Arrenurus genus
Bio Images UK / Malcom
Storey Bio Images UK / Malcom
Storey Like all mites, Water
Mites are close relatives of spiders. Like spiders, they
have eight legs and soft bodies. There are many different
kinds of mites. Some live in soil, some on plants. Water
Mites live in marshes, ponds, and lakes. They like shallow,
still water with lots of plants. There are many different
species of Water Mites; this page focuses on the ones in the
Arrenurus genus. Arrenurus mites grow up to
three millimeters long and are usually brown or greenish.
Males are bigger than females. Arrenurus mites
stay near the bottom. They can swim or crawl to get where
they'r going, but when they relax, they sink back to the
bottom. Arrenurus mites
are only active when there's daylight. NatureWatch NatureWatch Water Mites have an
interesting life cycle. After mating in late Spring or early
Summer, female mites lay eggs on stones or plants in the
water. Eggs are red, and one female lays up to 400 at one
time. Eggs hatch in one to six weeks, depending on the
species and temperature. Mite larvae hatch with
only 6 legs. Right away they swim around looking for an
aquatic insect. Water Mite larvae are parasites, and they
need a host to live on. Some insects chosen to be hosts
include dragonfly naiads, damselfly naiads, fly larvae
(including mosquitoes), true bugs, and stone fly nymphs. One
insect may carry around up to 20 mite larvae. Water Mite larvae munch
on their host while it carries them. When a mite larva has
grown enough, its exoskeleton (outer shell) becomes
bag-like. The larvae stays inside the bag and changes to a
nymph. As it changes, the "bag" stays attached to the
host. When the nymph is ready,
it leaves the host. The nymph has eight legs and looks a lot
more like an adult Water Mite. Water Mite nymphs eat the
same foods adults do, including small insects, aquatic
worms, and other mites (even their own kind). Nymphs
continue to eat and grow, until they are ready to go into
their fourth stage (egg, larvae, and nymph are the first
three stages). Each nymph finds some
algae, an aquatic plant, or another object to attach to. The
nymph shrinks inside another "bag" for about a week while it
changes to an adult. Predators of adult Water
Mites include aquatic insects, crustaceans (such as water
fleas and scuds), hydras, and small fish. In the larva stage, when
attached to its host, the mite may have a problem if the
host leaves the water. If this happens, the mite can pop out
of its bag, or hold on, hoping its host returns to the
water. If the host doesn't return, or the larva drops off on
land, it dies. Bio Images UK / Malcom
Storey
