Tag Archives: couple

Pair bonding may be the foundation of human and primate societies

New research into primate social structures offers insight into how human social life is organized.

Image via Pixabay.

Primates can develop quite complex social structures — just look at ours, we’re primates too. But exactly what made this family of species move towards a group rather than individual lifestyle? That’s what Luca Pozzi from the University of Texas at San Antonio (UTSA) Department of Anthropology, in collaboration with Peter Kappeler at the German Primate Center-Leibniz Institute for Primate Research, set out to understand.

The duo identified pair bonding as a key transition system between solitary and community lifestyles.

Our better halves

“The evolution of complex social systems in mammals, and more specifically in primates, is a challenging and exciting area of research. Our study shows that pair living—although rare—might have played a critical role in it,” says Pozzi.

“Living as a pair represents an evolutionary puzzle in the evolution of mammalian social systems because males could achieve higher rates of reproduction if they did not bond to a single female”.

Pozzi explains that social systems can work as an adaptive tool. Species need to adapt to their environmental conditions, he says, which is the same process that drives biological evolution. However, a modification of social behavior can accomplish the same goal at a much faster pace than natural selection. Among half of all primate species live in groups, he adds, while a third only form pairs; the rest (roughly one third) enjoy solitary lifestyles.

In order to understand what drives this behavioral adaptation process, which factors shape it, and how many times it occurred in the past, the team analyzed genetic data and behavioral observations of 362 primate species. The team found that the transition from a solitary way of life towards living in groups most often occurred through pair bonding. Thus, the propensity to form long-term pairs can be seen as the first step towards complex social structures, they explain.

There are two current hypotheses on the development of pair bonding, the team explains: the female spacing hypothesis and the paternal care hypothesis. The first hypothesis holds that “females pursue reproductive strategies that are not limited by the number of mates but by access to resources,” and that under certain conditions (such as high competition for food) females may spread out, limiting males’ ability to monopolize access to multiple females. The second one basically boils down to the idea that males may choose to focus on a single female because she either needs his help in raising the offspring (for protection, care, or provision) or to reduce the risk of strange males committing infanticide. Either way, the male in question enjoys greater net reproductive success even if he limits his mating opportunities. Evidence is mixed for both hypotheses, the team adds.

Up to now, the assumption was that these two hypotheses were mutually exclusive. But the team found that they were actually complimentary.

An initial ecological change led the females of a species to separate in space. Solitary males, which previously had several females living in their territory, were now only able to gain access to one female and started to invest more in their offspring to increase their chances of survival — thus reinforcing pair living. A further transition to group living was made possible through an improvement of the ecological situation, which allowed related females to live in close proximity once again, and they could then be joined by one or more males.

“However, the pair bond typical for humans within larger social units cannot be explained with our results, since none of our recent ancestors lived solitarily. Nevertheless, the advantages of paternal care also may have led to a consolidation of pair living in humans,” said Kappeler.

The paper “Evolutionary transitions towards pair living in non-human primates as stepping stones towards more complex societies,” has been published in the journal Science Advances.

Two-day long sexual ‘afterglow’ helps couples bond and feel more sexually satisfied after the deed

A study of newlywed couples found that partners show a sexual ‘afterglow’ after the deed which can last up to two days. This afterglow was linked with greater relationship satisfaction and a lower decline in satisfaction over time.

Image credits Alexas_Fotos / Pixabay.

Sex is a great couple activity to cement a relationship and help you bond with your partner. Even better, you don’t even have to leave the comfort of your house to do it. For all it’s usefulness to the couple and the obvious other benefits it brings to the table/bed/counter, people don’t usually have sex with their partners every day, but rather once every few days. So Andrea Meltzer, a psychological scientist at the Florida State University, and her team, theorized that the benefits of doing the do extends for longer than a day — providing a short-term boost to sexual satisfaction and promoting pair bonding between the partners, increasing overall relationship satisfaction over the long term.

“Our research shows that sexual satisfaction remains elevated 48 hours after sex,” says Meltzer, who was first author on the study.

“And people with a stronger sexual afterglow — that is, people who report a higher level of sexual satisfaction 48 hours after sex — report higher levels of relationship satisfaction several months later.”

Self-reported love

To test their theory, the team looked at data gathered from “two independent, longitudinal studies”, one with 96 newlywed couples and the other with 118 newlywed couples. These couples had completed at least three consecutive days of a 14-day daily diary task as part of a larger study looking at their daily sexual activity as well as sexual and marital satisfaction “at baseline” and 4 to 6 months later.

Every night before going to bed, the newlyweds were asked to independently report whether or not they had sex day with their partner that day. They also had to use a 7-point scale (1=not at all, 7=extremely) to rate how satisfied they were with their sex life, their partner, the relationship, and their marriage that day. They also completed three measures of marriage quality at the beginning of the study and during a follow-up session 4 to 6 months later.

Although the answers varied considerably among participants, on average they reported having sex 4 times during the two-week study. The team found a link between sex on a given day and greater self-reported sexual satisfaction over the next one or two days. So every ‘sex’ made the participants feel better about their sex lives for up to 48 hours. This link held strong throughout gender and age groups even after the team accounted for other factors such as personality traits, sexual frequency, or length of relationship.

All couples experienced a decline in marital satisfaction during the baseline and the follow-up session. But more importantly, participants who reported a relatively high level of sexual afterglow reported both higher initial marital satisfaction and less decline in satisfaction over the first 4 to 6 months of their marriage. The findings are consistent with those reached by the two independent studies, which Meltzer and her colleagues say provides strong evidence in favor of the sexual afterglow.

“This research is important because it joins other research suggesting that sex functions to keep couples pair bonded,” Meltzer concludes.

So what does this mean? Well, not only will sex feel good and make you feel life’s that one shade brighter afterwards, but it will also help maintain relationship quality over time. What more do you need? Grab that special someone and go bond the feathers out of each other.

The full paper “Quantifying the Sexual Afterglow: The Lingering Benefits of Sex and Their Implications for Pair-Bonded Relationships” has been published in the journal Psychological Science.

Lichens actually comprise a threesome, not a partnership

When the nature of lichens was discovered 140 years ago, they became the most prominent example of symbiosis, a term that defines a mutually beneficial relationship between two dissimilar organisms.

Image credit Pixabay

Image credit Pixabay

In the case of lichen, the filaments of a single fungus create protection for photosynthetic algae or cyanobacteria, which provide food for the fungus in return. However, a new study reveals that there is actually a third organism involved in this relationship – a yeast that likely provides the structure for “leafy” or “branching lichens.”

“These yeast are sort of hidden just below the surface,” said John McCutcheon, a genome biologist at the University of Montana, and senior author of the study. “People had probably seen these cells before and thought they were seeing something else. But the molecular techniques we used happened to be especially good for spotting the signal of a separate organism, and after years of looking at the data it finally occurred to us what we were seeing.”

McCutcheon’s team made the discovery after studying two lichen species obtained from Missoula, Montana mountains – Bryoria fremontii and B. tortuosa. Despite B. tortuosa possessing a yellow color due to the presence of vulpinic acid, genetic tests revealed identical fungus and alga in both species. However, they also discovered the genetic signature of a third species – a basidiomycete yeast – in both species, although it was more abundant in B. tortuosa.

Additional testing of 56 different lichens from around the world revealed that each one has its own variety of basidiomycete yeast, suggesting that lichens actually comprise a threesome, not a couple, essentially rewriting 150 years of biology.

The team believes that this newly discovered yeast could play a role in creating the large structures seen in macrolichens, which would explain why these particular lichens are hard to grow in the lab when using just a fungus and alga.

“This doesn’t prove that they’re necessary to create the structure of the macrolichens, or that they do anything else for that matter,” McCutcheon said. “But its early days. It took a lot of work just to discover that they were there. We’re interested if the yeast is making these important compounds, or possibly enabling the other fungus to make them. We don’t know, but it’s the obvious next question.”

Journal Reference: Basidiomycete yeasts in the cortex of ascomycete macrolichens. 21 July 2016. 10.1126/science.aaf8287