Working ants are more focused after drinking coffee! But this is just the first step to killing ants | Nature Trumpet

Welcome to the 59th issue of the Nature Trumpet column. In the past half month, we have collected the following natural news and research worth reading:

1) Caffeine makes ants smarter

2) Even poisonous frogs love to shake their feet

3) Tuna crab outbreak, but can't be eaten

4) Crows can count and strike

5) Rare giant squid robs the camera

6) The one-eyed 11-year-old wolf queen gave birth to another child

Ants drinking coffee

Give ants some caffeine and they'll get smarter!

In a new study, researchers fed 142 ants sugar water containing different doses of caffeine, of which the medium dose is similar to the energy drinks that humans drink. The results showed that ants that consumed low or medium doses of caffeine could find food faster , and they could also recall their previous routes and quickly return to the foraging point again. Ants that did not consume caffeine or consumed a lethal high dose of caffeine always went around in circles and could not find food.

Ants before drinking caffeinated sugar water (left) and after drinking caffeinated sugar water (right) | Laure-Anne Poissonnier

The researchers found that after consuming caffeine, the ants did not simply "run faster". In fact, their movement speed did not change, but they were more focused on their destination and took fewer detours, indicating that their learning ability was greatly improved.

Ants finding the bait | Forest and Kim Starr / Wikimedia Commons

However, this study may not be good news for ants, because the purpose of the study is to eliminate the invasive species, the Argentine ant, which has caused great harm to the ecology . The main method of ant removal at present is to use poison bait, but ants don't eat it much, and the effect has been poor. The researchers hope that ants that have consumed caffeine will find the poison bait faster and go home immediately to bring more companions to eat together. In this way, the poison will spread among the ant colony before they realize that it is poison.

Ant: I have a learning buff, but why am I dying faster? | Penarc / Wikimedia Commons

Poison frogs also shake their legs

Poison frogs are also foot-shaking enthusiasts!

The frog who shakes his feet | Sarah Westrick

They are called dyed poison dart frogs (Dendrobates tinctorius), which live in South America and secrete paralytic neurotoxins that are deadly to humans and most animals. This highly toxic frog loves to "shake its feet," which means tapping the ground with its hind toes. Researchers have found that dyed poison dart frogs start shaking their feet like crazy when they see prey . Is shaking their feet a practical function or a natural reaction when they are happy, just like a dog wagging its tail when it sees something delicious?

To answer this question, the researchers put some fruit flies in the tank of poison dart frogs. They found that if the fruit flies were placed in a transparent petri dish, the frogs could only see the fruit flies but could not eat or touch them. The frogs shook their legs about 50 times a minute; however, if they were free to hunt free-moving fruit flies, they shook their legs an average of 166 times per minute. In both cases, they were trying very hard to catch fruit flies, so the researchers speculated that shaking their legs was not just the excitement of seeing prey, but an action that actually played a role in predation.

Dyed poison dart frog on glass | Pogrebnoj-Alexandroff / Wikimedia Commons

They further speculated that the shaking of the feet may be a way to spread vibration signals to scare the prey and distract the prey . The researchers recorded the frequency of the poison dart frogs shaking their feet when hunting on four different surfaces (including leaves, soil, gel and glass), and found that the frequency of poison dart frogs shaking their feet on leaves was the highest, 255 times per minute, but the success rate of hunting on different surfaces was not much different. The researchers believe that this is because the frogs enjoy a buffet in the laboratory environment. In the complex forest environment, shaking their feet may really have the effect of deterring prey during hunting.

Leaves and soil are common natural environments for frogs to hunt. | _paVan_ / Wikimedia Commons

Tuna Crab Outbreak

Good news: Tuna and crab are exploding! Bad news: They can’t be eaten.

Recently, thousands of tuna crabs gathered in shallow waters near San Diego, USA, like a tide. The entire seabed was covered with tuna crabs, and some were washed up on the coast, with whole patches of red everywhere. However, experts warn not to eat tuna crabs, as they may contain toxins that are harmful to the human body .

Tuna and crab all over the floor | Jules Jacobs

Grimothea planipes is a crab that is named for its end-of-life in the stomachs of tuna (Grimothea planipes: are you polite?). Despite the word "crab" in their name, tuna crabs are not really crabs—they are armored shrimps, relatives of hermit crabs.

The waters near San Diego are not home to tuna crabs. Scientists believe that they may have been swept here by the ocean currents caused by the El Nino phenomenon . They are not good at swimming, just like a flock of passing birds, carried to an inexplicable destination by a tornado.

Dear predators, your crayfish buffet has been delivered | Anna Sagatov

Tuna crabs suddenly filled the seabed, and the predators were delighted, but there were too many of them. Even if the predators were full, there would still be hundreds of thousands of tuna crabs left. Unfortunately, the water temperature here is lower than the comfort zone of tuna crabs. Even if they don't fall into the stomach of the fish, the remaining ones will die soon .

Crows can count

Even crows can count, so how long can they go to college?

In a recently published study, researchers gave three small-billed crows a task: They were presented with a set of numbers and had to make one to four calls in response , followed by a peck on the enter key to indicate the end of the task. If they succeeded, they were rewarded with mealworms.

Shout and hear it | Alexis Lours / Wikimedia Commons

The result was that all three crows learned the game, and even when asked to make a single call, they were 100% correct . However, they were particularly reluctant to call four times, with only 40% correct, and when asked to call four times, they would simply go on strike and peck at the screen to end the task.

Before receiving the command and starting to call, they will have a reaction time (crow: brain loading); and before the correct sound is made, this reaction time will be longer, indicating that crows have an abstract concept of numbers and will plan in their minds before opening their mouths. In addition, researchers have found that based on the acoustic characteristics of their first call, it is possible to predict how many calls they will make in total - it seems that they have planned before they make the sound . However, occasionally there will be small mistakes in their calls, such as forgetting how many times they have called, which can also be heard from their voices.

After all, if you want to survive in a human city, you need some intelligence. | Marie-Lan Taÿ Pamart / Wikimedia Commons

To accurately produce a certain number of sounds, one needs to master the concept of numbers and have superb sound control ability. Before this, people have always thought that this is an ability unique to humans. This study is the first to prove that crows also have this ability - when humans shout "one, two, three" to count, crows may shout "quack quack" to count.

Squid Heist

Squid heist!

Recently, scientists discovered a squid that robbed a camera in the sea ! The culprit is a broad-fin squid, one of the most elusive squid species in the world, and few people have seen it alive. They also have the largest bioluminescent organ in the animal kingdom, which is equivalent to a built-in flashlight, but no one has ever seen this bioluminescent organ really light up before - until this sudden robbery.

Robbed, robbed! | UWA / Inkfish

At that time, scientists responsible for deep-sea exploration deployed cameras underwater. The camera installed on the lander sank to the bottom of the sea at a speed of 58 meters per minute. At a depth of more than 1,000 meters, a broad-fin squid suddenly emerged from the darkness, dived in front of the camera and entangled it . The robber's bioluminescent device was also shining brightly. Apparently, it mistook this for a fast-moving prey and prepared to use the headlights to scare the prey and complete the assault.

The giant bioluminescent organ of the Octopus scaupu | UWA / Inkfish

The squid's work was in vain, but scientists got valuable video footage. Most of the previous records of the broad-finned squid came from strandings and accidental captures, or the contents of whale stomachs. This time , they were able to film their hunting behavior in their natural habitat and see the bioluminescent device at work , all thanks to this broad-finned squid with poor eyesight.

Squid: Huh? The taste is wrong? Slip away | UWA / Inkfish

One-eyed wolf queen

The queen of Yellowstone's one-eyed wolves recently gave birth to her 10th litter.

The one-eyed wolf queen is numbered 907F, and she is already 11 years old this year. The average life span of a gray wolf is 3 to 4 years old, and the most common cause of death is being killed in a fight with other wolves. In the wild, only 1 out of every 300 wolves can live to the age of 11. It is rare to survive to this age, let alone give birth to a baby at this age, but 907F has given birth every year for 10 consecutive years.

Photo of 907F in April this year, when she was pregnant | Yellowstone Wildlife Project

907F is the leader of a large wolf pack, and her rich wolf life experience makes it easier for her pack to win in territorial struggles . As a wise queen, 907F also has some unique survival wisdom that she can pass on to her pack - how to cross the highway and avoid humans. She will look left and right carefully before crossing the highway, and the wolves she leads rarely leave Yellowstone Park so that they can stay away from hunters.

2020 907F (standing in the middle) and its wolf pack | Yellowstone Wildlife Project

As the leader of the wolf pack, she lived to be 11 years old and gave birth to babies every year. 907F was so powerful in the wolf pack that everyone almost forgot that she had a huge defect in her body - she only had one eye . Her left eye was sunken before she was 4 years old, probably because of an injury during hunting. Researchers at Yellowstone Park thought that she was about to die every year, but she was still alive and well the next year.

907F only has right eye working properly | Yellowstone Wolf and Cougar Project

Because of his old age, 907F has now taken a back seat in hunting, spending most of his time with the pups in the pack, and several of his offspring are now leaders of the pack.

907F lying in the snow in 2015 | Kira Cassidy / NPS

Author: Cat Tun

Editor: Mai Mai