Transcript Heath Blackmon - University of Texas at Arlington

“Whenever I hear of the capture of
rare beetles, I feel like an old
warhorse at the sound of a trumpet.”
Charles Darwin
Problems from Last Week
Make sure that you know the terms for
the anatomy of the groups we are
studying.
Entomology Lab
Week 3
1)Entognatha
1)Protura
2)Diplura
3)Collembola
2)Ectognatha - Insects
1)Ametabola:
1)Archeognatha
2)Zygentoma
2)Palaeoptera
1)Emphemeroptera
2)Odonata
Proturan Mouthparts
Phylogeny
Orders for Today
Collembola
Protura
Entognatha
Diplura
Hexapoda
Archeognatha
Thysanura
Insecta
Ectognatha
Zygentoma
Ephemeroptera
Palaeoptera
Odonata
Neoptera - “new wing” vast majority of insects
Order - Diplura
- Compound eyes absent
- Antennae longer than head, with 10
or more bead-like segments
- Abdomen with 10 visible segments
- Cerci present
Order - Protura
- Antennae absent
- Compound eyes absent
- Head conical, all mouthparts enclosed
within the head capsule
- Front legs directed forward
(probably sensory in function)
- Cerci and abdominal filaments entirely
absent
Order - Collembola
Compound eye
collophore
4-6 segment antenna
Furcula
Collembola
* Compound eyes absent or reduced to a cluster of
not more than 8 ommatidia
* Antennae 4- to 6-segmented
* Abdomen 6-segmented
* Ventral tube (collophore) present on first
abdominal segment
* Furcula (springtail) attached ventrally to fourth
abdominal segment
* Body frequently clothed with scales
Class Insecta
What are the synapomorphies shared by all insect
groups?
Traits unique to insects
* lack of musculature beyond the first segment of antenna.
* Johnston's organ in pedicel (second segment) of antenna. This
organ is a collection of sensory cells that detect movement of
the flagellum.
* a transverse bar forming the posterior tentorium inside the head
* tarsi subsegmented
* females with ovipositor formed by gonapophyses from segments
8 and 9
* annulated, terminal filament extending out from end of segment
11 of abdomen (subsequently lost in most groups of insects)
Traits typical of most insects
Wings
Compound Eyes and Ocelli
Exposed mouthparts
Well developed thorax
Metamorphosis
Leg with six segments
Antenna
Order - Archaeognatha
Bristletails
* Body cylindrical in shape and tapered posteriorly
* Thorax somewhat arched dorsally
* Compound eyes large, often touching; ocelli usually present
* Antennae long, thread-like, and multisegmented
* Tarsi 3-segmented
* Abdomen with ten complete segments
* Eleventh abdominal segment elongated to form a median
caudal filament
* Cerci present, shorter than median caudal filament
* Short, lateral styli (rudimentary appendages) present on
abdominal segments 2-9
Order - Zygentoma
Silverfish
* Body relatively flat, tapered and often covered with
scales
* Compound eyes small or absent
* Antennae long, thread-like, and multisegmented
* Abdomen with ten complete segments
* Eleventh abdominal segment elongated to form a
median caudal filament
* Cerci present, nearly as long as median caudal
filament
* Styliform appendages located on abdominal
segments 7-9
Order - Ephemeroptera
Mayflies
* Antennae short and bristle-like
* Front legs long and often held out in front of body
* Compound eyes large, usually covering most of the
head
* Wings: four membranous wings with many veins and
crossveins front wings large, triangular hind wings
smaller, fan-shaped
* Abdomen slender, bearing two (or sometimes three)
long terminal filaments
*Vestigial mouthparts
Order - Odonata
Dragonflies and Damselflies
* Antennae short and bristle-like
* Compound eyes large, often covering most of the head
* Four membraneous wings with many veins and crossveins
* One distinctively pigmented cell (stigma) on leading edge of wing
* Abdomen: long and slender
Odonata Wing
Nodus
Pterostigma
Costa (C) - the leading edge of the wing
Subcosta (Sc) - second longitudinal vein (behind the costa), typically
unbranched
Radius (R) - third longitudinal vein, one branch reaches the wing margin
Media (M) - fourth longitudinal vein, one to four branches reach the wing
margin
Cubitus (Cu) - fifth longitudinal vein, one to three branches reach the wing
margin
Anal veins (A1, A2, A3) - unbranched veins behind the cubitus
Names of crossveins are based on their position relative to longitudinal veins:
c-sc crossveins run between the costa and subcosta
r crossveins run between adjacent branches of the radius
r-m crossveins run between the radius and media
m-cu crossveins run between the media and cubitus
Today
Key Odonata to Family
View Collembola under the microscope
Next Week
Orthopteroids and Dermapterans