Lab 10. Identification of Immature Insects
In this lab you will learn how immatures are different from adult insects and you will identify the immature insects in your collection using a KWIK-KEY.
Objectives
The main objectives of this lab are to help you:
- learn to distinguish among nymphs, larvae, and adults
- identify (to order) the immature insects that you will submit with your insect collection
Activities
1. Review
Before lab, review Preserving Insects In Alcohol, and The Bug Bytes page on Morphogenesis.
2. Bring Materials for Lab
See the list at the bottom of this page (IMPORTANT: if you do not bring these materials, you will not be be able to complete this lab)
3. Prepare Collected Immatures
Assemble your collected immatures, or insects you think might be immatures, whether they are in glass vials or pinned. Ideally, your immature insects should be preserved in alcohol according to these instructions. It may be necessary to remove insects from the glass vials and examine them under a microscope to see the characters needed for identification. Don’t let the specimens dry out. Return them to the vial and replace any missing alcohol when you finish looking at them.
4. Lab Exercise: Identify Your Immature Insects
The “KWIK-KEY to Immatures and Wingless Adult Insects” is available in 2 forms:
KWIK-KEY Handout (print and bring to lab)
KWIK-KEY Online Guide (use with smartphone or computer)
Use whichever form suits you best. The KWIK-KEY works pretty well for most common nymphs and larvae, but it is not perfect. It may lead you astray on unusual or atypical specimens, and it is completely useless for pupae. Don’t bother to include pupae in your collection unless they are distinctive (like mosquito pupae) or you have some other way of knowing what they are (like a blow fly pupa collected from carrion).
All immatures you submit with your collection for grading must be identified to order; you are NOT required to identify them to family. Although identification of immatures to family is outside the scope of this course, you can still earn Family points for specimens that you identify and label correctly. Just include the family name under the order name on the ID label. Don’t waste a lot of time doing this, but if you have a distinctive immature like an ant lion, a hellgrammite, or a hornworm, you can look up the family name and earn those points without much effort!
5. Common Mistakes to Avoid
- Specimen is black and/or shriveled because it was not properly fixed in Kahle’s solution. See “Preserving Insects in Alcohol”.
- Date/locality label missing or formatted incorrectly. See “Guide to Making Insect Labels”.
- ID label missing or incorrect. See “Collection Instructions”.
- Failure to use laser-printer for permanent labels, or “archival” ink or pencil for temporary labels. See Guide to Making Insect Labels.
- Immature specimen is pinned without “immature” appearing on the ID label. See Guide to Making Insect Labels.
- Adult specimen is in alcohol without “adult” appearing on the ID label. See Guide to Making Insect Labels.
Materials
You will need the following materials for this lab:
- Your collected insects
- Preserving gear (signed out at beginning of semester = tote bag containing specimen box; pinning block; specimen viewing block; vials; Lepidoptera envelopes; several cut pieces of cardstock [specimen drying supports]; a few pins and paper points; spreading board)
- Labels, both temporary (cut pieces of paper) and permanent (printed from “Insect Labels form“)
- 70% ethyl alcohol and “Kahle’s Solution” (both provided in lab)
- Stereomicroscope (provided in lab)
- KWIK-KEY to Immatures and Wingless Adult Insects
- Smartphone or computer, to access class website.
