‘That’s very summery,’ said a friend after a critical look at my jacket. “Stronger, that fresh green color is reminiscent of spring. That really doesn’t fit with autumn.”
I myself am not very inclined to adjust the color of my clothes to the season. Neither do most insects. A social wasp is yellow-black all year round, a greenhorn – the butterfly, not a new student – is always green and the fly called black pinhead does not suddenly turn orange. Yet there are a few insects that change their coat when the seasons change; the green shield bug, Palomena prasina, for example.
In early summer the young of this bug, so-called nymphs, can be found on all kinds of trees and shrubs. They are born in a pink-red and black jacket, which they exchange for a green-black one after a molt. With their bulbous appearance, these nymphs resemble droll beetles. But unlike beetles, bugs do not have biting jaws, but a sucking snout, or rostrum. With that rostrum they can only consume liquid food, which in the case of the green shield bug consists of plant juices.
The green shield bug is also called green stink bug because of a malodorous liquid that it can excrete when it is bitten by a beak or beak. Or by human hands. That stuff sticks to your fingers for a long time and is unappetising. Not that I’ve tasted it myself, but predators often spit out these prey quickly. The odorous secretion thus serves as a defense.
In the nymphs, the gland that secretes this substance is on the top of the abdomen, but that is an inconvenient place when these bugs become adults. Then they get wings. These would cover the gland and prevent the stench from spreading. A stink bug that can’t smell doesn’t deserve its name. That’s why adult green stink bugs have their scent gland on the underside.
That dirty dust is not the only way to avoid a lot as a tasty snack. Once mature, these insects are completely invisible in the exuberant summer green. Except for the antennae and the darker, membranous part of the forewings, they bear the color of their name.
Until it gets colder outside and the leaves fall. In the fall, a bright green color would only stand out, so this bug plays a new trick. He takes on an autumn hue. He turns brown. It can go through the winter unnoticed and then change color back to fresh spring green in the spring. Against a backdrop of spring hues, it doesn’t look out of place when it mates to create new green shield bugs.
I also didn’t want to be out of tune and listened to the girlfriend’s advice. The fresh green jacket went off. Instead, I chose one in a color that resembled the winter hue of a green shield bug. I just don’t have a rostrum. And hopefully I don’t smell.
A version of this article also appeared in NRC Handelsblad of 23 October 2021
A version of this article also appeared in NRC in the morning of October 23, 2021
#doesnt #tasty #snack