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Mosquitoes are the bane of many people’s lives, especially since their bites not only cause an annoying itch; They can also spread deadly parasitic diseases. The larvae of some species are also vigorous. While most mosquito larvae feed on algae or similar bacteria and microorganisms, some predatory species feed on other insects, including the larvae of other mosquitoes. A team of scientists captured the unique attack patterns of these carnivorous predators in high-speed video, revealing how they capture their prey with lightning-fast attacks. recent studies Published in the Annals of the American Entomological Association.
Robert Hancock, a biologist at Metropolitan State University in Denver, was fascinated by predatory mosquito larvae when he first saw them attack their prey under a microscope during a college entomology class. He was impressed by the speed of the massive attacks: “The only thing we saw was a blur at work”, to remember. Scientists have long studied these caterpillars because they are very effective in controlling populations of other mosquito species. A predatory caterpillar can devour up to 5,000 caterpillars of prey before reaching adulthood.
Hancock first attempted to capture the extraordinary behavior of caterpillars on 16mm film in the 1990s by equipping a system with a microscope and camera – a process he believes has led to the loss of the film due to speed. of blistering. Now by attacking a college professor, he has been able to use all the advances in video and microscopy technology from his undergraduate years to learn more about biomechanics.
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a Corofora ciliata The larva attacks its prey by suddenly extending its neck and pushing its head away from the body towards the prey. (RJ Hancock et al., 2022)
Hancock and colleagues focused on three types of mosquito larvae in their experiments. Toxorhynchites amboinensis It is native to Southeast Asia and Oceania. The lab obtained adults from Ohio State University and collected weekly stages from special black plastic egg-laying cups. surofora ciliates The larvae were collected from shallow irrigation canals in citrus groves in River County, Florida. and samples Sabitus sinus Originating from a colony founded in the USO in 1988, adults and larvae were collected from the island of Maje in Panama.
The researchers caused blows by placing the predatory larvae in the chutes of the water wells, then delivering the larvae of live prey with goldsmith’s pliers. The surprising behavior was captured on video using high-speed micro-imaging. They used thermal protection filters for warm, bright fluorescent lamps under the microscope, otherwise the heat would have cooked the live larvae. The researchers even wore dark sunglasses for protection. Finally, they analyzed the resulting video clips to gain insight into the anatomy of the larvae and the sequence of movements involved in their strokes.
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a Sabitus sinus The larvae attack the larvae of the prey by using their tail to drag the prey towards its head. (RJ Hancock et al., 2022)
Both TX Amboinensis And . ciliates They are called “forced” predators, meaning they have to eat the larvae of other insects. “The different tribes of Culicidae are obligatory predators, despite their different association with different life stories. TX Amboinensis And B. ciliates “It is clear that it converged with a similar mechanistic strategy for capturing mosquito larvae,” the authors wrote. It involves abruptly extending the neck and pushing the head towards its prey, like a harpoon, which is generated by the release of regulated pressure. In the abdomen of a predatory larva, at the same time, the jaws open and close on impact to capture prey.
We were shocked and sometimes the “main” predator feeds on other larvae; They can also live on microbes, so they have developed a completely different strategy for catching prey. There is no tip like a spear. exactly the opposite, We were shocked The larvae use their tails – called a siphon because they also act as breathing tubes for the larvae – to drag prey into their lower jaws.
The strokes of the three types studied in the experiments lasted 15 milliseconds. According to Hancock, this behavior on a time scale is almost reflexive in nature, comparing blows to the act of swallowing, which involves the coordination of many small muscles. “All these things must work together: we all do it automatically”, He said. “This is what mosquito larvae have to target. It’s a package. “
DOI: Annals of the American Entomological Society, 2022. 10.1093 / aesa / saac017 (Information on DOIs)
