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title: "What the sources say about the Common Pill Bug | AnimalTracks.wiki"
description: "52 claims from the Common Pill Bug profile, each beside the words of the source that backs it."
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# What the sources say about the Common Pill Bug (*Armadillidium vulgare*)

> 52 claims from the Common Pill Bug profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Common Pill Bug](https://animaltracks.wiki/animals/common-pill-bug/)

## Armadillidium vulgare. Animal Diversity Web.

https://animaldiversity.org/accounts/Armadillidium_vulgare/

| The page says | The source says |
| :--- | :--- |
| rolls into a ball | Armadillidium vulgare exhibits a behavior of curling posterior joints in towards anterior joints in a sphere-like shape. This behavior, conglobation (note: tagline) |
| A land-living crustacean | Like most other crustaceans, isopods have flattened plate-like uropods (note: tagline; isopod = crustacean. Terrestrial: 'Habitat Regions terrestrial') |
| Under stones and logs and in garden soil | Common pillbugs can be found under pieces of natural debris such as stones or logs in forests, and in the soil of fields, gardens, or hedgerows. (note: stats.habitat) |
| native to the Mediterranean edge, now on nearly all landmasses | is native to the edge of the Mediterranean and has been introduced to nearly all worldwide terrestrial landmasses (note: stats.habitat) |
| Decaying leaves, with some roots, fruit and seeds | A. vulgare breaks down the decaying leaf litter of many plant species (note: stats.diet) |
| some roots, fruit | can also feed on small pieces of garden roots such as carrots, as well as fruit (note: stats.diet) |
| Curls into a ball when squeezed or shaken | has been observed in response to situations when the body is exposed directly to hard pressures or strong vibrations in the immediate area (note: stats.superpower) |
| it curls its rear body joints in toward its front ones into a sphere-like shape. The trick is called conglobation | curling posterior joints in towards anterior joints in a sphere-like shape. This behavior, conglobation |
| a shield for the softer belly and legs, or a way to cut water loss | Conglobation has been hypothesized to be either a defense mechanism used to shield the softer inner abdomen and limbs with the more stiff outer shell or an effective method of further preventing desiccation. |
| The genus was once named Armadillo, after the armored mammal that does something similar | The genus was once Armadillo , named after the similarly conglobating well-known armored mammal species. |
| birds such as the common starling can beat it | These defenses are inadequate against large predators, such as birds, including the Common Starling |
| tropical ants of the genus Leptogenys have mandibles long enough to pry rolled-up pill bugs apart | A genus of tropical ants, Leptogenys sp., have elongated mandibles that allow them to pry apart conglobated individuals. |
| a pill bug is an isopod, a crustacean that lives on land | Like most other crustaceans, isopods have flattened plate-like uropods (note: Order Isopoda per the classification table; terrestrial per Habitat Regions) |
| A typical young adult is 10 millimetres long and 5 wide | Typical young adults are 10 mm long and 5 mm wide. |
| 0.060 to 0.116 grams | Range mass 0.060 to 0.116 g |
| in the usual molt cycle, for about two days after a molt the new shell is soft, and the animal cannot move or eat and is open to predators and drying out | The molting cycle of males and non-reproducing females, called the normal intermolt, takes about 29 days. It begins with a 2 day period following the last molt, where the new, soft cuticle calicifies. The pillbug cannot move or eat, and is vulnerable to predation and dessication. |
| Females carry their eggs in a fluid-filled pouch called a marsupium for two to three months | Eggs are retained in the marsupium for two to three months until the mancas hatch. |
| fluid-filled pouch | they are stored in the marsupium, a fluid-filled pouch present in reproducing females |
| a range of 6 to 300 young, averaging 100 | Range number of offspring 6 to 300 Average number of offspring 100 |
| It moves slowly when the air is humid and faster when it is dry | individuals move slowly during periods of high humidity and more rapidly during dry periods as they search for more humid areas |
| it is usually more active at night | they are usually more active at night to further reduce desiccation risk |
| Roughly 13 metres a day in summer is its pace, falling to 6.6 in winter | Individuals travel roughly twice as much during summer (13 meters per day) as winter (6.6 meters per day) |
| It cannot swim | as they cannot swim |
| At 20 to 30 degrees Celsius, pheromones (scent signals) draw pill bugs into clumps, which cuts the surface each one exposes to the heat | When air temperature ranges between 20°C to 30°C, pheromones activate causing conspecifics to be attracted to one another and bunch together in a group. This behavior helps decrease the surface area of any one individual in the group, and thereby exposure to the moisture-depleting external heat. |
| It lives under stones and logs and in the soil of fields, gardens and hedgerows | Common pillbugs can be found under pieces of natural debris such as stones or logs in forests, and in the soil of fields, gardens, or hedgerows. |
| Mostly it eats decaying leaf litter | A. vulgare breaks down the decaying leaf litter of many plant species |
| some data suggest almost ten percent of its diet is its own droppings, which recycles microbes and nutrients it missed the first time | Some data suggest that almost ten percent of the pill-bug's diet comes from self-coprophagy, which recirculates microbes and nutrients that were not fully processed during original digestion. |
| Scientists suggest the shell shields the softer belly and legs, or that the ball helps the animal hold on to its body water | Conglobation has been hypothesized to be either a defense mechanism used to shield the softer inner abdomen and limbs with the more stiff outer shell or an effective method of further preventing desiccation. (note: FAQ1) |
| the ball helps the animal hold on to its body water | an effective method of further preventing desiccation (note: FAQ1) |
| around 10 millimetres by 5 in a young adult | Typical young adults are 10 mm long and 5 mm wide. (note: FAQ2) |
| travel about 13 metres a day in summer and 6.6 metres in winter | (13 meters per day) as winter (6.6 meters per day) (note: FAQ3) |
| Not Evaluated | IUCN Red List Not Evaluated (note: stats.conservationStatus; GBIF/ITIS hold no Red List category for the name) |
| it curls up when its body is pressed hard or the ground shakes nearby | hard pressures or strong vibrations in the immediate area (note: FAQ1) |
| Press hard on a common pill bug (*Armadillidium vulgare*) or shake the ground near it, and it curls its rear body joints in toward its front ones into a sphere-like shape | curling posterior joints in towards anterior joints in a sphere-like shape. This behavior, conglobation, has been observed in response to situations when the body is exposed directly to hard pressures or strong vibrations |
| Much of a pill bug's behaviour is a fight against drying out | Much of the behavior of Armadillidium vulgare revolves around a constant struggle to preserve body moisture and prevent unnecessary desiccation. |
| The species comes from the Mediterranean's edge and has been carried to nearly all landmasses | is native to the edge of the Mediterranean and has been introduced to nearly all worldwide terrestrial landmasses |
| and seeds | Armadillidium vulgare has also been known to be granivorous, although seeds are likely only eaten in absence of other, more desirable food sources (note: stats.diet) |
| Its body is an oval about twice as long as it is wide | Armadillidium vulgare has an oval body shape approximately twice as long as it is wide. (note: FAQ2) |
| Press hard on a pill bug or shake the ground near it, and it curls its body into a sphere-like ball | curling posterior joints in towards anterior joints in a sphere-like shape. This behavior, conglobation, has been observed in response to situations when the body is exposed directly to hard pressures or strong vibrations (note: vibe.reason) |

## Becker, Ziegler & Epple (2005). The mineral phase in the cuticles of two species of Crustacea consists of magnesium calcite, amorphous calcium carbonate, and amorphous calcium phosphate. Dalton Transactions.

https://doi.org/10.1039/b412062k

| The page says | The source says |
| :--- | :--- |
| found crystalline magnesium calcite plus two non-crystalline forms, calcium carbonate and calcium phosphate | the cuticles consist of crystalline magnesium calcite, amorphous calcium carbonate (ACC), and amorphous calcium phosphate (ACP) |
| a study of the cuticles (outer shells) of two woodlice species, this one included | The cuticules (shells) of the woodlice Porcellio scaber and Armadillidium vulgare were analysed |

## Leclercq et al. (2016). Birth of a W sex chromosome by horizontal transfer of Wolbachia bacterial symbiont genome. Proceedings of the National Academy of Sciences.

https://doi.org/10.1073/pnas.1608979113

| The page says | The source says |
| :--- | :--- |
| in which bacterial DNA has become a new sex chromosome | Wolbachia bacterial endosymbionts triggered the evolution of new sex chromosomes in the common pillbug Armadillidium vulgare (note: tagline) |
| Researchers found a 3-megabase insert of a feminizing Wolbachia genome inside the pill bug's own nuclear genome | We identified a 3-Mb insert of a feminizing Wolbachia genome that was recently transferred into the pillbug nuclear genome. (note: second half: Our results support the conclusion that the Wolbachia insert is now acting as a female sex-determining region in pillbugs) |
| The researchers concluded that the chromosome carrying the insert is a new W sex chromosome | the chromosome carrying the insert is a new W sex chromosome |
| a 3-megabase stretch of its DNA had moved into the pill bug's own genome | We identified a 3-Mb insert of a feminizing Wolbachia genome that was recently transferred into the pillbug nuclear genome. (note: FAQ4) |
| their results support it now acting as a female sex-determining region | Our results support the conclusion that the Wolbachia insert is now acting as a female sex-determining region in pillbugs |
| which would make a bacterium's DNA part of what decides whether a pill bug is female | bacteria-to-animal horizontal genome transfer represents a remarkable mechanism underpinning the birth of sex chromosomes |
| the authors concluded that this stretch now works as a female sex-determining region | Our results support the conclusion that the Wolbachia insert is now acting as a female sex-determining region in pillbugs (note: FAQ4) |

## Cordaux et al. (2004). Evidence for a new feminizing Wolbachia strain in the isopod Armadillidium vulgare: evolutionary implications. Heredity.

https://doi.org/10.1038/sj.hdy.6800482

| The page says | The source says |
| :--- | :--- |
| Wolbachia are bacteria that live inside cells and pass from mother to young | Wolbachia are intracellular maternally inherited alpha-Proteobacteria infecting a wide range of arthropods. |
| In this pill bug, at least two strains turn genetic males into females | Inoculation experiments indicated that the new wVulM bacterial strain also induces feminization in A. vulgare. (note: the other is wVulC, 'the known Wolbachia strain is responsible for feminization of genetic males') |
| Wolbachia is a bacterium that lives inside cells and passes from mothers to young | Wolbachia are intracellular maternally inherited alpha-Proteobacteria infecting a wide range of arthropods. (note: FAQ4) |
| in this species it turns genetic males into females | In the common pill bug Armadillidium vulgare, the known Wolbachia strain is responsible for feminization of genetic males. (note: FAQ4) |