Page 120 - One Million Things: Animal Life - The Incredible Visual Guide

PARASITES

In parasitic partnerships one animal, a parasite, exploits the
other, the host, in order to obtain food, shelter, or to reproduce.
Endoparasites, such as flukes and tapeworms, live inside their
hosts, while ectoparasites, such as lice, ticks, and mites, live
outside. Other types of parasite include parasitoid wasps and

brood parasites, like cuckoos.

HEADLICE
Seen here magnified and
in false color, headlice are
wingless insects that live
on human hair. They grip
the hair shafts with their
front legs to stop them
from being dislodged by
combing or washing.
When they descend on to CUCKOO
the scalp, they use their The female common cuckoo is a brood parasite that
mouthparts to pierce skin tricks another bird into raising her offspring. She lays
and suck blood, causing one egg in the host bird’s nest. After hatching, the
itching in the human host. young cuckoo pushes the host’s eggs out of the nest.
Now the center of attention, it grows rapidly.

PARASITOID
A parasitoid is an animal,
typically a wasp, that lays
its eggs on or in a living
host. The host provides
food for larvae when they
hatch, and dies in the
process. Here wasp larvae
are emerging from a
dead caterpillar.

LAMPREY BOTFLY LARVAE
This jawless fish is an ectoparasite The botfly lays its eggs on the
of trout, salmon, and other fish. It skin of mammals. The eggs hatch
into larvae that burrow under
uses its suckerlike mouth and
rows of small, pointed teeth to the skin and grow until they
clamp onto the side of its host. resemble large maggots (above).
The lamprey’s rasping tongue They then push their way back
wears a hole through the skin, to the surface and fall to the
then sucks out blood and tissues. ground to form a pupa that
will develop into an adult fly.

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