June 16, 2005

Feature Article - for release the week of June 19, 2005

Dan Culbert - Extension Horticulture Agent

WATCH DOODLEBUGS FOR SUMMER FUN

 

One of the lesser known creatures found in Florida Yards are ant lions, the larva of a dragonfly relative.  They dig cone shaped pits in sandy soil and trap ants as food.  Here in the South, the critters are known as doodlebugs.  They are beneficial insects that should be left alone because they are a “free landscape pesticide” - they eat many insect pests.

 

One Florida entomologist claims that a normal, healthy childhood in Florida requires knowledge and experiences with the doodlebug.  Parents looking for summer fun alternatives to television and video games might find that looking for and playing with these unusual Florida Yard inhabitants might occupy a child’s attention for some time. Who knows – they may spark an interest in the natural world.  Information for today’s column comes from University of Florida ’s Extension Entomologists and a website titled “The Ant lion Pit.”

 

The adult ant lion looks much like a damselfly, a dragon-fly like insect.  A big difference is that their antennae are shorter and are bent or clubbed. Adult insects measure 1-2 inches long and their body is colored brown to gray.  They have four equal-sized wings, 2-3 inches long, that may be either transparent or irregularly spotted. 

 

Adult doodlebugs rest in hidden places and are hard to notice.   At night they become active, searching for a mate and attracted to lights.  Females lay eggs in warm, dry sandy sites.  When a female finds the right spot, she taps her abdomen and then inserts a single egg below ground.  Several eggs may be laid in the same area, up to 20 eggs per site.

 

Eggs hatch into hungry ant lions. They dig a shallow upside-down cone-shaped pit up to an inch deep. As they move across the sand, they leave spiral-shaped trails. This curious motion gives these critters the nickname "doodlebugs." 

 

As the circle grows ever wider and deeper, the doodlebug throws out the soil with its head.  A pit can be built in 15 minutes. Finally it buries itself so that only the head, with large menacing looking mandibles, is above ground at the bottom of the pit.

 

They wait for an ant or other insect to slip on the loose sand and fall in.  As they slide over the edge and into the pit, the large jaws of the waiting ant lion paralyze the ant with an injection of poison. The ant lion then sucks out the vital juices. The juice-less skeletal remains of the prey are thrown out of the pit.

 

When prey manage to stop their slide into the crater, the ant lion throws sand at its next meal, causing the captive to lose its grip and continue the inevitable fall to its doom at the bottom.

 

Ant lions have forward-pointing hairs on their body that help anchor it in the soil.  This allows them to capture struggling prey much larger than itself.  Winged adult ant lions that are laying eggs may even be captured and eaten by their younger relatives. 

 

OBSERVING DOODLEBUGS

 

Ant lions pits can be found in sheltered, sandy areas where the soil easily shifts.  Look for dry, sunny spots sheltered from wind and rain, particularly on south-facing slopes.  Small populations can be seen in grass-free areas next to the air conditioners.  Other popular sites to view ant lions are under buildings built on piers, in sandy flower beds without mulch and under hedges or eaves of buildings.  One author reports that larger craters mean hungrier ant lions, and that bigger pits are built at the full moon.

 

Taking ant lions out of their habitat for closer observation is risky to the ant lion.  Be prepared to feed it with the ants you catch.  Twice-daily feedings will provide enough food for survival.  Put the ant lion in any container filled with a layer of at least 3 inches of sand to allow the insect to build its pits.  The container should also be at least 5 inches wide for each ant lion to prevent overcrowding.

 

Return ant lions to their source before it finishes its larval stage, or if kept longer, the container should be covered so that the adult won't escape. They have a knack for emerging from its cocoon when you're not watching.  A stick placed upright in the sand will provide the newly emerged adult with a place to rest while its wings expand and harden properly. If held captive any longer than a day after it emerges from its cocoon, adults will lose energy and may die before it has a chance to reproduce. 

 

If you encounter doodlebugs, don’t spray pesticides in their area unless absolutely necessary. They are beneficial insects and keep down pests in your Florida Yard.  Following this advice will also allow for a safer spot for kids (of all ages) to have some summer fun and a place to learn about their natural world.

 

For those with a computer, there are some really neat ant lion websites.  “The Ant lion Pit” shows videos of these fascinating animals as they feed and grow, and how and where to find ant lions.  I’ve placed these links below on our Okeechobee web page, http://okeechobee.ifas.ufl.edu.  If you need additional information on ant lions, email us at okeechobee@ifas.ufl.edu or call us at 863-763-6469.  Local residents can stop by our office at 458 Hwy 98 North in Okeechobee, and visit our County Master Gardeners from 1 to 5 PM on Tuesday afternoons.  Happy Lion-hunting! 

-30-

Trade names, where used, are given for the purpose of providing specific information. They do not constitute an endorsement or guarantee of products named, nor does it imply criticism of products not named. The Florida Cooperative Extension Service - Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information, and other services to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.  Florida Cooperative Extension Service / IFAS / University of Florida.  Larry A.  Arrington, Dean.   Last update: 03/05/2007 .  This page is maintained by Dan Culbert.