312
E. B. EDNEY
I. Introduction
Most reviews of desert biology deplore the lack of knowledge about animals that live there, and the point has recently been reemphasised by Lowe
(1968) in "Deserts of the World." Owing to this state of affairs, it is impossible at present to make firm statements regarding the comparative importance of different groups of animals insofar as biomass or anything else
is concerned. Hopefully this situation will be relieved as a result of the
current work being done by the Desert Biome Section of the International
Biological Program in the United States.
Arthropods certainly figure highly in regard to the number of species
concerned, and one might hazard the guess that they also contribute importantly to the total biomass. Insects, as usual, are the most conspicuous
arthropods present; mites, collembolans, beetles, ants, and grasshoppers
being particularly abundant, but wasps, dipterous flies, and lepidopterans
may also prove to be populous once they are looked for.
Schlinger and his colleagues at Riverside have been collecting information about the occurrence of arthropods at the Deep Canyon Desert Research Center near Palm Springs in California, and this information has
been stored in computer form for easy access. Examination of their records
shows an impressive variety of species (1160 to May, 1970) for a region
in which the annual rainfall is less than 75 mm (see Table I). Counts
of species numbers for other deserts are not common, but Pierre (1958)
estimates that there are 800 species of insects in the northern Sahara
Desert, as many as 200 of which occur in sandy areas, and the long term
intensive work of Schleeper (of Long Beach State University) and his
colleagues, on invertebrates of the Nevada Test Site, will add greatly
to our information about the numbers, distribution, and phenology of the
arthropods of that area.
Arachnids are common enough in most deserts. The large camel spider,
Galeodes (a solpugid) reported on by Cloudsley-Thompson (1961b) is
numerous in some areas, as are several species of tarantulas and scorpions.
One of the most conspicuous arachnids when it appears above ground is
the giant red velvet mite, Dinothrombium, of which there are several species in the Old and New Worlds (Tevis and Newell, 1962). The adult
mites emerge in large numbers after rain and feed voraciously on alate
termites with whose emergence their own is beautifully coordinated.
Centipedes are not uncommon; even a julid millipede occurs in large
numbers in the sand dunes of southern California. Most unexpected of
all, perhaps, is the presence of isopod crustaceans (woodlice or sowbugs)
in deserts. Several species occur in the North African, Asiatic, and New
E. B. EDNEY
I. Introduction
Most reviews of desert biology deplore the lack of knowledge about animals that live there, and the point has recently been reemphasised by Lowe
(1968) in "Deserts of the World." Owing to this state of affairs, it is impossible at present to make firm statements regarding the comparative importance of different groups of animals insofar as biomass or anything else
is concerned. Hopefully this situation will be relieved as a result of the
current work being done by the Desert Biome Section of the International
Biological Program in the United States.
Arthropods certainly figure highly in regard to the number of species
concerned, and one might hazard the guess that they also contribute importantly to the total biomass. Insects, as usual, are the most conspicuous
arthropods present; mites, collembolans, beetles, ants, and grasshoppers
being particularly abundant, but wasps, dipterous flies, and lepidopterans
may also prove to be populous once they are looked for.
Schlinger and his colleagues at Riverside have been collecting information about the occurrence of arthropods at the Deep Canyon Desert Research Center near Palm Springs in California, and this information has
been stored in computer form for easy access. Examination of their records
shows an impressive variety of species (1160 to May, 1970) for a region
in which the annual rainfall is less than 75 mm (see Table I). Counts
of species numbers for other deserts are not common, but Pierre (1958)
estimates that there are 800 species of insects in the northern Sahara
Desert, as many as 200 of which occur in sandy areas, and the long term
intensive work of Schleeper (of Long Beach State University) and his
colleagues, on invertebrates of the Nevada Test Site, will add greatly
to our information about the numbers, distribution, and phenology of the
arthropods of that area.
Arachnids are common enough in most deserts. The large camel spider,
Galeodes (a solpugid) reported on by Cloudsley-Thompson (1961b) is
numerous in some areas, as are several species of tarantulas and scorpions.
One of the most conspicuous arachnids when it appears above ground is
the giant red velvet mite, Dinothrombium, of which there are several species in the Old and New Worlds (Tevis and Newell, 1962). The adult
mites emerge in large numbers after rain and feed voraciously on alate
termites with whose emergence their own is beautifully coordinated.
Centipedes are not uncommon; even a julid millipede occurs in large
numbers in the sand dunes of southern California. Most unexpected of
all, perhaps, is the presence of isopod crustaceans (woodlice or sowbugs)
in deserts. Several species occur in the North African, Asiatic, and New