Life-history of an Owlfly

Introduction

Owlflies are one of the "ugly ducklings" of insects. The grotesque larvae are voracious predators in leaf litter and on trees. They sit and wait for prey to stray in between their oversize mandibles, seizing them and feeding on the body liquids within. The adults are elegant strong-flying insects which are sometimes confused with dragonflies.

Identification

Adult owlflies can be distinguished from other lacewings and similar insects by the long antennae (almost as long as the wing length) which have a large often bi-coloured club at the tip. As with most other lacewings the wing veins fork where they meet the margin of the wing.

Larvae are similar to antlion larvae, but are usually more flattened, and do not build pits to capture prey. The sides of the larval body have finger-like lateral processes on both thorax and abdomen. The mandibles have more than one large tooth on the inner margin.

Life history cycle

As with most Neuroptera there are three larval instars. Eggs are laid without stalks in masses on grass stems, and first instar larvae go through a short non-feeding communal state prior to becoming solitary predators. The pupa forms a spherical cocoon in leaf litter.

Habitat

In Australia the family is somewhat more diverse in arid and semi-arid regions

Distribution

All over Australia

Seasonality

Adults are normally only active during the hotter months of summer. For this species the eggs hatched in February, second instar larvae were present by June, third instar before August, and the adult emerged in late October. The seasonality may have been affected by rearing in captive conditions indoors.

Feeding and diet

Both adults and larvae are predators. Adults hawk flying insects in much the same way that dragonflies do. Larvae are sit and wait predators of many invertebrates, although they will move in response to nearby movement of potential prey to assist in prey capture.

Other behaviours and adaptations

They are the strongest fliers amongst insects in the order Neuroptera, with adults of some species active during the day, although most Australian species are seen at night when they are attracted to artificial lighting. The adults of many species release a strong somewhat noxious smell when they are handled, presumably to deter birds and other predators.