Publications by authors named "Caroline Deimel"

7 Publications

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Early nighttime testosterone peaks are correlated with GnRH-induced testosterone in a diurnal songbird.

Gen Comp Endocrinol 2021 Oct 21;312:113861. Epub 2021 Jul 21.

Max Planck Institute for Ornithology, Evolutionary Physiology Research Group, Seewiesen, Germany; University of Konstanz, Department of Biology, Konstanz, Germany.

Experimental manipulation has established testosterone as a potent, pleiotropic regulator coordinating morphology, physiology and behavior. However, the relationship of field-sampled, unmanipulated testosterone concentrations with traits of interest is often equivocal. Circulating testosterone varies over the course of the day, and recent reports indicate that testosterone is higher during the night in diurnal songbirds. Yet, most field studies sample testosterone during the morning. Sampling at times when levels and individual variation are low may be one reason relationships between testosterone and other traits are not always observed. Testosterone is regulated by the hypothalamic-pituitary-gonadal axis, with gonadotropin-releasing hormone (GnRH) initiating the endocrine cascade. Research has examined GnRH-induced testosterone levels with traits of interest, yet the relevance of these induced levels and their relationship with endogenously produced levels are not fully clear. Using photostimulated male great tits (Parus major) we tested the hypotheses that circulating testosterone levels peak during the night and that GnRH-induced testosterone concentrations are positively related to nightly testosterone peaks. Blood was sampled during first, middle or last third of night. One week later, baseline and GnRH-induced testosterone levels were sampled during mid-morning. Morning baseline testosterone levels were low compared with night-sampled levels that peaked during the first third of the night. Further, GnRH-induced testosterone was strongly positively correlated with levels observed during the first third of the night. These data suggest that morning testosterone samples likely do not reflect an individual's endogenous peak. Instead, GnRH-induced testosterone levels do approximate an individual's nightly peak and may be an alternative for birds that cannot easily be sampled at night in the field. These findings are likely to have implications for research aimed at relating traits of interest with natural variation in sex steroid hormone levels.
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http://dx.doi.org/10.1016/j.ygcen.2021.113861DOI Listing
October 2021

Connecting the data landscape of long-term ecological studies: The SPI-Birds data hub.

J Anim Ecol 2021 09 4;90(9):2147-2160. Epub 2020 Dec 4.

Stazione Ornitologica, Monreale, Italy.

The integration and synthesis of the data in different areas of science is drastically slowed and hindered by a lack of standards and networking programmes. Long-term studies of individually marked animals are not an exception. These studies are especially important as instrumental for understanding evolutionary and ecological processes in the wild. Furthermore, their number and global distribution provides a unique opportunity to assess the generality of patterns and to address broad-scale global issues (e.g. climate change). To solve data integration issues and enable a new scale of ecological and evolutionary research based on long-term studies of birds, we have created the SPI-Birds Network and Database (www.spibirds.org)-a large-scale initiative that connects data from, and researchers working on, studies of wild populations of individually recognizable (usually ringed) birds. Within year and a half since the establishment, SPI-Birds has recruited over 120 members, and currently hosts data on almost 1.5 million individual birds collected in 80 populations over 2,000 cumulative years, and counting. SPI-Birds acts as a data hub and a catalogue of studied populations. It prevents data loss, secures easy data finding, use and integration and thus facilitates collaboration and synthesis. We provide community-derived data and meta-data standards and improve data integrity guided by the principles of Findable, Accessible, Interoperable and Reusable (FAIR), and aligned with the existing metadata languages (e.g. ecological meta-data language). The encouraging community involvement stems from SPI-Bird's decentralized approach: research groups retain full control over data use and their way of data management, while SPI-Birds creates tailored pipelines to convert each unique data format into a standard format. We outline the lessons learned, so that other communities (e.g. those working on other taxa) can adapt our successful model. Creating community-specific hubs (such as ours, COMADRE for animal demography, etc.) will aid much-needed large-scale ecological data integration.
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http://dx.doi.org/10.1111/1365-2656.13388DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8518542PMC
September 2021

Is genetic drift to blame for testicular dysgenesis syndrome in Semliki chimpanzees (Pan troglodytes schweinfurthii)?

J Med Primatol 2018 May 25. Epub 2018 May 25.

Department of Anthropology, Indiana University, Bloomington, IN, USA.

Background: We present 3 likely cases of testicular dysgenesis syndrome (TDS) within a community of chimpanzees (Pan troglodytes schweinfurthii). We tested whether genetic drift may be the culprit, as a genetic cause has been suspected to account for TDS among other wildlife.

Methods: We successfully sequenced a 367-bp segment spanning the first hypervariable region within the D-loop of the mitochondrial genome for 78 DNA samples.

Results: We found 24 polymorphic sequence sites consisting of 7 singletons and 17 parsimony informative sites. This sample contained 9 haplotypes with a diversity index of 0.78 (SD = 0.03). All tests against the null hypothesis of neutral polymorphisms were non-significant (P > .10). The mismatch distribution of pairwise differences does not fit a Poisson's curve (raggedness index = 0.166; SSD = 0.12; P = 1).

Conclusions: Thus, we found no significant signs of genetic isolation, population expansion, or genetic bottleneck. Alternative causes of TDS and how they might pertain to this population are discussed.
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http://dx.doi.org/10.1111/jmp.12352DOI Listing
May 2018

Extinctions, genetic erosion and conservation options for the black rhinoceros (Diceros bicornis).

Sci Rep 2017 02 8;7:41417. Epub 2017 Feb 8.

Cardiff School of Biosciences, Sir Martin Evans Building, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, United Kingdom.

The black rhinoceros is again on the verge of extinction due to unsustainable poaching in its native range. Despite a wide historic distribution, the black rhinoceros was traditionally thought of as depauperate in genetic variation, and with very little known about its evolutionary history. This knowledge gap has hampered conservation efforts because hunting has dramatically reduced the species' once continuous distribution, leaving five surviving gene pools of unknown genetic affinity. Here we examined the range-wide genetic structure of historic and modern populations using the largest and most geographically representative sample of black rhinoceroses ever assembled. Using both mitochondrial and nuclear datasets, we described a staggering loss of 69% of the species' mitochondrial genetic variation, including the most ancestral lineages that are now absent from modern populations. Genetically unique populations in countries such as Nigeria, Cameroon, Chad, Eritrea, Ethiopia, Somalia, Mozambique, Malawi and Angola no longer exist. We found that the historic range of the West African subspecies (D. b. longipes), declared extinct in 2011, extends into southern Kenya, where a handful of individuals survive in the Masai Mara. We also identify conservation units that will help maintain evolutionary potential. Our results suggest a complete re-evaluation of current conservation management paradigms for the black rhinoceros.
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http://dx.doi.org/10.1038/srep41417DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5296875PMC
February 2017

Links between breast cancer and birth weight: an empirical test of the hypothesized association between size at birth and premenopausal adult progesterone concentrations.

Horm Cancer 2015 Aug 17;6(4):182-8. Epub 2015 Apr 17.

The Kinsey Institute for Research in Sex, Gender and Reproduction, Indiana University, Morrison Hall 313, 1165 East Third Street, Bloomington, IN, 47405, USA.

Some studies have reported that birth size is a risk factor for breast cancer, but the reasons for this observation are unknown. Ovarian hormone concentrations may be a link between birth size and breast cancer, but the few tests of this hypothesis are inconsistent, perhaps because of differences in sample composition, inclusion of anovulatory cycles, or use of one hormonal measurement per woman. We present results from the first study to use daily hormonal measurements throughout a woman's complete ovulatory cycle to test the hypothesized relationship between birth size and adult progesterone concentrations. We used a study sample and accompanying data set previously obtained for another research project in which we had collected daily urine samples from 63 healthy premenopausal women throughout a menstrual cycle. Multivariate regression was used to test for trends of individual progesterone indices (from 55 ovulatory cycles) with birth weight or ponderal index, while controlling for age, adult BMI, and age at menarche. Our main finding was that neither birth weight nor ponderal index was associated with biologically significant variation in luteal progesterone indices; the best-estimated effect sizes of birth size on these progesterone indices were small (3.7-10.2%). BMI was the only significant predictor of mean peak urinary progesterone, but it explained <6% of the variance. Our findings, in light of what is currently known regarding associations of breast cancer risk with birth size and adult size, suggest that environmental factors (particularly those that vary by socioeconomic status and affect growth) may underlie associations between birth size and cancer risks without there being any association of birth size with adult ovarian hormone concentrations.
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http://dx.doi.org/10.1007/s12672-015-0221-6DOI Listing
August 2015

Daily torpor is associated with telomere length change over winter in Djungarian hamsters.

Biol Lett 2012 Apr 14;8(2):304-7. Epub 2011 Sep 14.

Department of Integrative Biology and Ecology, Research Institute for Wildlife Ecology, University of Veterinary Medicine, Vienna 1160, Austria.

Ageing can progress at different rates according to an individual's physiological state. Natural hypothermia, including torpor and hibernation, is a common adaptation of small mammals to survive intermittent or seasonal declines in environmental conditions. In addition to allowing energy savings, hypothermia and torpor have been associated with retarded ageing and increased longevity. We tested the hypothesis that torpor use slows ageing by measuring changes in the relative telomere length (RTL) of Djungarian hamsters, Phodopus sungorus, a highly seasonal rodent using spontaneous daily torpor, over 180 days of exposure to a short-day photoperiod and warm (approx. 20°C) or cold (approx. 9°C) air temperatures. Multi-model inference showed that change in RTL within individuals was best explained by positive effects of frequency of torpor use, particularly at low body temperatures, as well as the change in body mass and initial RTL. Telomere dynamics have been linked to future survival and proposed as an index of rates of biological ageing. Our results therefore support the hypothesis that daily torpor is associated with physiological changes that increase somatic maintenance and slow the processes of ageing.
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http://dx.doi.org/10.1098/rsbl.2011.0758DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3297381PMC
April 2012

Evidence for the consumption of arboreal, diurnal primates by bonobos (Pan paniscus).

Am J Primatol 2009 Feb;71(2):171-4

Max-Planck-Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig, Germany

We present evidence for the consumption of a diurnal, arboreal, group living primate by bonobos. The digit of an immature black mangabey (Lophocebus aterrimus) was found in the fresh feces of a bonobo (Pan paniscus) at the Lui Kotale study site, Democratic Republic of Congo. In close proximity to the fecal sample containing the remains of the digit, we also found a large part of the pelt of a black mangabey. Evidence suggests that the Lui Kotale bonobos consume more meat than other bonobo populations and have greater variation in the mammalian species exploited than previously thought [Hohmann & Fruth, Folia primatologica 79:103-110]. The current finding supports Stanford's argument [Current Anthropology 39:399-420] that some differences in the diet and behavior between chimpanzees (P. troglodytes) and bonobos are an artefact of the limited number of bonobo study populations. If bonobos did obtain the monkey by active hunting, this would challenge current evolutionary models relating the intra-specific aggression and violence seen in chimpanzees and humans to hunting and meat consumption [Wrangham, Yearbook of Physical Anthropology 42:1-30].
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http://dx.doi.org/10.1002/ajp.20634DOI Listing
February 2009
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