Lemurz shows that there is no one formula for everlasting love
Humans are not the only mammals that form long-term relationships with one special partner. But new research suggests that in some species, the brain chain that makes love intimate may not be the same in others.
The study, published in the February 12 issue of the journal Scientific reports, compares monogamous species to a group of closely related lemurs with distant first cousins from the island of Madagascar.
Red belly lemurs և mango lemurs are one of the few species of lemongrass in which male and female partners work together year after year to raise their children and protect their territory.
After mating, couples spend most of their waking hours gathering together or cuddling side by side, often wrapping their tails around each other’s bodies. Males and females of these species spend one third of their lives with the same mate. The same cannot be said of their closest relatives, who often change partners.
For biologists, monogamy is somewhat mysterious. This is partly because it is rare in many groups of animals. Although about 90% of bird species show some loyalty to one mate, only 3% to 5% of mammals. The vast majority of the approximately 6,500 known mammalian species have, so to speak, open relationships.
“It’s an unusual arrangement,” said lead author Nicholas Greb, a postdoctoral fellow in the laboratory at Duke University professor Christine Drea.
What raises the question? What makes some species biologically prone to long-term mating while others play on the field?
Studies of rodents over the past 30 years have shown two hormones released during mating, oxytocin and vasopressin, which suggest that the key to domestic love may be the difference between acting on the brain.
Some of the first indications came from influential research on meadow wolves, small mammals like mice that, unlike many rodents, live together. When researchers compared the brains of monogamous meadows with their lewd counterparts, montage-meadow holes, they found that meadow cups had more “parking” for these hormones, particularly in parts of the brain’s reward system.
Since these “hug chemicals” were found to cause male-female connections in holes, researchers have long wondered if they could work the same way in humans.
That’s why the team led by Duke turned to the Limurs. Despite being the most distant relatives of our primates, lemons are more genetically identical to humans than wolves.
The researchers used an imaging technique called autoradiography to map the binding sites of oxytocin and vasopressin in the brains of 12 natural lemurs that died of natural causes at Duke Lemur Center.
The animals were seven species with a solid red abdomen and mongo lemurs, along with five species of the same genus.
“They are really the only comparable natural experiment to find biological signatures of monogamy in primates,” Greb said.
Comparison of brain imaging results in lemurs revealed significant differences in hormone receptor density and distribution compared to previously bovine monkeys. In other words, oxytocin and vasopressin appear to affect different parts of the brain in lemurs, which means that they can also have different effects depending on the location of their target cell.
But researchers in the Lemurs were surprised to find some consistent differences between the monogamous species of “prodigal animals”.
Grebe says. “We do not see evidence of a double bond,” which is similar in the brains of rodents.
As a next step, the team is studying how couples behave towards each other if oxytocin is blocked by feeding them an adversary that temporarily prevents oxytocin from binding to its receptors in the brain.
So what can lemurs teach us about love? The authors say that their findings warn against drawing simple conclusions based on rodent experiments on how human social behavior evolved.
Oxytocin may be a “devotion drink” for volleys, but it can be a combination of many brain chemicals and interactions, along with environmental factors, that create long-term bonds between limors and other primates, including humans, Greb said.
“There are probably a number of different ways in which monogamy is established inside the brain, depending on which animals we look at,” said Greb. “More is happening than we initially thought.”
Reference. “The neural relations of the diversity of the education system. Distribution of oxytocin և vasopressin receptors in monogamous, non-monogamous Eulemur “by Nicholas Grebe, Annika Sharma, Sara Freeman, Michel Palumbo, Heather Patissaul, Karen Bales և Christine Drea, February 12, 2021 Scientific reports,
DOI: 10.1038 / s41598-021-83342-6:
There were other authors. Annika Sharman Duke, Sarah Freeman of Utah State University, Michelle Palumbo of the California Center for National Primate Studies, Heather Patissaul North Carolina State Universityand Karen Bales at the University of California, Davis.
This work was supported by grants from the National Science Foundation (SBE-1808803), the National Institute of Mental Health (NIMH R21MH115680), the Charles Trent Memorial Foundation in Ossetia, the Charles Lafitte Research Foundation, and Duke University.