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How to look for insects ‘Hilltopping’ in the spring

In a joint effort to expand the knowledge and understanding of the flora and fauna of Polk County, Conserving Carolina and botanist David Campbell need your help in locating this month’s “Polk County’s Most Wanted Animal Behavior” — hilltopping.

With the arrival of spring, be on the lookout for an interesting insect behavior known as “Hilltopping.”  Hilltopping is a mate-seeking behavior employed by many groups of insects such as butterflies, dragonflies, beetles, and flies. Simply put, insects will seek out the highest points in the landscape and congregate there to seek mates.

Males will compete with one another to occupy the highest points and defend them against other males. Females will arrive to seek out and mate with the “fittest” males that occupy the best locations. This is an excellent strategy.

Insects are small and relatively short-lived, so any advantage that they can employ to find a mate in the shortest time possible is very beneficial.

Hilltopping may be observed on small mounds or the highest mountain peaks; the key is to be observant. On good days in the spring and summer, sharp-eyed individuals may be rewarded by seeing dozens of species, sometimes numbering in the hundreds, interacting and engaging in fascinating and seldom observed behaviors. 

Butterflies, like Mourning Cloak (Nymphalis antiopa) and Anglewings (Polygonia spp.) are often the most visible members of the “hilltopping community” in our region, but they are by no means the most numerous. On one occasion, David Campbell observed several dozen very rarely seen beetles of a species that normally reside deep underground in ant nests. They were on top of a small red clay hill adjacent to the Catawba River. He had never seen these beetles on any occasion before, and only knew about them through what he had read in books. Subsequently, he went back the following year to the exact same site, and saw this beetle species again. Hilltopping was the key.

Some locations are better than others.  A path, trail, or dirt road that crests on a ridge and that has a relatively open space around it may be an excellent site to observe this phenomenon. Sunny days are the best, particularly in the morning. Scan flowers, rocks, and the leaves of trees located in sunny patches, and look up. Careful observers may be greeted with a surprise when they see numerous hoverflies and dragonflies cruising around, looking for love, right above their heads.

Polk County, with its many elevational changes and hilly topography, is an ideal area to observe these fascinating insect displays. There is very little known about this behavior, so if you encounter any particularly good locations to observe hilltopping, please let us know. Photos are encouraged and can be sent with comments or questions by e-mail to Pam Torlina at Conserving Carolina, 828-859-5060 or pam@conservingcarolina.org.

Visit Conserving Carolina’s website, conservingcarolina.org/our-impact/education, for more information about “Polk County’s Most Wanted” and to download and print a “Pocket Guide” with all of the “Most Wanted” plants, animals, and habitats that you can be on the lookout for when you’re out in the field.

Conserving Carolina, your local land trust, is dedicated to protecting and stewarding land and water resources vital to our natural heritage and quality of life and to fostering appreciation and understanding of the natural world.

– Written by David Campbell