Gardener Spots Surprise Visitors On Plants: 'I Didn't Think Gardening Came With A Free Show'

Gardening is a hobby for those who don't need instant gratification. Planting, weeding, and fertilizing all join together to bring long-term results. So when drama unfurls among your vegetable leaves, it's the makings of a major surprise. A gardener luckily had their phone on hand to capture a video of a fly and a caterpillar battling it out on a tomato plant. The video, posted on Reddit by user @no1_2_nobody, inspired sympathy for the caterpillar on the part of several commenters. Well, save your tender feelings for a creature more worthy: This striped green caterpillar is, yes, quite lovely, but it's a pernicious tomato hornworm making its way to chomp on the tasty fruit.

In the video, the tomato hornworm, looking very annoyed and slightly vulnerable, is doing its best to fight off a pesky fly. If this bug is what some Reddit commenters believe it to be, the hornworm has cause to be more than annoyed. Although its quick, flitting movements make the fly hard to identify with certainty, it's likely a tachinid fly. These guys are good bugs that'll chase pests from your garden. They feast on a number of garden pests and are valuable pollinators.

Gardeners don't typically catch sight of the sneaky tachinid flies at work. That makes @no1_2_nobody's video itself pretty remarkable. So what is the fly doing to the hornworm? Like the parasite it is, the fly is going to use the worm as a host for its offspring. But how does this happen, and are hornworms its only prey?

For a group of bugs that's the most numerous of its kind — and gruesome ones, at that — it's surprising these insects aren't better known. Tachinids are the largest group of insect parasitic flies, and there are pretty grisly aspects to their reproductive cycle. Tachinid flies infest their hosts in different ways depending on the species. Some lay eggs on foliage to be eaten by the caterpillars, some glue eggs to the host's exterior, and others inject eggs directly into the host. By any of these means, the eggs hatch in or on the host and consume it from within.

The young develop at an alarming pace, pupating within four to 14 days. As hungry gobblers of unwanted pests, this seems like great news for gardeners. However, these warriors fight slowly. On average, the larvae feed on the host's innards for one to two weeks before the host dies. This is a long time to wait for a threat to your tomato crop to drop dead. As a means of pest control, you'll be better off with a quicker option that's also non-toxic and cheap. Hit your pantry up for some cornstarch; this powder, a common kitchen ingredient you already have, can repel hornworms from your precious tomato crop.

Still, tachinid flies play other roles in the garden. They feed on some adult beetles and larvae of bugs like certain moths, grasshoppers, beetles, and crickets. Sadly, butterfly larvae are among their most preferred snacks, so if you want to attract butterflies to your garden, you certainly don't want tachinids as part of your anti-pest army.