Breaking News
March 22, 2019 - TMJ disorders could be treated with tissue-engineered implants after successful animal study
March 22, 2019 - Team-based approach is key to successful care of pregnant women with heart failure
March 22, 2019 - Study identifies gene variant associated with accelerated cellular aging
March 21, 2019 - Salk scientists show how background noise from neurons can interrupt focused attention
March 21, 2019 - New class of drugs could help treat patients diagnosed with ovarian cancer
March 21, 2019 - Tecentriq Approved for Small Cell Lung Cancer
March 21, 2019 - Adipocyte glucocorticoid receptors play a role in developing steroid diabetes
March 21, 2019 - Climate change can affect nutrient content of crops, harming human health
March 21, 2019 - Podcast: KHN’s ‘What The Health’ Surprise! Fixing Surprise Medical Bills Is Harder Than it Looks
March 21, 2019 - Chemistry researchers patent new method for making anti-leukemia compounds
March 21, 2019 - UIC scientists identify hidden proteins in bacteria
March 21, 2019 - New Australian drug trial achieves remarkable results in patients with acute myeloid leukemia
March 21, 2019 - Females live longer when they have help raising offspring
March 21, 2019 - How did orthodontists sell orthodontics?
March 21, 2019 - In the Spotlight: From dietitian to physician assistant student
March 21, 2019 - The CRISPR Revolution: What You Need to Know
March 21, 2019 - FDA Chief Calls For Stricter Scrutiny Of Electronic Health Records
March 21, 2019 - Combined glucocorticoid and antioxidant therapy could benefit premature babies
March 21, 2019 - Low levels of certain eye proteins could serve as predictor for Alzheimer’s
March 21, 2019 - Post-traumatic holocaust survivors transmit negative views on aging to offspring
March 21, 2019 - City of Hope receives $7.5 million in grant awards to study cutaneous T cell lymphoma
March 21, 2019 - New video game-led training device helps stroke survivors regain arm mobility
March 21, 2019 - Compounds in coffee could slow prostate cancer growth
March 21, 2019 - New mobile DNA element in Wolbachia may contribute to improved disease control strategies
March 21, 2019 - Phase 2 Clinical Trial of Bermekimab Shows Potential New Standard of Care for Treatment of Hidradenitis Suppurativa, Including Significant Pain Reduction without Antibiotics
March 21, 2019 - More than one-third of patients risk major bleeding by doubling up on blood thinners
March 21, 2019 - A skeptical look at popular diets: Thumbs up for Mediterranean
March 21, 2019 - PTSD After Cardiac Arrest Predicts More Heart Trouble
March 21, 2019 - Role of immunological imprinting in elicitation of new antibodies
March 21, 2019 - Breast cancer relapse predictor tool may soon be a reality
March 21, 2019 - New computer program developed by TGen lights up cancer-causing genetic mutations
March 21, 2019 - FDA warns two breast implant makers for failure to comply with post-approval study requirements
March 21, 2019 - Butler Hospital receives COBRE grant to enhance research on neuropsychiatric illnesses
March 21, 2019 - Majority of osteoporosis clinical practice guidelines ignore patients’ voices
March 21, 2019 - Generic messages don’t help patients to lose weight
March 21, 2019 - Eisai and Imbrium Therapeutics Announce U.S. FDA Filing Acceptance of New Drug Application for Lemborexant for the Treatment of Insomnia
March 21, 2019 - Two-drug combos using popular calcium channel blocker show superiority in lowering BP
March 21, 2019 - First-in-human pilot study shows positive results for ‘bacteria-phobic’ catheter
March 21, 2019 - Itamar Medical launches next-generation WatchPAT system for home sleep apnea testing
March 21, 2019 - Study estimates health and economic impacts of healthy food prescriptions
March 21, 2019 - Detecting fungal disease in crops with multispectral imaging system
March 21, 2019 - MIT announces creation of the Alana Down Syndrome Center
March 21, 2019 - Next-generation LVAD device clinically superior, safer for heart failure patients
March 21, 2019 - Allergan Announces FDA Approval of Avycaz (ceftazidime and avibactam) for Pediatric Patients
March 21, 2019 - Mutations in noncoding genes could play big role in regulating cancer, study finds
March 21, 2019 - A medical student’s thoughts on Match Day
March 21, 2019 - Are eggs good or bad for you?
March 21, 2019 - New analysis reveals precision oncology insights for colorectal cancer
March 21, 2019 - Pollutants appear to weaken immune system and increase pathogen virulence
March 21, 2019 - Researchers develop and validate scale for rating severity of mononucleosis
March 21, 2019 - Scientists identify generation of key immune response in mice on introducing solid food
March 21, 2019 - New nanomaterial could restore internal structure of damaged bones
March 21, 2019 - Selective destruction of prostate tumor as effective as complete prostate removal
March 21, 2019 - 2011 to 2015 Saw Increase in Psychiatric ED Visits for Youth
March 21, 2019 - Tapeworm drug targets common vulnerability in tumor cells
March 21, 2019 - WVU researcher discovers higher suicide rate among Medicaid-insured youth
March 21, 2019 - Off the beaten path for global health residency
March 21, 2019 - European Parliament’s report calls on EU to develop policies to regulate endocrine-disrupting chemicals
March 21, 2019 - Women with undiagnosed diabetes in pregnancy more likely to experience stillbirths
March 21, 2019 - Fish consumption can help prevent asthma, study reveals
March 21, 2019 - Royal Holloway professors to lead new to research into curing Neurofibromatosis type 1
March 21, 2019 - NSF offers grant to improve treatment approaches for pelvic organ prolapse
March 21, 2019 - Your Apple Watch Might Help Spot a Dangerous Irregular Heartbeat
March 21, 2019 - Research team uncovers critical new clues about what goes awry in autistic brains
March 21, 2019 - From March Madness to medicine with help from mentors
March 21, 2019 - Mental health disorders among young adults may be on the increase
March 21, 2019 - New study examines smarter automatic defibrillator
March 21, 2019 - UC Riverside research shows how natural selection favors cheaters
March 21, 2019 - Mother’s diet during pregnancy can impact lung-specific genes of her offspring
March 21, 2019 - AeroForm Tissue Expanders makes breast reconstruction after mastectomy more comfortable
March 21, 2019 - New project focuses on creating more responsive, intuitive prosthetics
March 21, 2019 - New case study describes adolescent patient with rapid-onset schizophrenia and Bartonella infection
March 21, 2019 - Umass Amherst food scientist honored with 2019 Young Scientist Research Award
March 21, 2019 - Smell of skin could lead to early diagnosis for Parkinson’s
March 21, 2019 - Difference in brain connectivity may explain autism spectrum disorder
March 21, 2019 - Untangling the microbiome — with statistics
March 21, 2019 - Human microbiome metabolites enhance colon injury by enterohemorrhagic E. coli, study shows
March 21, 2019 - Written media can improve citizens’ understanding of palliative care
March 21, 2019 - New research aims to find how asthma symptoms are aggravated
March 21, 2019 - New $9.7 million NIH grant project seeks to improve hearing restoration
Aging edible dormice found to shorten hibernation for increase in reproductive activity

Aging edible dormice found to shorten hibernation for increase in reproductive activity

image_pdfDownload PDFimage_print

Edible dormice are extremely long-lived for their size thanks to their seasonal dormancy. The animals are veritable record holders in this “discipline”, with hibernation periods lasting between at least six and a maximum of eleven months. The factors influencing the variable duration of the hibernation period, apart from the specific environmental conditions, have so far been unknown. Researchers at Vetmeduni Vienna hypothesised that older animals should shorten their winter dormancy in favour of a reproductive advantage. This hypothesis has now been confirmed in a database analysis, published in Scientific Reports, of dormice populations living in large outdoor enclosures. The shortened winter hibernation of aging males and females were due to an increase in reproductive activity. Older animals also delay the onset of hibernation and emerge earlier in the season.

Mammals usually have a clear correlation between body size and life history, with smaller species tending to have a shorter lifespan. Various strategies exist, however, through which small mammals, including several species of rodents, can extend their lifespan. One of the most successful of these strategies, besides flight or arboreality to escape ground predation, is hibernation. Animals like the edible dormouse (Glis glis) hibernate to avoid predators and to get through seasonal periods of low food availability. Dormice are true “sleepyheads”, with an average length of dormancy between eight and nine months. The benefit of torpor, with a considerably reduced metabolism, is an exceptionally high life expectancy of up to 13 years. This makes them the Methuselah among the otherwise short-lived small rodents.

Nevertheless, older dormice appear to deliberately shorten their dormancy period, thus sacrificing the safety and life-prolonging effect of hibernation. So far, however, there had been no clear evidence that age even has an effect on hibernation and whether there was an age-related correlation between the investment in reproduction and winter dormancy. Researchers from the Institute of Wildlife Ecology at Vetmeduni Vienna could now show for the first time that the onset of hibernation is delayed in older animals, that the animals emerge earlier, and that the dormancy period is generally shorter because the older animals invest more energy in reproduction.

With age, reproduction becomes more important than life-prolonging winter rest

The evaluation of the data, which had been collected over a period of ten years from a dormouse population kept under natural conditions, revealed that the observed shorter winter dormancy in older animals was due to their own reproductive pressure regardless of sex. Dormice with offspring invest a lot of energy into raising their young and enter hibernation later. Late hibernators include not only mother animals, however; even males remain active longer. “After all, the guys can’t afford to miss a potential mating opportunity should a female lose her litter and again become receptive,” explains study director Claudia Bieber. “In fact, edible dormice do not show any age-related decline in reproduction. Actually, the older the animal, the larger the litter.” These rodents remain sexually active even at an advanced age, and the pressure on the animals to remain reproductively successful thus outweighs the potential risk of predation or lack of food reservoirs.

The data analysis also confirmed that the animals, regardless of their reproductive success in the previous year, emerge from hibernation earlier the older they are. “With the decreasing chances of surviving another year, older animals accept the risk of being taken by a predator,” Bieber says. The pressure on potential predators such as owls, is especially high during early spring as these animals must provide their own young with food at this time of year. But early emergence also allows dormice to more easily occupy high-quality food territories, which considerably influences their ability to successfully rear their young. Young dormice, on the other hand, spend more time in the safety of their underground burrows, as they still have a long life ahead of them and are not under the same pressure to reproduce.

No learning effect in response to safe environment – far-reaching insights for hibernation research

The semi-natural conditions of a protected enclosure did not influence the data, Bieber confirms. “We made sure to have fluctuating food conditions, foxes and owls were present around the enclosures, and the dormice clearly reacted to their presence. The animals also responded with a higher alertness when humans approached the enclosures.” Taking into account the risk of predation and the food conditions, the age-related observations could not be simply explained as a learning effect. An increased investment in reproduction with age was also observed in a free-living population. “Our results are far-reaching and are a confirmation of life history theory, according to which species should always pursue a strategy that ensures a maximum number of offspring. Our study clearly demonstrates that winter dormancy is not only a strategy to save energy during periods of low food availability but that, depending on the age of the animals, hibernation duration is flexible to ensure as long a life as possible with many offspring,” says Bieber.

Source:

https://www.vetmeduni.ac.at/en/infoservice/press-releases/presse-releases-2018/trading-sex-for-sleep-aging-dormice-shorten-their-hibernation-for-more-reproduction/

Tagged with:

About author

Related Articles