Psocoptera
are an
order
of
insects
that are commonly known as
booklice
,
barklice
or
barkflies
.
[1]
They first appeared in the
Permian
period, 295–248 million years ago. They are often regarded as the most primitive of the
hemipteroids
.
[2]
Their name originates from the
Greek
word ψῶχος,
psokhos
meaning
gnawed
or
rubbed
and π τ ε ρ ά,
ptera
meaning
wings
.
[3]
There are more than 5,500 species in 41 families in three suborders. Many of these species have only been described in recent years.
[4]
They range in size from 1–10 millimeters (0.04–0.4 in) in length.
The species known as booklice received their common name because they are commonly found amongst old
books
—they feed upon the paste used in
binding
. The barklice are found on trees, harmlessly feeding on algae and
lichen
. No member of this order is currently considered
endangered
; in fact, in 2007,
Atlantopsocus adustus
, a species native to Madeira and the Canary Islands, was found to have colonized the mild
Cornish coast
of southwest England.
[5]
Psocids are small, scavenging insects with a relatively generalized body plan. They feed primarily on fungi, algae, lichen, and organic detritus in nature.
Psocids lay their eggs in minute crevices or on foliage, although a few species are known to be
viviparous
. The young are born as miniature, wingless versions of the adult. These
nymphs
typically molt six times before reaching full adulthood. The total lifespan of a psocid is rarely more than a few months.
[6]
Hoell, H.V., Doyen, J.T. & Purcell, A.H. (1998).
Introduction to Insect Biology and Diversity, 2nd ed
. Oxford University Press. pp. 404–406.
ISBN
0-19-510033-6