Intro

1. Site
   Identification

Instructions for dissections of Phragmites

We will provide a basic data record sheet for the dissections that you can download from this website. You can obviously create your own but make sure that the essential information is recorded. Most likely, students working with individual stems will make notes on pieces of paper for each stem and then create a clean copy for record keeping. It is important that all stems are individually numbered and that the quadrat for each stem is known. That suggests that working with a single quadrat is the safest approach preventing confusion. Number stems consecutively, even if moving to a new quadrat. Have all materials for storage or rearing of insects ready before beginning the dissections. Ideally, you can work in several teams on long lab benches (Phragmites stems are very long) processing each stem separately.

1. Open the first bundle and take a single shoot.
   
2. Measure the length (in cm) and diameter (in mm, using calipers) of the stem. The length of the stem is from the base of where the shoot was cut to the flowers or shoot tip. Make sure to stretch out the entire stem. The diameter is measured just above the lowest internode that is available. Do not measure the internode because that will inflate the stem diameter. pictures
   
3. Record whether the plant has flowered or not
   
4. Record whether the stem is broken or not (if you folded the stem do not record this as broken)
   
5. Note whether there is any bird damage to the stem (large holes, such as from bird beaks, as opposed to small holes which might be due to insects) (Provide picture).
   
6. Record whether side shoots have formed (Provide picture)
   
7. Dissect the stem with a pocketknife starting at the bottom. Go slowly; do not slice through it completely in a way that would injure the insects that might be living inside. Some species are small and difficult to spot. Be careful not to overlook these or the ones in the shoot tips. On plants that have not flowered often we find maggots living in the shoot tips. picture These are called shoot tip flies. Carefully dissect the tip all the way to the end. Occasionally the tips form a gall (hard tissue, larger diameter than the stem) and the larva is found inside.
   
8. Record which species you find and where. Keep the insects for rearing (see below) or as reference specimens in alcohol. If you decide to take reference specimens, very often it is important to keep parts of the stem where you found the insects as well. This will often help in identifying the species. (for more details see the descriptions of the different insect species below)
   
9. If you find an insect, stop dissecting. picture
   • Create a simple drawing of the insect as it looks in the stem or identify it using the picture guide provided later (see common insects in Phragmites in North America section).
   • When you see an insect that you or others in your class have not seen before, share your finding with the class and come up with a name that will be used for counting this insect during all future dissections. For easier communication with other participants we have provided common names for most species (see below) but for some they do not exist. You may need to use the Latin names. This introduces the students to the scientific concept of naming species.
   • Notice any other organisms or structures that might be present where the insects are present (such as fungi, galls, etc.).
   • If you find an insect or a structure that you are unable to identify using our materials (we expect surprises!), please create a drawing, take a picture and try to rear the insect (most often, only adults can be identified to species by a taxonomist. We often send specimens to the Natural History Museum in Washington DC to help with identification). Send information about your finding to Cornell University, send a picture or the sample and we will help in identifying the organisms (if possible).
   • picture Once all data about an insect have been recorded and the species is identified (if possible), you can put the insect in a jar, petri-dish or vial and wait for it to complete development. Adult insects usually emerge within a few weeks after stems are brought into room temperature. This shows students how morphologically different larvae and adult insects really are. These adult insects can also be added to an existing insect collection at the school (or starting one). This is a great opportunity to learn more about insect life cycles and how different temperatures may influence the speed of development.

   If no insects are found in a particular stem, or if you have completed recording findings on your data sheet, go back to step one and dissect another stem. Insects will not be present in every stem.
   

10. If no insects are found in a particular stem, or if you have completed recording findings on your data sheet, go back to step one and dissect another stem. Insects will not be present in every stem.

                        [Back]                                                              [Next]

Copyright 2002. Bernd Blossey. Cornell University
For problems or questions regarding this web contact Raj Smith.