So if most of you guys are like me you probably come back from bug hunting with a container looking like this:
If you also happen to be like me, you also want to know what everything you caught is. Well, that's what this thread is for.
Below are 8 species of sizable terrestrial isopod found in the eastern US. They can be found in many moist habitats, but some have their preferences. Although antennal segmentation and other characteristics are the best ways to distinguish isopods, I feel that the following pictures and descriptions are the most pragmatic way for the average hobbyist to identify his or her catch.
(Sorry in advance for the uncropped pictures; I didn't even think I would get this guide up today!)
Armadillidium nasatum
This species is one of the two commonly found that can roll up into a ball. They can be found in a variety of habitats from leaf litter to cracks in landscaping rocks. Although most individuals aren't as colorful or as big as their cousin, some, like the erythristic individual pictured, can be very striking. When rolled up in a ball, this species leaves a small gap in the very center of the crease of its body.
Armadillidium vulgare
These are the classic big rolly pollies everyone has kept as a pet at one time or another. They are found just about anywhere moist. Some individuals have bright yellow colors making them resemble other more uncommon species, but they can be distinguished by the fact that A. vulgare has an incredibly large range and does not leave a little gap when rolled up in a ball.
Cylisticus convexus
This species has a leggy look and is often a strange grey-purple color. They can be found everywhere if you look hard enough but they prefer to hide inside of rotting wood. They are very fast and can roll up into a tear shape.
Oniscus asellus
This is perhaps the only species of isopod on the list that is almost never found outside its preferred habitat. They can be incredibly large and have a white "skirting" on the sides of their body. They can be found in great numbers underneath moist, rotting bark, and sometimes around the wooden supports of compost heaps.
Philoscia muscorum
This is a somewhat smaller species that prefers leaf litter on forest floors. They can also be found under logs and stones in forests. They are very fast and resemble roaches. Some individuals can be a very bright yellow or brick red. One of the ways they can be identified is that their head resembles a single black dot.
Porcellio scaber
This is probably the most common isopod in many areas. They are usually a slate blue but can be orange, mottled yellow, mottled orange, gray, or a myriad of other color and pattern schemes. They have a rough appearance, and when flipped over, have two pairs of white gills on the underside of their "tail." They also have a small horn-like bump between their eyes, which can distinguish them from several other species.
Porcellio spinicornis
P. spinicornis is, in my opinion, one of the most attractive isopods. Individuals often have a large amount of yellow coloration with contrastingly darker heads. They can be tricky to distinguish from P. scaber, especially if the individual in question lacks a lot of yellow, but generally the presence of even a bit of yellow spotting indicates that it is P. spinicornis. They prefer to hide around stones, bricks, and cement blocks, but can be found pretty much anywhere else.
Trachelipus rathkii
This is the most difficult species to distinguish from P. scaber. The two have color forms that look very similar, but T. rathkii is more commonly found having the shown mottled red-gray color pattern. When flipped over, T. rathki has 5 pairs of white gills on the "tail", whereas P. scaber only has 2 pairs. T. rathkii prefers rotting logs but can be found anywhere moist.
If you also happen to be like me, you also want to know what everything you caught is. Well, that's what this thread is for.
Below are 8 species of sizable terrestrial isopod found in the eastern US. They can be found in many moist habitats, but some have their preferences. Although antennal segmentation and other characteristics are the best ways to distinguish isopods, I feel that the following pictures and descriptions are the most pragmatic way for the average hobbyist to identify his or her catch.
(Sorry in advance for the uncropped pictures; I didn't even think I would get this guide up today!
)Armadillidium nasatum
This species is one of the two commonly found that can roll up into a ball. They can be found in a variety of habitats from leaf litter to cracks in landscaping rocks. Although most individuals aren't as colorful or as big as their cousin, some, like the erythristic individual pictured, can be very striking. When rolled up in a ball, this species leaves a small gap in the very center of the crease of its body.
Armadillidium vulgare
These are the classic big rolly pollies everyone has kept as a pet at one time or another. They are found just about anywhere moist. Some individuals have bright yellow colors making them resemble other more uncommon species, but they can be distinguished by the fact that A. vulgare has an incredibly large range and does not leave a little gap when rolled up in a ball.
Cylisticus convexus
This species has a leggy look and is often a strange grey-purple color. They can be found everywhere if you look hard enough but they prefer to hide inside of rotting wood. They are very fast and can roll up into a tear shape.
Oniscus asellus
This is perhaps the only species of isopod on the list that is almost never found outside its preferred habitat. They can be incredibly large and have a white "skirting" on the sides of their body. They can be found in great numbers underneath moist, rotting bark, and sometimes around the wooden supports of compost heaps.
Philoscia muscorum
This is a somewhat smaller species that prefers leaf litter on forest floors. They can also be found under logs and stones in forests. They are very fast and resemble roaches. Some individuals can be a very bright yellow or brick red. One of the ways they can be identified is that their head resembles a single black dot.
Porcellio scaber
This is probably the most common isopod in many areas. They are usually a slate blue but can be orange, mottled yellow, mottled orange, gray, or a myriad of other color and pattern schemes. They have a rough appearance, and when flipped over, have two pairs of white gills on the underside of their "tail." They also have a small horn-like bump between their eyes, which can distinguish them from several other species.
Porcellio spinicornis
P. spinicornis is, in my opinion, one of the most attractive isopods. Individuals often have a large amount of yellow coloration with contrastingly darker heads. They can be tricky to distinguish from P. scaber, especially if the individual in question lacks a lot of yellow, but generally the presence of even a bit of yellow spotting indicates that it is P. spinicornis. They prefer to hide around stones, bricks, and cement blocks, but can be found pretty much anywhere else.
Trachelipus rathkii
This is the most difficult species to distinguish from P. scaber. The two have color forms that look very similar, but T. rathkii is more commonly found having the shown mottled red-gray color pattern. When flipped over, T. rathki has 5 pairs of white gills on the "tail", whereas P. scaber only has 2 pairs. T. rathkii prefers rotting logs but can be found anywhere moist.
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