the entire group is captured. Because each animal is only captured once and traps are typically placed in close proximity to active foraging areas, the order in which animals are captured provides an indication of the foraging activity of different individuals and of the spatial organisation of the group within the burrow system. Here, we compare the association of capture order with breeding status, sex, and body mass in four species and subspecies of social bathyergids, which vary in group size and represent all three social genera within the family Bathyergidae. We show that in naked and Damaraland mole-rats (Heterocephalus glaber and Fukomys damarensis), male and female breeders are captured later than non-breeders, whereas in two different subspecies of the genus Cryptomys only female breeders are captured later than non-breeders. The effect sizes vary largely and are 10 times larger in naked mole-rats as compared to Fukomys and 3–4 times larger than in Cryptomys. Among non-breeders, sex effects are notably absent in all species and body mass predicted capture order in both naked and Damaraland mole-rats. In naked mole-rats, larger non-breeders were captured earlier than smaller ones, whereas in Damaraland mole-rats intermediate-sized non-breeders were captured first. Our data suggest that there are similarities in behavioural structure and spatial organisation across all social bathyergid species, though the most pronounced differences within groups are found in naked mole-rats.
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Finn KT, Thorley J, Bensch HM, Zöttl M. Subterranean Life-Style Does Not Limit Long Distance Dispersal in African Mole-Rats. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.879014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Dispersal from the natal site to breeding sites is a crucial phase in the life history of animals and can have profound effects on the reproductive ecology and the structure of animal societies. However, few studies have assessed dispersal dynamics in subterranean mammals and it is unknown whether dispersal distances are constrained by living underground. Here we show, in social, subterranean Damaraland mole-rats (Fukomys damarensis), that a subterranean lifestyle does not preclude long distance dispersal and that both sexes are capable of successfully dispersing long distances (>4 km). Body condition did not predict dispersal distance, but dispersers from larger groups traveled farther than individuals from smaller groups. Subsequently we show in a phylogenetically controlled comparative analysis of dispersal distances in subterranean and surface-dwelling rodents that living underground does not constrain dispersal distances and that dispersal capacity is mainly a consequence of body size in both lifestyles.
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Begall S, Bottermann L, Caspar KR. Self-Domestication Underground? Testing for Social and Morphological Correlates of Animal Personality in Cooperatively-Breeding Ansell’s Mole-Rats (Fukomys anselli). Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.862082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Ansell’s mole-rats (Fukomys anselli) are sexually dimorphic subterranean rodents that live in families consisting of a single breeding pair and their late-dispersing non-breeding offspring. Most individuals exhibit a conspicuous white head patch, which results from integumental depigmentation. Alongside other morphological, physiological, and social characteristics, skin depigmentation in these social rodents mirrors traits that presumably evolved as byproducts from selection against aggression in domestic animals, making them a potential candidate species for a self-domesticated wild mammal. Here we explored whether the expression of the white head patch, sexual dimorphism, and reproductive division of labor are reflected by different personalities in Ansell’s mole-rats. We tested locomotory activity and risk-taking as well as aggression and affiliative behavior in 51 individuals originating from nine captive families in various experimental set-ups. In line with the concept of animal personality, we recovered consistent individual responses over time. While sex had no influence on any tested variable, reproductive status was found to affect risk-taking behavior but not other personality dimensions. Discriminant function analysis revealed that family members clustered more closely together than expected by chance, suggesting that group affiliation rather than sex or social status determines behavioral profiles in this species. Finally, we failed to recover any consistent correlation between head patch expression and behavior, which conflicts with predictions of the self-domestication hypothesis. We argue that many domestication-like traits in Ansell’s mole-rat and its congeners evolved in the framework of subterranean adaptation and call for a cautious application of the self-domestication concept to wild mammals.
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Lutermann H. Socializing in an Infectious World: The Role of Parasites in Social Evolution of a Unique Rodent Family. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.879031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Transmission of parasites between hosts is facilitated by close contact of hosts. Consequently, parasites have been proposed as an important constraint to the evolution of sociality accounting for its rarity. Despite the presumed costs associated with parasitism, the majority of species of African mole-rats (Family: Bathyergidae) are social. In fact, only the extremes of sociality (i.e., solitary and singular breeding) are represented in this subterranean rodent family. But how did bathyergids overcome the costs of parasitism? Parasite burden is a function of the exposure and susceptibility of a host to parasites. In this review I explore how living in sealed burrow systems and the group defenses that can be employed by closely related group members can effectively reduce the exposure and susceptibility of social bathyergids to parasites. Evidence suggests that this can be achieved largely by investment in relatively cheap and flexible behavioral rather than physiological defense mechanisms. This also shifts the selection pressure for parasites on successful transmission between group members rather than transmission between groups. In turn, this constrains the evolution of virulence and favors socially transmitted parasites (e.g., mites and lice) further reducing the costs of parasitism for social Bathyergidae. I conclude by highlighting directions for future research to evaluate the mechanisms proposed and to consider parasites as facilitators of social evolution not only in this rodent family but also other singular breeders.
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Oosthuizen MK, Bennett NC. Clocks Ticking in the Dark: A Review of Biological Rhythms in Subterranean African Mole-Rats. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.878533] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Biological rhythms are rhythmic fluctuations of biological functions that occur in almost all organisms and on several time scales. These rhythms are generated endogenously and entail the coordination of physiological and behavioural processes to predictable, external environmental rhythms. The light-dark cycle is usually the most prominent environmental cue to which animals synchronise their rhythms. Biological rhythms are believed to provide an adaptive advantage to organisms. In the present review, we will examine the occurrence of circadian and seasonal rhythms in African mole-rats (family Bathyergidae). African mole-rats are strictly subterranean, they very rarely emerge aboveground and therefore, do not have regular access to environmental light. A key adaptation to their specialised habitat is a reduction in the visual system. Mole-rats exhibit both daily and seasonal rhythmicity in a range of behaviours and physiological variables, albeit to different degrees and with large variability. We review previous research on the entire circadian system of African mole-rats and discuss output rhythms in detail. Laboratory experiments imply that light remains the strongest zeitgeber for entrainment but in the absence of light, animals can entrain to ambient temperature rhythms. Field studies report that rhythmic daily and seasonal behaviour is displayed in their natural habitat. We suggest that ambient temperature and rainfall play an important role in the timing of rhythmic behaviour in mole-rats, and that they likely respond directly to these zeitgebers in the field rather than exhibit robust endogenous rhythms. In the light of climate change, these subterranean animals are buffered from the direct and immediate effects of changes in temperature and rainfall, partly because they do not have robust circadian rhythms, however, on a longer term they are vulnerable to changes in their food sources and dispersal abilities.
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Finn KT, Janse van Vuuren AK, Hart DW, Süess T, Zöttl M, Bennett NC. Seasonal Changes in Locomotor Activity Patterns of Wild Social Natal Mole-Rats (Cryptomys hottentotus natalensis). Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.819393] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Differences in individual locomotor activity patterns may be linked to a number of ecological factors, such as changes in ambient temperature or photoperiod. Observations on subterranean mammals suggest that they exhibit diel rhythms despite the lack of visual cues in their underground burrows, but it is unknown how seasonality and individual characteristics affect their activity. In this study we use RFID technology to monitor daily activity patterns of wild, social Natal mole-rats (Cryptomys hottentotus natalensis) during the summer and winter to investigate how their activity varies with season and whether their activity depends on individual characteristics such as body mass, sex and reproductive status. We found that in winter, individuals were more active during the time with the highest soil temperatures, whereas in summer, they showed a bimodal activity pattern during early morning and late afternoon coinciding with cooler soil temperatures. Individual characteristics, including reproductive status, did not affect general activity indicating that reproductive and non-reproductive individuals contribute equally to cooperative behaviors. We suggest that the activity patterns may be a behavioral adaptation to avoid extreme burrow temperatures and a mechanism to maintain a stable core body temperature. We highlight the advantages of RFID technology to study wild small mammal movements.
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11
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Mynhardt S, Harris-Barnes L, Bloomer P, Bennett NC. Spatial population genetic structure and colony dynamics in Damaraland mole-rats (Fukomys damarensis) from the southern Kalahari. BMC Ecol Evol 2021; 21:221. [PMID: 34879824 PMCID: PMC8653584 DOI: 10.1186/s12862-021-01950-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Accepted: 11/26/2021] [Indexed: 11/25/2022] Open
Abstract
Background Non-random associations within and among groups of social animals can provide valuable insight into the function of group living and the evolution of social behaviour. Damaraland mole-rats (Fukomys damarensis) demonstrate extremely high levels of reproductive skew, and dispersal is considered to be male-biased in onset and frequency, although asymmetry in dispersal distance is yet to be investigated. Dispersal may be positively correlated with increasing favourable environmental conditions, such as rainfall, however, the effects of ecological constraints on dispersal and colony fission–fusion dynamics have not previously been demonstrated on a spatial scale. Here we provide the first spatial population genetic study for this species. We investigated genetic structure in a population of Damaraland mole-rats from the southern Kalahari in South Africa over 3 years, combining observational dispersal data from mark-recapture with population genetic data to evaluate (1) sex-bias in frequency and distance of dispersal in this species, and (2) the effect of rainfall on fission–fusion dynamics of colonies. Results Our results demonstrate (1) that both males and females favour local dispersal but on rare occasions may disperse over distances greater than 400 m, (2) that males may disperse over greater distances than females, and (3) that males more frequently immigrate into established neighbouring colonies than females, who predominantly disperse by colony fission, i.e. multiple individuals “budding” from their native colony into a neighbouring territory, thereby establishing new colonies. Furthermore, our results demonstrate (4) elevated dispersal and colony fission in association with increased rainfall, supporting the hypothesis that rainfall may play a significant role in the maintenance and/or disruption of reproductive skew in Damaraland mole-rat populations. Conclusion This study represents the first fine-scale spatial population genetic study in Damaraland mole-rats, and provides relevant insights into colony fission–fusion dynamics in a social and cooperatively breeding species. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-021-01950-2.
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Affiliation(s)
- Samantha Mynhardt
- Molecular Ecology and Evolution Programme, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa. .,Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa.
| | - Lorraine Harris-Barnes
- Molecular Ecology and Evolution Programme, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Paulette Bloomer
- Molecular Ecology and Evolution Programme, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa.,Mammal Research Institute (MRI), University of Pretoria, Pretoria, South Africa
| | - Nigel C Bennett
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa.,Mammal Research Institute (MRI), University of Pretoria, Pretoria, South Africa
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Soil hardness of burrows related to the usage frequencies of the lesser Japanese mole, Mogera imaizumii (Talpidae). RUSSIAN JOURNAL OF THERIOLOGY 2021. [DOI: 10.15298/rusjtheriol.20.2.02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Luna F, Okrouhlík J, McKechnie AE, Bennett NC, Šumbera R. Non‐shivering thermogenesis in four species of African mole‐rats differing in their sociality. J Zool (1987) 2021. [DOI: 10.1111/jzo.12892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- F. Luna
- Laboratorio de Ecología Fisiológica y del Comportamiento Instituto de Investigaciones Marinas y Costeras (IIMyC) CONICET‐UNMdP Mar del Plata Argentina
| | - J. Okrouhlík
- Department of Zoology Faculty of Science University of South Bohemia České Budějovice Czech Republic
- Department of Zoology and Entomology Mammal Research Institute University of Pretoria Pretoria South Africa
| | - A. E. McKechnie
- Department of Zoology and Entomology Mammal Research Institute University of Pretoria Pretoria South Africa
- South African Research Chair in Conservation Physiology South African National Biodiversity Institute Pretoria South Africa
| | - N. C. Bennett
- Department of Zoology and Entomology Mammal Research Institute University of Pretoria Pretoria South Africa
| | - R. Šumbera
- Department of Zoology Faculty of Science University of South Bohemia České Budějovice Czech Republic
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Vejmělka F, Okrouhlík J, Lövy M, Šaffa G, Nevo E, Bennett NC, Šumbera R. Heat dissipation in subterranean rodents: the role of body region and social organisation. Sci Rep 2021; 11:2029. [PMID: 33479351 PMCID: PMC7820455 DOI: 10.1038/s41598-021-81404-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 12/30/2020] [Indexed: 01/29/2023] Open
Abstract
The relatively warm and very humid environment of burrows presents a challenge for thermoregulation of its mammalian inhabitants. It was found that African mole-rats dissipate body heat mainly through their venter, and social mole-rats dissipate more body heat compared to solitary species at lower temperatures. In addition, the pattern of the ventral surface temperature was suggested to be homogeneous in social mole-rats compared to a heterogeneous pattern in solitary mole-rats. To investigate this for subterranean rodents generally, we measured the surface temperatures of seven species with different degrees of sociality, phylogeny, and climate using infrared thermography. In all species, heat dissipation occurred mainly through the venter and the feet. Whereas the feet dissipated body heat at higher ambient temperatures and conserved it at lower ambient temperatures, the ventral surface temperature was relatively high in all temperatures indicating that heat dissipation to the environment through this body region is regulated mainly by behavioural means. Solitary species dissipated less heat through their dorsum than social species, and a tendency for this pattern was observed for the venter. The pattern of heterogeneity of surface temperature through the venter was not related to sociality of the various species. Our results demonstrate a general pattern of body heat exchange through the three studied body regions in subterranean rodents. Besides, isolated individuals of social species are less able to defend themselves against low ambient temperatures, which may handicap them if staying alone for a longer period, such as during and after dispersal events.
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Affiliation(s)
- František Vejmělka
- Department of Zoology, Faculty of Science, University of South Bohemia, 370 05, České Budějovice, Czech Republic
| | - Jan Okrouhlík
- Department of Zoology, Faculty of Science, University of South Bohemia, 370 05, České Budějovice, Czech Republic
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Pretoria, 0002, South Africa
| | - Matěj Lövy
- Department of Zoology, Faculty of Science, University of South Bohemia, 370 05, České Budějovice, Czech Republic
| | - Gabriel Šaffa
- Department of Zoology, Faculty of Science, University of South Bohemia, 370 05, České Budějovice, Czech Republic
| | - Eviatar Nevo
- Institute of Evolution, University of Haifa, 3498838, Haifa, Israel
| | - Nigel Charles Bennett
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Pretoria, 0002, South Africa
| | - Radim Šumbera
- Department of Zoology, Faculty of Science, University of South Bohemia, 370 05, České Budějovice, Czech Republic.
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15
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Okrouhlík J, Šumbera R, Gardner B, Schoemann K, Lövy M, Bennett NC. Are southern African solitary mole-rats homeothermic or heterothermic under natural field conditions? J Therm Biol 2020; 95:102810. [PMID: 33454040 DOI: 10.1016/j.jtherbio.2020.102810] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 12/08/2020] [Accepted: 12/12/2020] [Indexed: 10/22/2022]
Abstract
Abandoning of a stable body temperature (Tb), a phenomenon known as heterothermy, is an adaptation to cope mainly with a lack of food and water, especially in species inhabiting daily or seasonally variable environments. There is increasing evidence that African mammals avoid adverse conditions by heterothermy and eventually by entering torpor. Members of subterranean rodent family, the African mole-rats (Bathyergidae), are suitable candidates to study both phenomena, because of the diversity of their strategies in respect of maintaining stable Tb ranging from homeothermic species to a mammal with the most labile Tb, the naked mole-rat. Currently, there are field data on daily and seasonal Tb in one social species only and such information are lacking for any solitary mole-rat. In our study, we recorded yearly Tb in two solitary bathyergids, the Cape mole-rat Georychus capensis and the Cape dune mole-rat Bathyergus suillus from South Africa using intraperitoneally implanted dataloggers. Since this region is characterised by changing ecological characteristics, we expected either decreases of Tb within 24 h indicating daily torpor and/or longer-term decreases of Tb, which would indicate multiday torpor. Although we found seasonally phase shifted low amplitude daily Tb cycles, we did not find any remarkable and regular daily and/or seasonal Tb deviations, likely showing an absence of torpor in both species. Due to absence of this energy saving mechanism, we may speculate that both species could be vulnerable to ongoing global climatic change.
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Affiliation(s)
- Jan Okrouhlík
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa; Department of Zoology, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic
| | - Radim Šumbera
- Department of Zoology, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic.
| | - Brett Gardner
- Werribee Open Range Zoo, Veterinary Hospital, Zoos Victoria, K Road, Werribee, Victoria, 3029, Australia
| | - Keegan Schoemann
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Matěj Lövy
- Department of Zoology, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic
| | - Nigel Charles Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
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16
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Montoya-Sanhueza G, Bennett NC, Oosthuizen MK, Dengler-Crish CM, Chinsamy A. Long bone histomorphogenesis of the naked mole-rat: Histodiversity and intraspecific variation. J Anat 2020; 238:1259-1283. [PMID: 33305850 DOI: 10.1111/joa.13381] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023] Open
Abstract
Lacking fur, living in eusocial colonies and having the longest lifespan of any rodent, makes naked mole-rats (NMRs) rather peculiar mammals. Although they exhibit a high degree of polymorphism, skeletal plasticity and are considered a novel model to assess the effects of delayed puberty on the skeletal system, scarce information on their morphogenesis exists. Here, we examined a large ontogenetic sample (n = 76) of subordinate individuals to assess the pattern of bone growth and bone microstructure of fore- and hindlimb bones by using histomorphological techniques. Over 290 undecalcified thin cross-sections from the midshaft of the humerus, ulna, femur, and tibia from pups, juveniles and adults were analyzed with polarized light microscopy. Similar to other fossorial mammals, NMRs exhibited a systematic cortical thickening of their long bones, which clearly indicates a conserved functional adaptation to withstand the mechanical strains imposed during digging, regardless of their chisel-tooth predominance. We describe a high histodiversity of bone matrices and the formation of secondary osteons in NMRs. The bones of pups are extremely thin-walled and grow by periosteal bone formation coupled with considerable expansion of the medullary cavity, a process probably tightly regulated and adapted to optimize the amount of minerals destined for skeletal development, to thus allow the female breeder to produce a higher number of pups, as well as several litters. Subsequent cortical thickening in juveniles involves high amounts of endosteal bone apposition, which contrasts with the bone modeling of other mammals where a periosteal predominance exists. Adults have bone matrices predominantly consisting of parallel-fibered bone and lamellar bone, which indicate intermediate to slow rates of osteogenesis, as well as the development of poorly vascularized lamellar-zonal tissues separated by lines of arrested growth (LAGs) and annuli. These features reflect the low metabolism, low body temperature and slow growth rates reported for this species, as well as indicate a cyclical pattern of osteogenesis. The presence of LAGs in captive individuals was striking and indicates that postnatal osteogenesis and its consequent cortical stratification most likely represents a plesiomorphic thermometabolic strategy among endotherms which has been suggested to be regulated by endogenous rhythms. However, the generalized presence of LAGs in this and other subterranean taxa in the wild, as well as recent investigations on variability of environmental conditions in burrow systems, supports the hypothesis that underground environments experience seasonal fluctuations that may influence the postnatal osteogenesis of animals by limiting the extension of burrow systems during the unfavorable dry seasons and therefore the finding of food resources. Additionally, the intraspecific variation found in the formation of bone tissue matrices and vascularization suggested a high degree of developmental plasticity in NMRs, which may help explaining the polymorphism reported for this species. The results obtained here represent a valuable contribution to understanding the relationship of several aspects involved in the morphogenesis of the skeletal system of a mammal with extraordinary adaptations.
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Affiliation(s)
- Germán Montoya-Sanhueza
- Department of Biological Sciences, University of Cape Town, Cape Town, South Africa.,Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Nigel C Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Maria K Oosthuizen
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | | | - Anusuya Chinsamy
- Department of Biological Sciences, University of Cape Town, Cape Town, South Africa
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17
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Francioli Y, Thorley J, Finn K, Clutton-Brock T, Zöttl M. Breeders are less active foragers than non-breeders in wild Damaraland mole-rats. Biol Lett 2020; 16:20200475. [PMID: 33023382 DOI: 10.1098/rsbl.2020.0475] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
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-breeding helpers in natural groups. Here, we show that, in wild Damaraland mole-rats (Fukomys damarensis), breeders show lower activity in foraging areas than non-breeding group members. Both breeders and non-breeders displayed variation in activity across the different seasons. Our results suggest that group living allows social mole-rat breeders to reduce their investment in energetically costly behaviour, or alternatively, that the high cost of reproduction in this species forces a behavioural trade-off against foraging investment.
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Affiliation(s)
- Yannick Francioli
- Ecology and Evolution in Microbial Model Systems, EEMiS, Department of Biology and Environmental Science, Linnaeus University, Kalmar, Sweden
| | - Jack Thorley
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Kyle Finn
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, South Africa
| | - Tim Clutton-Brock
- Department of Zoology, University of Cambridge, Cambridge, UK.,Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, South Africa
| | - Markus Zöttl
- Ecology and Evolution in Microbial Model Systems, EEMiS, Department of Biology and Environmental Science, Linnaeus University, Kalmar, Sweden
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18
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Evaporative water loss in seven species of fossorial rodents: Does effect of degree of fossoriality and sociality exist? J Therm Biol 2020; 89:102564. [DOI: 10.1016/j.jtherbio.2020.102564] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 01/09/2023]
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19
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Rosario Carotenuto A, Guarracino F, Šumbera R, Fraldi M. Burrowing below ground: interaction between soil mechanics and evolution of subterranean mammals. J R Soc Interface 2020; 17:20190521. [PMID: 31910769 DOI: 10.1098/rsif.2019.0521] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The evolution of species is governed by complex phenomena in which biological and environmental features may interact dynamically. Subterranean mammals dig tunnels whose diameter minimizes energetic costs during excavations and display anatomical adaptations in order to burrow structurally stable tunnels according to specific features of the soil. These animals weight from less than 50 g up to 1-2 kg, and dig tunnels with diameters from 3 to 15 cm. The use of allometric laws has enabled these data to be correlated. However, since tunnels need to be stable with respect to the geomechanical characteristics of the resident soils, a mathematical treatment linking the admissible dimensions of tunnels to the environment here suggests a mechanically grounded correlation between the body mass of subterranean mammals and the maximum dimensions of tunnels. Remarkably, such theoretical findings reflect very well the empirical allometric relationship and contribute to explain the wide differences observed in body sizes of subterranean mammals. In this respect, a far from ancillary role of environmental mechanics on the morphological evolution of subterranean mammals can be hypothesized.
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Affiliation(s)
- Angelo Rosario Carotenuto
- Department of Structures for Engineering and Architecture, University of Napoli Federico II, Napoli, Italy
| | - Federico Guarracino
- Department of Structures for Engineering and Architecture, University of Napoli Federico II, Napoli, Italy
| | - Radim Šumbera
- Department of Zoology, Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Massimiliano Fraldi
- Department of Structures for Engineering and Architecture, University of Napoli Federico II, Napoli, Italy
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20
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Šklíba J, Vlasatá T, Lövy M, Hrouzková E, Meheretu Y, Sillero‐Zubiri C, Šumbera R. The giant that makes do with little: small and easy‐to‐leave home ranges found in the giant root‐rat. J Zool (1987) 2019. [DOI: 10.1111/jzo.12729] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- J. Šklíba
- Faculty of Science University of South Bohemia Ceske Budejovice Czech Republic
| | - T. Vlasatá
- Faculty of Science University of South Bohemia Ceske Budejovice Czech Republic
| | - M. Lövy
- Faculty of Science University of South Bohemia Ceske Budejovice Czech Republic
| | - E. Hrouzková
- Faculty of Science University of South Bohemia Ceske Budejovice Czech Republic
| | - Y. Meheretu
- Department of Biology College of Natural and Computational Sciences University of Mekelle Mekelle Ethiopia
| | - C. Sillero‐Zubiri
- Wildlife Conservation Research Unit Zoology Department University of Oxford Oxford UK
- Born Free Foundation Horsham UK
| | - R. Šumbera
- Faculty of Science University of South Bohemia Ceske Budejovice Czech Republic
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21
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Lacey EA, O’Brien SL, Sobrero R, Ebensperger LA. Spatial relationships among free-living cururos (Spalacopus cyanus) demonstrate burrow sharing and communal nesting. J Mammal 2019. [DOI: 10.1093/jmammal/gyz117] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Abstract
Spatial relationships among conspecifics can provide insights into numerous aspects of social behavior. Spatial data may be particularly important for characterizing the behavior of difficult-to-study species such as subterranean rodents, direct observations of which are challenging. To characterize the social organization of the cururo (Spalacopus cyanus), a subterranean species in the rodent family Octodontidae, we used radiotelemetry to quantify spatial relationships within populations of this species located in Parque Nacional Bosque Fray Jorge and Santuario de la Naturaleza Yerba Loca, Chile. Specifically, we sought to determine if adults in this diurnal species share burrows and subterranean nests, the two criteria typically used to identify subterranean rodents as social. Analyses of radio fixes collected during February–March 2003 revealed that cururos at both Fray Jorge and Yerba Loca shared nighttime nest sites; cluster analyses of these data identified multiple spatially distinct subsets of adults in each population. Overlap of minimum convex polygons constructed from radio fixes collected during daylight hours suggested burrow sharing by animals in both populations. Cluster analyses of overlap values revealed the same spatially distinct groups of individuals identified from analyses of nest sharing; in addition, these analyses revealed one cluster of animals in each population that was not evident from analyses of nighttime data. Collectively, these results confirm that cururos are social, with adults in both study populations sharing burrow systems and communal nests. Our findings add to the growing understanding of social organization in octodontid rodents and reveal a new system for comparative studies of the ecology and evolution of behavioral variation in burrow-dwelling mammals.
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Affiliation(s)
- Eileen A Lacey
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, CA, USA
| | - Shannon L O’Brien
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, CA, USA
| | - Raúl Sobrero
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (ICiVet-Litoral), Universidad Nacional del Litoral (UNL)/Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Esperanza, Santa Fe, Argentina
| | - Luis A Ebensperger
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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22
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Voigt C, ter Maat A, Bennett NC. No evidence for multimodal body mass distributions and body mass-related capture order in wild-caught Damaraland mole-rats. Mamm Biol 2019. [DOI: 10.1016/j.mambio.2018.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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23
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Šumbera R. Thermal biology of a strictly subterranean mammalian family, the African mole-rats (Bathyergidae, Rodentia) - a review. J Therm Biol 2019; 79:166-189. [DOI: 10.1016/j.jtherbio.2018.11.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 11/09/2018] [Accepted: 11/09/2018] [Indexed: 12/12/2022]
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24
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van Jaarsveld B, Bennett NC, Hart DW, Oosthuizen MK. Locomotor activity and body temperature rhythms in the Mahali mole-rat (C. h. mahali): The effect of light and ambient temperature variations. J Therm Biol 2019; 79:24-32. [DOI: 10.1016/j.jtherbio.2018.11.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/22/2018] [Accepted: 11/23/2018] [Indexed: 10/27/2022]
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25
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Torrents‐Ticó M, Bennett NC, Jarvis JUM, Zöttl M. Sex differences in timing and context of dispersal in Damaraland mole‐rats (Fukomys damarensis). J Zool (1987) 2018. [DOI: 10.1111/jzo.12602] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. Torrents‐Ticó
- Global Change and Conservation Lab (GCC) Faculty of Biological and Environmental Sciences University of Helsinki Helsinki Finland
- Department of Zoology University of Cambridge Cambridge UK
| | - N. C. Bennett
- Mammal Research Institute Department of Zoology University of Pretoria Pretoria South Africa
| | - J. U. M. Jarvis
- Biological Sciences University of Cape Town Rondebosch South Africa
| | - M. Zöttl
- Department of Zoology University of Cambridge Cambridge UK
- Ecology and Evolution in Microbial Model Systems, EEMiS Department of Biology and Environmental Science Linnaeus University Kalmar Sweden
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26
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Sociality does not drive the evolution of large brains in eusocial African mole-rats. Sci Rep 2018; 8:9203. [PMID: 29907782 PMCID: PMC6003933 DOI: 10.1038/s41598-018-26062-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 05/02/2018] [Indexed: 11/15/2022] Open
Abstract
The social brain hypothesis (SBH) posits that the demands imposed on individuals by living in cohesive social groups exert a selection pressure favouring the evolution of large brains and complex cognitive abilities. Using volumetry and the isotropic fractionator to determine the size of and numbers of neurons in specific brain regions, here we test this hypothesis in African mole-rats (Bathyergidae). These subterranean rodents exhibit a broad spectrum of social complexity, ranging from strictly solitary through to eusocial cooperative breeders, but feature similar ecologies and life history traits. We found no positive association between sociality and neuroanatomical correlates of information-processing capacity. Solitary species are larger, tend to have greater absolute brain size and have more neurons in the forebrain than social species. The neocortex ratio and neuronal counts correlate negatively with social group size. These results are clearly inconsistent with the SBH and show that the challenges coupled with sociality in this group of rodents do not require brain enlargement or fundamental reorganization. These findings suggest that group living or pair bonding per se does not select strongly for brain enlargement unless coupled with Machiavellian interactions affecting individual fitness.
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27
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Examining object recognition and object-in-Place memory in plateau zokors, Eospalax baileyi. Behav Processes 2018; 146:34-41. [DOI: 10.1016/j.beproc.2017.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 11/08/2017] [Accepted: 11/08/2017] [Indexed: 12/13/2022]
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28
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Vlasatá T, Šklíba J, Lövy M, Meheretu Y, Sillero-Zubiri C, Šumbera R. Daily activity patterns in the giant root rat (Tachyoryctes macrocephalus
), a fossorial rodent from the Afro-alpine zone of the Bale Mountains, Ethiopia. J Zool (1987) 2017. [DOI: 10.1111/jzo.12441] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- T. Vlasatá
- Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
| | - J. Šklíba
- Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
- Institute of Entomology; Biology Centre CAS; České Budějovice Czech Republic
| | - M. Lövy
- Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
| | - Y. Meheretu
- Department of Biology; College of natural and computational sciences; University of Mekelle; Mekelle Ethiopia
| | - C. Sillero-Zubiri
- Wildlife Conservation Research Unit; Zoology Department; University of Oxford; Oxford UK
| | - R. Šumbera
- Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
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29
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Ngalameno M, Bastos A, Mgode G, Bennett N. The pattern of reproduction in the mole-rat Heliophobius from Tanzania: do not refrain during the long rains! CAN J ZOOL 2017. [DOI: 10.1139/cjz-2016-0153] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The genus Heliophobius Peters, 1846 comprises at least six cryptic, topotypical species in the Heliophobius argenteocinereus Peters, 1846 species complex. The current study investigated the breeding patterns of a wild-caught population from Tanzania where the putative species Heliophobius argenteocinereus emini Noack, 1894 resides. Individuals were collected on a monthly basis for an entire calendar year. Assessment of fœtus presence, gonadal histology, reproductive-tract morphometrics in combination with gonadal steroid (plasma progesterone and œstradiol-17β in females and testosterone in males) measurements and field observations revealed that rainfall is important for the onset of breeding. The results further confirmed that breeding is limited to a single, yearly reproductive event synchronised to the long rainfall pattern. The distinct breeding peak in July is associated with an elevation in gonadal mass, increase in concentrations of reproductive hormones, and presence of Graafian follicles and corpora lutea in the ovaries of females. These reproductive parameters coincided with the end of the long rainfall period, whereas presence of young in the maternal burrow system corresponded with the start of the short rainfall of East Africa. These findings confirm Heliophobius has a single breeding opportunity each year, and this species is therefore vulnerable to any changes that may impact their climatically attuned breeding patterns.
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Affiliation(s)
- M.K. Ngalameno
- Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
- Sokoine University of Agriculture, P.O. Box 3000, Morogoro, Tanzania
| | - A.D.S. Bastos
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
| | - G. Mgode
- Sokoine University of Agriculture, P.O. Box 3000, Morogoro, Tanzania
| | - N.C. Bennett
- Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
- SARChI Chair of Mammal Behavioural Ecology and Physiology, Department of Zoology, University of Pretoria, Pretoria 0002, South Africa
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30
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Šklíba J, Lövy M, Burda H, Šumbera R. Variability of space-use patterns in a free living eusocial rodent, Ansell's mole-rat indicates age-based rather than caste polyethism. Sci Rep 2016; 6:37497. [PMID: 27922127 PMCID: PMC5138616 DOI: 10.1038/srep37497] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 10/10/2016] [Indexed: 11/15/2022] Open
Abstract
Eusocial species of African mole-rats live in groups cooperating on multiple tasks and employing division of labour. In captivity, individuals of the same group differ in cooperative contribution as well as in preference for a particular task. Both can be viewed as polyethism. However, little information is available from free-ranging mole-rats, which live in large burrow systems. We made an attempt to detect polyethism in the free-living Ansell's mole-rat (Fukomys anselli) as differences in individuals' space-use patterns. We radio-tracked 17 adults from five groups. Large individuals, including breeding males, spent more time inside the nest than smaller individuals. Breeding females were more often located <10 m from the nest in comparison to non-breeding females, who were relatively more often located 30-90 m and exclusively >90 m from the nest. One non-breeding female even conducted a brief intrusion into a neighbouring group's territory via an open tunnel connection. A significant part of the variability in mole-rat space-use patterns was explained by body mass which is probably related to age in this species. This result can therefore be attributed to age polyethism. There was no apparent discontinuity in the space-use patterns of non-breeders that would indicate existence of castes.
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Affiliation(s)
- Jan Šklíba
- Department of Zoology, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic
- Institute of Entomology, Biology Centre CAS, Branišovská 1160, 370 05 České Budějovice, Czech Republic
| | - Matěj Lövy
- Department of Zoology, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic
| | - Hynek Burda
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, 45117 Essen, Germany
| | - Radim Šumbera
- Department of Zoology, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic
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31
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LaZerte S, Kramer D. Activity of eastern chipmunks (Tamias striatus) during the summer and fall. CAN J ZOOL 2016. [DOI: 10.1139/cjz-2016-0064] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Measuring activity of small mammals in the field is challenging because they are often out of view. We used a novel method, based on temperatures of collar radio transmitters, to quantify the proportion of time eastern chipmunks (Tamias striatus (L., 1758)) spent active, curled up resting, and torpid during the summer and fall of 2 years in southern Quebec. Time active over the 24 h day was lower in a nonmast (8%) than a mast (26%) year. In the mast year, activity varied strongly from a low of 7% during the summer lull to a high of 35% in the fall. Chipmunks that exploited a feeder had higher activity (33%) than chipmunks that did not (19%). Activity was higher during the day, but some activity occurred at night. Daily activity patterns varied strongly among seasonal periods. There was no evidence of torpor during the summer lull. Torpor started much earlier in the nonmast than in the mast year and occurred more at night than during the day. Overall, our study suggests that activity in this food-storing hibernator is positively influenced by food availability and indicates that thermosensitive radiotelemetry is a promising method for recording continuous activity.
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Affiliation(s)
- S.E. LaZerte
- Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montreal, QC H3A 1B1, Canada
- Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montreal, QC H3A 1B1, Canada
| | - D.L. Kramer
- Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montreal, QC H3A 1B1, Canada
- Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montreal, QC H3A 1B1, Canada
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32
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Šklíba J, Lövy M, Koeppen SCW, Pleštilová L, Vitámvás M, Nevo E, Šumbera R. Activity of free-living subterranean blind mole ratsSpalax galili(Rodentia: Spalacidae) in an area of supposed sympatric speciation. Biol J Linn Soc Lond 2015. [DOI: 10.1111/bij.12741] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jan Šklíba
- Department of Zoology; Faculty of Science; University of South Bohemia; Branišovská 31 37005 České Budějovice Czech Republic
| | - Matěj Lövy
- Department of Zoology; Faculty of Science; University of South Bohemia; Branišovská 31 37005 České Budějovice Czech Republic
| | - Stephan C. W. Koeppen
- Department of General Zoology; Faculty of Biology; University of Duisburg-Essen; Universitätsstr. 5 45141 Essen Germany
| | - Lucie Pleštilová
- Department of Zoology; Faculty of Science; University of South Bohemia; Branišovská 31 37005 České Budějovice Czech Republic
| | - Miloš Vitámvás
- Department of Zoology; Faculty of Science; University of South Bohemia; Branišovská 31 37005 České Budějovice Czech Republic
| | - Eviatar Nevo
- Institute of Evolution; University of Haifa; Haifa 31905 Israel
| | - Radim Šumbera
- Department of Zoology; Faculty of Science; University of South Bohemia; Branišovská 31 37005 České Budějovice Czech Republic
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33
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Begall S, Berendes M, Schielke CKM, Henning Y, Laghanke M, Scharff A, van Daele P, Burda H. Temperature preferences of African mole-rats (family Bathyergidae). J Therm Biol 2015; 53:15-22. [PMID: 26590451 DOI: 10.1016/j.jtherbio.2015.08.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 08/04/2015] [Accepted: 08/04/2015] [Indexed: 11/15/2022]
Abstract
Many animals are able to detect small temperature differences and show strong temperature preferences during periods of rest and activity. Mammals inhabiting the subterranean ecotope can adapt their digging and foraging activity in shallow tunnels temporarily to periods with favourable ambient air and soil temperatures. Moreover, subterranean mammals have the unique opportunity to select for their nests in soil depths with certain, daily and seasonally constant temperatures. Our knowledge on nest temperatures in several species of subterranean mammals is based on measurements of temperatures in empty nests. We can expect, however, that the temperature in an occupied nest is higher (due to the "igloo effect"). We performed two experiments regarding the temperature preference in five species of African mole-rats (Bathyergidae, Rodentia: Fukomys anselli, F. mechowii, F. micklemi, Heliophobius argenteocinereus, and Heterocephalus glaber). In a first experiment, the animals were tested pairwise (except for the solitary silvery mole-rats, H. argenteocinereus, that were tested singly) in an apparatus consisting of seven chambers with a temperature gradient ranging between 16 and 37°C (air temperature). While the smaller species (<110g; F. anselli, F. micklemi, H. glaber) chose chambers with average air temperatures around 29°C, the larger mole-rats rested preferably at lower temperatures of approximately 25.6°C (F. mechowii) and 27.7°C (H. argenteocinereus). A strong negative correlation between body mass and preferred air temperature was detected across species. Thus, the results comply with the surface-volume-rule. Contrary to expectations, temperature preference of naked mole-rats (H. glaber) did not deviate from those of furred small mole-rats, but followed the general trend with smaller species preferring higher temperatures. In a second experiment, Ansell's mole-rats (F. anselli) were tested in groups of four, six and nine animals and the preferred temperatures were compared to the values obtained for pairs. The preferred mean air temperatures did not differ among the groups of different sizes. We discuss our findings in the light of ecophysiological adaptations to cope with the ambient conditions proposed by the "thermal stress hypothesis". Furthermore, we suggest that while soil temperature is decisive during digging as the mole-rats warm up or cool due to tight contact between body and soil (conduction), resting animals prevent heat loss through conduction by building a nest.
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Affiliation(s)
- Sabine Begall
- Department of General Zoology, Institute for Biology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 5, D-45117 Essen, Germany.
| | - Meike Berendes
- Department of General Zoology, Institute for Biology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 5, D-45117 Essen, Germany
| | - Charlotte K M Schielke
- Department of General Zoology, Institute for Biology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 5, D-45117 Essen, Germany
| | - Yoshiyuki Henning
- Department of General Zoology, Institute for Biology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 5, D-45117 Essen, Germany
| | - Marzena Laghanke
- Department of General Zoology, Institute for Biology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 5, D-45117 Essen, Germany
| | - Andreas Scharff
- Department of General Zoology, Institute for Biology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 5, D-45117 Essen, Germany
| | - Paul van Daele
- Department of Vertebrate Morphology, Ghent University, B-9000 Ghent, Belgium
| | - Hynek Burda
- Department of General Zoology, Institute for Biology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 5, D-45117 Essen, Germany
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Voigt C. An example of burrow system architecture of dispersing Damaraland mole-rats. AFRICAN ZOOLOGY 2015. [DOI: 10.1080/15627020.2014.11407627] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Okrouhlík J, Burda H, Kunc P, Knížková I, Šumbera R. Surprisingly low risk of overheating during digging in two subterranean rodents. Physiol Behav 2015; 138:236-41. [DOI: 10.1016/j.physbeh.2014.10.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 10/28/2014] [Accepted: 10/30/2014] [Indexed: 10/24/2022]
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Šklíba J, Lövy M, Hrouzková E, Kott O, Okrouhlík J, Šumbera R. Social and Environmental Influences on Daily Activity Pattern in Free-Living Subterranean Rodents. J Biol Rhythms 2014; 29:203-214. [DOI: 10.1177/0748730414526358] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Predictable daily activity patterns have been detected repeatedly even in mammals living in stable environments, as is the case for subterranean rodents. Whereas studies on activity of these rodents under laboratory conditions almost exclusively have concerned themselves with the influence of light, many field studies have revealed signs of an association between the activity pattern and daily fluctuations of temperature under the ground. This would assume that behavioral thermoregulation is probably involved. The only exceptions to the relationship between temperature and activity are 2 eusocial mole-rats of the genus Fukomys (Bathyergidae, Rodentia), which indicates that activity patterns could be affected also by social cues. To better understand how social and environmental factors influence the activity pattern in a eusocial mole-rat, we monitored the outside-nest activity in another species of this genus, the Ansell’s mole-rat ( Fukomys anselli), which has a relatively small body mass, high conductance, and more superficially situated burrows. Its daily activity had 1 prominent peak (around 1400 h), and it was tightly correlated with the temperature measured at depth of foraging burrows. Since F. anselli has high thermoregulatory requirements to maintain stable body temperature below the lower critical temperature, we conclude that the observed pattern is probably the result of minimizing the cost of thermoregulation. There were no significant differences in the daily activity patterns of breeding males and females and nonbreeders. Members of the same family group tended to have more similar activity patterns, but consistent activity synchronization between individuals was not proven. From the comparison of available data on all subterranean rodents, we assume that social cues in communally nesting mole-rats may disrupt (mask) temperature-related daily activity rhythms but probably only if the additional cost of thermoregulation is not too high, as it likely is in the Ansell’s mole-rat.
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Affiliation(s)
- Jan Šklíba
- Department of Zoology, Faculty of Science, University of South Bohemia, Cˇeské Budeˇjovice, Czech Republic
| | - Matěj Lövy
- Department of Zoology, Faculty of Science, University of South Bohemia, Cˇeské Budeˇjovice, Czech Republic
| | - Ema Hrouzková
- Department of Zoology, Faculty of Science, University of South Bohemia, Cˇeské Budeˇjovice, Czech Republic
| | - Ondřej Kott
- Department of Zoology, Faculty of Science, University of South Bohemia, Cˇeské Budeˇjovice, Czech Republic
| | - Jan Okrouhlík
- Department of Zoology, Faculty of Science, University of South Bohemia, Cˇeské Budeˇjovice, Czech Republic
| | - Radim Šumbera
- Department of Zoology, Faculty of Science, University of South Bohemia, Cˇeské Budeˇjovice, Czech Republic
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Katandukila JV, Bennett NC, Chimimba CT, Faulkes CG, Oosthuizen MK. Locomotor activity patterns of captive East African root rats,Tachyoryctes splendens(Rodentia: Spalacidae), from Tanzania, East Africa. J Mammal 2013. [DOI: 10.1644/13-mamm-a-095.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Patzenhauerová H, Šklíba J, Bryja J, Šumbera R. Parentage analysis of Ansell's mole-rat family groups indicates a high reproductive skew despite relatively relaxed ecological constraints on dispersal. Mol Ecol 2013; 22:4988-5000. [PMID: 23992451 DOI: 10.1111/mec.12434] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 06/11/2013] [Accepted: 06/18/2013] [Indexed: 11/27/2022]
Abstract
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 where reproduction is monopolized by a stable breeding pair, but the value could be decreased by breeding-male and breeding-female turnover, shared reproduction and extra-group mating. The frequency of such events should be higher in species or populations inhabiting mesic environments with relaxed ecological constraints on dispersal. To test this prediction, we studied patterns of parentage and relatedness within 16 groups of Ansell's mole-rat (Fukomys anselli) in mesic miombo woodland. Contrary to expectation, there was no shared reproduction (more than one breeder of a particular sex) within the studied groups, and proportion of immigrants and offspring not assigned to current breeding males was low. The within-group parentage and relatedness patterns observed resemble arid populations of 'eusocial' Fukomys damarensis, rather than a mesic population of 'social' Cryptomys hottentotus. As a possible explanation, we propose that the extent ecological conditions affect reproductive skew may be markedly affected by life history and natural history traits of the particular species and genera.
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Affiliation(s)
- Hana Patzenhauerová
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Květná 8, 60365, Brno, Czech Republic
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