Sand-Borne Vibrations in Prey Detection and Orientation of Antlions

Abstract

Pit-building antlions capture their prey by digging funnel-shaped pits in loose sand and then laying in wait for prey to fall inside the trap. Behavioral experiments studying predator–prey interactions and measurements of vibrations propagated in sandy substrates revealed that antlions are extremely sensitive to substrate vibrations produced by prey crawling on the sand surface. Prey produce low-frequency sand-borne vibrations, and to locate a source of vibration, antlions rely on time differences of waveforms arriving at their receptors—tufts of hairs positioned on lateral parts of the mesothorax and metathorax. In this chapter, the role of physical properties of sand in substrate-borne vibration transmission is discussed. 16.1 Introduction It is well known that some insect predators detect their prey according to vibra-tions produced by the prey during crawling on solid surfaces (Č okl and Virant-Doberlet 2003b; Cocroft and Rodríguez 2005). This chapter describes the role of vibrations in predator–prey interactions in antlion larvae. Antlions (Myrmeleontidae) are holometabolous insects whose larvae are known to dig conical pitfall traps in sand or loose soil to catch prey at the bottom of the trap. However, only one-tenth of antlion species are pit-builders. The other sand-dwelling antlions lurk, buried in the substrate, without constructing pits. Often, only the jaws and antennae of the buried pit-building larva are visible. This sit-and-wait predator feeds on small arthropods that slide into the trap. Well documented is the catching behavior of pit-building antlion species of the genera Myrmeleon and Euroleon (for a review see