It is likely the adult emergence coincides with the summer rains we usually get in July and August. The humidity rises, plants start to grow again, and more insects of many kinds are active.
Interestingly, the brown damselflies we see each year are probably females because the males are often bright blue or violet.
What insects do you see at the same time year after year?
What is phenology? It is the study of the timing of certain measurable events in the life cycles of living creatures. Examples might be time of migration or nesting in particular species of birds, date of flowering in certain plants, or mushroom formation in a certain type of fungus. The occurrence of these events is often related to climate. Spring is a great time to study phenology (in places with distinct seasons), because it is relatively easy to recognize key events, like when lilacs are flowering around your neighborhood.
Why is studying phenology important? Some events, such the the running of sugar maple sap, are significant for people who use it as a source of food. In one study from 1963 to 2003, researchers found the maple trees started running sap on average eight days earlier, which isn’t too much of a problem. The problem was that the trees started to bud (and stopped running the proper quality of sap) 11 days earlier, shortening the season by 10 percent. Other events may impact human health, such as when pollen sheds from certain allergenic plants. Interestingly, not all living things react in the same way to changes in temperature. Some events, particularly those later in the year, may actually be slowed.
In this somewhat long video, some of the members of the network explain what phenology is and how the network came about. Try watching the first part at least. It shows David Bertelsen climbing the same mountain in Arizona that he has climbed for the past 30 years. He diligently records information on some 600 species of plants that he encounters!
Look under “Participate” on the USA National Phenology Network website to learn how you can get involved through Nature’s Notebook.
Even if you aren’t interested in participating, go check out the Educator’s Clearinghouse! They have four pages of website links to free educational materials, lesson plans and activities to explore.
Take the pond damselfly in this photograph. These delicate, light-brown damselflies arrive each year in our yard in August and September.
We found them in August 2012 and
in the September of 2011.
