Why do puppies and cats shake their bodies after being splashed with water? | Nature Trumpet

Welcome to the 69th issue of the Nature Trumpet column. In the past half month, we have collected the following natural news and research worth reading:

1) The laziest insect, lying flat even after its nest was demolished

2) Critically endangered monkeys can survive by drinking salt water

3) Male mosquitoes fall in love with each other through hearing, and will not mate if they are deaf

4) Why does a dog shake its head when it gets wet?

5) The cat understands! The cat understands!

6) Investigating smuggling, the Rat Team made great contributions

The laziest insect

A tiny bug less than three millimeters in size may be the most prone insect in the world.

The lazy bug is coming! | References [1]

Their scientific name is Dunatothrips aneurae, a small insect of the family Thripidae, which lives in the Australian outback and usually lives in small nests in trees. They live a carefree life with almost no threat from predators. The biggest difficulty they may encounter is that if there is a hole in the nest, they have to face the high temperature outside.

Scientists recently discovered that some of these little bugs seem to do nothing - neither reproduce nor forage, just lie flat every day . If the nest is destroyed, only one or two females will come out to repair it, while the rest of the members continue to lie flat and enjoy the fruits of their labor.

Their nests are tiny in the golden silk trees | University of Hull

Scientists initially suspected that these lazy bugs might be a reserve workforce that would only start working if other members disappeared. However, even if the actively working bugs were removed, the remaining members just lay flat as before.

Finally, the scientists removed all the bugs in the nest, leaving only one lazy bug behind. It was supposed to work now! Unexpectedly, even when it was left alone, it rarely laid eggs or even did not lay eggs at all, and it was also slow to do things. It took five times longer to repair the nest than the normal bugs.

Dr James Gilbert spent three years in Australia studying the lives of these bugs | University of Hull

Why haven't these lazy group members been driven out yet? Scientists believe that these little bugs may be blown away just by standing on the leaves, and they may die at any time. Therefore, they tolerate the existence of lazy companions. After all, some of them may take over the work after their death and help their offspring survive . Moreover, these lazy bugs can also increase the humidity of the nest just by lying down to breathe, which helps the group survive, so it is not useless.

Monkey drinking salt water

There are fewer than 100 golden-headed langurs (Trachypithecus poliocephalus) left in the world, and they have the unique ability to survive by drinking salt water.

Golden-headed langurs use their tails to roll up salt water to drink | References [2]

The golden-headed langur is one of the rarest primates in the world and feeds mainly on leaves. They live on an isolated island in Vietnam where fresh water is very scarce. In order to survive in such an environment, they have evolved a strong adaptation ability to roll up salt water with their tails to drink, and a unique gene allows them to tolerate the high sodium content in salt water .

The golden-headed langur population is small and prone to problems caused by inbreeding and low genetic diversity. The good news is that scientists recently conducted genetic analysis on them and found that the genetic information responsible for their important functions still maintains a certain diversity , which allows them to adapt to changing environmental conditions and is conducive to the recovery of their population.

Golden-headed langurs are semi-arboreal | New England Primate Conservancy

It is estimated that when the habitat was not disturbed, the number of golden-headed langurs once reached 4,000-5,000. Because they live on small islands, they have no natural enemies, or rather, their only natural enemy is humans - it is rumored that their internal organs have medicinal effects, which has brought them to death , and their number has dropped sharply due to poaching. In addition, the loss of habitat has also caused their number to decrease year by year.

In 2004, there were only 40 of them left. Their number has now recovered to 85 , but they are still critically endangered and conservation plans are urgent.

Deaf mosquitoes don't mate

Humans fall in love at first sight, but male mosquitoes fall in love at first hearing.

Recently, scientists have discovered that the reason why male mosquitoes are attracted to females is actually very simple - it is the sound of female flapping wings . Female Aedes aegypti will flap their wings at a frequency of about 500 Hz. When males hear such sounds, they will fly up and mate with females quickly in the air. Moreover, if males are played the sound of female wings flapping, they will make preparations for mating even if there is no female present.

Female on left, male on right | NIAID / Wikimedia Commons

Except for the sound of female wings flapping, nothing else seems to arouse the sexual interest of male mosquitoes. Scientists used CRISPR-Cas9 technology to knock out the gene encoding TRPVa in Aedes aegypti, making them deaf. The results showed that once male mosquitoes can no longer hear anything, they become indifferent and have no interest in mating even if they live with female mosquitoes for several days. However, only male mosquitoes will fall in love at first sight, and females can still mate even if they lose their hearing.

The normal male mosquito on the left mates many times in a few minutes, while the hearing-impaired male mosquito on the right has no interest in females | Reference [3]

Aedes aegypti spreads dengue fever, leukemia and other insect-borne viruses, affecting hundreds of millions of people every year. Scientists have been racking their brains to kill mosquitoes. It has been found that deaf male mosquitoes no longer mate, and scientists may be able to create sterile male mosquitoes to suppress the mosquito population.

Dog shake shake shake

If a dog gets wet, he or she will immediately start shaking it off - why is that?

I'm shaking | kallerna / Wikimedia Commons

In a new study, scientists figured out how dogs' "auto-drying" function works. They found that there is a receptor called C-LTMR in the skin of mammals. If liquid stimulates this receptor, the animal will perform continuous shaking behavior. When they use optogenetics to activate this receptor, mice will shake as if they were caught in the rain even without liquid stimulation; if the genetic information of this receptor is knocked out in the genes of mice, they will shake 58% less than normal mice after getting wet.

Furry mammals, including cats, dogs and mice, all have this "automatic drying" function. Moreover, because they are all transmitted by the same skin receptors, their reactions are surprisingly consistent, generally shaking back and forth three times .

This is actually a defensive measure - in addition to getting wet, other physical stimuli can also activate C-LTMR receptors. For example, if a parasite crawls across the skin, they will also start shaking mode and get rid of potentially harmful things in one go.

Get rid of the bad stuff! | Mickey Samuni-Blank / Wikimedia Commons

So do humans, who are not furry, have an "auto-drying" function? If you touch the skin on the back of your neck, humans often shiver, but it is not known whether this has the same evolutionary history as the shivering reaction of cats and dogs.

Cats can associate

Cats' ability to understand language may have surpassed that of human toddlers.

What? Humans finally discovered that they are not as smart as us? | Agaz rafi / Wikimedia Commons

Scientists wanted to know if cats could associate images with language. They recruited 31 cat volunteers and asked them to watch a picture on a computer screen and play a meaningless word : one picture was paired with "kararu" and the other was paired with "parumo"; the loop continued until the cats lost interest and looked away. During this period, the cats did not receive any food rewards and were completely self-taught.

Cat volunteers are studying hard | References [5]

After a break, the cat volunteers were put in front of the screen again. This time, the picture and voice were reversed. The picture that was originally paired with "kararu" was now paired with "parumo". The scientists found that the cats' pupils dilated and stared at the screen, clearly showing their confusion - the word was wrong! ?

In the same test, cats have surpassed human infants - cats only need two 9-second learning sessions to learn the combination of pictures and words, while human infants need at least four 20-second sessions. This also shows that in our daily lives, pet cats at home can associate objects with words by listening to humans talk. As for whether they want to pay attention, that is another matter.

Don't let humans find out we're smart, or we'll be fired | Jeanne Griffin / Wikimedia Commons

Rat made great contributions

Shushu has made great contributions again!

Let us say: Thank you Shushu! | APOPO

The African giant rat is one of the largest rodents, with a body length of 70-80 cm including the tail and a lifespan of 4-8 years. Recently, a group of African giant rats (Cricetomys ansorgei) were trained to become a reconnaissance team to detect wildlife smuggling.

During training, a hamster with good performance is eating reward food | APOPO

Through olfactory training, they learned how to smell pangolin scales, ivory, rhino horns and East African blackwood , which are commonly illegally trafficked animals and plants. They also have customized small vests. Once they find the target substance, they can use their front paws to pull the small ball on the chest of the vest, making a beeping sound to alert the keepers.

When they find smuggled animals and plants, they pull the ball to sound the alarm | APOPO

Dogs seem to be more common in smuggling detection, so why train African giant rats?

In a container full of goods, their smaller size allows them to easily squeeze in and out of the cracks and quickly complete their tasks; they can also be lifted high to perform screening work from the ventilation system of the container. Moreover, rats are as capable as dogs at work - during training, it was found that even if they have not been exposed to previously learned smells for several months, they can still respond quickly when they smell them again, and their memory is similar to that of dogs . After the training, rats can accurately identify the smell of common smuggled wildlife and plants among 146 non-target substances.

Super detective, take the case seriously! | APOPO

The non-profit organization APOPO trained the African giant rats to detect smuggled goods. They also trained the African giant rats to do mine clearance work. The famous "hero rat" Magawa has found more than 100 mines or other explosives in his life, and was awarded the Gold Medal of Honor by the British Veterinary Charity, which is one of the highest animal honors in the UK.

Magawa the Golden Hero Mouse | APOPOP

References

[1] https://besjournals.onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2656.14204

[2] https://www.nature.com/articles/s41467-024-52811-7

[3] https://www.pnas.org/doi/10.1073/pnas.24043241

[4] https://www.science.org/doi/10.1126/science.adq8834

[5] https://www.nature.com/articles/s41598-024-74006-2

[6] https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1444

Author: Cat Tun

Editor: Mai Mai