Daily Invader

Chesapeake Bay Insects, Isopoda, Amphipoda, etc.

Watermilfoil Moth (Acentria ephemerella)


Watermilfoil Moth (Acentria ephemerella) eats Eurasian Watermilifoil.



Watermilfoil Moth eats Eurasian Watermilfoil (Myriophyllum spicatum), a trait that excited managers interested in controlling the invasive plant. The Watermilfoil Moth was studied for biocontrol of Eurasian WaterMilfoil, but to our knowledge, was not deliberately released because research showed that the moth’s diet of submerged plants was too broad and included many native plants such as eelgrass. Nowadays, biocontrol researchers want their bugs to be fairly specific in their diet. Nevertheless, this moth was introduced to North America unintentionally as the plant spread. In 1996, Douglas Ferguson collected a free-flying moth in Doncaster MD. Additional collections were made in 1997 and 2000 3-5 km from the upper Bay in Charlestown, MD. But while the occurrence of larvae in Chesapeake Bay seems likely, it has not been verified. Complete Record  


Seaside Earwig (Anisolabis maritime)


The Seaside Earwig (Anisolabis maritime) is a small creature with a big yuck factor.


The Seaside Earwig is one of Dr. Fofonoff’s, the creator of NEMESIS, favorite species because it’s easy to find, even on his old sailboat, and has the ‘yuck factor’ that kids enjoy. They live in family groups in the debris at the high tide mark and are naturally distributed on floating driftwood and other flotsam, but they live in mostly nearshore habitats. Their nearshore home is the likely reason why they have a nearly worldwide distribution. These creatures were often transported in dry ballast (rocks and soil used to weight wooden sailing ships) and cargo. The native region of the species is uncertain, but the Mediterranean region from which they were described in 1832 seems a likely choice. The first collections of the Seaside Earwig in North America were from South Carolina in 1853, but they are now common throughout the East Coast of the US. The first records in Chesapeake Bay were in 1916, and it is present along much of the shoreline of the Chesapeake and the adjacent Atlantic coast. Complete Record 


Sea Roaches (Ligia exotica)


Sea Roaches (Ligia exotica) are perfectly camouflaged so you don’t see them hiding in the rocks.




Sea Roaches are semi-terrestrial isopods that were widely distributed by shipping. They were first described in France in 1828 from an arriving ship in the port of Marseilles but are believed to be native in the Indo-Pacific, from Japan and China south to Madagascar and South Africa. They are widely distributed along the east coast of the United States where they are believed to have arrived with dry ballast in the early to mid-1800s. Sea Roaches were first collected in the Chesapeake Bay region at Hog Island VA in 1924, and are now quite abundant and common throughout the tidal portion of the Bay and on rock jetties along the Atlantic coast and Atlantic Bay shores. They are one of Dr Fofonoff’s, the creator of NEMESIS, favorite species. He has been known to collect them near his home and keep them as pets, feeding them leftover Japanese food such as seaweed salad. Complete Record  


Gribbles (Limnoria tripunctata)


Gribbles (Limnoria tripunctata) are wood-bores and have been spread around the world by ship.

A Gribble (Limnoria tripunctata) is a wood-boring isopod. This isopod was described and classified in 1952. Prior to 1952 it was thought that L. Lignorum and L. tripunctata were the same species. Because of their recent classification and near worldwide distribution, it is impossible to know where they are native and where they are introduced. They were first seen in Norfolk, VA in 1967, but remain rare in Chesapeake Bay, although they are probably abundant along the Atlantic coast. Because of this species' habit of boring into wood, it was likely transported around the world in the times of wooden sailing ships and may still be transported this way, but to a lesser degree. Complete Record.



Mile-A-Minute Weevil (Rhinoncomimus latipes)


Mile-A-Minute Weevils (Rhinoncomimus latipes) were brought over from China to control Mile-a-Minute weed.




Mile-A-Minute Weevil eats Mile-a-Minute weed (Polygonum perfoliatum) in eastern Asia where they are both native. After the introduction of Mile-a-Minute weed into the US, researchers from the Animal and Plant Health Inspection Service went looking for a potential biocontrol agent. Research on the weevil started in 1996 by the US Forest Service. They found that the weevil’s diet was specific to the Mile-a-Minute weed. The weevil rarely ate other species nor did it successfully reproducing on them. Feeding by the weevil was found to damage or kill small Mile-a-Minute plants and reduced growth and seed output in larger plants. Following years of careful research, the weevils were released in New Jersey and Delaware in 2004. Success at these initial sites lead to further releases in 2007 into at 65 sites in New Jersey, Pennsylvania, Delaware, Maryland, and West Virginia. These sites included areas near the tidal Delaware River and Chesapeake Bay. The weevil has been successful in its mission to control Mile-a-Minute weed, reduction in the weed have been seen in test plots around the Chesapeake Bay and other release sites. Complete Record


Isopod Synidotea laevidorsalis


Synidotea laevidorsalis is a small isopod shrouded in mystery and debate.



Synidotea laevidorsalis is an isopod that is about 1 inch (35mm max) long that lives along the shoreline among seaweed and with the hydroids of the fouling community on docks and pilings. Due in part to its small size and the lack of molecular analyses, the species’ identity and native status is still being debated. Based on current research, we consider S. laevidorsalis to be a northwest Pacific species that has be widely introduced around the world through hull fouling and ballast water. It has been found on both the west and east coasts of the United States. SERC researchers and the University of Maryland, collected isopods from settling plates in Norfolk VA in 2002 that are believed to be S. laevidorsalis and again in the James River 2005-2006. This species has also been found in South Carolina and Delaware Bay. Complete Record


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