Psocoptera: So small, so obscure, so diverse

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Psocoptera So small, so obscure, so diverse
(A quick primer by Ernest C. Bernard)
GO AHEAD, KEY ME OUT.I DARE YA!
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Some key mouthpart characters
Postclypeus
Maxillary palpus
Head views
Labrum
Mandible
Lacinia
Labium
Mandible excavated or not excavated posteriorly.
Mandible
Not excavated
Excavated
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Some more mouthpart characters
Labrum of Psocidae
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Two-segmented labial palps (Lepidopsocidae)
Laciniae
One-segmented labial palps (Psocidae)
Psocidae
Lepidopsocidae
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Characters that sound made-upmeso-precoxal
bridges (PB), trochantins (T)
These characters are very important in
family-level taxonomy in the suborder
Psocomorpha. Carefully pull the head and
prothorax away from the rest of the body, and you
should be able to see these characters clearly.
Meso-precoxal bridges wide, meso-trochantins
narrow throughout.
Meso-precoxal bridges narrow, meso-trochantins
wide at their bases.
PB
PB
T
T
Lachesillidae
Psocidae
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Wingless Psocoptera
Brachypterous, micropterous, and wingless species
are found among many of the Psocoptera families.
The two most commonly encountered are
Liposcelididae and Trogiidae. Members of both
families can be found in dry plant material such
as bird or squirrel nests, or under bark, and
both can often be found in homes. The
liposcelidids pictured here came from dry bat
guano. The common booklice found in old volumes
usually are liposcelidids. These creatures can
be collected easily with a fine paint brush
dipped in alcohol.
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Winged Psocoptera Suborder Trogiomorpha

• Forewing without pterostigma
• Antennae with more than 18 flagellomeres.

Lepidopsocidae
Psyllipsocidae
Few winged trogiomorph psocopterans are found in
the mid-South region. By far the most common are
the lepidopsocids, which have pointed, heavily
scaled wings. Most of the scales (and the
antennae) fall off in preservative, but the
pointed wings are diagnostic. Lepidopsocids are
attracted to lights at night.
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Wings of Trogiomorpha
R1
R2
R3
R45
M1
M2
M3
Cu1a
Cu2
Cu1b
Lepidopsocidae (above), Psyllipsocidae (right).
Note the lack of a pterostigma on the forewings.
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Winged Psocoptera Suborder Troctomorpha

• Antennae with 13 flagellomeres
• Pterostigma usually absent

Winged Troctomorpha are represented in the
southern Appalachians apparently by just one
species, Stimulopalpus japonicus
(Amphientomidae). From above, this species
resembles at first glance a planthopper or
microlepidopteran. The wings are scaled but are
not pointed as in Lepidopsocidae. Also, the
antennae of S. japonicus are much less fragile
than those of lepidopsocids and so remain
attached in their entirety. Interestingly, the
two collections from the Smokies that contained
S. japonicus also contained lepidopsocids.
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Winged Psocoptera Suborder Psocomorpha

• Antennae with no more than 11
  flagellomeres
• Pterostigma present on forewing.

Psocomorpha contains the vast majority of
Psocoptera. Their appearance is highly variable,
from humble brownish species with clear wings to
heavily patterned forms with exuberantly mottled,
marbled, and spotted wings. However, color
patterns usually are not a reliable guide to
family classification.
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Psocomorpha Mandibles excavated
In this group, the families Amphipsocidae,
Caeciliidae, Dasydemellidae, and Epipsocidae are
found in the southern Appalachians. Once the
mandibular character has been determined,
separation of these families is straightforward.
Caeciliidae is a large and common family.
Amphipsocidae contains a single species in the
U.S., easily recognized by its wing pattern.
The other characters of importance are the size
of the labral sclerites, presence/absence of
ventral abdominal vesicles, and presence and
location of wing setae.
Mandible excavated posteriorly
Labral sclerites
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Forewing of Amphipsocidae
The only U.S. species, Polypsocus corruptus, has
a distinctive wing pattern and abundant wing
setae on both the dorsal and ventral surfaces.
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Caeciliidae
Caecilius flavidus
This family is recognized by the presence of 1-3
ventral abdominal vesicles. These vesicles
usually are swollen in preserved specimens.
Forewing setae occur only on the dorsal surface.
Amphipsocids have the vesicles but the forewing
setae occur on both surfaces. Caeciliids are
common in the U.S. and should be easily collected
by beating or sweeping foliage, and by
hand-collecting.
Vesicles
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Forewings of Caeciliidae
Setae occur along the veins on the dorsal surface
only. Note prominent pterostigma and the arched
Cu1a vein.
Cu1b
Cu1a
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Psocomorpha I Mandibles not excavated
Family group Homilopsocidea mesoprecoxal
bridges wide, meso-trochantins narrow throughout
vein Cu1a in forewing usually not joined to M, or
absent (Families Ectopsocidae, Elipsocidae,
Lachesillidae, Mesopsocidae, Peripsocidae,
Philotarsidae).
M
M
Cubital loop
Cu1
Cu1b
Cu1a
Peripsocidae
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Homilopsocidea(continued)
Philotarsidae
Ectopsocidae
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The six families in the southern Appalachian
region are separated on the presence and
orientation of forewing setae, number of tarsal
segments (2 or 3), presence of Cu1a, number of
labral sensilla, and certain characters of the
external genitalia.
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Psocomorpha II Mandibles not excavated
Family Group Psocetae meso-precoxal bridges
narrow, meso-trochantins wide basally vein Cu1a
in forewing joined to M (Families Myopsocidae,
Psocidae). Myopsocidae has three-segmented
tarsi, Psocidae has two-segmented tarsi.
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Psocetae (continued)
In the Psocetae, wing patterns often are
diagnostic. The genus Trichadenotecnum
(Psocidae) has a radial series of spots in each
marginal wing cell.
Cu1a
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Psocidae Appearance
Loensia sp.
Trichadenotecnum sp.
The Psocidae exhibit a wide range of color
patterns on the body and wings. Sexes exhibit
dimorphism in the size of the eyes (much larger
in males), as well as in the external genitalia.
Psocids prefer bark as a habitat.
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