Potamothrix bedoti
(Piquet, 1913)
Common Name:
A tubificid worm
Synonyms and Other Names:
Tubifex (Ilyodrilus) and Euilyodrilus, tubificid, annelid
Identification:
The body of this oligochaete consists of 33–90 segments and displays a rounded to triangular prostomium. There are dorsal and ventral bundles along its length of up to 5 chaetae, most of which are bifurcate. There are also 2 modified, blade-shaped spermathecal chaetae located on any one of segments 6–12. The clitellum is generally found on segments 8 and 9 or 9 and 10 and the male pores are usually on segment 9 (Timm 1970; Timm 1972; Spencer 1978; Steinlechner 1987; Wang and Liang 2001).
Potamothrix bedoti is typically around 7–12 mm long but specimens of 18 mm have been recorded from Estonia (Timm 1970; Timm 1972; Spencer 1978; Finogenova and Poddubnaja 1990; Wang and Liang 2001).
Size:
7 to 18 mm
Native Range:
Potamothrix bedoti is native to parts of the Ponto-Caspian region within the Black Sea, Caspian Sea, and Aral Sea drainages (Finogenova 1990).
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This map only depicts Great Lakes introductions.
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Great Lakes Nonindigenous Occurrences:
Species of this genus were probably introduced to the Great Lakes before 1959 and simply remained undetected. Potamothrix bedoti has been recorded from Lake Ontario, Lake Superior, Lake Erie, Lake Michigan, Lake Huron, and Cayuga Lake, New York state, which is part of the Lake Ontario drainage (Stimpson et al. 1975; Spencer 1978; Nalepa et al. 2002; Grigorovich et al. 2003; Spencer and Hudson 2003).
Table 1. Great Lakes region nonindigenous occurrences, the earliest and latest observations in each state/province, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Potamothrix bedoti are found here.
Table last updated 4/25/2024
† Populations may not be currently present.
Ecology:
Potamothrix bedoti occurs at depths of 1–190 m. It is generally associated with eutrophic conditions and fine substrates containing high proportions of clay and silt. It occurs in rivers, lakes, and springs, typically in freshwater, but has been recorded in slightly brackish waters of 0.1‰ salinity. It occurs at water temperatures of 0–34ºC and pH of around 7–9 (Timm 1970, 1972; Spencer 1978; Probst 1987; Sauter and Gude 1996; Cellot and Juget 1998; Melbrink 1999; Wolfram et al. 2002; Timm and Mols 2005; Yildiz and Balik 2005, 2006).
Potamothrix bedoti usually reproduces asexually. Sexual reproduction is rare and when it does occur it is often followed by resorption of the genital organs, and then continued asexual reproduction. Individuals have been known to survive up to 5 years and a cloned group can persist up to around 15 years. Asexual reproduction in individuals from Estonia occurs between 11.5–26ºC, while sexual reproduction, resulting in cocoons, occurs at temperatures of 14–18.5ºC. In each cocoon there are usually 1–5 embryos (Timm 1972; Timm 1984; Wang and Liang 2001).
In general, tubificids are known to feed selectively and probably favor heterotrophic aerobic bacteria found in the sediments (Ratsak and Verkuijlen 2006).
Means of Introduction:
Unknown, but shipping is a strong possibility (Grigorovich et al. 2003).
Status:
Established in Great Lakes (US EPA 2008).
Great Lakes Impacts:
Summary of species impacts derived from literature review. Click on an icon to find out more...
Current research on the environmental impact of Potamothrix bedoti in the Great Lakes is inadequate to support proper assessment.
There is little or no evidence to support that Potamothrix bedoti has significant socio-economic impacts in the Great Lakes.
There is little or no evidence to support that Potamothrix bedoti has significant beneficial effects in the Great Lakes.
Potential:
Some studies suggest that Potamothrix spp. may have a positive impact on native oligochaetes in Europe. The benefit could result from the numerous bacteria found in Potamothrix spp. faeces, which could allow for improved feeding by natives (Milbrink and Timm 2001).
Management:
Regulations
There are no known regulations for this species.
Note: Check federal, state/provincial, and local regulations for the most up-to-date information.
Control
Biological
While no there are no known biological controls specifically for Potamothrix bedoti, Brown trout, Salmo trutta L., has been shown to prey on oligochaetes, and its removal from an experimental environment led to rapid multiplication of benthic fauna (Wahab et al. 1989). However, brown trout is itself nonindigenous to the Great Lakes region and across nearly all of the United States.
Research on benthic macroinvertebrate communities in southwestern Lake Ontario before and after the invasion of Dreissena polymorpha (zebra mussels) and Dreissena bugensis (quagga mussels) suggests that the presence of Dreissena helps to improve benthic habitat, facilitating increases in macroinvertebrates, including the tubificids Potamothrix vejdovskyi and Spirosperma ferox (Stewart and Haynes 1994). This indicates that control of invasive quagga and zebra mussels could facilitate improved control of benthic macroinvertebrates such as the tubificids.
Physical
Potamothrix bedoti has been shown to be more likely to occur in substrate with a high clay and silt content, but information on its ability to survive in other substrates is not available (Sauter and Gude 1996). However, this does indicate that substrate type is a possible physical control method to be further explored.
Chemical
While there are no known chemical controls specifically for Potamothrix bedoti, declines in Oligochaeta in southern Lake Michigan were recorded between 1980 and 1993 in correlation with reductions in phosphorus loads (Nalepa et al. 1998), suggesting that reduction of excess nutrients would help to reduce oligochaete populations.
Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.
Remarks:
Potamothrix bedoti is synonymous with Tubifex (Ilyodrilus) bedoti and Euilyodrilus bedoti.
References
(click for full reference list)
Author:
Kipp, R.M., J. Larson, A. Fusaro, and T. Makled
Contributing Agencies:
Revision Date:
9/12/2019
Citation for this information:
Kipp, R.M., J. Larson, A. Fusaro, and T. Makled, 2024, Potamothrix bedoti (Piquet, 1913): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI, https://nas.er.usgs.gov/queries/greatlakes/FactSheet.aspx?Species_ID=2703&Potential=N&Type=0&HUCNumber=DHuron, Revision Date: 9/12/2019, Access Date: 4/25/2024
This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.