Love and Biology

From Ihle, Kempenaers, and Forstmeier

From Ihle, Kempenaers, and Forstmeier

If two people marry each other to mutually benefit each other’s rise to the top of the political ladder or because their combined wealth will give their child a worry free life, what’s love got to do with it? If a man married his wife because his mother arranged it, would that affect the affection he showed towards their son? Researchers of the German Max Planck Institute for Ornithology studied zebra finches to find out if being able to freely choose one’s mate, ensured reproductive success.

The zebra finch is a monogamous species of bird that tends to stay with its chosen mate for life. With only one mate, however, the rate at which baby finches can be produced is limited. With the goal of creating offspring that will continue to pass down genes, many organisms including lions, deer, and crickets choose the polyandrous route and mate with numerous partners. The married zebra finch is not at a disadvantage, however. Fitness is a means of gauging success in passing on genes. This study found the relative fitness of finch pairs that chose their mate and compared it to those whose mate was chosen for them.

160 zebra finches freely chose a partner of the opposite sex. Following, half of the pairs were assigned to a random partner instead of their chosen one. Two more rounds of either allowing pairs to stay together or force choosing a partner for them followed this. After each pairing cycle, the couples were allowed to court and mate (get to know each other and have sex). Either good parenting or good genes would be the factor to determine if the group of finches choosing their own mate or the group with their mate chosen for them as having more fitness.

The study found the pairs of finches whom chose their own partners (C) were 37% more reproductively fit than pairs with mates force chosen for them (F). Many factors played into this:

– (C) vs. (F)
– Divorce rate: 8% vs. 24%
– Disappeared or buried eggs: 12% vs. 19%
– Offspring mortality: 32% vs. 52%
– Male courting outside his pair: Once every five hours vs. once every three hours

The higher fitness of zebra finch pairs that chose their own mates (C) supports the behavioral compatibility model. The finch pairs may have chosen each other based on harmony in parenting or general behavior according to the study. The downfalls seen within the (F) pairs were lower nest attendance by males, reduced motivation to care for young, chronic stress with a forced mate, lower female responsiveness, and higher male cheating rates with compatibility not increasing as marriages lengthened.

Is love the ultimate motivator for ensuring family success? Studies with people follow similar conclusions to this study in that emotionally satisfying relationships showed more commitment and less domestic violence. Lions can have their harem. I for one am a proponent of love (and so is science it seems).

Reference:
Malika Ihle, Bart Kempenaers, Wolfgang Forstmeier. Fitness Benefits of Mate Choice for Compatibility in a Socially Monogamous Species. PLOS Biology, 2015.
DOI: 10.1371/journal.pbio.1002248

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Resveratrol Vs. Exercise

Photo provided by  Anthony L. Hall

Photo provided by Anthony L. Hall

Exercise proves itself yet again as a more powerful way to stay healthy than taking dietary supplements. The department of sport science at Chungnam National University is where research was done to study the effectiveness of exercise versus resveratrol on fighting fat.

Resveratrol is a nutrient found in many foods that has become famous in recent years for its benefits of reducing blood pressure, protecting the heart, and preventing neuro-degenerative diseases. Specifically related to this research, resveratrol can increase metabolism, reduce lipids in the body, and help weight loss. It has been touted as an alternative to exercise.

To test this, 30 obese mice were assorted into three groups of 10: (R) mice were given resveratrol five days per week (10mg/kg of body weight), (E) mice exercised (30-60 minutes of treadmill running for five days a week), (C) mice acted as the control. All mice were on a low fat diet for eight weeks along with their group’s regimen during the study. The concluding results showed an average weight loss of 15% for (E) mice and about 5% for (R) compared to the controls (C). The higher weight loss most likely resulted from increased fat breakdown and blockage of new fat creation seen from exercise.

Although resveratrol has many highly sought after health benefits, it cannot beat good ol’ fashioned exercise in the battle against obesity.

Reference:
Jun Hyun Jeong, Hee Geun Park, Young Ran Lee, Wang Lok Lee. Moderate exercise training is more effective than resveratrol supplementation for ameliorating lipid metabolic complication in skeletal muscle of high fat diet-induced obese mice. The Journal of Exercise Nutricion & Biochemistry, 2015
http://dx.doi.org/10.5717/jenb.2015.19.2.131