The bluebottle is 9 to 13 mm long. Its thorax and abdomen are dark blue and have a matte lustre. They develop in protein-rich foods, such as meat, fish and cheese, but also on animal carcasses. While house flies only make a quiet buzzing noise when they fly, bluebottles, flesh flies and green bottle flies can be identified by their loud humming.
These flies are also known as blow flies, which stems from the older English term “fly blow”, meaning “to infect with eggs”.
As the flies linger on carrion and foodstuffs, and they also seek out wounds, they are not just unappetising, but they also transmit germs. They are therefore considered to be a pest in terms of both health and hygiene. The maggots, which develop in meat, cheese or fish, make the foods inedible quickly.