Can anyone recommend a technique for studying the behavior of tiny, highly mobile insects in field settings?
In particular, I am in the process of designing protocols to study the host plant use and movement of a highly mobile, and very skittish, green mirids (Hemiptera). I am having problems linking host feeding with particular individuals within agricultural settings. Any advice on working with small fast moving insects (any taxa) would be appreciated.
do you release the mirids? or is the resident population what you want to study?
In Tephritid fruit flies, some species being controlled by means of Sterile insect technique, mass-reared sterilized males are marked with a fluorescent dye that allows identification of each released individual. We have performed some competitions between strains and/or between batches subjected to different treatments (for improvement of mating) on which each treatment was labelled with a different fluorescent color. This dye was neutral to the fly, and persist in the fly for weeks.
There is a lot of works and literature citing them, you can check also at FAO/IAEA Entomology joint unit for many of these SCI papers or technical papers (which are more clear indicating brands, where to buy in different countries, success in release trials, a a long etc).
I work with Culicoides so understand the problems of working with small insects.One technique that may be of interest is immunomarking - the use of proteins to mark individuals or habitats. In this case you could treat individual host plants with the marker and then use ELISA to subsequently indentify insects that have been feeding or resting on it. Have a look at papers such Haglar and Jones 2010 Ent. Exp. et Appl 135: 177-192. Is there a possibility of marking the phloem of the plants by radioisotopes? Hope thats a start, anyway.
I work with Culicoides so understand the problems of working with small insects.One technique that may be of interest is immunomarking - the use of proteins to mark individuals or habitats. In this case you could treat individual host plants with the marker and then use ELISA to subsequently indentify insects that have been feeding or resting on it. Have a look at papers such Haglar and Jones 2010 Ent. Exp. et Appl 135: 177-192. Is there a possibility of marking the phloem of the plants by radioisotopes? Hope thats a start, anyway.
Have a look at the following paper, and see if this could be applied to your system :
Wheye, D., Ehrlich, P.R., 1985. The use of fluorescent pigments to study insect behaviour: investigating mating patterns in a butterfly population. Ecological Entomology 10, 231–234.
The most practical and widely-adopted method is by using flourescent powder and marking individuals or treatment groups with specific colours. This has been demonstrated well in the field in e.g. Drosophila and various larger, mobile species (e.g. Lepidoptera). One is mainly limited here by the number of colours available.
Depending on the research question, it is also possible to use harmonic radar tags, but the transmitter has to be very large if you are working on very small insects. This type of approach is essentially limited by how much one is willing to spend on the system. A good review of techniques is available in Tim New's book: http://www.amazon.com/Insect-Conservation-Handbook-Approaches-Techniques/dp/019929822X
Another possible method is using honey bee tags (unique numbers that are glued on to individuals) but possibly mirid bugs are a bit small for this approach. The advantage of this technique is one can track individuals more easily (e.g. for mark-recapture statistics).
It really depends on what the research question is. If you are interested in seeing what hosts these mirids may be feeding on, you can survey host plants (labor intensive, but otherwise inexpensive). If you are interested in individuals, there has been some work done on taking individual insects and then amplifying the plants' 18S gene from the insect's gut and the n conducting a BLAST search in Genbank. There are a lot of caveats to the information that you get, but there are advantages over immunomarking / fluorescent powder marking. Those techniques only tell you if a bug went from point A to point B and nothing about what they did in between. Also, you'll need some good luck in capturing enough individuals to generate some meaningful data. For the plant PCR method, you might contact Claudia Nischwitz at Utah State University. But first figure out what exactly you want to accomplish.
If particular host plant have an identifiable isotopic signature, this may "mark" the individuals feeding on...(see Ponsard et al / Ostrinia nubilalis and corn versus hop/mugwort host plant)...
1) I use a monocular from Orion that can focus quickly at rather close distances
2) I use Canon cameras at about 2 meters distance that have good IS and high zoom. A Canon Powershot SX10IS uses eneloop AA batteries, easily changed in the field, and it can quickly go from stills to video. The optical zoom goes to 20x and the macro is great if you need to get close up. In bright sun, you absolutely need a viewfinder. In the field AA batteries are best, and newer models do not use them.
If you need to follow individuals over time, you can try marking on a conspicuous surface. Try to mark several insects individually. You may see them again several times in, say, an hour, if you are observing in a 3 meter radius cylinder. Of course marked individuals will leave and new ones come in. But this can all be data.
If you are working with the mirids in transgenic cotton, you may be able to use a dip-stick method of detecting specific Bt toxins expressed by the plant and picked up by the insect. I'm not sure it would work with a phloem feeder, but maybe. See Spencer JL, Mabry TR & Vaughn TT (2003) Use of transgenic plants to measure insect herbivore movement. Journal of Economic Entomology 96: 1738–1749.
We used acrylic paint to mark the individuals. But we work with coleoptera and it is quite simple to mark the elitrae. I don't know if it work with Hemiptera also.
I strongly recommend you look at the work by James Hagler and co-authors on tracking insect movement and feeding behaviour. His body of work presents a range of options and pros/cons for each. Which one is best for you will depend on your question and the behaviour of your insect. You'll probably have to try a few options to find the best. James is very open to collaboration so you could try contacting him direct.
U can use simple traps to study dispersal, flight behaviour etc. For host range, many advanced techniques are available as suggested by many colleagues above. You need to define the parameters you want to study.
do you release the mirids? or is the resident population what you want to study?
In Tephritid fruit flies, some species being controlled by means of Sterile insect technique, mass-reared sterilized males are marked with a fluorescent dye that allows identification of each released individual. We have performed some competitions between strains and/or between batches subjected to different treatments (for improvement of mating) on which each treatment was labelled with a different fluorescent color. This dye was neutral to the fly, and persist in the fly for weeks.
There is a lot of works and literature citing them, you can check also at FAO/IAEA Entomology joint unit for many of these SCI papers or technical papers (which are more clear indicating brands, where to buy in different countries, success in release trials, a a long etc).
Specimens of the first of the new species here described were received by the Commonwealth Institute of Entomology from Mr. G. Swaine, Entomologist to the Department of Agriculture, Tanganyika Territory, who reported it as injurious to shoots and young fruits of the cashew nut, Anacardium occidentale L., and of the second through the British Museum...