Female gorillas must balance the reproductive costs of staying with or leaving an older male

Date: September 11, 2019

Source: Max Planck Institute for Evolutionary Anthropology

When a gorilla group's silverback is close to the end of his reproductive years, females face a dilemma: Should they stay with him until he dies or leave him for another male? A team of researchers has now found that both strategies bear its costs: females face reproductive costs of staying with an older male as well as costs when they transfer to a new silverback.

In western lowland gorillas, groups consist of several females and only one adult male, the silverback. With his impressive body size, he protects his group against predators and other adult males. Females rely on this protection and never travel alone, however they may change groups multiple times during their lives. "Female gorillas seem to have different strategies when it comes to reproduction and transfer," says Marie Manguette, first author of the study. "We have observed females transferring to another group after every weaned offspring and therefore up to six times in their lives, while others have stayed and bred with the same male for 20 years."

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Scientific evaluation of rhino diets improves zoo

Study highlights success of changing diet for reproduction in endangered species

Date:  October 26, 2017

Source:  San Diego Zoo Global

A recently published study in the journal Pachyderm highlights the ongoing effort of accredited zoos to address challenges and improve the sustainability of endangered species populations in their care. The study, co-authored by scientists from San Diego Zoo Global and Mars Hill University, evaluated fertility issues in captive-born southern white rhinos and determined that diets including soy and alfalfa were likely contributors to breeding challenges.

"The captive southern white rhinoceros (SWR) population is not currently self-sustaining, due to the reproductive failure of captive-born females," said Christopher Tubbs Ph.D, San Diego Zoo Global and lead author of the paper. "Our research into this phenomenon points to chemicals produced by plants present in captive diets, such as soy and alfalfa, as likely causes."

Read more  

Female dolphins have weaponised their vaginas to fend off males

11 October 2017

By Josh Gabbatiss

Some female dolphins have evolved a secret weapon in their sexual arms race with males: vaginas that protect them from fertilisation by unwelcome partners.

Penises come in a wide variety of shapes and sizes, especially in dolphins and other cetaceans. That seems to imply a similar diversity in vaginas, but Dara Orbach of Dalhousie University, Canada, says there is “a huge lag” in our understanding of female genitalia.

That is partly because it is tricky to visualise vaginal structure. To overcome this problem, Orbach has created silicone moulds of cetaceans’ vaginas, revealing complex folds and spirals.

“There’s this unparalleled level of vaginal diversity that we had no idea existed before,” Orbach says.

Similarly complex vaginal structures are found in several species of duck. Orbach’s collaborator Patricia Brennan of Mount Holyoke College, Massachusetts, has previously found evidence that duck vaginas have evolved to make it harder for males to force copulation. So Orbach wondered if female cetaceans’ unusual vaginas had also evolved to keep out unwanted sperm.

Orbach, Brennan and their colleagues obtained genitals from marine mammals that had died of natural causes: common and bottlenose dolphins, common porpoises and common seals. They inflated the males’ penises with saline to see how they looked when they were erect, and compared them with the vaginal moulds. They also took CT scans of penises inserted into the corresponding vaginas, to determine whether they fitted in easily and the best positions.

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Rise of male individuals in stingless bees colonies leads to queen's death

August 30, 2017

Queens of stingless bee species (Meliponini) face a reproductive dilemma. If they mate with males with which they turn out to share the same sex determination gene, half of their offspring will consist of males, and the colony's workforce will fall by half, given that effectively only the females are workers.

In addition, males with both paternal and maternal (diploid) genetic material as a result of this unfortunate choice by the queen only consume the resources collected by workers and are usually sterile, contributing to diminished reproductive chances for the colony. A research project supported by the São Paulo Research Foundation (FAPESP) involving a team of scientists in universities of Brazil, Belgium, and the United Kingdom shows that the emergence of diploid males from this type of mating also leads to the death of the queen in colonies of the stingless bee species Scaptotrigona depilis.

According to Ayrton Vollet-Neto, first author of the study, the results suggest that this behavior may be common to all stingless bee species because it occurs in phylogenetically distant genera.

One possible explanation for the death of a queen that doesn't comply with the role of maintaining a proportional rate of worker bees in the colony is that a replacement daughter queen will be able to mate and ensure the colony's survival. Otherwise, the most probable outcome would be the death of the colony. "If the queen is killed quickly, she can be replaced by a daughter that will have a chance to mate with a male that doesn't have the same sex allele," Vollet-Neto said.

Read more at: 

Warming world harming insects' reproduction, says study

By Mark Kinver Environment reporter, BBC News

10 January 2017

A warming world harms insects' ability to reproduce, which could have long-term consequences, scientists warn.

UK researchers also found that insects in northern latitudes were more vulnerable than their southern-dwelling cousins.

The team added that many insects were unable to move great distances while they are juveniles. Therefore, they are at risk from a warming climate.

The findings have been published in the Journal of Evolutionary Biology.

"You get an extreme heat weather event that [the insect] cannot escape from because they are juveniles, so they can't move as much," explained co-author Rhonda Snook from the University of Sheffield, UK. 

"They live through it because it does not kill them, but then they have the subsequent problem of reproducing."

Lasting damage

Dr Snook said the insects in the team's experiments were exposed to a temperature increase of 5.5C (9.9F) for 10 days, which was enough to cause permanent damage to the insects' ability to reproduce.

She said the team was interested in studying the effect of temperature rises in organisms that were unable to move away from their immediate environment.

"Lots of insects in their juvenile stage can't move very far because they are larvae or because they are small nymphs - they are smaller and they do not have wings so they are not as mobile so they're stuck where they are."

Dr Snook told BBC News that the team carried out the experiments on fruit flies but she expected the results to be replicated in many other insects.

"I think that this is going to be a very common effect, a very common phenomenon across insects."

The team examined the effect of increased ambient temperature rise on two populations of fruit flies: one from Spain and another from Sweden.

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Personality tests for fish could help boost reproduction rates

Date: November 9, 2016

Source: University of Stirling


Aquaculture experts from the University of Stirling and the Institute for Food and Agricultural Research and Technology (IRTA) in Catalonia, have found the way fish, Senegalese sole, cope with stress is determined by their personality and remains consistent regardless of the situation they are in.

Experts hope the first study to test stress copying styles in mature Senegalese sole, will help farmers screen fish from a young age to help the species reproduce in captivity and improve aquaculture production.

Scientists found when faced with confinement, restraint or a new environment, younger fish known as juveniles and older fish known as breeders, had similar behavioural patterns and levels of activity, showing consistent responses in animals of different ages.

There was also a correlation between how individuals with the same sort of personality acted across the various tests, suggesting that those who are reactive and fearful or proactive and curious, maintain this behaviour.


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Predictive model to analyse the reproductive status of wolf packs

June 20, 2016

Researchers at the Universitat de València's Cavanilles Institute of Biodiversity and Evolutionary Biology evaluated the usefulness of bioacoustic tools as a means of establishing the reproductive status of wolf populations.

Population monitoring is crucial for wildlife management and conservation. Wildlife researchers have increasingly applied tools that mimic the sounds of animals in order to establish ecological parameters such as distribution and abundance. The wolves respond to the simulated calls with what are known as chorus howls, which can then be analysed.

What the scientists are working on is the development of tools that can analyse the acoustic structure of chorus howls to ascertain the presence of wolf pups, as an indicator of the reproductive health of the pack. The complexity of the wolf chorus is such that this is a difficult task even for experienced observers, creating the need for accurate predictive tools.

Vicente Palacios of the Cavanilles Institute explains that to develop the tools, they first analysed 110 Iberian chorus howls of packs whose make-up was known, including packs with and without pups. The analysis revealed that the acoustic energy distribution of packs with pups was concentrated at higher frequencies than packs without. Based on this and other energy distribution features identified in the study, the team built mathematical models that were able to accurately predict the presence (or absence) of pups in 94 percent of the cases analysed.

As José V. López-Bao of the University of Oviedo says, the quantitative analysis of chorus howls is an objective method for establishing reproductive status that gives accurate results, is easy to implement and is independent of the observer's subjective experience. "These advantages become significant when monitoring large wolf packs, or cases where many observers are involved," he adds.

Read more at: 

Night frog species uses a never-before-seen mating method

JUNE 15, 2016

by Chuck Bednar

An elusive, nocturnal breed of frog native to the Western Ghats region of India has a few never-before-seen tricks up its sleeve when it comes time to get intimate, as scientists have found that the creatures use a previously unknown mating position when actively reproducing.

Sathyabhama Das Biju, an amphibian expert from the University of Delhi, and an international team of colleagues were studying Bombay night frogs (Nyctibatrachus humayuni) in the forests of the Western Ghats for weeks before finding out that the amphibians utilized a sexual position previously unknown to science, adding to the six already known to be used by frogs.

According to Science News, video footage shows the male frog positioning himself loosely on the back of the female, with his limbs on the ground, tree branches or leaves in a position known as a dorsal straddle. He then releases his sperm onto her back, and leaves before the female lays her eggs. She then lays the eggs, and the sperm trickles down her back and legs onto them.

To date, Bombay tree frogs are the only of the more than 6,600 known species of frogs to use this technique, The Guardian noted, and in most cases, the male directly grasps onto the waste, armpits or head of his mate. However, in this case, they steadied themselves using branches or leaves that were nearby before releasing his sperm directly onto the female’s back.

Read more at

Panda feces study provides insights into microbiome, reproductive troubles

Date: May 18, 2016

Source: University of Wisconsin-Madison

A stomachache can put a real damper on your love life -- especially if you're a giant panda.

One minute it's breeding season and you're happily dining on fresh bamboo leaves, the next you're left clutching your stomach while your gastrointestinal lining passes through your system. It exits your body as a thick, gooey, gelatinous mass.

This is exactly what seems to happen to captive giant pandas, and the researchers behind a new study published in Frontiers in Microbiology are beginning to suspect it may play a role in their struggles to reproduce.

"We think they are sloughing off the internal mucous membrane of their gastrointestinal tract and because of this, they get really sick, which coincides with gestation," says Garret Suen, a University of Wisconsin-Madison professor of bacteriology and co-author of the panda poop and feeding behavior study. "The pandas stop eating and they produce these painful, membranous fecal pellets."

No one quite understands why these gelatinous masses, called mucoids, happen but Suen and his co-authors believe bamboo may be a factor. Evolutionarily speaking, giant pandas are not built to eat a sole diet of bamboo. As bears, their digestive systems are designed to break down meat and small amounts of plant material, yet in the wild and in captivity these bears are exclusively herbivorous. The study suggests this may lead to digestive troubles that could negatively affect panda pregnancy. It motivated the researchers to take a closer look at the gut bacteria involved.

"Gastrointestinal diseases are a major cause of mortality in wild and captive pandas but scientists understand very little about their digestive process," says co-author Ashli Brown Johnson, state chemist and Mississippi State University associate professor of biochemistry, molecular biology, entomology and plant pathology. "By studying the microbial community in the panda's gastrointestinal tract, we gain a better understanding of panda nutrition, which could help improve the health and reproduction of the endangered species."

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Big monkey voice 'means less sperm'

By Victoria Gill

Science reporter, BBC News

23 October 2015 

The deep, growling roar of the howler monkey may hide reproductive shortcomings, according to biologists.

A study by an international team of scientists has revealed that the primates either develop big voices, or big testes - but not both.

Scientists made the discovery while trying to understand the "evolution of the animals' incredible roars".

The findings suggest such evolutionary trade-offs may be more common that previously thought.

They are published in the journal Current Biology.

Howler monkeys are named for their impressive howling roars - sounds they make to intimidate rivals and impress potential mates.

And their anatomical musical instrument is a bone in their throat called the hyoid bone, which acts as a resonator

Read on ...

Baleen hormones increase understanding of bowhead whale reproduction

Date:

January 4, 2015

Source:

Society for Integrative and Comparative Biology (SICB)

Summary:

Wild animals provide a unique challenge for physiologists because they are difficult to capture and monitor in their natural habitats. As a result, scientists are increasingly learning about organisms by extracting steroid hormones out of keratinized tissues. This includes hormones such as testosterone, progesterone, and cortisol that are deposited in feathers, human hair, and reptile claws as these tissues grow. A onetime capture and removal of a single sample can provide a scientist with a record of fluctuating amounts of hormone in the body over the growth period of the collected sample. This technique provides a wealth of information about an animal, including its reproductive history. Development of this method is now underway to monitor the reproduction of one of the largest organisms on earth, the bowhead whale.

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Rare bush frog breeds in bamboo, researchers discover

Date:

October 28, 2014

Source:

National University of Singapore

Summary:

Researchers have discovered a new reproductive mode in frogs and toads -- breeding and laying direct developing eggs in live bamboo with narrow openings -- which was observed in the white spotted bush frog (Raorchestes chalazodes). This critically endangered frog is currently only one of two species known to adopt this novel reproductive strategy.

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Researchers discover what causes honeybees to prepare for reproduction

When a colony of honeybees reaches the first stage in its reproductive cycle it builds a special type of comb used for rearing male reproductive bees, called drones. But what triggers that first stage?

A team of experts from the Department of Neurobiology and Behaviour at Cornell University, led by Michael Smith, set out to answer that question reports the journalNaturwissenschaften - The Science of Nature.

Reproduction isn’t always a honeybee colony’s top priority. Early in a colony’s development, its primary focus is on survival and growth.

However, when the colony reaches a certain stage, its workers start investing in reproduction. The first step is building cells of drone comb, the special comb made up of large cells in which the drones are reared.

Drones develop from unfertilised eggs. Their sole purpose in a colony is to mate with virgin queens from other colonies, thereby spreading the genes of the colony that produced the successful drones.

Read on ...

Having and raising offspring is costly phase of life for baboon moms

Date:

May 19, 2014

Source:

Springer Science+Business Media

Summary:

Observations made over the past 29 years in Kenya as part of one of the world's longest-running studies of a wild primate show how having offspring influences the health of female baboons. These observations highlight that females are mostly injured on days when they are likely to conceive. In addition, injuries heal the slowest when they are suckling their young. Reproduction can be dangerous and energetically costly, exposing individuals to physical harm, infectious disease and reduced immunity.

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How Queen Bees Reign Over Reproduction

By Tanya Lewis, Staff Writer | January 16, 2014 02:29pm ET

When it comes to reproduction in social insects, nobody competes with the queen.

For some time, scientists have known that queen insects give off chemical signals that prevent workers from reproducing. When a queen kicks the bucket, the signals wear off, and the workers become fertile again. Now, researchers have found that queen ants, wasps and bumblebees all use a similar type of chemical to signal fertility, which their ancestors evolved millions of years ago.

Read on

Mystery of 'Zombie Worm' Development Unveiled

Mar. 12, 2013 — How do bone-eating worms reproduce? A new study by Norio Miyamoto and colleagues from the Japan Agency for Marine-Earth Science and Technology sheds light on this question through a detailed observation of the postembryonic development and sexual maturation of Osedax worms, also known as "zombie worms." These worms typically inhabit vertebrate bones on the seafloor.

The study is published online in Springer's journal Naturwissenschaften -- The Science of Nature.

An adult female exposed from a bone.

(Credit: Norio Miyamoto/Naturwissenschaften)

Osedax is Latin for "bone-devourer," which refers to how the worms bore into the bones of whale carcasses to reach enclosed fats and oils, on which they rely for sustenance. The first two species of Osedax were discovered by scientists in 2002. To date, information about the postembryonic development of these marine worms, Osedax species, is lacking. In order to understand their development and maturation, Miyamoto and team induced settlement of the bone-eating worm's larvae (Osedax japonicus specifically) by adding small pieces of whale bone to the petri dishes in which they were cultivating the larvae. After a period of time, they dissected the bones to observe the juvenile worms.

Read on:  http://www.sciencedaily.com/releases/2013/03/130312134518.htm

Reproductive Workings of a Harvester Ant Dynasty

Feb. 12, 2013 — Ants are just about everywhere you look, and yet it's largely unknown how they manage to be so ubiquitous. Scientists have understood the carnal mechanism of ant reproduction, but until now have known little of how successful the daughters of a colony are when they attempt to found new colonies.

For the first time, Stanford biologists have been able to identify specific parent ants and their own children in wild ant colonies, making it possible to study reproduction trends.

And in a remarkable display of longevity, an original queen ant was found to be producing new ants several decades after mating, sending out daughter queens throughout her 20- to 30-year lifespan.

"Most animals produce offspring for a while, and then they enter a life stage where they don't," Gordon said. "These queen ants are mating once, storing that sperm in a special sac, keeping it alive and using it to fertilize eggs for another 25 years."

From an ecological viewpoint, an ant colony is much like a tree putting out seeds, with the potential to create new trees. An ant queen produces genetically identical worker ants that live in the same colony, and also produces sons, and daughter queens. The daughter queens, after mating, establish new colonies of their own.

Deborah Gordon, a biology professor at Stanford and a senior fellow at the Stanford Woods Institute for the Environment, has been studying a particular population of harvester ant colonies in southeastern Arizona for 28 years, meticulously recording when a new colony rises or an older one falls.

Read on:  http://www.sciencedaily.com/releases/2013/02/130212154619.htm

Owl Monkeys Who 'Stay True' Reproduce More Than Those With Multiple Partners

Jan. 23, 2013 — Breaking up is hard to do -- and can be detrimental to one's reproductive fitness, according to a new University of Pennsylvania study.

Focusing on wide-eyed, nocturnal owl monkeys, considered a socially monogamous species, the research reveals that, when an owl monkey pair is severed by an intruding individual, the mate who takes up with a new partner produces fewer offspring than a monkey who sticks with its tried-and-true partner.

The findings underscore how monogamy and pair-bonds -- relatively rare social formations among mammals -- can benefit certain individuals, with potential implications for understanding how human relationship patterns may have evolved.

Eduardo Fernandez-Duque and Maren Huck report on the research inPLOS ONE. Fernandez-Duque is an associate professor in Penn's Department of Anthropology. Huck completed a postdoctoral fellowship in Fernandez-Duque's laboratory and is now a professor at the University of Derby in the United Kingdom.

Since 1997, Fernandez-Duque and colleagues have monitored an owl monkey population in a portion of Argentina's Chaco region. Their behavioral observations, demographic data and physiological sampling have provided a wealth of information on the animals.

Read more:  http://www.sciencedaily.com/releases/2013/01/130123195256.htm

Antarctic molluscs 'switch sex'

Antarctic bivalves have surprised scientists who have discovered that the animals switch sex.

The reproduction of Lissarca miliaris was studied in the 1970s and the species was first described in 1845.

But their hermaphrodite nature had remained unknown until they were studied by scientists from the National Oceanography Centre, Southampton.

Researchers suggest the molluscs could switch between the sexes to efficiently reproduce in the extremely cold ocean.

The results are published in the journal Polar Biology.

"The previous reproductive study only looked at the large eggs and broods," said PhD student and lead author Adam Reed.

This earlier work showed how females brood their young for up to 18 months, from "large yolky eggs" to "fully shelled young", and found that females can support as many as 70 young inside their hinged shell.

But concentrating on reproduction at a cellular level, Mr Reed and colleagues discovered that the eggs were actually present in males.

Continued:  http://www.bbc.co.uk/nature/19543557