Mosquito meals and mysterious ant ‘milk’

Mosquito blood meals reveal historical past of human infections

Blood-sucking mosquitoes have their makes use of. An revolutionary strategy that analyses their final blood meals can reveal proof of an infection within the folks or animals that the flying bugs feasted on.

Scientists say that the tactic may very well be used to review folks’s and animals’ previous publicity to a spread of pathogens, whereas avoiding the moral and sensible problems with testing them immediately.

Researchers have beforehand detected publicity to pathogens by testing blood from mosquitoes for antibodies, markers of previous an infection that may flow into in blood for months to years, from particular animal hosts.

The approach utilized by Carla Vieira, a illness ecologist on the QIMR Berghofer Medical Analysis Institute in Brisbane, Australia, can detect antibodies in blood from a spread of animals and other people.

She targeted on Ross River virus, a doubtlessly debilitating mosquito-borne illness that’s endemic to Australia and islands within the southern Pacific Ocean.

Vieira and her colleagues trapped roughly 55,000 mosquitoes in parks in Brisbane in 2021 and 2022. From these bugs that had not too long ago had a meal, they squeezed out a few millilitres of blood and examined it for antibodies that may bind to Ross River virus. In addition they sequenced DNA fragments within the blood to determine the animal that the insect had feasted on.

In preliminary outcomes introduced on the Worldwide Congress of Infectious Ailments in Kuala Lumpur in November, Vieira reported that 480 of the trapped mosquitoes had been engorged with blood. Greater than half of these had consumed folks, some 9% on cows and 6% on kangaroos, amongst different animals. Of the 253 samples containing blood from folks, greater than half included antibodies in opposition to Ross River virus — “a very excessive inhabitants”, she says. Near three-quarters of the cows and kangaroos additionally had proof of publicity.

“This can be a novel and interesting strategy, which demonstrates revolutionary methods to make use of the atmosphere round us to be taught extra about publicity to an infection,” says Shelly Bolotin, a vaccine scientist on the College of Toronto in Canada.

Mysterious ‘milk’ from ant pupae helps feed colony

For the primary time, researchers have noticed ants secreting a milk-like fluid that nourishes others within the colony.

The analysis, printed on 30 November (O. Snir et al. Nature https://doi.org/jpb8; 2022), reveals that as pupae — an in any other case inactive developmental stage — ants produce a nutrient-rich fluid that’s consumed by each adults and larvae.

Newly hatched larvae depend upon this fluid to develop and survive, akin to how mammalian newborns depend upon milk. If the ant adults and larvae don’t devour the fluid, it builds up and turns into contaminated with fungi, which kill the pupae.

“We recognized a mechanism that unites the colony, binding ants throughout developmental levels — adults, larvae and pupae — right into a coherent entity, the superorganism,” says co-author Orli Snir, a biologist on the Rockefeller College in New York Metropolis.

“It’s actually stunning that no one else observed this earlier than,” says Patrizia d’Ettorre, an ethologist at Sorbonne Paris North College, France. “The pupae had been thought-about ineffective [because] they’re motionless, they spin a cocoon round them in some species, they don’t eat, they’re simply moved round by the [ant] staff, so that they [wouldn’t] contribute something to ant society. However this paper exhibits that this isn’t true.”