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Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

Carpenter ants here and there: Camponotus spp.


These jaws were made for chewing wood.


This week we continue our adventures, first in Maryland and then in the jungles of Costa Rica, to meet a mighty impressive carpenter ant.

Here: In a previous episode, we met black carpenter ants, Camponotus pennsylvanicus, real bruisers of the ant world, robust, black giants. Unlike odorous house ants that often enter homes to snack on sugary substances, carpenter ants often set up their home in our home. In the natural world, dead wood is the chosen habitat for the colony. Unlike termites that use wood as a source of nutrients, carpenter ants excavate wood and build elaborate galleries to house the colony. Moisture is important to the carpenter ant colony and decaying stumps, fallen wood, and hollow trees are excellent nest sites. Due to high ambient moisture levels, these outdoor sites, called primary colonies, provide shelter for egg-laying queens, juvenile ants, and workers. However, a plugged rain gutter, leaky pipe in a wall void or water-soaked window sill may provide a damp-wood situation that allows carpenter ants to invade a home. Workers of these satellite colonies create galleries for developing larvae and pupae. Satellite colonies can cause serious structural damage to homes and the longer the colony is in place the greater will be the damage.


Major workers are more than twice the size of minors in many ant species, including black carpenter ants.

Carpenter ants enter homes in spring in search of food, and an occasional ant indoors does not necessarily signal the presence of an infestation. However, the presence of large numbers of wingless workers and several winged carpenter ants (these are reproductive queens and males) indoors in spring are highly indicative of an infestation. Although spring, summer, and fall are the typical season to observe carpenter ants, I have seen them active indoors on a warm winter day in homes that are infested. What should you do if you have a carpenter ant infestation? First and foremost, the carpenter ant colony must be located and destroyed, the damaged wood should be removed and replaced, and any conditions leading to the founding of the colony, such as leaking pipes or other conditions creating wet wood, must be fixed to prevent recurring infestations. Applications of insecticides to exposed colonies or the use of ant baits may be used indoors by homeowners to destroy colonies. All directions and precautions on the pesticide label should be read and strictly followed. Treatments of concealed colonies in voids behind walls or in ceilings are for professional pest control applicators who have the knowledge, techniques, and tools to perform these services.

How can carpenter ants be foiled in the first place? Remove stumps, wood piles, and wooden objects near the home that might house parent colonies outdoors. Carpenter ants will live in the dead wood of standing trees. They do not kill trees. Unless the tree is a hazard because of structural defects, it is not necessary to remove it simply because it is colonized by ants. Colonies in standing dead trees can often be eliminated with baits. Carpenter ants can gain entry to a home via branches that touch the home. Keep trees and shrubs near the home pruned to eliminate plant-to-house contact.

En garde!

There: In the lowland rainforest of Costa Rica, the gorgeous golden carpenter ant, Camponotus sericeiventris, builds colonies in cavities of living trees and decaying trunks of standing dead trees. I had the good fortune to encounter one of the striking major workers on the leaf of a low hanging branch. As I approached this beauty, she turned, assumed an alert and somewhat aggressive position with abdomen slung forward beneath her body and carefully observed me between bouts of grooming. I often handle insects just to get up close and personal, but accounts of the golden carpenter ant’s ability to deliver wicked bites dissuaded me from doing so. Colonies of golden carpenter ants are comprised of large major workers whose tasks include colony defense and food gathering, and smaller workers who also gather food but attend to the queen and brood as well. Golden carpenter ants are widely distributed throughout Central and South America but sometimes appear in the United States, likely stowaways on produce shipped from the tropics.


Constant grooming keeps this golden beauty looking almost as sharp as her jaws.

Ants are notorious for their ability to produce a vast array of volatile chemicals used for communication and defense. Golden carpenter ants are no exception. In a behavior called “anting”, several species of birds have been observed anointing their plumage with secretions from ants. This behavior has been explained as a way to use secretions produced by the ants to remove parasites, soothe or stimulate the skin, or condition feathers. In a fascinating account, capuchin monkeys were observed to pluck swarming golden carpenter ants from a branch and actively rub them on their fur. While the exact purpose for this behavior remains obscure, golden carpenter ants clearly play a role in the anointing antics of capering capuchins. Here or there, carpenter ants play important roles as recyclers of plant material.     



In the wild, capuchins utilize fragrances collected from ants for purposes known only to them.


“The ant Camponotus (Myrmepomis) sericeiventris Guérin and its mimic” by William Wheeler, “Polymorphism and Division of Labor in the Neotropical Ant Camponotus sericeiventris Guerin (Hymenoptera: Formicidae)” by C. E. Busher, P. Calabi, and J. F. A. Traniello, and “True anting by capuchin, Cebus capucinus” by J. T. Longino  were used as references for this episode.