Tomatoes, Caterpillars, Wasps, and Mortality, Part II
Okay, I think we have all waited long enough to find out who this third party greenhouse inhabitant is. Ready? It’s a wasp! Somewhat more specifically, it is most likely a Braconidae Wasp, which is recognized under a large umbrella of 17,000 species – in this case, probably the Cotesia congregata. Although it is safe to assume it is a wasp, I have only been able to come to this conclusion based on the evidence left behind. Just the type of evidence a parasitoid wasp would leave behind.
One glorious morning while whiling away the day in the greenhouse with my fellow co-workers, ever the vigilant man with a keen sense of awareness, I find the evidence commonly associated with the Hornworm: an abundance of feces, half eaten tomatoes, and abnormally short branches with missing leaves among the those untouched. A heartbreaking display of destruction. Yet, the usual suspect responsible for this travesty wasn’t quite the same as I remembered it to be this time around. The Hornworm adorned a new mane-like addition down the entire length of it’s body, like a clustering of short grain white rice standing on end perpendicular to the surface of the caterpillar. A strange sight for sure, and mentally noted but, in the end, I take the quill-covered caterpillar outside to meet its destiny between the ground and the bottom of my boot. An act I assure you I perform with mixed emotions.
As some of you may have surmised by now, those were not grains of rice covering our protagonist. The grains I observed were in fact many Cotesia congregata wasp in their cocoon state after having been injected into their host by the parent wasp’s stinger, incubating, and eventually eating their way out of the worm in order to move from the larval stage to wasp via cocoon. An alarming conclusion to come to and a strange unsettling feeling to accompany it.
I know I said earlier my feelings were mixed when I disposed of the plump pest out on the hard unforgiving earth but I must admit that up until this particular discovery, I felt little when dealing out the ultimate punishment and in-order to avoid the label of sociopath I exaggerated the truth. I know this doesn’t look good but please, let me redeem myself. I’m a changed man!
Ultimately I am amazed at nature’s system of checks and balances when biodiversity is allowed to flourish. The Hornworm is rendered a mild pest when the parasitoid wasp is allowed to carry out it’s beginning stages of life. This is all due to the big qualifier when one is labeled a parasitoid. A parasitoid is as such because not only does it feed off the host as all parasites do, it also either kills the host in the process or leaves it sufficiently more inactive and sterile thus keeping the Hornworm population in check. So we get more tomatoes and there is no need to spray any pesticide. This does mean letting the caterpillar alone upon discovery and in-turn letting the wasp pupates carry out there parasitoid function rather than the ole boot-to-earth quick and easy way, allowing the wasps to reach maturity and go on to insert more eggs into more Hornworms.
This amazing display of nature unfolded before me and I couldn’t help but feel sorry for the worm whose unfortunate fate had already been sealed. I know that this in an insect who as far as we know is not self aware and is trudging along acting out its life’s predetermined genetic blueprint, yet I can’t help but imprint my own human empathy upon this doomed creature. My mind quickly scales up this amazing yet brutal act of nature projecting its short life cycle upon our own and that unfortunate end we all must deal with. This emotional response may seem extreme but I think it’s completely normal to get a little morbid around a birthday…