Interesting Facts about A.vulgare

Pillbug (Armadillidium vulgare) rolling up.  Photo credit to Robert McRobbie via Flickr. Used with permission.

Unique special abilities: 
 Pillbugs are often confused with Sowbugs, however there are a few important differences between the two organisms.  Sowbugs have two appendages on the posterior end of their bodies.  These tail-like appendages are not present in pillbugs.  Pillbugs, on the other hand, can roll into a ball when they perceive a threatening stimuli.  Sowbugs are not able to induce this defense strategy (Potter 2010).  

Seasonal climbing:
A.vulgare changes feeding habits according to seasons, and will strategically choose feeding locations to make the most of their time outside of their dark homes.  During winter months when many Crustaceans. Drawing from Kunstformen der Natur (1904), plate 86: Decapoda. Accessed via WikiMedia Commons{PD-US}plants are dead mush on the ground and leaves remaining on living plants are green, the organism will remain on the floor of its habitat to seek food.  However, during summer months when leaves at the top of plants are dry and there's less dead plant matter on the forest floor, A. vulgare will climb plants for food (Paris 1963).

More like a crab than an insect?:
Many commonly mistake A. vulgare for an insect, but in reality they are crustaceans.  Crustacea is a subphylum under the phylum Arthropoda that includes approximately 30,000 different species, including crabs, shrimp, and lobsters (a number of different crustaceans may be observed in the image to the right). They are characterized by a number of different traits; a few of these traits are two sets of antennae, compound eyes, gills for respiration, and pairs of appendages on each body segment (Animal Diversity 1999).

Blue Armadillidium vulgare.  Photo taken by Glenn van Windt, found via Flickr.  Used with permission.The mysterious blue Armadillidium vulgare:
It is not uncommon to encounter a blue A.vulgare while trekking through the woods, especially in their Japanese habitats.  However, contrary to popular thought, these little blue guys are not a rare find with mutations in their genes to make them appear blue, and they certainly do not have any special abilities! When infected by a virus within the genus Iridiovirus, A. vulgare's DNA becomes infected and their outer pigmentation is altered and appears to be a blue-violet color.  The virus also causes decreased responsiveness to water and light, thus shortening the lifespans of the infected organisms significantly (Karasawa et al. 2012). As is described in both the Form and Function and Habitat pages, A.vulgare depends upon its photoreceptors to judge how long it can be in a certain amount of light without losing too much internal water due to its lack of a cuticle layer that most other terrestrial organisms possess.

Evaporation instead of urination:

Interestingly enough, A. vulgare does not urinate at all.  Most organisms must convert high ammonia levels from waste into urea before passing it out of the body via urination.  Roly poly bugs, however, have a high tolerance for ammonia and can simply pass liquid waste directly through their exoskeletons to dispose of them (Animal Diversity 1999).

 Love the skin you’re in:
After the A. vulgare undergo a molt, they eat the recently shed skin.  This is because the exoskeleton is full of calcium that will go into the formation of their new exoskeleton (Woodland Park Zoo 2013).

Feeling blue:
Human blood contains a chemical called hemoglobin that carries the oxygen.  Hemoglobin contains iron so it takes on a red color.  The blood of the A. vulgare uses a chemical called hemocyanin which contains copper instead of iron.  This gives it a blue color rather than red (Raham 1986).

The A. vulgare has been observed performing acts of cannibalism.  In these cases the culprits are usually adult A. vulgare feeding on the newly born individuals.  In most cases, the individuals being fed upon are previously deceased.  Rest assured that the A. vulgare may be cannibals, but they are certainly not murderers (Paris 1963).

A delicacy:
Though it may not make sense to human beings, the A. vulgare eat their own feces.  This process, called coprophagy, is completed in order to extract any copper (and other nutrients) not taken out during its first time through the digestive system.  The digestive system of the A. vulgare is relatively simple; it is basically a straight tube connecting the mouth and anus.  Feces make up approximately nine percent of the A. vulgare’s diet (Raham 1986).

The authors' personal experiences and other things to note:
We chose to do our project on the Armadillidium vulgare because we both remember coming across these adorable little guys very often while digging in the dirt when we were little.  These non-creepy bugs were one of the very few outside creatures who did not give us the heebie-jeebies.  Because we have such fond memories of the pillbugs, we decided we wanted to learn more about them.  Pillbugs are important to the world because of they play an important role in many ecosystems around the world as decomposers.  They are also used in forensic entomology to solve murders.  Check out our other pages to get more information on these cool creatures!

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