You will never guess what kind of animal this doorknob is! | Nature Trumpet

In the past half month, we have collected these interesting natural news:

1) An "alien creature" appeared, hanging all over door handles;

2) To stop lions from fighting, people used "love hormones";

3) The fish learned addition and subtraction, and got a good score on the test;

4) Being big and dumb may be the winning formula;

5) Okra can be used to remove microplastics from water.

Door handles all over the body

Guess what animal this thing that looks like a squeeze toy is👇

Figure | References [1]

I kid you not, this is the queen ant still in the larvae stage!

This strange-looking queen belongs to the common house ant (Monomorium triviale), which is mainly distributed in China, Japan and South Korea. The queen ant develops from a fertilized egg cell. As it grows up, the larvae's exoskeleton will be shed regularly, and each time they molt, they will change their appearance. The first few looks are mediocre, but in the final stage, the appearance of the queen ant larvae becomes very unique: its body is almost hairless, but it has 37 lumps like door handles, which looks like a curious-looking toy (it seems to feel good).

When they first hatch, the queen ant larvae look ordinary | References [1]

These strange lumps are made of skin and stratum corneum, and are twice as thick as other parts of the body, but there are neither muscles nor ducts inside. As for the purpose of these lumps, no one knows yet, and researchers have proposed many possibilities: as a support for the body, a weapon to prevent being killed by other larvae, an adhesive tool for attaching to the top and walls of the nest, and for grabbing food... Scientists are preparing to study the behavior of the larvae to find out the real purpose of the "door handles".

The busy common house ant | SShattuck, antwiki.org

Spraying "love hormones" on lions

As top predators, lions never have the word "making friends" in their dictionary. When they encounter their own kind, their first choice is to roar the other party away or have a big fight - until they are sprayed with oxytocin.

Oxytocin is very important for human partnerships and childbirth, so it is called the "love hormone." Researchers sprayed oxytocin on the noses of 23 lions, and the lions' facial features softened immediately. Their faces, which were originally wrinkled and aggressive, instantly became calm and serene. The lions, who had just been "intolerant of any sand in their eyes," suddenly became much more tolerant of their peers in the same space - when playing with toys, the average distance between two lions was 7 meters; after spraying oxytocin, the distance dropped to 3.5 meters. Moreover, the lions' vigilance against intruders also decreased.

It is not easy to spray lions with oxytocin. Researchers need to lure them to the railing with raw meat first, and then spray them when they are eating. These oxytocin will go directly into the lion's brain along the trigeminal nerve and olfactory nerve. However, if they need to fight for food, lions will not buy into oxytocin - no matter what love hormones, they will fight to get food!

Due to the reduction of habitat, many lions were transported to the reserve. These lions come from different hometowns and do not know each other, but they have to live together. Researchers hope that giving lions oxytocin can increase their curiosity, reduce fear and aggression, and make them live better in an environment full of strange lions.

Fish can count

Two kinds of fish have learned addition and subtraction within 5!

The fish that acquired this skill are zebra cichlids and pearl stingrays. Through training, they first learned to associate colors with algorithms: blue is considered "+1" and yellow is considered "-1". In subsequent experiments, the fish will see a card with blue or yellow graphics, and then calculate the correct answer based on the number of graphics. For example, if you see two blue graphics on the card, you need to calculate 2+1=3 (two graphics represent "2" and blue represents "+1"), and then swim through the door with three blue graphics. When they swim into the correct door, they will get food rewards.

Experimental setup: 1) Starting area; 2) Experimental area; 3) Gate; 4) Decision area, where the fish need to choose the door with the correct number of patterns; 5) Graphic display; 6) Feeding tube, where they can get food from the corresponding tube after choosing the correct door; 7) Projector, used to project different patterns. | References [4]

In the experiment, 6 zebra cichlids and 3 pearl stingrays all learned this addition and subtraction. Zebra cichlids learned faster, mastering it after an average of 28 times of learning, while pearl stingrays needed an average of 68 times. However, although the latter learned slowly, they were steady and got more correct answers in the final test: when doing addition, pearl stingrays chose 169 out of 180 tests, with a correct rate of 94%; zebra cichlids got 296 out of 381 tests correct, with a correct rate of only 78%. Compared to addition, they don't seem to be so good at subtraction, with the subtraction accuracy of pearl stingrays being 89% and zebra cichlids only 69%.

The zebra cichlid Pseudotropheus zebra (top) has stripes, and the pearl stingray Potamotrygon motoro (bottom) has spots | Top: lienyuan lee; Bottom: Karelj / Wikimedia Commons

The researchers believe that the ability to count is not a critical survival skill for these two fish, but if they can count how many stripes or spots another fish has, they may be able to identify the fish by appearance.

Is size more important than IQ?

It’s often thought that mammals were able to survive the extinction of the dinosaurs by having bigger, smarter brains – but that conclusion may be about to change!

Asteroid impact caused the extinction of dinosaurs | Don Davis/NASA

Scientists have conducted CT scans on some mammal fossils from within 10 million years after the extinction of the dinosaurs. The results show that after the extinction of the dinosaurs, the brain proportions of mammals not only did not increase, but also shrunk! Instead, their body size grew rapidly, and they can be said to be large and clumsy, completely different from today's mammals.

Researchers speculate that for mammals at that time, body size was much more important than intelligence. On the one hand, the dinosaurs had just become extinct, and their larger size could fill the original ecological niche of the dinosaurs. On the other hand, the brain requires a lot of energy, but the earth's environment after the asteroid impact was very harsh, and a proportionally larger brain might have hindered their energy intake and made them unable to make ends meet.

A Paleocene mammal skull (left) and an Eocene mammal skull (right), the latter being significantly larger | Reference [5]

It was not until 10 million years after the extinction of the dinosaurs that the ancestors of modern mammals began to develop larger brains, more developed senses, and more complex motor skills. This is because when mammals gradually increased in number, the ecosystem began to saturate, and they had to compete with each other for resources. At this time, their brains - especially the cortex used for sensory integration - began to grow, making them smarter and more sensitive, and more advantageous in competition. Gradually, mammals evolved the largest brains in the animal kingdom, allowing them to still be distributed all over the world today.

Removing microplastics with okra

Today, when microplastics are almost everywhere, scientists have discovered a way to safely remove microplastics from water - using extracts from plants such as okra and aloe vera!

In the traditional wastewater treatment process, there are two steps to remove microplastics: microplastics floating on the water surface can be skimmed off directly; other microplastics in the water require the addition of flocculants or sticky chemicals to make them clump into lumps and eventually separate them from the bottom of the water - however, the common flocculant polyacrylamide can decompose into toxic substances in some cases and is not safe.

Okra | Dileep Kaluaratchie / Wikimedia Commons

Scientists have been looking for safe alternatives and finally chose polysaccharides extracted from plants. Polysaccharides can attract pollutants such as microplastics and even bacteria, and are more effective than traditional flocculants. Researchers have also found different optimal plant polysaccharide ratios for different water bodies. For example, if you want to remove microplastics in seawater, the combination of okra and fenugreek polysaccharides is the best; okra polysaccharides plus tamarind polysaccharides can better remove microplastics in freshwater.

Fenugreek seeds (top) and tamarind fruit (bottom), both used as spices | Wikimedia Commons

Humans ingest tens of thousands of microplastics from water every year. Although the impact of microplastics on human health is still unclear, researchers hope that by putting these plant extracts into large-scale wastewater treatment, everyone can drink cleaner and safer water.

References

[1]https://mapress.com/zt/article/view/zootaxa.5105.2.5

[2]https://www.livescience.com/m-triviale-queen-ant-larva

[3]https://www.cell.com/iscience/fulltext/S2589-0042(22)00319-4

[4]https://www.nature.com/articles/s41598-022-07552-2

[5]https://www.science.org/doi/10.1126/science.abl5584

[6]https://www.eurekalert.org/news-releases/945817

Author: Cat Tun

Editor: Mai Mai

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