By Darryn Murray – Bushwise trainer
Having had a look at the above picture with no scale reference, one would be forgiven for thinking that we might be looking at something out of Jurassic Park or even Alien vs Predator. These amazing creatures are called Antlions and we are going to have a look at their secretive existence.
With an adult male thumb nail for size reference, the Antlion larva measures roughly 10-12mm.
The Antlion is in some cases referred to as a Doodlebug, this is due to the patterns that it leaves in the sand as it moves below the surface. This is believed to look like someone has been “drawing” in the sand.
The pitfall trap:
Due to the fact that the adult Antlion’s only goal in life is to mate and reproduce before it dies, it can’t afford to spend too much time looking for food. As a result of this most of the feeding is done in the larval stage. Some species’ adults feed on pollen and nectar but typically they stop feeding after the larval stage. The larvae begin the process of building themselves a pitfall trap by locating suitably soft, sandy soil.
Once they have found their preferred soil type, they begin digging themselves in. The process is started by moving backwards in circular motions and using its head in a shovel-like manner to remove sand, creating a cone-like depression in the soil. The trap is complete when the larvae are buried just below the surface of the soil in the centre of the pit trap as can be seen in the cross section drawing below.
Now the waiting game begins, any unsuspecting insect that gets itself stuck in the pit trap will struggle to get out. This flailing around in the soft sand alerts the Antlion to the presence of its next potential meal.
Using its head the same way it did during the construction process, to shovel soil, it flings soil particles over the victim struggling to get out. This causes a small scale avalanche in the soil and the victim ends up at the bottom of the pit trap right in the strong snapping jaws of the Antlion.
The whole process can be seen in the pictures a, b, c and d above.
- The Antlion lies in wait for a potential victim within the pitfall trap
- Unsuspecting insects fall into the conical shaped pit trap
- As the insect tries to escape, the loose sand tires it out but also gives the Antlion the opportunity to shovel sand at it causing the avalanche and bringing the victim closer to it.
- The Antlion captures its prey by using its strong jaws and begins the feeding process.
The feeding process:
Feeding is accomplished by using the sickle shaped mandibles or jaws to grab and hold onto prey. Several sharp protrusions inject a potent venom into the prey as well as enzymes to start digesting its soft parts. The Antlion “sucks” the victim dry and then simply discards the exoskeleton by using its head and “shovelling” the carcass out of the pit before resetting the trap and going back to waiting.
From beast to beauty:
What starts off looking like something from outer space, cocoons itself into a ball made from soft silky material and sand. When it emerges it is vastly different and almost resembles a dragonfly or damselfly. However, these adult Antlions are rather poor at flying, sometimes only managing short distances before falling to the ground.
Life cycle of the Antlion
Although the Antlion isn’t necessarily the “Lion” that guests are travelling to Africa to see, pound for pound they are just as ferocious and dangerous to their prey as their large brown namesakes. Spending time focused on the smaller aspects of the bush leads to a better understanding of the larger bits and pieces happening around us. This is what our Wildlife Research Expedition is all about.