Friend or Foe; Sometimes it's Hard to Tell

A group of orange bugs huddled on a Thai Long Green eggplant caught my attention in the garden. The bugs were walking around the fruit, but venturing no further. All stayed close together, and looked menacing with their bright orange bodies and long black legs. It did not look like the bugs were eating the eggplant, so I left them there while I went inside to discern their identity.

After much research on google, I identified the bugs as assassin bug nymphs (also called milkweed assassin bugs). These nymphs are beneficial even though immature, consuming lots of garden pests as they develop into adults. I was thrilled to have them around. The next day, the group was still on the eggplant, but in their midst was a big single bug. It was obviously the first of the nymphs to mature, and had not yet left the company of its siblings. Based on my earlier research, this was definitely not a mature assassin bug.

To my disappointment, I found a photo of a leaf footed bug that was an exact match to the bug on the eggplant. Leaf Foots are definitely not a friend in the garden, feasting on vegetables and destroying plants. In fact, I found one website that ranked the Leaf Foot as one of the top five pests in the vegetable garden. The orange and black nymphs turned out to be immature Leaf Foots, not Assassins. The photos of the two types of nymphs look incredibly similar, making identification tricky.

Butterflies that are not poisonous often mimic those that are toxic as a form of defense. Birds that have eaten a Pipevine Swallowtail (toxic) only to later become violently ill are not likely to go back for seconds. Other Swallowtails that are not toxic including the Black Swallowtail and the Spicebush Swallowtail have colors similar enough to the Pipevine Swallowtail to scare off any birds with unpleasant memories of food poisoning. I'm guessing the similarities between the two nymphs is another case of mimicry -- the leaf foots' colors are meant to scare off predators even though they possess neither the keen hunting skills nor the bite of the assassin bugs.


















I went back outside and easily squashed all the leaf foots. They weren't exactly camouflaged with their bright orange and black bodies on our green eggplant, and the fact that they were all together made for a quick job. I was fooled by their appearance once, but it definitely won't happen again. I'm just mad that I let the adult get away.