First two records of a new Sow Bug invader in California!

Common Shiny Woodlouse (Oniscus asellus) is native to Northern Europe, but has become the most frequently encountered Terrestrial Isopod in much of NorthEastern North America.

It can be distinguished by the scalloped flat and jagged edges of its body segments, the 3 segments that make up the tip of its antennas and the often greenish-gold flecks on the back.

Photo: (c) AJC ajcann.wordpress.com, some rights reserved (CC BY-SA)

@metsa discovered the first ever published record* of Common Shiny Woodlouse from California in San Francisco in 2014. And this week @kestrel has discovered the second in the East Bay!

Its unclear whether this little invader will ever become as common in California as they have become in much of the NorthEast. But its certainly possible, and if they do, tracking their spread could be very interesting. So keep your eyes peeled for these little buggers if you happen to be exploring California!

• by 'published record' I mean records published to the Global Biodiversity Information Facility - for all I know there's a record buried in a museum or agency somewhere. But, hey, publish or perish right? There's also no mention of Oniscus asellus in either Jass and Kalausmeier, 2001 or Garthwaite and Lawson, 1992 which cover Terrestrial Isopods in all of California and the Bay Area respectively.

Posted on April 20, 2016 02:20 AM by loarie