Forest Field Trip
In this lab you will observe and collect insects commonly associated with forest trees, dead wood, and soil litter.
The main objectives of this lab are to help you:
- learn where to look for insects and how to collect them safely
- use a Berlese funnel to extract insects from soil litter
You will need the following materials for this lab:
- Wide-mouth collecting jars or plastic boxes
- Insect net (optional)
- Killing jar (optional)
- Nail polish remover – acetone (optional)
- Insect pins
- Paper “points”
- Permanent ink pen – fine point
- Date/locality labels
- 4-dram glass vials
- 70% ethyl alcohol
- Berlese funnel – milk jug, screen, and jar with alcohol
- Hatchet, knife, or screwdriver
For your second field trip and insect collecting expedition, visit a forest environment where you can find a dead wood and a thick layer of decaying vegetation (leaf litter) on the forest floor. If possible, avoid forested areas that are dominated by only a single tree species. A more diverse insect fauna is usually associated with a highly diverse plant community.
Your forest field trip is a good opportunity to collect insects in the following ecological categories:
- Leaf chewing
- Wood dwelling
- Gall maker
- Leaf roller
- Soil Dwelling
- Litter inhabitant
- Leaf miner
- Social Insect
Watch the Forest Field Trip video to get a preview of what these insects look like and where to find them.
Tour the following picture galleries to see examples of insects in these ecological categories:
- Foliage feeders (leaf chewers, rollers, and miners)
- Insect galls
- Soil-dwelling insects
- Wood-dwelling insects
Examine the foliage of trees and bushes – be on the lookout for leaf miners and leaf rollers. Collect any unusual growths you find on leaves or twigs: these may be insect galls. Put a white sheet or painter’s drop cloth under the branches of a tree or bush and shake the overhanging vegetation vigorously.
Pry the bark off dead wood with a hatchet, knife, or screwdriver. Look for termites and the adults or larvae of wood boring beetles. Roll over logs and look under stones for nocturnal insects that hide in the daytime. Be sure to replace the log or stone so you don’t disrupt the habitat any more than necessary.
Gather a few handfuls of moist, well-decayed leaf litter and put it in a plastic trash bag. Take this sample home and use it when you set up a Berlese funnel (see below).
3. Pin and Preserve
Mount your insect specimens on pins or points according to the instructions.
Carefully dissect any galls you found and look for insect inhabitants. Preserve these insects in Kahle’s solution or 70% ethanol. Make a Berlese funnel from a plastic milk jug following the instructions at http://www.cals.ncsu.edu/course/ent525/soil/berlese.html
Transfer your litter sample into the funnel and let it sit in a warm spot for several days until the sample dries out. Look in the alcohol container for springtails (Collembola) and other litter inhabitants that were living in your sample.
Use Kahle’s solution as a fixative for the leaf miners, leaf rollers, termites, and other soft-bodied immatures you collect. Large caterpillars, maggots, white grubs, and the larvae of bess beetles should be dropped in boiling water for one minute before going into Kahle’s solution. After one week, replace the Kahle’s solution with 70% ethanol for permanent storage. You can save and reuse the Kahle’s solution for other specimens.
Be sure to put a date/locality label on every specimen, using the format described in the instructions. Use the Label Request Form if you need customized labels (ENT 425 students only). Keep good notes to help you remember which insects fulfill ecological categories. You will add Ecology labels later after you have identified the specimen.