High-speed video captures how cannibalistic mosquito larvae snag their prey

Mosquitoes are the bane of many people’s existence. They can also spread potentially fatal parasitic diseases. Even the larvae of certain species can be formidable. Most mosquito larvae feed on algae and bacteria, and similar microbes, but some predatory species feed on other insects, including the larvae of other mosquitoes. High-speed video captures the unique attack methods of cannibalistic predators, revealing how they catch their prey with lightning speed. Recent research It was published in the journal Annals of the Entomological Society of America.

Co-author Robert Hancock, a biologist at Metropolitan State University in Denver, discovered that predatory insects were the first to see mosquito larvae attacking prey under a microscope during an undergraduate entomology class at the university. Fascinated by mosquito larvae, he was impressed by the speed of their attacks. he rememberedScientists have long studied these larvae because they can control populations of other mosquito species so efficiently. Although he has only one predatory larvae, he can devour as many as 5,000 prey larvae before reaching adulthood.

Hancock first attempted to capture the striking behavior of larvae on 16mm film in the 1990s by jelly-rigging a setup with a microscope and camera. strike. Now a university professor, he has been able to take advantage of all the advances in video and microscopy technology from his undergraduate days to learn more about the biomechanics involved.

Hancock and his co-authors focused on three species of mosquito larvae for their experiments. Toxorhynchites amboinensis It is native to Southeast Asia and Oceania. In the lab, we obtained adults from Ohio State University and collected instars weekly from special black plastic he cups for spawning. Solofora ciliate Larvae were collected from shallow irrigation ditches in a citrus orchard in River County, Florida.and a sample of Sabetes Cyaneus They came from the first established colony at OSU in 1988, collecting adults and larvae from Mahe Island, Panama.

The researchers placed predatory larvae in slides in water-filled wells and elicited aggression by presenting live prey larvae with jeweler’s forceps. Impressive behavior was captured on video using high-speed micro-cinematography. They used a heat protection filter for the hot bright illumination under the microscope. Even researchers wore dark sunglasses for protection. Finally, we analyzed the resulting videos to glean insights into the sequence of movements associated with larval anatomy and aggression.

both send.Amboinensis When Ps.ciliate It is what is known as a “obligatory” predator, meaning it must consume the larvae of other insects. “Despite different associations and different life histories in different tribes of Culicidae, obligate predators send.Amboinensis When Ps. ciliate We seem to have converged on a similar mechanical strategy for preying on mosquito larvae,” the authors write. increase.

Sabetes It is a “conditional” predator that only occasionally eats other larvae. Because they can also live on microbes, they have evolved markedly different strategies for capturing prey. No harpoon-like head firing. Instead, Sabetes Larvae use their tails, known as siphons, to sweep prey into their mandibles, as they also serve as the larval respiratory tract.

Attacks for all three species studied in the experiment took 15 ms. According to Hancock, that timescale indicates that the action is almost reflexive in nature, likening the blow to the act of swallowing, which involves the coordination of several small muscles. We all do it automatically.” He said“And that’s exactly what these mosquito larval attacks should be. It’s a package deal.”

DOI: Annals of the Entomological Society of America, 2022. 10.1093/aesa/saac017 (About DOIs).