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The original title: "it launches its own head to prey on its own kind, and eventually grows into something we hate."

Photo Source: what do sharks and mosquito larvae have in common in the original video screenshot-they are both aquatic carnivores and face some unique predation challenges.

We can't help but get rid of the mosquitoes that disturb people's dreams every summer. While some people hate mosquitoes, others are obsessed with this species. After all, how interesting, magical and fascinating it is that their larvae can eject their heads-literally launching heads-for hunting. (it may not be. )

Robert Hancock, a biologist at Metropolitan State College (Metropolitan State University of Denver) in Denver, became fascinated by mosquitoes in the 1980s. He was full of curiosity and interest in nature when he was a graduate student at Ohio State University (Ohio State University). He hopes to help improve global health by better understanding insects, one of the vectors of disease.

At that time, his professor took out the larvae of Toxorhynchites amboinensis, a giant mosquito, and some tiny prey for students to observe. "take a microscope and see if you can figure out how this mosquito larva catches its prey." The professor assigned such a task. "in the end, we all did it," though it all happened so fast that it could only vaguely discern the general movements of mosquito larvae shoveling prey into their mouths, Hancock said.

Robert Hancock, a professor of biology at Metropolitan State College in Denver, USA Photo: Alyson McClaran / MSU Denver since then, Hancock has become more and more obsessed with mosquitoes and insects. In particular, the larger giant mosquitoes, "they have beautiful legs and can swing around," Hancock said. He began to observe the mosquito more closely. He noticed that when the mosquito larvae live in the water, they prey on the larvae of other insects (usually the larvae of other mosquitoes) and then eat them crazily. "it looks like a game in which they compete to stuff hot dogs into their stomachs."

But Hancock has been trying to figure out what happened the moment the mosquito larvae hunted. But this swift predation always happened so fast that there was no equipment or technology to analyze the details with high-resolution and slow-motion lenses. Now, after more than 30 years of technological development, Hancock has finally filmed the story that happened in 15 milliseconds. The study was published in the Annals of the American Entomological Society (Annals of the Entomological Society of America) in October 2022.

Jaw-dropping through microphotography, Hancock and his team captured the amazing and terrifying process of Toxorhynchites amboinensi larvae launching head hunting. "We lost our jaw as soon as we saw it," Hancock said. "No one can believe what we saw."

The Toxorhynchites amboinensi larva preys on its prey by launching a sequence image of its head. Source: using a camera that can capture more than 4000 frames per second, the researchers observed that the head of mosquito larvae ejected from the body like a harpoon. They speculate that this process may be through the body constantly twisting like an accordion to squeeze a stream of liquid into the head to provide power. But it's one thing to get your head close to your prey, another to catch it. It can be seen from the video that there is a "brush"-like structure on each side of the head of the mosquito larva. When its head is precisely close to its prey, the brushes fan out to form what the researchers call a "fragile basket-like structure" and sweep the prey into the import.

This kind of ferocious and violent attack may surprise most people. Because mosquitoes as we know them are always secretly sucking on the subcutaneous blood of animals such as humans, or on plant juices and nectar. Generally speaking, it is a more "elegant" way of predation. However, mosquito eggs are mostly hatched in the water, and the larvae do not show the familiar dandelion-like flying posture for a few weeks. In the aquatic stage, the appearance and feeding style of these larvae are very different from those of adults.

The Psorophora ciliata larva preys on its prey by firing sequence images of its head, which is larger than T. amboinensis. Source: in the original paper, in addition to T. amboinensis, who fascinated Hancock, he also photographed the hunting process of Psorophora ciliata larvae of another species of scaly mosquitoes, which have a stronger harpoon head and a longer range.

Sequence images of indigo mosquito larvae sweeping their prey through a tail siphon. Source: in the original paper, Hancock and his colleagues captured the predation of a third carnivorous mosquito, Sabethes cyaneu, whose metal color is highly recognizable and is also known as the most beautiful mosquito in the world. Indigo mosquitoes do not shoot heads as well as the first two mosquitoes, but their bodies are very flexible and often wobble in the water. They breathe in oxygen through the siphon at the tail, but this structure has more than one effect. As the body swings, the siphon is more like a "bait". When attracted to the prey, the indigo mosquito larva rolls its long body toward the defenseless prey, grabs it with its tail, and quickly stuffs it into the mouthpiece.

This violent mosquito larva predation image is the result of decades of work by Hancock. "We have never seen either of these two predation methods before," Hancock said.

There are many species of mosquitoes belonging to the mosquito family, and most of the larvae are facultative predators, that is, they can feed on debris, microorganisms or other organic matter, including decaying substances. So it is "very clever" that the three species of mosquito larvae in this study can evolve their hunting ability to become completely predatory (actively preying on other creatures). Even in terms of their complex and precise hunting process, it is somewhat comparable to top predators such as sharks and lions. "if you look at their predation alone, they are used by very complex and highly evolved predators, but they happen to be larval mosquitoes," said LJ LJ Zwiebel, a mosquito researcher at Vanderbilt University University in the US, who was not involved in the new study.

Zweiber has been focused on the mosquitoes that carry and transmit malaria. He found that these insects, even in the weakest larval stage, have evolved a well-developed sense of smell and high environmental adaptability. Over hundreds of millions of years of evolution, they have selectively selected "skill points", making these mosquito larvae particularly good at surviving to the adult stage.

Hancock's most energetic adult Toxorhynchites amboinensis actually lives mainly on plant sap and is not a vector of human disease. But their larvae, as greedy larval predators that feed on other insects, can be used to manage and control the growth of other mosquito populations. The experimental results show that the Psorophora ciliata larvae that can shoot head hunting may eat the larvae of all other insects in the same body of water. Therefore, putting them into a relatively large body of water can theoretically play a greater role in killing mosquitoes.

The rainbow blue and silver Sabethes cyaneus "looks like a sports car," Hancock said. Photo: Katie Custer / Metropolitan State University of Denver now that they have finally caught mosquito larvae and figured out how they hunt, Hancock seems to have fulfilled a long-cherished wish in life. But he won't be satisfied. "I can't take my eyes off these mosquitoes. They're so beautiful," Hancock said. Sometimes, he feels like both a scientist and an artist, because he is always attracted by the colors of his subjects. After completely metamorphosis, the mosquito indigo mosquito mentioned in the article has extremely beautiful rainbow-colored scales. "it looks like a sports car," Hancock said.

Humbly rejoice that when mosquitoes grow up, they just stab people with needle-like mouthparts.

Links to papers:

Https://academic.oup.com/aesa/article/115/6/461/6746937?login=false#380607872

Reference link:

Https://www.smithsonianmag.com/smart-news/mosquito-larvae-launch-their-heads-to-capture-prey-180980949/

Https://www.sciencenews.org/article/mosquito-head-neck-launch-video-footage

Https://www.cbc.ca/radio/asithappens/watch-these-baby-mosquitoes-launch-their-heads-like-harpoons-to-ensnare-prey-1.6608739

Https://www.nytimes.com/2022/10/04/science/mosquito-larvae-harpoon.html

This article comes from the official account of Wechat: global Science (ID:huanqiukexue), written by: bad week, revision: 27

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