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Comment by Dr. Krishna Kumari Challa on July 16, 2023 at 2:19pm

UV Light – More Than Just Sunburns

Comment by Dr. Krishna Kumari Challa on July 16, 2023 at 2:14pm

Robot assisted surgery with four arms

Comment by Dr. Krishna Kumari Challa on July 16, 2023 at 1:04pm

Crows and magpies using anti-bird spikes to build nests, researchers find
Dutch study identifies several examples of corvids’ ‘amazing’ ability to adapt to the urban environment.

Birds have never shied away from turning human rubbish into nesting materials, but even experts in the field have raised an eyebrow at the latest handiwork to emerge from urban crows and magpies.

Nests recovered from trees in Rotterdam in the Netherlands and Antwerp in Belgium were found to be constructed almost entirely from strips of long metal spikes that are often attached to buildings to deter birds from setting up home on the structures.

The discovery prompted researchers at the Natural History Museum in Rotterdam and the Naturalis Biodiversity Center in Leiden to scour the internet for further examples, leading to the identification of another anti-bird spike nest in Glasgow. One of the reviewers of the study then flagged a fourth nest in Enschede in the Netherlands.

While the Rotterdam nest was made by crows, the other three were built by magpies, which construct large dome-like nests. The crows used the anti-bird spikes as a sturdy construction material, but the magpies may have appreciated their intended use: they placed most of the spikes on the nest’s roof where they could deter predators, including other birds and weasels.
It is not the first time birds have been found to incorporate urban materials into their nests. In 1933, a South African museum reported a crow’s nest fashioned from hard-drawn copper, galvanised iron and barbed wire. Nails, screws and even drug users’ syringes have all found their way into birds’ nests.
Part 2

Comment by Dr. Krishna Kumari Challa on July 16, 2023 at 1:00pm

Birds build nests from anti-bird spikes

Crows and magpies are building nests with the metal spikes meant to deter them from perch.... Carrion
crows (Corvus corone) and Eurasian magpies (Pica pica) in The Netherlands, Belgium and Scotland were observed to have plucked the sharp metal pins off buildings to use in their nests. The magpies even put most of the spikes on top of their nests, perhaps in an anti-bird effort of their own (crows eat magpies’ eggs).

https://www.hetnatuurhistorisch.nl/fileadmin/user_upload/documents-...

Comment by Dr. Krishna Kumari Challa on July 14, 2023 at 12:13pm

Global study details microplastics contamination in lakes and reservoirs

Around 14 million tons of plastic end up in the ocean every year. But that is not the only water source where plastic represents a significant intrusion.

Scientists found microplastics in every lake they sampled. 

A new paper, titled "Plastic debris in lakes and reservoirs," reveals that concentrations of plastic found in freshwater environments are actually higher than those found in so-called "garbage patches" in the ocean. The article is published in Nature.

Veronica Nava et al, Plastic debris in lakes and reservoirs, Nature (2023). DOI: 10.1038/s41586-023-06168-4

Comment by Dr. Krishna Kumari Challa on July 14, 2023 at 11:54am

Humans' impact on Earth began a new epoch in the 1950s called the Anthropocene, scientists say

From climate change to species loss and pollution, humans have etched their impact on Earth with such strength and permanence since the middle of the 20th century that a special team of scientists says a new geologic epoch began then.

Called the Anthropocene—and derived from the Greek terms for "human" and "new"—this epoch started sometime between 1950 and 1954, according to the scientists. While there is evidence worldwide that captures the impact of burning fossil fuels, detonating nuclear weapons and dumping fertilizers and plastics on land and in waterways, the scientists are proposing a small but deep lake outside of Toronto, Canada—Crawford Lake—to place a historic marker.

It's quite clear that the scale of change has intensified unbelievably and that has to be human impact. This puts the power of humans in a somewhat similar class with the meteorite that crashed into Earth 66 million years ago, killing off dinosaurs and starting the Cenozoic Era, or what is conversationally known as the age of mammals. But not quite. While that meteorite started a whole new era, the working group is proposing that humans only started a new epoch, which is a much smaller geologic time period.

The scientists aims to determine a specific start date of the Anthropocene by measuring plutonium levels at the bottom of Crawford Lake. Crawford Lake, which is 79 feet (29 meters) deep and 258,333 square feet (24,000 square meters) in area, was chosen over 11 other sites because the annual effects of human activity on the earth's soil, atmosphere and biology are so clearly preserved in its layers of sediment. That includes everything from nuclear fallout to species-threatening pollution to steadily rising temperatures.

The remarkably preserved annual record of deposition in Crawford Lake is truly amazing.

The Anthropocene shows the power—and hubris—of humankind. But the reality is that our power to transform the environment has far exceeded our understanding of the consequences and our capacity to change course.

Source: 2023 The Associated Press

https://phys.org/news/2023-07-humans-impact-earth-began-epoch.html?...

Comment by Dr. Krishna Kumari Challa on July 11, 2023 at 11:39am

The latter possibility is particularly intriguing as it suggests that male harvestmen can permanently 'lay down their weapons' and adopt a new lifestyle that doesn't rely on competition. So even when males have fewer legs to stand on, they can still find ways to reproduce.

If that's the case, then Charles Darwin's theory of sexual selection, which puts great emphasis on sexual ornaments and weapons, may not be fully comprehensive; there could be other ways to snag a mate in nature.

In fact, the same male dung beetles that Darwin once used to support his theory of sexual selection over a century ago, turned out to be trimorphic as well. This means that not all male dung beetles possess large mandibles for fighting other males or wooing females.

--

While trimorphism can be a result of different genetics, creating various male roles in a society, in the case of dung beetles and harvestmen, the phenomenon seems to have less to do with how animals are born and more to do with how they grow up.

What happens in their youth seems to determine how they develop sexually.

Further research will be needed to explore what sets alpha and beta males apart.

https://academic.oup.com/beheco/article/34/4/613/7160263?login=false

Part 2

Comment by Dr. Krishna Kumari Challa on July 11, 2023 at 11:38am

An Arachnid that has three Different Kinds of Male

Scientists have found a rare species of arachnid in New Zealand that hosts three different types of males. Recent findings on the species are forcing a rethink of animal mating systems and the evolution of reproductive strategies.

We've known since 2020 that while male harvestmen (Forsteropsalis pureora) – or daddy longlegs, as you might better know them – look the same and have similar genes, there seemed to be three distinct types.

At the top of the hierarchy sits the large alpha male, which has short yet strong pincer-like jaws that it uses to pin down competition when fighting for territory or mates.

Next comes the beta male, which has longer and thinner pincers. And in last place is the gamma male, which is seven times smaller than the other two.

Not only do gamma males look different from the others, but they also act differently.

Instead of battling for female mates like their larger peers, researchers found these smaller, weaponless males have all but given up the fight.

Their tactic for survival involves sneaking around and looking for undefended females to reproduce with.

The rare pecking order is known as trimorphism, and researchers only discovered it among animals for the first time in 2009.

Now, researchers at the University of Auckland – many of whom conducted the 2020 study – think they have figured out why trimorphism evolves among harvestmen in particular.

According to the new study, if a male harvestman loses a leg in his youth, voluntarily 'dropping' a limb to avoid a hungry predator, the harvestman can't regrow the lost limb and is 45 times more likely to grow up smaller and weaker than his peers. Perhaps this is because they can't get enough food for their development because their hunting is impeded.

Or maybe there's no point in investing in big fighting weapons when they're already disadvantaged when it comes to fighting. So, the arachnids' resources may be invested in other things, such as testes size, sperm count, or aerobic poise, to ensure they make the most of the mating opportunities they get.

Part 1

Comment by Dr. Krishna Kumari Challa on July 11, 2023 at 11:25am

Fertility Mystery: IVF Success Is Higher if Eggs Harvested in Summer

There's something about the seasons that seems to impact human reproduction for unknown reasons.

A new study  has found in vitro fertilization (IVF) is most successful when eggs are harvested in the summer.

It doesn't seem to matter when the frozen embryo is actually transferred to a person's womb, only when it is originally collected.

If eggs are retrieved in summer, the live birth rate is 31 percent; if eggs are collected in autumn, the live birth rate is 26 percent.

Meanwhile, eggs collected in winter and spring sit between these two success rates.

While previous IVF studies found seasons have no consistent impact on embryo transfers, implantation, pregnancy, or live birth rates, egg collection seems to be a different matter.

Of all these embryos, those collected on days with more than 10 hours of sunshine were 28 percent more likely to result in a live birth than those collected when the sun showed its face for less than 7 hours a day.

However, the actual temperature of the day didn't seem to have an impact.

The research was done in hindsight, so it can't reveal a direct cause and effect.

 a similar 2022 study in the Northern Hemisphere found that the season and temperature at the time of egg retrieval significantly impacted the subsequent live birth rate.

Specifically, eggs collected during summer in Boston were 42 percent more likely to result in a live birth than those collected during winter. Meanwhile, eggs collected on the warmest days were 34 percent more likely to result in a live birth than eggs collected on the coldest days.

The findings suggest that seasons can have an important effect on a person's ovarian function, although not necessarily the receptiveness of their uterus or the early development of a fetus.

The two studies disagree, however, on whether ambient temperature or the duration of bright sunshine is the more important seasonal factor impacting embryo retrieval, possibly via vitamin D or the production of melatonin.

Maybe it's neither.

https://academic.oup.com/humrep/advance-article/doi/10.1093/humrep/...

Comment by Dr. Krishna Kumari Challa on July 10, 2023 at 1:49pm

Animals who mate during a heat wave less likely to reproduce successfully, new study shows

As the planet continues to warm due to global climate change, the frequency and intensity of extreme weather events, such as heat waves, is rising. Heat waves are not just uncomfortable for humans; they also pose significant challenges for animals. Heat stress caused by these extreme events can disrupt all aspects of animal reproduction. The findings also show that when a heat wave occurs during mating, offspring are smaller and have lower survival rates.

Understanding how animals are affected by climate change is vital, and the research looked at the potential effects of heat waves, and in particular, the role of the timing of a heat wave event, within an organism's reproductive cycle.

Researchers  found that the timing of the heat wave really matters: when it occurs a few days before or after mating, it has little to no effect on reproductive processes. In contrast, when the heat wave occurs during mating, parents are less likely to reproduce successfully, and their offspring are smaller and have lower survival.

The research provides novel insights and can improve the ability to make informed predictions about the ecological consequences of heat waves under climate change.

The implications of these findings extend well beyond this specific insect species, and they highlight the need to investigate these effects more broadly.

Predicting how wild populations will be affected by climate change is a challenging endeavor. This study provides another piece of the puzzle and helps us form a more complete picture of how heat waves might shape animal reproduction and population survival.

Natalie Pilakouta et al, The consequences of heatwaves for animal reproduction are timing‐dependent, Functional Ecology (2023). DOI: 10.1111/1365-2435.14386

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