August 2004 - FMCS-Freshwater Mollusk Conservation

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A review of the United States distribution of Melanoides tuberculatus
(Müller, 1774), an exotic freshwater snail
Tamara K. Anderson
University of Colorado Museum
Boulder, Colorado
Address for Correspondence: 285 Smith Street, Lander, Wyoming 82520
E-mail: tamander@onewest.net
INTRODUCTION
Melanoides tuberculatus (Müller, 1774), the red-rim melania, is native to Africa, the Middle East, and southeast Asia (Pilsbry
and Bequaert 1927), but is now common in tropical to semi-tropical areas around the globe. The species is live-bearing and
generally considered to be parthenogenetic, although evidence exists for sexual reproduction in some populations (Livshits and
Fishelson 1983; Heller and Farstey 1990). M. tuberculatus is a secondary host of several parasites that affect various species of
fish and birds.
Melanoides tuberculatus has invaded many areas of the globe with varying effects on the local gastropods. Abbott (1973) noted
its spread into Puerto Rico, Mexico, and central America in the 1970s. M. tuberculatus may have a competitive advantage over
native snails due to its ability to reach high densities (Pontier et al. 1991). In Mexico, the arrival of M. tuberculatus coincided
with decreases in native gastropod populations (Contreras-Arquieta et al. 1995, as cited in Contreras-Arquieta 1998). Several
studies in the Caribbean also showed negative impacts on Biomphalaria glabrata (Pointier and McCullough 1989; Pointier et al.
1989; Pointier 1993). M. tuberculatus may also have contributed to the decline in B. glabrata in Venezuela (Pontier et al. 1994).
In Africa, however, M. tuberculatus does not appear to displace freshwater pulmonate snails (Mkoji et al. 1992). Due to the
potential effects on the aquatic community, the distribution of this species is important to track.
METHODS
In July 2001, I surveyed aquatic mollusks in Bridal Veil Falls and portions of Cascade Creek, Cool Creek, and the Cheyenne
River on The Nature Conservancy's Whitney Preserve and adjacent properties in southwestern South Dakota. An informal
sampling design allowed baseline information to be gathered with a minimum effort. The substrate at eleven points was sampled
using a net and sieve bucket.
In addition to my own survey results in South Dakota, I used available literature sources to research locations of Melanoides
tuberculatus. Through the internet, I found records of occurrence at the Florida Natural History Museum, the Philadelphia
Academy of Natural Sciences, and the Smithsonian Institution. Database searches at the Illinois Natural History Museum, the
Bailey-Mathews Shell Museum, and the National Museums and Galleries of Wales failed to yield any U.S. records for M.
tuberculatus. I visited the Field Museum of Natural History in Chicago and searched their collections in person. Contacts at the
Delaware Museum of Natural History, the University of Michigan, and the Santa Barbara Museum of Natural History provided
records from those collections. Personal communications with others who had recent field observations resulted in additional
location information.
RESULTS
Shells of Melanoides tuberculatus were collected from one point in Cascade Creek. The water temperature at the collecting site
was 21 o C. The shells measured from 5.3 mm to 13.8 mm in length. Robert Herschler confirmed the identification of the samples
(pers. com.). Voucher specimens were deposited at the Field Museum of Natural History in Chicago (Voucher #296306).
The known current distribution of Melanoides tuberculatus is summarized in Figure 1 and Table 1*. The distribution discussed
here is limited to museum records, published literature reports, and personal communications with other scientists known to be