Being a couch potato could have led to marital bliss in mantis shrimps

Date:

January 4, 2015

Source:

Society for Integrative and Comparative Biology (SICB)

Summary:

Being monogamous is an advantage for mantis shrimp, helping them to avoid predators, new research shows. A study shows that social monogamy, where one lives and shares resources with a single partner for an extended period of time, is rare in nature. So why did it evolve at all?

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Owl monkeys don't cheat

March 2014: True monogamy is rare in the animal kingdom. Even in species that appear to "mate for life," genetic maternity and paternity tests have revealed that philandering often takes place.

Yet a new study by University of Pennsylvania researchers shows that Azara's owl monkeys (Aotus azarae) are unusually faithful. The investigation of 35 offspring born to 17 owl monkey pairs turned up no evidence of cheating.

In addition to this the males were found to be significantly involved in caring for the couple’s young.

"Our study is the first of any primate species, and only the fourth for a pair-living mammal, to show genetic monogamy, or real faithfulness, between partners," said study author Eduardo Fernandez-Duque, an associate professor in Penn Arts and Sciences' Department of Anthropology. "Paternal care in owl monkeys now makes sense. The males are making a huge investment in their own offspring."

The Penn evolutionary anthropologists have been studying a population of these primates in Argentina's Chaco region for 18 years. Previous work had shown that male and female owl monkeys form strong pair-bonds and that males contribute significantly to raising young by carrying them on their bodies, playing with them and feeding them solid foods.

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Be Mine! Why Monogamy Evolved in Mammals

Male primates may have become monogamous to protect their offspring from being killed by rival males, a new study finds. However, others disagree, saying monogamy evolved in mammals so that males could guard their mates.

A team of British and Australian researchers compared data across 230 primate species over 75 million years, and found that the threat of infanticide — specifically, the threat of baby primates being killed by unrelated males — likely triggered monogamy.

Since infants are dependent on their mothers throughout childhood, and since female primates typically delay further conception while they are nurturing their young, male competitors may see advantages in doing away with babies that their rivals have sired, said study lead author Christopher Opie, a postdoctoral research fellow in the department of anthropology at the University College London in the United Kingdom. 

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Hawksbill turtles' monogamous sex life revealed

By Michelle Warwicker, BBC Nature

The sex lives of critically endangered hawksbill turtles have been revealed by scientists studying the animals in the Seychelles.

Previously, little had been understood about the mating habits of the turtles, which live underwater and often far out at sea.

Researchers were surprised to find that the turtles are mainly monogamous, with females storing sperm from one male and using it to fertilise multiple egg clutches.

The study, led by researchers from the University of East Anglia, Norwich, UK, was published in the online journal Molecular Ecology.

"Sperm storage" is found in animals including reptiles, birds and some turtles, tortoises and terrapins.

Females can store viable sperm from multiple males for long periods of time, meaning that their egg clutches are sometimes fertilised by more than one father.

Researchers carried out DNA testing from hawksbill turtle hatchlings on Cousine Island in the Seychelles to identify how many males were involved in fertilising eggs during a breeding season.

The tests revealed a monogamous mating system: most egg clutches were sired by just one male, and no males had fertilised more than one female during the 75-day season.

Read more:  http://www.bbc.co.uk/nature/21261584

Urban Coyotes Never Stray: New Study Finds 100 Percent Monogamy

ScienceDaily (Sep. 25, 2012) — Coyotes living in cities don't ever stray from their mates, and stay with each other till death do them part, according to a new study.

The finding sheds light on why the North American cousin of the dog and wolf, which is originally native to deserts and plains, is thriving today in urban areas.

Scientists with Ohio State University who genetically sampled 236 coyotes in the Chicago area over a six-year period found no evidence of polygamy -- of the animals having more than one mate -- nor of one mate ever leaving another while the other was still alive.

This was even though the coyotes exist in high population densities and have plenty of food to eat, which are conditions that often lead other dog family members, such as some fox species, to stray from their normal monogamy.

To cat around, as it were.

Continued: http://www.sciencedaily.com/releases/2012/09/120925142549.htm

Monogamy and the Immune System: Differences in Sexual Behavior Impact Bacteria Hosted and Genes That Control Immunity

ScienceDaily (Aug. 30, 2012) — In the foothills of the Santa Cruz Mountains two closely related species of mice share a habitat and a genetic lineage, but have very different social lives. The California mouse (Peromyscus californicus) is characterized by a lifetime of monogamy; the deer mouse (Peromyscus maniculatus) is sexually promiscuous.

Researchers at the University of California Berkeley recently showed how these differences in sexual behavior impact the bacteria hosted by each species as well as the diversity of the genes that control immunity. The results were published in the May 2012 edition of PLoS One.

Monogamy is a fairly rare trait in mammals, possessed by only five percent of species. Rarely do two related, but socially distinguishable, species live side-by-side. This makes these two species of mice interesting subjects for Matthew MacManes, a National Institutes of Health-sponsored post-doctoral fellow at UC Berkeley.

Continued:  http://www.sciencedaily.com/releases/2012/08/120830141405.htm

For Monogamous Sparrows, It Doesn't Pay to Stray (but They Do It Anyway)

ScienceDaily (May 22, 2012) — It's quite common for a female song sparrow to stray from her breeding partner and mate with the male next door, but a new study shows that sleeping around can be costly.

The 20-year study, which is reported in The American Naturalist, found that offspring conceived outside sparrows' social pairs go on to have lower reproductive success than within-pair offspring. The findings throw a monkey wrench into theories about why ostensibly monogamous animals might be inclined to cheat.

Most bird species display some form of monogamy. Bonded pairs stay together for a breeding season, a few seasons, or sometimes for life. But beneath this veneer of monogamy, there's plenty of hanky-panky in most species. Why promiscuity exists in monogamous species is "one of the biggest remaining enigmas in evolutionary ecology," said Jane Reid, a research fellow at the University of Aberdeen and one of the study's authors.

One hypothesis for this is that when a female strays she makes it count by mating with a male of higher genetic quality than her social mate. The result is higher-quality offspring that have a better chance of carrying a female's genes into future generations. This study, however, turns that explanation on its head.

Continued:  http://www.sciencedaily.com/releases/2012/05/120522152659.htm