Ant Exhibition


(1996~1997)
at Museum of Comparative Zoology
in Harvard University Museums of Natural History

 

Table of Contents

Related Links

Table of Contents

Map


Table of Contents

Edward O. Wilson, Pellegrino University Professor, Curator in Entomology, as born in 1929 in Birmingham, Alabama. He came to Harvard as a Ph.D. student in 1951, and has been a member of the faculty since 1956. This lengthy career has been typical in many respects for an evolutionary biologist: his focus has been on whole organisms, their history through geological time, and their role in the environment. Also, like most evolutionary biologist, Wilson chose to concentrate on one particular group of organisms. In his case, the favored group was ants, but it might equally well have been birds (for example), or flowering plants, or protozoans. There are considerable advantage to such specialization. By narrowing the focus in this manner, it is possible to cut deeply into the biology of the organisms, amass huge amounts of details, and thereby make unexpected discoveries.
The purpose of this exhibition is to illustrate the evolutionary biology approach, using details from the fascinating lives of ants drawn from the research of Wilson and his students and postdoctoral associates at Harvard University.

Table of Contents

A Typical Ant Society: Camponotus socius

The social behavior of ants has been a central theme in the research of Edward Wilson. Ants vary enormously in the size of their colonies and the details of their social organization, but some fundamental properties are shared by almost every ant society.

Let's illustrate these properties by using colonies of Camponotus socius a beautiful sand-nesting species that occurs in Florida and the southern parts of gulfcoast states.

  1. Ants are holometabolous insects - they have four distinct life stages: egg, larva, pupa, and adult. Eggs are small, elongate, and usually kept in clusters. The whitish, grub-like larvae are fed by the workers. Pupae are resting stages during which time the larvae transform into adults, the ants we commonly see. In Campontus socius the eggs are pale orange and pupae are covered by tan, silk cocoons. Can you find them in these colonies?
  2. All ants colonies are female societies. Males are present for only a brief time each year. All of the ants you see in those colonies are female.
  3. Almost all ant societies show reproductive division of labor. Ant females occur in two forms. In each colony one (or sometimes a few) queens lay eggs that produce new ants. The remainder of the colony members are sterile females known as workers. In Camponotus socius, each colony has one queen that is much larger than the workers - see if you can spot her. In this species the workers vary considerably in size. The largest (sometimes called soldiers) defend the nest and store liquid food. The smaller workers rear the young, find food, and maintain the nest.

Table of Contents

The Red Imported Fire Ant - Solenopis invicta -

The notorious Red Imported Fire Ant (Solenopis invicta), the American South's "ant from hell," was accidentally introduced into the port of Mobile, Alabama, sometime in the 1930's. Its native range is northern Argentina and southern Brazil, and the first immigrant colonies probably made their ways north as stowaways on cargo ships. The species then spread throughout the southern United States, where today its vast populations of fiercely stinging workers make it a major pest.

 

First Fire Ants Found

The first colonies were found in 1942 by young Ed Wilson when he has 13 years old (shown here with sweep net collecting insects). They were in vacant lot next to his home near the Mobile docks. From his college years onward, he used the fire ants as subjects for biological studies. As a result, of this research and that of others, the fire ant was one of the first species whose chemical communication system was decoded, as described in the accompanying video.

Table of Contents

Leafcutter Ants - Atta cephalotes


Table of Contents

Sociobiology

Sociobiology is a relatively new discipline that has grown out of the study of creatures like leafcutter ants. It is broadly defined as the systematic study of the biological basis of social behavior in all kinds of organisms. By comparing the lives of ants with those of other social animals - as diverse as fishes, and the great apes - scientists have been able to develop a clearer picture of the way coordinated social groups arise in evolution.

 

In his book Sociobiology: The New Synthesis (1975), Wilson helped to create the new discipline. When he extended the same biological principles to human beings, however, the subject became far more complex and also controversial, due both to the powerful intervening role of culture and the sociopolitical ideas implicit in viewing heredity as a contributor to human nature.

Table of Contents

The Diversity of Ants

The approximately 10,000 known species of ants display among themselves a dazzling array of physical types and modes of life.
The large eyes of tropical Asian Myrmoteras are used to help locate prey, which the huntress ant then capture with its unusual mandibles.

Little or nothing is known about many ants in both temperature and tropical areas. Recurvidris, from tropical Asia, is not common, and nothing is yet known about its social organization or diet.



Table of Contents

Museum Collections

The Museum of Comparative Zoology housed the largest and most nearly complete collections of ants in the world, comprising almost one million specimens representing at least 5,000 species. Specimens are kept in wooded "Cornell drawers" containing trays of ant specimens used in research. Each tray usually contains representatives of a different species.

 

Here, the first drawer contains examples of the enormous diversity from around the world. Drawer two contains samples of the over 100 ant species that occur in New England. Drawer three illustrates some of the many different lifestyles of New England ants.

Drawer 1,2,3

Drawer 4,5,6

.

 

Describing New Species

Describing new species is a fundamental process in studying biodiversity. Ants are collected in the field using simple tools like those in the near by case. They are brought back to the Museum, and glued to triangles of stiff white paper, as in the fourth drawer. Labels are made and placed on each pin, linking the ants with the information recorded when they are collected (see drawer 5).

 

Thanks to the hard, almost imperishable nature of the outer chitinous skeleton of ants and other insects, the method is very efficient; many specimens preserved this way in the museum collection are over a hundred years old.

 

The newly collected specimens are then painstakingly compared to the other known species in the genus. If they differ significantly, they may be described as a new species. Representative specimens are carefully described, illustrated, and recognized rules. The name may describe the species, the region or habitat in which it occurs, or may name the new ant in honor of a person.

 

One ant is always chosen to be the Holotype (i.e. the specimen to which the new name is officially linked). Other specimens may be designated as "Paratypes". Type specimens provide permanent and authoritative documentation of species' characteristics and are therefore extremely valuable. The last drawer illustrates the look of type specimens resulting from the Pheidole project. The final step will be publishing the descriptions with the illustrations. No new name is valid until it is published. The illustration following are examples of new species described in .....( not recorded)

Table of Contents

The Pheidole Project

Museum collections are vital tools in biologist' effort to explore the earth's biodiversity by revising and extending the classification of the world's organisms. A typical ongoing study is illustrated here. With collaborator William L. Brown of Cornell University, Edward Wilson is currently reclassifying the enormous ant genus Pheidole in the Western Hemisphere. The two biologists have already defined over 600 species, of which 315 are new to science!




Table of Contents

Tools for the Trade

Here are some of the simple tools of the mymecologist (biologist who specializes on ants) in the field. Not surprisingly, they include trowels, bottles and forceps. Collecting tools are of three types. Shovels, trowels, and axes are used to break into nests. The aspirator (a simple lung-powered "vacuum cleaner") is used to pick up ants as they run about. Specimens are then stored in vials containing alcohol, and a field notebook is used to recorded important information about each collection: locality, date, collector, habitat and nest types.

This page was edited by Japanese Ants Database Group, under the permission of Dr. E.O. Wilson.