This text is mainly a translation of the text Aktivitets och undersökningstips in
Trollsländor - ett kompendium by Tobias Ivarsson.
I have made minor changes, to make it useful even for non-Swedish odonatologists.
"Trollsländor - ett kompendium" is written for youth odonatologists, but I think some part of the text even is useful
as inspiration for older odonatologists.
Different dragonfly species fly at different times of the summer. Some Swedish species start flying in May but other
species are not seen until beginning of July. When the late flying species start flying, some of the early species already have
disappeared. Thus all dragonfly species at a place can't be found during a single visit. The best time for seeing many different species
are at the turn of the month June/July (southern Sweden). Write down the date for the first and last appearance of the
species at your home district, differs the time from year to year?
There's still many places in Sweden (and many other countries around the world) badly checked for dragonflies. It's easy and fun
to be helpful for the inventory of the Swedish dragonflies. One can just check some lake or stream at random or make
an well planned expedition. Buy a map, select an interesting area of that map and check all lakes, ponds, steams and swamps
in that area. During such a trip you will get very good knowledge about what species living in that area and what kind of
biotope each species prefer.
Preferable such expeditions is made by bike or walking. It's much harder to find dragonflies when traveling by car. Find out what
species you find, write down species, date, name of water and a description of the way to the water.Please register your findings in artportalen a Internet based reporting system.
Male dragonflies often keep territories where they fly around and keep other males away. The size of the territories
differs depending on area and species. The territories of males are perfect for studies.
Investigate for example those questions:
Knowledge about the territory can be used for photography and catching as the dragonflies fly along the same paths,
find such a path and wait for the dragonfly with your net or camera.
- Which species flies where? Along the shore, over open water, along muddy parts etc.
- Do the males fly all the time, or do they rest sometimes?
- How big is the territory?
- Draw the different territories on a map.
- Do the males fight only with other males of the same species or are all males attacked?
- Make a model of a dragonfly and place it in the territory, are this model attacked?
How old can a dragonfly be? How far can it fly?
Such questions can be answered by marking the individuals. Catch the dragonfly and mark the wings with a permanent marker.
Recatching the dragonfly will answer your questions.
Be very careful while doing this, injury of the dragonfly might decrease the lifetime and your examination date will be
faulty. Don't catch and mark rare dragonflies.
There's a few ways of collecting dragonflies, catching and killing male ones are one bad method. I think living dragonflies are nicer than killed
dragonflies! The dragonflies often lose the nice colors as dead. On better alternative is to collect exuvier, empty larva skins.
Exuvier are found at straws and stones at the shore. The exuviers can be determined to species using some book with
a larva key.
Raising of dragonfly larvae are very interesting, it's quite hard but I've tried. My results and ideas are found
Dragonfly sex is very fascinating and gives you many opportunities for studies:
- For how long time do the dragonfly mate?
- Were do they mate
- For how long time are the dragonflies in tandem before they mate?
- How do the dragonfly lay her eggs? Does the dragonfly put her eggs in some plant?
- Does the dragonfly lay her eggs under the water surface? For how long time can she be under the water surface?