Man scratch the itch with hand; Shutterstock ID 404139892; purchase_order: Photo; job: News web; client: New Scientist; other: Shutterstock/Monster e
What is the survival advantage to insects of their bites making us itch?
Gillian Peall
Macclesfield, Cheshire, UK
Biting insects are after our blood. To make it easier for them to imbibe it, their saliva contains an anticoagulant to stop clotting. The chemicals in their saliva enter our bloodstream, activating our immune system, which then sends a shedload of chemicals called histamines to the site in order to fight off the intruders. It is the histamines that cause the…
