A polypipin’ we will go, a polypipin’ we will go
Heigh ho, the dairy-o, a polypipin’ we will go
A polypipin’ we will go, a polypipin’ we will go
We’ll catch a tiger beetle and put him in a vial
And then we’ll let him go (not!)

Okay, maybe my adaptation of the popular children’s song A Hunting We Will Go isn’t the best, but if you want to collect tiger beetles in the genus Tetracha then you’ve got to try the method that my friend Kent Fothergill has dubbed “polypipin’.”

What exactly is polypipin’? Well, it’s when you look for stuff under polypipe—a big plastic tube with holes in it that some farmers use to irrigate their crops. The tube is laid across one end of their field, and when water is pumped into it the water leaks out of the holes along the length of the tube and runs down the furrows between the rows. This is a popular method of irrigation in the Mississippi Delta because the terrain is flat and the equipment costs are much lower than center pivot irrigation systems. Of course, the tube also provides excellent cover for insects and other small critters that live in and around agricultural fields, and these include tiger beetles in the genus Tetracha.

I wish I could take the credit, but it was Kent who had the great idea to use polypipin’ as a way to survey for T. carolina (Carolina metallic tiger beetle) in the Mississippi Lowlands (“bootheel”) in southeast Missouri. This is a common species across the southern tier of the United States, but prior to this survey the occurrence of this species in Missouri was not well understood. While a number of specimens had been collected in the bootheel over the years prior to the survey, some regarded Missouri records of the species to be a result of vagrants migrating into the state rather than residents (Pearson et al. 2006). Tiger beetles in the genus Tetracha are nocturnal and take refuge during the day, so they are not often encountered unless one goes at at night with a flashlight. Kent was interested in determining the status of this species in Missouri and had noticed their tendency to take refuge under polypipe—where they could be easily found during the day by simply lifting up the pipe. Rather than give up on sleep, Kent and colleagues surveyed agricultural fields throughout the bootheel by looking under polypipe and demonstrated not only that T. carolina is well established in and a resident of the bootheel, but that it is actually quite abundant and may reside even further north in Missouri than just the bootheel (Fothergill et al. 2011).

I don’t know what it is, but there is just something really fun about polypipin’. Being an agricultural entomologist by day, I have ample opportunity to do a little polypipin’ of my own as I travel across the southern U.S. looking at soybean fields, including this past September when I found myself in fields with polypipe in Arkansas and Mississippi. These photos were taken in Starkville, Mississippi near the Mississippi State University campus, and as has happened in every other case where I’ve looked, I found adults of T. carolina quite abundant underneath the polypipe. Some were found simply resting on the soil surface beneath the pipe, but a great many were observed to have dug burrows under the pipe for added shelter.

Polypipin’ works as a survey tool for T. carolina because of that species’ propensity for agricultural fields and other moist, treeless habitats. I’ve not yet found T. virginica (Virginia metallic tiger beetle) under polypipe, but that species is more fond of forested rather than treeless habitats. Perhaps an agricultural field next to forest with polypipe laid on the side adjacent to the forest might produce this species. At any rate, polypipin’ might offer a tool to better define the entire northern distributional limit of T. carolina—all one has to do is look.

REFERENCE:

Fothergill, K., C. B. Cross, K. V. Tindall, T. C. MacRae and C. R. Brown. 2011.Tetracha carolina L. (Coleoptera: Cicindelidae) associated with polypipe irrigation systems in southeastern Missouri agricultural lands. CICINDELA 43(3):45–58 [pdf].

Pearson, D. L., C. B. Knisley & C. J. Kazilek. 2006. A Field Guide to the Tiger Beetles of the United States and Canada. Oxford University Press, New York, 227 pp. [Oxford description].

Copyright © Ted C. MacRae 2013