Erica Zaid
Male dusky antechinus can lose up to 3 hours of sleep per day when in heat.
CNN
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For some people, getting enough sleep is happiness. But for Australia’s small marsupials, sex is more of a priority than waking up, and they’re willing to sacrifice hours of sex each day for a happy ending.
Australian-based scientists have discovered that mouse-sized Male Antechinus trade sleep for more time for reproduction during the heat cycle, and one monitored male cut his sleep time in half during this period.
The study was published Thursday in the journal current biologyResearchers say this is the first time they have shown direct evidence of this type of “extreme” sleep restriction in a land-dwelling mammal.
“Animals need to reproduce to pass on their genes, but they also need sleep to survive,” lead author Erika Zaid, an animal behavior researcher at Melbourne’s La Trobe University, told CNN.
“Long-lived animals like humans and elephants don’t have the pressure to reproduce in a short period of time. They have the luxury of being able to sleep for as long as possible. They want (and need) every day,” she said.
francesca leonard
First author Erika Zaid held dim antechinus, 15 of which were observed in the study.
Male antechinus, unlike females, are single-parous and can reproduce only once in their lives, so sleeping for long periods of time is a luxury and could mean losing the opportunity to pass on their genes, Zaid explained. Researchers say dusky antechinus spend an average of 15.3 hours a day sleeping during the non-breeding season.
“Sleep restriction in breeding male Antechinus is likely an adaptive behavioral response driven by strong sexual selection,” the paper states. Because of this, they compete with other males to reproduce with as many females as possible and die as soon as their first and last breeding season ends.
To study solitary marsupials, researchers examined two species of Antechinus, the dusky Antechinus (Antechinus swainsonii) and the wild agile Antechinus (Antechinus agilis), both in captivity and in the wild.
The researchers found that males of both species were not only more active during heat, but also slept less during the same period.
The data showed that the males slept three hours less each night for three weeks, which was roughly the length of their heat cycle. Males live only 11 months, reproduce once in a lifetime and die, Zaid said, but females can reproduce multiple times.
Sleep scientist John Lesk, an associate professor of zoology at La Trobe University who worked on the study, said sleep is “an essential and seemingly universal behavior in the animal kingdom”.
“A loss of three hours of sleep each night affects a person’s ability to wake up, but Antechinus did this for three weeks. Therefore, Antechinus is tolerant of sleep deprivation and thrives on less sleep during this period.” “They may have an unknown mechanism, or they may accept the physiological cost of being awake to ensure paternity before they die,” Lesk told CNN.
The paper suggests that the decrease in sleep is due to reproductive pressure on males during the only breeding season, and due to increased sleep time. Sexual activity during the same period was positively correlated with an increase in the male hormone testosterone.
Researchers used accelerometers (devices used to measure the acceleration of moving objects) to track the movements of 15 dusky antechinus, 10 of them male, before and during estrus. .
The researchers took blood samples to measure hormonal changes and electrophysiological recordings from the four men to measure sleep duration.
Blood samples were also collected from 38 wild alert antechinus (20 males) to determine whether oxalate, a biomarker of sleep deprivation, similarly decreases during the mating period.
Although the reduction in oxalate suggests that the agile Antechinus were sleep-deprived during estrus, the results showed that there was no significant difference between males and females, which is similar to that found in wild females. Zaid points out that this may suggest that the male is also suffering from a lack of sleep. Harassment during the estrus period.
Erica Zaid
A cool temperate rainforest in southern Australia. The dim and alert Antechinus loses sleep due to sexual activity during the breeding season.
“Our study is the first to compare activity levels in males and females before, during and after the breeding season, and to use accelerometry, electrophysiology and metabolomics to reliably link rest and sleep.” the researchers said in their paper.
Volker Sommer, professor of evolutionary anthropology at University College London, told CNN: “It’s more like a pre-breeding impasse where they keep their guard up. The males are forced to stay awake because their competitors are awake as well.” Sommer was not involved in the study.
Although the results do not pinpoint the cause of post-breeding male die-offs, there are several possibilities, including elevated levels of corticosteroids (steroid hormones) and lack of sleep.
Lesk said the researchers next wanted to investigate how male antechinus cope with three weeks of sleep restriction.
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