Preference of antlion and wormlion larvae (Neuroptera: Myrmeleontidae; Diptera: Vermileonidae) for substrates according to substrate particle sizes

Abstract

Sand-dwelling wormlion and antlion larvae are predators with a highly specialized hunting strategy, which either construct efficient pitfall traps or bury themselves in the sand ambushing prey on the surface. We studied the role substrate particle size plays in these specialized predators. Working with thirteen species of antlions and one species of wormlion, we quantified the substrate particle size in which the species were naturally found. Based on these particle sizes, four substrate types were established: fine substrates, fine to medium substrates, medium substrates, and coarse substrates. Larvae preferring the fine substrates were the wormlion Lampromyia and the antlion Myrmeleon hyalinus originating from desert habitats. Larvae preferring fine to medium and medium substrates belonged to antlion genera Cueta, Euroleon, Myrmeleon, Nophis and Synclisis and antlion larvae preferring coarse substrates were in the genera Distoleon and Neuroleon. In addition to analyzing naturally-occurring substrate, we hypothesized that these insect larvae will prefer the substrate type that they are found in. Specifically, we tested substrate preference in a choice experiment for four species of antlions. This was then compared to the substrate that the larvae were naturally found in. Larvae of the four antlion species were allowed to choose among eight substrates differing according to their particle size. Our findings show that the majority of M. hyalinus larvae built pits in the finest sand fraction, and the majority of N. microstenus larvae were found in a coarser fraction. The other two species, M. immaculatus and E. nostras, constructed majority of their pits in a medium sand fraction. These results support the hypothesis that neuropteran larvae prefer specific substrates for pitbuilding or ambushing prey, and that this - in combination with other abiotic and biotic factors - may drive selection of appropriate habitats.

Keywords

• neuroptera
• myrmeleontidae
• diptera
• vermileonidae
• antlions
• wormlions
• substrate particle size
• substrate selection
• pit-builder
• non-pit-builder
• habitat selection