Coloured scanning electron micrograph (SEM) of a dog flea (Ctenocephalides canis) head. The flea lives as an ectoparasite on a variety of mammals, particularly domestic dogs and cats. Dog fleas have high, narrow head capsules and spines, bristles and combs cover the body. This shape helps with forward movement through dense fur, prevents dislodgement and steadies the flea during feeding. Dog fleas can see, although their eyes serve only as light sensors. They can detect changes in light and dark, but can't see visual images. The fleas have antennae on both sides of their head, located slightly behind the eyes. The antennae are delicate sense organs which can detect touch, smell, heat, humidity and vibration. The mouthparts are adapted for piercing host skin and sucking blood. The fleas may occasionally bite humans, but cannot breed without their preferred hosts. Magnification: x150 when printed at 10cm wide. |