Activities
1. Assemble your insect specimens, microscope, cork observation block, and labeling equipment.
Your insects should already be pinned, pointed, or spread according to the Insect Collection Instructions. Each specimen should have a Date/Locality label showing where, when, and by whom it was collected (see Collection Instructions). Handle your specimens with great care. Once they are dry, they become very brittle. Use the cork observation block to position your specimens for viewing under the microscope; it helps reduce accidental breakage.
2. Identify dragonflies and damselflies – order Odonata.
Use How to Know the Insects by Bland and Jaques as an identification guide. The key to families of Odonata begins on page 71.
Couplet #1 separates dragonflies (suborder Anisoptera) from damselflies (suborder Zygoptera). The distinction is based on the shape of the hind wing: broad at the base in dragonflies and narrow at the base (petiolate) in damselflies (see Figure 70).
Dragonflies key out in couplets 2-7. Damselflies key out in couplets 8-10. The arculus and nodus (see Figure 70) are features of wing venation that can be used as landmarks to locate important features of venation. In dragonflies, look for similar triangles near the arculus. In damselflies, look for the origin of the M3 vein near the nodus.
SpotID — You will NOT be asked to identify any families of Odonata on the lab practical.
3. Identify grasshoppers, katydids, and crickets – Order Orthoptera
Use How to Know the Insects by Bland and Jaques to identify your insects. The key to families of Orthoptera begins on page 91. Be sure you can distinguish between three-segmented and four-segmented tarsi. Do NOT count the arolium (an adhesive pad between the claws) as a tarsal segment and don’t confuse the pads beneath the segments with the segments themselves. Some tarsal segments may have more than one ventral pad.
SpotID — Learn to recognize and distinguish the members of Orthoptera that belong to the following three families:
Family |
Key characters |
Acrididae — grasshoppers and locusts |
- short antennae (shorter than body)
- three-segmented tarsi
- tympana located on sides of first abdominal segment
|
Tettigoniidae — katydids |
- long, filiform antennae (longer than body)
- four-segmented tarsi
- tympana located on tibiae of front legs
|
Gryllidae — crickets (house crickets,
field crickets, and tree crickets) |
- long, filiform antennae
- three-segmented tarsi
- tympana located on tibiae of front legs
|
4. Identify true bugs – Order Hemiptera, suborder Heteroptera
All true bugs have a tubular proboscis (beak) that arises from the front of the head. This proboscis may be short and aimed forward (as in water scorpions or giant water bugs), or it may be long, segmented and, when not in use, curved backwards beneath the head (as in stink bugs and assassin bugs). Forewings (hemelytra) are leathery or parchment-like at the base and membranous toward the apex. At rest, they fold over the insect’s back to form an “X”.
Use How to Know the Insects by Bland and Jaques as an identification guide. The key to families of suborder Heteroptera begins on page 134.
Errors/Corrections — Make the following changes or corrections in the key to Heteroptera:
24a — Revise punctuation to read: Lips around scent gland openings (on side of thorax between middle and hind coxae) greatly reduced or absent;
SpotID — Learn to recognize and distinguish the members of Heteroptera that belong to the following six families:
Family |
Key characters |
Belostomatidae — giant water bugs |
- short proboscis
- single claw on front legs
- broad, flat dorsal surface of body
|
Gerridae — water striders |
- long legs
- claws ante-apical
- fringe of hairs at tip of tarsus
|
Notonectidae — backswimmers |
- keel-shaped dorsal surface
- ventral surface darker in color than dorsal surface
- fringed hind legs lack claws
|
Reduviidae — assassin bugs |
- three-segmented proboscis
- head elongate, narrowing behind eyes
- groove along midline of prosternum
|
Miridae — plant bugs |
- ocelli absent
- wings angle down behind abdomen
- cuneus present on front wings
|
Pentatomidae — stink bugs |
- shield-shaped body
- five-segmented antennae
- large, triangular scutellum
|
5. Identify insects in the order Hemiptera, suborder Homoptera
The suborder Homoptera includes cicadas, leafhoppers, treehoppers, froghoppers (spittlebugs), planthoppers, psyllids, whiteflies, aphids, mealybugs, and scale insects. All of these insects feed on plants. They have piercing-sucking mouthparts in the form of a short proboscis (beak) that arises near the back of the head, just in front of the forelegs. In profile (side view), the head of these insects often has a characteristic “wedge” shape with a blunt frons protruding in front of the eyes. Forewings are uniform in texture – entirely membranous or entirely parchment-like. At rest, they usually fold tent-like over the abdomen.
Use How to Know the Insects by Bland and Jaques as an identification guide. The key to families of Homoptera begins on page 157.
Errors/Corrections — Make the following changes or corrections in the key to Homoptera:
2a — Substitute: Ocelli located on dorsal sclerite (vertex) or frontal sclerite (frons) …… 9
2b — Substitute: Ocelli located on lateral sclerite (gena) …… Superfamily Fulgoroidea (STOP HERE – use this superfamily name for your specimens)
16b — …………………. Superfamily Coccoidea (STOP HERE – use this superfamily name for your specimens)
18b — ………………….. Superfamily Aphidoidea (STOP HERE – use this superfamily name for your specimens)
SpotID — Learn to recognize and distinguish the members of Homoptera that belong to the following six families (or superfamilies):
Family |
Key characters |
Cicadidae — cicadas |
- large body size
- three ocelli
|
Cicadellidae — leafhoppers |
- comb-like rows of long spines along tibiae of hind legs
|
Cercopidae — spittlebugs
(froghoppers) |
- large bristles clustered at the distal end of each leg segment
|
Membracidae — treehoppers |
- large pronotum covers head and extends backwards over abdomen
|
Aphidoidea (superfamily) — aphids |
|
Coccoidea (superfamily) — scale insects |
- sessile, sac-like body
- covered by protective “shell”
|