Investigation of Pit Size Versus Larval Size in an Antlion

1767 Words4 Pages

Investigation of Pit Size Versus Larval Size in an Antlion

The purpose of this study was to test whether there was a relationship between the size of an antlion and the size of its pit. Fieldwork was undertaken at UT's Brackenridge Field Laboratory in Austin, Texas. There we selected two aggregations of larval antlions from which to obtain the data. Pit diameter and slope were measured to obtain the pit volume. After pits were measured, larvae were collected and weighted in the lab with an analytical balance. Regressions of larval weight versus pit diameter, slope, and pit volume were obtained. All three variables showed significant coefficients of determination (R-squared * 0.7). These results are then compared to previous studies that found weaker relationships between larval size and pit size. Possible reasons for these differences are discussed.

Introduction

The antlion got its name from early European scholars who likened the insect to, a small creature, extremely hostile to ants. Antlion larvae are carnivorous predators that feed mainly on small mobile arthropods such as ants, as well as the occasional spider, beetle, fly, caterpillar, wasp, and mite that falls into its pit. Our research was conducted on the species Myrmeleon crudalis, which is from the order Neuoptera. This species lives preferably in sheltered, sandy regions and builds shallow, cone-shaped pits in the surrounding substrate. The larvae use these pits to capture their prey. The insect falls into the pit and is unable to climb up the loose sand on the sides of the pit. The antlion lies buried at the bottom of the pit and catches its prey with its strong, piercing mandibles. The larvae secrete digestive enzymes through the mandibu...

... middle of paper ...

...anisms - orb-weaving spider and antlion

Spider builds its web on principle of least-weight structure

This minimizes amount of material needed to catch prey - a balance of energy expenditure and success rate

Spider constructs its web so that large, harmful prey fly through

Antlions may function in same way

Lucas proposes antlions regulate pit diameter so large prey can escape

Studying trap biomechanics increases understanding of advantages, disadvantages, and constraints placed on trap-building predators

Also increases understanding of evolutionary adaptations these organisms display in trap-building behavior

Does pit size increase with increase in larval size in late instars?

Do late instars stop making pits?

What is the average weight at the time of pupation?

Like the orb-web spider, do antlions balance energy cost and success rate?

Open Document