BOOKS: Arachnids

From ANIMAL PEOPLE, April 2010:

Arachnids by Jan Beccaloni
Univ. of Calif. Press (2120 Berkeley Way, Berkeley,
CA 94704), 2009. 320 pages, hardcover. $39.95.

The spider on the cover of Arachnids scared me. I didn’t
think I could get through a book containing 176 color photos and 24
drawings of creepy creatures. I turned the pages, however, and
learned something.

“Spiders aren’t the only arachnids,” reminds Beccaloni.
Ticks and mites are arachnids too. Spiders are the most common
arachnids, with about 40,000 types, but there are also scorpions
and tick beetles. Descended from trilobites, like insects and
crustaceans, arachnids are older than dinosaurs, first appearing
about 440 million years ago. They are not insects; they have no
wings. They usually have twelve eyes. Yet vision is among their
minor senses. Mostly nocturnal, they rely mostly on touch and taste
to find food.
Arachnids live primarily in warm, humid environments such as
rainforests. Other frequent habitats are caves, deserts, and
inside gardens. Nearly all arachnids are predators. Methods they use
to obtain food include theft, ambush, and in the case of spiders,
building nets to capture bugs.
A clad is a group of species sharing a common ancestor.
There are more than 900 Theraph-osidae spiders in the Mygalomorph
clad. The best known is the tarantula, also called a bird-eating
spider in Asia and a baboon spider in Africa. Tarantulas mostly live
in underground burrows. Large and hairy, tarantulas were named
after Taranto, Italy, which became notorious in the Middle Ages as
home of allegedly venomous wolf spiders whose bite was said to cause
insanity. Wolf spiders, however, though also called tarantulas,
are not part of the tarantula family.
A full page color photo on page 37 of the Brazilian wandering
spider, Phoneu-turia, made my skin crawl. This large gray spider
has long legs known as palps and sharp chelicerae (appendages near
the mouth) that look as if they could scarf down a small dog or cat.
Phoneuturia is among South America’s most poisonous spiders. Run if
you see one.
There are 108 species of whip scorpions or vinegaroons
(Uropgyi) and all look terrifying. Their armored palps give the
impression they are ready for battle. Their whip-like tails can
thrash predators, hence their name. When threatened, they emit a
spray so disgusting you want to choke. They are also known as
vinegaroons because their spray contains acetic acid. Whip scorpions
eat frogs, toads, worms, and slugs. Four families of this species
live in Southeast Asia. Others inhabit the southeastern U.S. and
South America, favoring hot tropical climates. Except in weather wet
enough to saturate the ground, whip scorpions also live in burrows
or under rocks.
Mites are diverse and are the smallest family of arachnids.
Ticks and mites belong to the Acari family, with seven orders and
over 45,000 species. Most mites have no eyes. They can be found in
decomposing matter, on plants, in marine habitats, and inside
animals. Ear mites cause problems for dogs and cats. Mites can also
live inside bat anuses, owl lungs, and seals’ nasal passages.
In humans mites cause typhus, scabies and asthma. The dust
mite is particularly aggravating to humans. A common allergen, dust
mites live in carpets, furniture and mattresses. Dust mites can
live inside clothing too. If you move, they hitch a ride and move
with you, unless you carefully clean every part of your home and
furnishings. Some mites attack plants. Mites have destroyed entire
citrus crops, and have caused major economic losses to farmers
around the world.
Ticks, on the other hand, are ecoparasitic mites that feed
only on their host’s blood. They transmit diseases such as Lyme
disease, tick fever, and Rocky Mountain spotted fever that afflict
both humans and animals.
Ticks do well in steamy climates, but can survive in cold
habitat too. Once a tick attaches itself to a host, it typically
remains for a long time. Resistant to starvation, ticks can lay
thousands of eggs. If you have pets and live in an area prone to
ticks, seriously consider tick prevention methods.
Arachnids fascinated me. Arachnids themselves still unnerve
me, but the pictures in the book Arachnids are stunning, and the
descriptions of the twelve categories of arachnids and their anatomy,
circulatory systems, venom glands and habitat are descriptive,
informative, and easy to follow.