“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 LabWeek 3

1)Entognatha1)Protura2)Diplura3)Collembola

2)Ectognatha - Insects1)Ametabola:

1)Archeognatha2)Zygentoma

2)Palaeoptera1)Emphemeroptera2)Odonata

Proturan Mouthparts

Phylogeny Orders for Today

Hexapoda

Ectognatha

Entognatha

Insecta

Diplura

Protura

Collembola

Thysanura

Archeognatha

Zygentoma

Ephemeroptera

Odonata

Neoptera - “new wing” vast majority of insects

Palaeoptera

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

Furcula

collophore

4-6 segment antenna

Compound eye

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 - ArchaeognathaBristletails

* 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 - ZygentomaSilverfish

* 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 - EphemeropteraMayflies

* 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 - OdonataDragonflies 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 WingNodus

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 subcostar crossveins run between adjacent branches of the radiusr-m crossveins run between the radius and mediam-cu crossveins run between the media and cubitus

TodayKey Odonata to Family

View Collembola under the microscope

Next Week

Orthopteroids and Dermapterans