Archbold Biological Station
Biennial Report 1995-1996
P.O. Box 2057 Lake Placid, Florida 33862 USA
Phone: 863-465-2571 FAX: 863-699-1927
back to biennial 1995 home page
Known distribution of the exotic ant Strumigenys eggersi in Florida. The 1979 (above) map (Smith 1979) may reflect limited distribution or limited collecting. The 1996 (below) map shows records in the Archbold collection and indicates baseline data on the northern and western distribution in Florida
Project Director: Mark A. Deyrup
The Arthropod Collection as a Long-Term
The most complete biological data set is in the field, where, we hope, it will have long-term persistence. A minuscule sample of these data are monitored to provide, eventually, long-term documentation of changes. Withdrawn from these dynamics, the specimens of the Archbold Biological Station arthropod collection rest unchanging in their multitudes, crowded into their tall green mausolea in the bug lab. In some unconventional but literal sense, any collection that aspires to represent all the insects and spiders of a large area of natural habitat is a long-term data set, since it takes so long to collect, identify, and catalog the thousands of species on a site. Most long-term data sets, however, are designed to show processes, and the Archbold arthropod collection also functions in this sense.
As there are no other local collections of arthropods, the Station collection often serves as an "anchor point" as the first documented occurrence of a species in Highlands County or a nearby area. Among the ants, for example, there are seven exotic species whose first U.S. records are represented by specimens in the Archbold collection. In the distant future, this should give some idea of faunal changes. We do not expect the diversity of native arthropods to decrease very rapidly, as long as we maintain a good representation of natural habitats, but we do expect continued invasions of exotic species (see maps, this page). In the very long term, the accumulation of exotic species and the modification of surrounding habitats could begin to affect the arthropod biodiversity of the Station, especially if there were some kind of unnatural disaster, such as the spraying of the whole county with a wide-spectrum insecticide in an attempt to limit the spread of a disease carried by arthropods. We hope, however, that knowledge of arthropod biodiversity at the Station will not become relevant as a long-term data set under these circumstances.
Other long-term studies at the Station, particularly those dealing with plants or birds, may be enriched by the resources of the arthropod collection. Thanks to the availability of this large collection, it is possible to look at details of Florida scrub-jay diet, or the pollinators of various scrub plants. Contrary to what one might think, rare species may not be at all specialized in their relationships with arthropods. Scrub lizards, for example, eat a great variety of arthropods, and scrub buckwheat flowers are visited by dozens of species of Hymenoptera and Diptera. Beyond the convenience of identifying many species immediately, rather than sending them off to various specialists, there is always an advantage to informed field work. It is useful, for example, to know in the course of a study of the insects visiting palmetto flowers that a pair of tiphiid wasps that look very different may be male and female of the same species, while two lycid beetles that look almost exactly alike are not even in the same genus. A reference collection in close proximity to prime natural habitats quickly becomes a necessary luxury to the field biologist.
Long-term studies generally require an intensity and uniformity of data collection that precludes monitoring the populations of thousands of species. Nonetheless, the certainty that many thousands of species occur on a site puts our limited research in perspective. The species that we monitor and manage according to our long-term studies are representatives standing in for huge communities.
The reality of biological diversity both humbles and exalts our efforts. The dimensions of arthropod diversity on the Archbold Biological Station are still uncertain. Nearly 5000 species are documented (see fig., this page), probably less than half the species present. The list naturally over-represents the larger species and those which can be collected by general methods. One of the biggest groups of arthropods, the mites, is almost completely unknown. Any time that we examine a specialized system, such as the insects associated with a particular type of plant, we are likely to find a few species that were not on the Station list. Likewise, specialized scientists can quickly expand a section of the list. When, for example, George Melika (see page 12) came to work on oak gall wasps in 1995, the tally of gall wasps went from 9 to 85. In spite of its deficiencies, however, the Archbold collection of arthropods is one of the largest and most complete collections available at a field station anywhere.
Projects by Karl Krombein and Beth Norden. Karl Krombein is a Research Associate of the Station who did some of his early work with the collaboration of Richard Archbold. In recent years Beth Norden, also of the Smithsonian Institution, has been Krombeins partner in studies of bees and wasps. During 1995-96 they have continued their work at Archbold, discovering in two relatively brief but intense visits two new kinds of relationships between particular groups of insects. The first deals with the relationship between velvet ants of the genus Ephuta and their victims, which are spider wasps. Velvet ants are thought to attack the mature larva of the spider wasp, but Krombein and Norden found evidence that the female velvet ant sneaks into the wasp burrow, destroys the wasp egg that has been deposited on a paralyzed spider, and substitutes her own egg. This is the first example of prey usurpation in the group. It may be much easier for the velvet ant to find nests of spider wasps while the nests are being provisioned by the wasp and traces of her activity, perhaps even the scent of her spider prey, are much more evident than later, when the wasp larvae are left to mature on their own. The other discovery was a new species of tiny robber fly (3-4 mm long) that apparently lays its eggs in the burrows of small ground-nesting bees, a completely novel behavior among the robber flies. Nobody knows what the larva of this robber fly (recently named Townsendia arenicola) does in the bee burrows, but since this fly is common at Archbold and is not known from any other place, further work on its biology is most likely to be done here.
Lohrer, F.E . (Editor). 1998. Archbold Biological
Station, Biennial Report 1995-1996. Archbold Biological Station, Lake Placid. 62 pp.
© Archbold Biological Station, 1998, October.
Webmaster: Fred Lohrer.