Pill bugs aren't bugs, but they are roly-poly, charmingly weird, harmless and even helpful

Capsule bugs aren’t bugs, however they’re roly-poly, charmingly bizarre, innocent and even useful

4 minutes, 56 seconds Read

Capsule bugs grow to be lively in spring. They overwinter as adults in a sheltered place. (Photograph: Oonagh Degenhardt/iNaturalist)

Potato bug, roly-poly, doodlebug, sowbug, wooden shrimp, capsule bug, woodlice – we name these little guys, which resemble pea-sized armadillos, by many names relying upon what a part of the nation we reside in. Most are misnomers, because the bugs usually are not bugs in any respect, however quite tiny crustaceans with laborious exoskeletons. That’s proper, capsule bugs (Armadillidium vulgare) are extra intently associated to lobsters and crabs than to ants and beetles. They’re the one crustaceans tailored to residing their total life on land.

These little guys don’t chunk, sting, or transmit illnesses. They don’t infest your meals, your clothes, or your wooden. Maybe that’s the reason folks really feel no shyness about poking them to observe them roll up right into a ball.

Capsule bugs draw their antennae inside to roll up right into a ball, known as conglobation, when triggered by vibrations, stress or when the temperature reaches 104 levels Fahrenheit – serving to stop water loss. (Photograph: Jef C. Taylor)

Capsule bugs are tiny – about half an inch lengthy – and darkish grey, with seven pairs of legs and two pairs of antennae. They feed primarily on decaying vegetation and animals, quite than in your tender new garden shoots. They’re decomposers who break down natural materials, returning vitamins to the soil and bettering it within the course of.

Capsule bugs want a number of moisture to outlive (though they can not survive below water), so through the day they relaxation below rocks, leaves, mulch, logs and flowerpots and maybe sometimes in your damp basement. They arrive out primarily at evening or when the temperature drops and the relative humidity of the air will increase; in different phrases, they emerge when they’re least prone to dry out.

Capsule bugs have photoreceptors – eyes – on either side of the pinnacle, however they will detect solely the presence or absence of sunshine. (Photograph: Oonagh Degenhardt; iNaturalist: Aniedes)

Like all crustaceans, capsule bugs breathe via gills, which soak up oxygen from water and transport it into blood vessels that carry the oxygen to the remainder of the physique. These gills should stay moist. If a capsule bug dries out, its gills don’t work correctly, and it may suffocate from lack of oxygen.

Capsule bugs eat their very own fecal matter. Scientists suppose this habits, known as coprophagy, advanced to assist capsule bugs retain hard-to-find copper – as a result of capsule bugs wouldn’t have iron-based hemoglobin of their blood like we do; as a substitute their blood incorporates hemocyanin, which depends on copper to move oxygen. When oxygenated, capsule bug blood is pale blue.

A capsule bug’s exoskeleton incorporates seven plates, which give it an armadillo-like look. (Photograph: Joe MacIndawar/EarthwiseAware.org)

People and most different animals urinate to take away wastes from their our bodies, however capsule bugs launch ammonia and different wastes as gases via small pores of their exoskeletons. Capsule bugs have one other uncommon attribute. They’ll soak up water at each ends – by ingesting water via their mouths or wicking up water via two small tubes, known as uropods, after they press their anus towards moist surfaces.

Capsule bug mating is temporary: it lasts only some seconds. The male climbs onto the feminine’s again and makes use of its first pair of limbs to switch sperm to the feminine’s underside genital pores. The feminine can retailer the sperm for a whole 12 months to make use of in a number of broods.

Capsule bugs wouldn’t have ears and can’t hear. They sense vibrations via their antennae. (Photograph: Josiah Sofa/iNaturalist)

The feminine capsule bug could carry two dozen fertilized eggs in a pouch beneath her physique. The eggs hatch after three to 4 weeks. When hatched, the children could keep within the mom’s pouch for an additional week or two. Then they go away and reside independently for 2 to a few years. A feminine capsule bug can have as much as three broods per 12 months.

As they develop, younger capsule bugs molt their outdated exoskeleton each week or two for 18 weeks. This molting is a little bit uncommon because it happens in two phases: First, the capsule bug sheds the entrance half of its exoskeleton. A couple of days later, it sheds the again half. This course of helps stop the capsule bug from drying out. Grownup capsule bugs molt about each 29 days. For 2 days after a molt, whereas the exoskeleton hardens, the capsule bug can’t transfer or eat; throughout this time the capsule bug is susceptible to predation or drying out.

To seek out others, a capsule bug makes use of its antennae to sense pheromones emitted by different capsule bugs. (Photograph: Jef C. Taylor)

Capsule bugs are native to southern Europe and northern Africa. They arrived on this continent with Europeans, both by hitching a experience within the soil of imported vegetation or within the earthen ballast of ships that received discarded ashore when holds had been crammed with different items. Regardless of the methodology of introduction, capsule bugs at the moment are discovered all through North America and the world.

If on a wet day you see a capsule bug, don’t hurt this helpful little crustacean. Flip it the wrong way up briefly, maybe, to check out its gills. Then launch it to go on its unassuming approach.

Research have proven that capsule bugs can survive three months with out meals. (Photograph: Quinton Zondervan)


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Jeanine Farley is an academic author who has lived within the Boston space for greater than 30 years. She enjoys taking pictures of our city wild issues.


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