Deep in the Piney Woods of East Texas, late instars of the buck moth caterpillar (Hemileuca maia) have begun wandering. Covered with hollow spines attached to poison sacs, they represent one of the fewer than twenty North American caterpillar species capable of stinging, though buck moth larvae do not inflict the kind of harm that southern flannel moths deliver. Despite that, they remain well protected by their chemical defenses.
Variations in color do not hide the telltale white dots or the prominent spines; as aposematic warnings go, these are sufficient for predators to know the danger involved should they grab one of the caterpillars.
But the second-growth woods of East Texas offer more than the usual hunters, more than those who must deal with poisonous weapons covering the insects. Yes, deep in the Piney Woods an ambush has been set for the buck moth caterpillar, and the perpetrators have no fear of these natural weapons.
Small enough to slip in under the caterpillar’s defenses, spined soldier bug nymphs (Podisus maculiventris) lie in wait on a tree limb as a lone caterpillar ventures forth, a wanderer from this usually gregarious clan. And upon that limb, one predatory stink bug at the rear and one in front, the buck moth larva realizes too late that its built-in protection offers little help against attackers who can move beneath the spines and who target the insect’s undefended underside.
Each nymph, not yet an adult, knows to keep its proboscis extended, a weapon and feeding tube always ready to pierce the soft flesh of the caterpillar. They move in, stab, eat, move back when the insect flails in the false hope that it can defeat this ambush. Its only escape is to let go of the branch and fall to the ground, but it cannot reason well enough to know that. So it stands its ground against the marauders, feeling each stab in its legs and belly, whipping its abdomen and head from time to time but accomplishing nothing.
When I leave behind this scene of nature’s amoral persistence, the bugs have once again attacked the caterpillar’s legs, one at the end and one nearer the front. For its part, the caterpillar sits still, then flails, then sits still, then tries to escape, a cycle that repeats without effect, for the ambush is unending, unflinching, unyielding. So long as they remain on the small branch, the attackers will prevail.
Deep in the Piney Woods of East Texas, death is a way of life, a way to survive, and chemical defenses mean little when an ambush strikes when and where you are most vulnerable. Yes, deep in the Piney Woods an ambush plays out, and one dies so two may live.