Agriculture Reference
In-Depth Information
attended by 200 to 300 earthworm scientists, including many international systematists. All the
symposia included sections on taxonomy, distributions, and biogeography of earthworms.
FUTURE TRENDS AND RESEARCH IMPERATIVES IN
EARTHWORM TAXONOMY
One of the major problems for earthworm taxonomy in North America and elsewhere has been the
paucity of earthworm systematists and their geographical isolation.
Gordon Gates, one of the most productive taxonomists, died in 1987. Although he began
publishing on earthworm systematics in 1926, it was not until the latter part of his career that he
devoted much time to describing the Lumbricidae and other earthworms of North America.
Before 1950, taxonomists included Frank Smith (publication period 1985 to 1937) and Henry
Olson (publication period 1928 to 1940), who made significant contributions to earthworm taxon-
omy and distributions, respectively. In the past few decades, Dorothy McKey-Fender and William
Fender have concentrated on the taxonomy and distribution of the native and exotic earthworm
fauna of the west coast of North America, and Sam James has investigated the endemic species of
the southeastern and plains areas of the United States.
Since 1972, I have collected earthworms widely throughout North America, and the results of
these collections have been published primarily as distribution data, with relatively minimal con-
tributions to systematics
series put together in
a single source the essential basic reference data for anyone involved in the taxonomy and nomen-
clature of earthworms or who need a ready, up-to-date reference list of species authorities have
described. The fourth supplement (Reynolds and Wetzel 2004a) should be available at the end of
2004. I suggest the following priorities for future earthworm research.
sensu stricto
. The
Nomenclatura Oligochaetologica
T
E
T
RAINING
OF
ARTHWORM
AXONOMISTS
For more than 2 decades, it has been obvious that the scarcity of competent earthworm systematists
and taxonomists was detrimental to progress in research by ecologists and others (Reynolds 1973a;
Reynolds et al. 1974a,b). Institutions that normally employ taxonomists and encourage their devel-
opment (e.g., museums, departments of agriculture, and universities) have not done so in North
America. There is a need for a concerted effort to support this type of research before there are
few or no earthworm taxonomists remaining. However, the large number of scientists actively
working in various aspects of earthworm biogeography and taxonomy elsewhere in the world is
most gratifying and bodes well for the future of the science.
E
P
E
T
ARTHWORM
ARTHENOGENESIS
AND
FFECTS
ON
AXONOMY
A major exotic group of earthworms in North America (Megascolecidae and pheretimoid groups)
has long been plagued with taxonomic problems, which have resulted from the incidence of
widespread parthenogenesis among its species (Gates 1972). Parthenogenesis also occurs within
the Lumbricidae. One study showed that localized populations of
(Jaenike et
al. 1980, 1982; Jaenike and Selander 1985) have exhibited parthenogenesis. Previously, taxonomic
problems with some morphotypes of what is now recognized as
Octolasion tyrtaeum
may be
attributed to parthenogenesis. The issue of parthenogenesis in earthworms has only recently received
more attention and may have major impacts on earthworm taxonomy.
Dendrodrilus rubidus
E
S
ARTHWORM
URVEYS
It is obvious from the data in
Table 4.1
that, in spite of what has already been achieved, there are
major areas of North America in which there have been no earthworm surveys. In certain areas
