Ever fished for doodlebugs or taught a child how to fish for doodlebugs? If so, which one were you after? Was it a tiger beetle larva, as shown in the photo, or was it an antlion larva, as discussed in this past Bug's Eye View? Both insects are colloquially referred to as doodlebugs; both can be extracted from their larval lair using a long grass stem, and both are sufficiently strange-looking that creatures modeled after them have appeared in science fiction movies.
This is the larva of the Carolina tiger beetle, a large, fast-moving, colorful beetle that can be seen scurrying over the soil of gardens and tilled fields throughout the South. Their colors are striking, a blend of metallic greens, purples and other colors. They also have big eyes and impressively large mandibles. They look like predators, and they are. So are the larvae, but they are not as mobile as the adults. There are many other species of tiger beetles and some of the adults are even more colorful.
Tiger beetle larvae are “sit and wait” predators. They live in vertical tunnels in the soil, resting with their head at the surface, where they can grab insects or spiders that wander too close. Notice the location of the eyes on the larva in the photo and how those large, sickle-shaped mandibles point upward, at what appears to be an awkward angle? They don’t dart forward out of their hole to catch prey, instead they flip the head backward. Everything is setup perfectly for this behind the head catch. Tunnels of larger larvae are roughly pencil-sized, both in diameter and depth. and they will rebuild these if destroyed by tillage operations. In my vegetable garden, when I hill up the tomato and pepper row and cover it with black plastic, they will promptly rebuild their tunnels and cut a head-sized hole through the plastic.
So how does one fish for this kind of doodlebug? Find an area with some pencil-sized tiger beetle tunnels, break a long, slender grass stem about eight to ten inches long and insert it into one of the tunnels. Then sit patiently with your fingers poised around, but not touching the grass stem. Wait until you see the stem begin to move. Then wait just a little longer and quickly jerk the stem from the hole. If you are lucky the larvae will have the stem grasped firmly in its mandibles, and you’ve caught your first tiger beetle.
While admiring the size of the mandibles and posing for pictures you will notice those two large hooks on that hump on the lower part of the back. These help anchor the larva in its tunnel when it is struggling to capture larger prey. Chicken chocker is another colloquial name for tiger beetle larvae and it is easy to see why. But do they really deserve this name? My wife has free range chickens, and they sometimes enter the garden, where I sometimes fish for tiger beetles. So far, I have been able to constrain scientific curiosity, and I pray for strength to continue to resist temptation. Some of these chickens have names!
Trivia Question: What is the mascot of the LSU Entomology Club?
A: Toad Bug B: Hercules Beetle C: Stink Bug D: Tiger Beetle
Blake Layton, Extension Entomology Specialist, Mississippi State University Extension Service.
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