In Britain, it is likely that the Sarlacc, the monstrous sand-pit-dwelling beast from ‘The Return of the Jedi’ is better known than the almost-as-rare (here, anyway) ant-lion Euroleon nostras. As an adult, E. nostras looks superficially like a lacewing with speckled wings and clubbed antennae and is the same order, the Neuroptera, though ant-lions are parcelled into the family Myrmeleonidae. However it is the larva which tends to be most well known and which allows me to draw comparisons, however nerdy and spurious, with the desert-dwelling Sarlacc - the idea for which may even have been inspired by the ant-lion in the first place...
|The Sarlacc - grrrr...|
Ant-lions are named after their predatory larvae (Plant 1999), each of which digs a funnel-shaped pit (2.5-5 cm deep and 2.5-7.5 cm wide at the top) by using its abdomen as a plough or shovel, heaping the grains onto its head and throwing them away from the pit as is spirals downwards from the initial circle which will form the rim. Pits are dug in dry, sunny, sheltered locations, particularly on south-facing slopes, and require light moveable soil such as sand. The pit can be complete in only 15 minutes, after which the larva buries itself at the base of the funnel, jaws protruding, awaiting the tumbling-in of unwary prey. Many types of invertebrate may be taken, althugh as the name suggests, ants are the commonest prey – in the case of the Sarlacc, the prey is larger in the form of bipedal humanoid captives (thrown in by Jabba the Hutt), or indeed the luckless bounty-hunter Boba Fett.
|An ant-lion larval pit - best be wary...|
Being loose, the sand at the rim means that prey can fall straight down to the larva which bites with large curved, ‘piercing-sucking’ mandibles – however, if the prey only falls part of the way, the larva throws sand at it, causing it to slide to its doom. Not only can the larva capture prey larger than itself, but forward-pointing bristles on its body anchor it firmly so that prey can’t pull it out of the pit.
|Ant-lion larvae - born to bite!|
Once the larval period ends (this can be lengthy), the larva burrows deeper into the sand and builds a cocoon in the form of a hollow silken sphere. This is where it pupates and after about three weeks an adult emerges via a ‘hatch’ and climbs to the surface.
|A cocoon and larval 'skin' post-emergence.|
Adults are up to 30mm long with a 70mm wingspan, and although they may drink and feed, their primary activity is reproduction, with adults surviving for a few weeks. Volatile compounds are known to be produced by adult males of E. nostras, and although the function in uncertain, they may act as ‘aggregation’ pheromones (Yasseri & Parzefall 1996). Whatever the chemical basis, mating tends towards the acrobatic, with the female gripping a twig while the male dangles below her, attached only by his genital apparatus. Egg-laying occurs, unsurprisingly given the larval lifestyle, in warm sand.
|An adult - note spotted wings, clubbed antennae and less ferocious attitude.|
On the British mainland, this species is only confirmed from the Minsmere area of the Suffolk coast, although there have been unconfirmed reports from Norfolk which are of juveniles which may prove to be this or another ant-lion species – certainly, given that E. nostras was overlooked for a long time, it is possible, if not likely, that others have been too.
Plant, C.W. (1999). The Suffolk ant-lion Euroleon nostras. British Wildlife, 10 (5), 303-309
Yasseri, A.M., Bergstrøm, G., Franke, W. & Wassgren, A.-B. (1996). Laboratory studies on the role of volatile compounds in mating of the antlion Euroleon nostras (Geoffroy in Fourcroy, 1785): behavioural and chemical aspects (Insecta: Neuroptera: Myrmeleontidae). Pp. 289-297 in Pure and Applied Research in Neuropterology. Proceedings of the Fifth International Symposium on Neuropterology. Cairo, Egypt, 1994. M. Canard, H. Aspöck, & M. W. Mansell. (eds.). Toulouse, France.
Thank you to Fritz Geller-Grimm for making his excellent images of Euroleon nostras available to use wisely by publishing them as being licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. The Sarlacc image is, I imagine, copyright of Lucasfilms or something like that.