|
FIELD ANTS
COMMON NAME: Field ant
SCIENTIFIC NAME: Formica spp. 
CLASS / ORDER / FAMILY: Insecta / Hymenoptera / Formicidae
METAMORPHOSIS: Complete
INTRODUCTION. The common name of field ant comes from their abundance outdoors. This is the largest genus of ants in the United States north of Mexico. It contains approximately one-sixth of our entire ant fauna. A few species are commonly called “thatching ants” because of their habit of constructing a mound or thatch of plant material, many times grass is used. They are found throughout the entire United States.
RECOGNITION. Workers polymorphic, 1/8-3/8” long and their color is from brown, black, reddish or a combination of these colors. The head has distinct ocelli, the posterior border of the head is not indented. The antenna is 12-segmented and is not clubbed. The thorax does not have spines and the thorax profile is not evenly rounded on the upper side. A pedicel, 1-segmented node is usually rounded dorsally. The gaster has a round anal opening, surrounded by circlet of hairs. A functional stinger is absent, but the beast will bite and spray formic acid into wound if provoked. These ants are very numerous in many areas of the United States.
BIOLOGY. Because of the size and diversity of this genus, few generalizations can be made. They exhibit such behavior as slave-making and temporary social parasitism of various kinds and several different methods of nest construction. A colony is founded by several means including by a single inseminated female. A few species, such as F. rufibarbis Wheeler, have gynecoid workers or workers which can and do lay eggs as they can also function as substitute queens. It is known that colony size varies considerably, for instance, colonies of F. rufa McCook have nests of up to 20,000-94,000 ants.
HABITS. The habits are diverse within this genus. However, most species causing problems around structures are either one of those species called thatching ants or are associated with masonry walls, concrete sidewalks and structures. Thatching ant species construct their mound of plant materials. They often utilize grass but also twigs, leaves, and/or pine needles. Such nests are often located around small trees, shrubs, or rocks. Other Formicine ants typically construct their nests in the cracks of sidewalks, along foundation walls, at the base of trees, etc. Such ants include the California red-and-black field ant. F. occidua Wheeler, and the brown field ant, F. cinerea Mayr. Members of the genus Formica rarely nest in homes but occasionally enter in search of sweets.
Field and thatching ants feed primarily on honeydew from aphids (plantlice), mealy-bugs and scale insects, which are found on trees and shrubs. However, some species such as the silky ant.(F. fusca Linnaeus), tend aphids for honeydew but are also general scavengers-predators and will feed on meats.
|
