In Awe of Ambush Predators

by Aditi Mishra and Jagath V :

Behold the tiny antlion larva. It is small and some would say, ugly. But, what it lacks in looks, it makes up in cunning.

So who are the antlions and why have they earned this name?

 

Antlions are a group of at least 2000 insect species. Wherever there is sand, there is an antlion calling it home. (I say at least 2000 because who knows how many more are waiting to be discovered, annotated and venerated.)

They are sometimes also called doodlebugs because they leave funny patterns in sand. Why do they do it? Stay tuned you will see.

So in true Disney fashion, these menacing and honestly scary looking larvae morph into lacewings as adults. As the name suggests, they emerge as dainty creatures with wings so diaphanous as if they were crafted in a lace maker’s dream.

While the adults are kind of pretty and are interesting, nothing beats what these guys do for a living at their larval stage.

They are called antlions for a reason. “Ants” because that makes up a large portion of their diet and lions because well, they devour them like hungry lions devour a gazelle.

And like male lions, they wait for their meal to arrive.
(Check out this cool study as well, that shows that while female lions cooperate and hunt, males indulge in ambushing their prey alone https://www.sciencedirect.com/science/article/pii/S0003347213000468 ).

Well it is not just waiting, a trap has to be built first for an ignorant ant to walk into. These tiny bugs (harmless to humans and crops) build funneling or spiraling pits in the sand. No wonder these traps look like doodles in the sand to us, hence the endearing name “doodlebugs”.

Once the trap is set, it’s time to hide. Food is unpredictable and the wait is often long. But the antlion is prepared. If the feast is bountiful it will grow into a beautiful lacewing this season itself. If not, it will bide its time, and take many seasons, even several years to debut as a lacewing. Depending on where it is from, it might conceal itself under sand, leaves, or debris.

It’s time to forage for today. The scout ant is out making rounds. A tumble throws her off her path. Her antennae and tiny eyes are chock full of sand. She shakes her head to see and smell again. Sands are slippery, but what is this? The tiny flecks of sands, from her vigorous head shaking triggered an avalanche of sand. The scout cannot stop tumbling now. She is tumbling down the pit.

In a quick flash of events a pair of pincer like mandibles emerge and grasp the scout’s waist in a deadlock. She struggles, she fights with every last bit of energy. But the mandibles tilt her towards the pit. The more she struggles, the deeper she sinks. Finally, a second pair of mandibles emerge and pierce her belly between her natural armor of cuticular plates. The scout is still struggling; she might still make it.

But no – it’s too late. The antlion has successfully injected a minute dose of poison in her by then. Enough to get the prey to stop struggling. Once the scout is dead, enzymes would be pumped into her. Her insides would be digested and extracted. The table would be set and the antlion will feast.

 

https://www.youtube.com/watch?v=tdYICrDG7dQ

Reference: Griffiths, David. “The feeding biology of ant-lion larvae: prey capture, handling and utilization.” The Journal of Animal Ecology (1980): 99-125.