What happens if a male wasp without a stinger encounters a predator? | Nature Trumpet

Welcome to the 24th issue of the Nature Trumpet column. In the past half month, we have collected the following natural news worth noting:

1) The remains of the last thylacine were finally found

2) To prevent manatees from starving, people feed them lettuce

3) When encountering a predator, male wasps will sway their genitals wildly

4) New drones save innocent bats

5) Scientists discovered the snake clitoris

6) After more than 9,000 years, some black bears are no longer black

The remains of the thylacine

The remains of the last thylacine on Earth have finally been found, but it's not Benjamin as previously thought.

A male and female thylacine | Smithsonian Institution

The thylacine (Thylacinus cynocephalus) is a magical animal with the body of a wolf and the stripes of a tiger, but it is neither a wolf nor a tiger. It is a quoll with a pouch on its body. They were once the top predator on the island of Tasmania, but they went extinct after being hunted by humans. The last thylacine died in a local zoo, but its remains mysteriously disappeared.

It was previously believed that the last thylacine on Earth was a male named Benjamin, who died in 1936. But recently people discovered that it was actually a female thylacine who died at the time, and Benjamin died in 1933, the second-to-last thylacine in the world .

Last year, the National Film and Sound Archive of Australia (NFSA) colour-restored Benjamin's video, which is the longest surviving video of a thylacine. The video was shot in 1933, shortly before Benjamin died.

The discovery was made by staff at the Tasmanian Museum, who recently found the skin and bones of the last thylacine in a storage room. Everyone realized that the disappearance of the thylacine specimen was actually a misunderstanding - after the last thylacine died, its body was sent to the museum; but later people had mistakenly believed that Benjamin was the last thylacine, but Benjamin's photo did not match the stripes on the specimen, so they thought the last thylacine specimen had disappeared.

There are no photos of this last female thylacine. Her body had been skinned and her skeleton was cut into several parts. It is not known how old she was when she died, but her teeth were badly worn, indicating that she was very old when she died.

The last thylacine skull | Tasmanian Museum & Art Gallery

Transporting lettuce to feed manatees

To prevent the manatees from starving to death, people decided to feed them lettuce.

Manatees living in Florida's Indian River usually feed on water plants, but the water plants have died in large numbers due to pollution, so they often starve . In winter, the starving manatees have no choice but to come to the vicinity of the power plant and warm themselves in the hot water discharged by the power plant, but food is still a problem.

Manatee | NOAA

Last winter, the Florida Fish and Wildlife Conservation Commission fed manatees more than 90,000 kilograms of lettuce. But a large number of manatees still did not survive the winter. In December last year, as many as 22 manatees died in one county in Florida alone.

This year, the government was worried that the manatee disaster would happen again, so it prepared early, improved logistics and financial management, and launched an enhanced emergency feeding operation for manatees this month. Truckloads of lettuce are being shipped to the Indian River, and this year the manatees will eat more vegetables than last year.

Manatee | Sam Howzit/Wikimedia Commons

In addition to the emergency feeding operation, the administration has also developed other response measures, including inspecting and handling carcasses, rescuing affected animals, and some private aquariums and zoos will be responsible for caring for some manatees that are too weak.

The good news is that as of early December this year, no manatees have been found dead . Hopefully, with the efforts of people, they can spend this winter munching on lettuce in peace.

Male wasp flails its genitals

Only female wasps have stingers that can inject venom , so what do male wasps without stingers do when they encounter danger? Recently, scientists have found the answer - they will shake their genitals wildly!

The incident started with an unlucky but lucky graduate student who was handling a male wasp (to be precise, Anterhynchium gibbifrons of the Vespidae subfamily) that she thought had no offensive power, when she suddenly felt a stinging pain in her finger. However, male wasps do not have stingers. Although they have long, retractable stingers on both sides of their genitals, they are used to fix females during mating. Could it be that male wasps use their reproductive stingers as weapons?

A tree frog stung by a genital sting spits out the wasp | Shinji Sugiura

So she and the professor designed an experiment: they put a tree frog in the cage of a male wasp and set up a camera to watch the tree frog being stung. Sure enough, when the wasps were swallowed by the tree frog, they would use their genitals to slam the frog's tongue in an attempt to sting the frog. This strategy was very effective, and 35.3% of the wasps were able to escape from the tree frog's mouth in the end; but if the male wasps had their genitals removed, they would all be swallowed by the tree frog.

Tree frog: Back off! Back off! Back off! | Shinji Sugiura

However, the male wasp's reproductive sting is still inferior to the female's sting. When tree frogs try to eat wasps, they spit out the female 87.5% of the time; and they are also very selective, only picking the weak ones, so male wasps are twice as likely to be eaten by tree frogs as females .

Drones save bats

Millions of animals, especially bats, die every year under the blades of wind turbines.

Recently, scientists have invented a new technology that can save innocent bats. They installed the device on a drone , which can transmit ultrasound and light at the same time, giving bats a combination of auditory and visual signals designed specifically for them, keeping them away from dangerous areas. The drone is in constant motion, which allows the signal to fluctuate; if the signal is fixed, like a scarecrow in a field, the animals will gradually get used to it and eventually ignore it directly.

This is what a drone looks like | Yuval Werber et al., 2022

The effect of this new technology is very significant: within 400 meters below the drone, the activity of bats has been reduced by about 40% . Before this, the way to reduce bat casualties was very simple and direct - turning off the wind turbines during the period when bats were particularly active. However, this inevitably reduced the efficiency of wind power generation. With this new technology, bats are safe, and wind power generation can also be safe and efficient.

Snake clitoris

As early as the 1800s, people knew that male snakes have bifurcated hemipenes , and that the hemipenes of different species vary from one another, ranging from two toothpicks to large and delicate ones. But little is known about the sexual organs of female snakes.

Western diamondback rattlesnake hemipenis | Tess Thornton / Wikimedia Commons

Until recently, scientists dissected 10 snakes from 9 different species and found that the female snake's sexual organs are also bifurcated hemiclitoris , triangular structures, covered by the skin under the tail, and have erectile tissue and nerve bundles. They also observed the size and shape of different hemiclitoris and found that they are as varied as the hemipenis.

Snake hemiclitoris | Megan J. Folwell et al., 2022

Scientists speculate that because snakes have a highly developed sense of touch, if their hemi-clitoris is stimulated during mating, mating may become more frequent and last longer, thereby increasing reproductive success rates; stimulating the clitoris may also increase lubrication and prevent females from being injured by the male's spiny hemi-penis.

Compared with male genitals, female genitals have been neglected in scientific research , and there are very few studies to refer to, which limits our understanding of sexual reproduction in vertebrates. The discovery of the hemiclitoris is just the beginning of research. Next, scientists will further study the neural structure of the hemiclitoris and its role in mating.

Mating snakes | Joshua Tree National Park

Black bears are not black

Although the American black bear (Ursus americanus) is called a black bear, its fur is not necessarily black. Among the 16 subspecies, four subspecies are cinnamon brown , which is somewhat similar to brown bears. A study recently published in Current Biology revealed the mystery of this color.

Cinnamon-haired American black bear (U. americanus cinnamomum) | Appalachian Encounters / Wikimedia Commons

The researchers analyzed 151 American black bears from across the United States and Canada. Most of the brown-haired black bears live in the West , and their hair color is associated with a gene mutation . The mutation is located in the gene for TYRP1 (tyrosinase-related protein 1), a protein related to pigment expression. The mutation may affect the binding of TYRP1 protein to zinc cofactors, changing the ability of protein localization, and ultimately leading to a reduction in pigment synthesis.

This gene mutation appeared 9,360 years ago, and it is a very young mutation that has not yet spread throughout North America, and is only concentrated in the southwest. Researchers speculate that the shape of cinnamon hair can be preserved, and it should have some adaptive advantages , such as helping black bears regulate their body temperature or compete with brown bears, but current experimental data cannot support these two hypotheses. In any case, in the past 9,000 years, they have become brown black bears.

Black American black bear｜HBarrison / flickr

References

[1] https://www.livescience.com/extinct-tasmanian-tiger-thylacine-australia-museum

[2] https://phys.org/news/2022-12-lettuce-florida-week-manatee-starvation.html

[3] https://doi.org/10.1016/j.cub.2022.11.030

[4] https://doi.org/10.1002/rse2.316

[5] https://royalsocietypublishing.org/doi/10.1098/rspb.2022.1702

[6] https://doi.org/10.1016/j.cub.2022.11.042

Author: Maotun, Mai Mai

Editor: Mai Mai

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