SEPTEMBER
2011

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

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Check out these books by Tom Turpin:

Flies in the face of fashion

What's Buggin You Now?

 

 

 

09-08-11

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Insect Stalkers Frequent Fall Flowers


Insect numbers in temperate climates show a significant decline during the month of September compared to July and August. Biologically, insects are cold-blooded creatures and by necessity have completed their adult life when the page of the calendar reads September.

Some people dislike insects, and the arrival of fall is reason enough to breath a sigh of relief. On the other hand, a few people are on the prowl for insect specimens during early fall. These are students who are required to make an insect collection.

Collections have long been a method used by middle school and high school educators to teach aspects of biology, including curatorial techniques and biodiversity. Leaves and insects serve such a purpose nicely. So once school begins, many are the students who traipse the lawns, parks and byways in search of leaf or insect.

Unfortunately the beginning of the school is not the best time of the year for either quality leaves or abundance of insects. This means that some parents have encouraged their children to begin such collections during summer vacation months.

It also means that some specimens are passed down from older to younger siblings for use in such an assignment. That, of course, is not the way teachers think collections should be made and has prompted such devious teacher techniques as dusting submitted collections with a powder that will glow under ultraviolet light. Such insects can then be easily detected should they show up in subsequent collections.

The entrepreneurial spirit of students also shines through in such times. I refer, of course, to students who discover that they can earn money by selling extra specimens to those in need. Insect collections are also an important aspect of some college entomology courses. I know for certain that at that level a number of dollars have changed hands in order to complete a collection with a given number of insect orders represented.

And there are other ways to procure an insect or two for the class requirement. I remember one fifth-grade student who had a periodical cicada in her collection. No periodical cicadas had emerged in our area that year. So expecting to hear a story of a family vacation to the Eastern Seaboard, I asked her where she had collected the specimen. To which the student replied, "In a garage sale." There is more than one way to collect an insect, I guess!

One of the best places to collect insects in the fall is on the blossoms of late-blooming flowers, such as goldenrod. As it turns out human insect collectors are not the only creatures to have discovered that late-blooming flowers are good insect-stalking locations. Insects that are predators on other insects also gather on the blossoms. Two of the most common of such predators are praying mantids and ambush bugs.

These insects are aptly named. Praying mantids are so dubbed because they often appear in a prayerful pose. It is from this stance that the mantids reach out with their front legs - called raptorial because, like the talons of a hawk, they function to catch things – and procure their next meal.

Ambush bugs get their name by being masters of the surprise attack. The coloration and shape of these bugs allow them to blend into the surroundings and not be visible to other insect visitors to the flowers. Ambush bugs also have raptorial front legs to facilitate capture of their prey.

Fall flowers could be considered nature's summary statement for the season - the last blossoms, the last nectar, the last insects - before the declining temperatures put a stop to the growth of plants and the activity of cold-blooded animals, such as insects. These flowers could be considered a temperate region fall equivalent to a desert oasis.

It is here where the flower feeders, including bees, find their last pollen and nectar. It is here that insect predators can find a last meal. It is here that insect collectors capture the last few insects for their collections. Unless, of course, they decide it is more convenient to purchase a specimen from a friend!  

 

 

Writer: Tom Turpin
Editor: Olivia Maddox