The lab uses insects that were dried or fixed beforehand (grasshopper, rose chafer); live insects are not killed. First record the insect’s length and colour. Then divide the body into head, thorax and abdomen. On the head look at the eyes, antennae (smell) and mouthparts with a lens; compare antenna shapes. Identify the leg segments, claws and the difference between front and hind legs. On the thorax carefully lift the two pairs of wings with tweezers and compare fore- and hindwings. Then, with the teacher’s help, cut off the wings and find the abdominal segments and, with a lens, the spiracles. Record results in drawings and a table.
Worked examples
Table entry: “Grasshopper: 4 cm, green; 3 body parts; thread-like antennae; jumping hind legs; 2 pairs of wings.” This is a precise observation result.
Grasshopper and beetle antennae differ: thread-like in the grasshopper, fan-like in the rose chafer. The difference is linked to their way of life.
Class activity
Work in pairs: one looks through the lens, the other writes, then swap. Safety: use scissors and tweezers under adult supervision, point tips away from yourself; wash hands afterwards. Do not catch and kill insects outside class.
Practice
1
What kind of insects are used in the lab?
Dried or fixed specimens from collections.
2
Into what parts do we divide the insect body?
Head, thorax, abdomen.
3
How do we distinguish fore- and hindwings?
The forewing (hard in beetles) is the front pair; the hindwing is thin, membranous and used for flying.
4
Why do we look for spiracles on the abdomen?
Tracheae open to the outside air through openings on the sides of the abdomen.