Volume 41, Number 1, January 1995:
Collection and Maintenance of Ants
and
Studying Ants: A Beginning
by Mark B. DuBois

Text-only version

ISSUE HOME PAGE

ABOUT THIS ISSUE
- about KSN
- about the author

IN THIS ISSUE
- introduction
- collection
- maintenance, observation ant farm
- maintenance, classroom use
- project observations
- literature cited
- books for children on ants

Studying Ants: A Beginning
by Mark B. DuBois
- males, queens and worker ants
- establishing a colony
- caring for young
- growth of an ant colony
- ant senses
- gardening ants
- harvester ants
- parasitic ants
- acrobat ants
- army ants
- questions, activities and investigations with ants
- further reading

SLIDESHOW
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Collection and Maintenance of Ants to Use for Teaching
by Roger D. Akre, Laurel D. Hansen, and Elizabeth A. Myhre

and

Studying Ants: A Beginning
by Mark B. DuBois

ACROBAT ANTS

These common ants are easily recognized by the way they hold the gaster (tail segments of the abdomen) over the thorax with the tip pointing forward, like a scorpion tail. These ants are often seen walking single file along a twig or vine - hence the name. They are also identified by their heart-shaped gaster (when viewed from above). Their nests are usually constructed in the soil, in rotting wood, or in hollow stems. Most nests contain several thousand workers. They are quite aggressive and many workers will emerge from a nest once it is disturbed. Although they lack a sting, they possess a strong bite which can be painful.

Most Crematogaster feed on "honeydew" and on dead insects. Honeydew is produced by insects such as aphids, scale insects, and leafhoppers that ingest large quantities of plant sap for food. Since sap is high in sugars and water, but low in proteins, these insects must consume large quantities of sap to obtain a full diet. The excess sugar and water is passed through their digestive tract almost unchanged and is defecated as honeydew. When extremely abundant, these small insects can damage plants and transmit diseases between plants.

Aphids and scale insects are relatively immobile throughout most of their lives since their mouthparts are inserted deep into plant tissues. In the absence of ants, aphids forcibly expel the honeydew droplets or kick the droplets away. However, if an individual is tended by ants, it retains the droplet of honeydew until its abdomen is touched by the antenna of an ant. It then defecates the sugar droplet which the ant licks up.

Both ant and aphid benefit from this relationship. The ants are provided by a relatively stable food supply and insects tended by ants are less likely to be eaten by predators. Although ants do not actively protect aphids, they respond to rapid or erratic movements which force predators to move elsewhere. Crematogaster species even carry aphids into their ant nests and expose them to roots to feed while being protected from bad weather.

However, when the food requirements of the ants become more restrictive, such as when there are many larvae and a need for increased protein, the ants may ignore the honeydew. If there are shortages of foods high in proteins, ants may attack aphids and kill them for food.

Figure 8. Crematogaster punctulata, alitrunk petiole, and postpetiole, lateral view (slightly from above). Legs removed.