winged adults, the presence of shelter tubes over foundation walls, or the sudden 
collapse of the surface of infested wood. 
The principal food of subterranean termites is cellulose, which they obtain from 
wood and other plant tissues. As a result, these termites are not only destructive to 
the woodwork of buildings, utility poles, fence posts, and other wood products, but 
also to paper, fiberboard, and various types of fabrics derived trom cotton and other 
plants. Shrubs, nursery stock, ornamental plants, and many kinds of shade trees are 
damaged occasionally. Trees killed by other insects, fire, or disease, particularly in 
the South, are attacked and the timber rendered unmerchantable unless it is utilized 
shortly after being killed. 
In attacking wood, subterranean termites usually feed on the soft springwood 
only. As a result, their galleries run with the grain. These galleries are charac- 
teristically stained on the inside with grayish specks of excrement and earth but are 
free of pellets like those found in the galleries of nonsubterranean termites. 
Subterranean termites occur throughout most of the United States and in southern 
Canada. They are common in most of the eastern half of the United States and along 
the Pacific Coast. It is considered likely that the native species have occupied their 
present ranges for millions of years; however, there seems to be an increase in their 
destructiveness northward. This increase has probably resulted from the general 
adoption of central heating plants in structures, from changes in building practices, 
the wider use of termite-susceptible wood in construction, and from the tremendous 
expansion of suburban homes into forested areas. 
The eastern subterranean termite, Reticulitermes flavipes (Kollar), is the 
predominant species in the Eastern United States. It occurs from the East Coast to 
the Great Plains and from the Gulf of Mexico north to Ontario. In general, R. 
flavipes occupies regions of high humidity. Dead wood in forested areas 1s com- 
monly infested with this species. It will attack wood from most of the species of 
trees in this part of the country. Infestations also occur in the woodwork of 
buildings, in cellulose materials in storage, and in poles and posts. 
Every mature colony of the eastern subterranean termite contains some or all of 
seven castes during the year: larvae or immatures, nymphs, soldiers, workers (a 
“true” worker caste is not believed to exist in Reticulitermes), alates or winged 
reproductives, and primary and supplementary (or replacement) reproductives. 
Larvae hatch from the eggs and are precursors of all the other castes (fig. 14A). 
Workers (fig. 14B) are soft-bodied, grayish white, and slightly less than 6 mm 
long. They are the individuals responsible for the maintenance of the colony and the 
gathering of food. Soldiers (fig. 14C) are similar to the workers except for their 
much larger, long heads, their larger and more formidable mandibles, and their 
slightly greater length. Soldiers cannot feed themselves but contribute to colony 
labor by defending it. Nymphs (fig. 14D) develop from larvae and eventually molt 
into reproductives (fig. 14E). These reproductives are soft-bodied and brown to 
black, have two pairs of long, whitish opaque wings of equal size, and are 10 to 12 
mm long. The winged reproductives fly from their colony to form new colonies. 
Colonizing flights occur during the day, most frequently after the first warm days 
of spring, often following a warm rain in April or May. They may also occur during 
the remainder of the warm season and sometimes even in the fall, especially in the 
South. In heated buildings, flights occasionally occur during the winter. The 
individuals in these flights are attracted by strong light. When they emerge within 
buildings, they gather about windows and doors. Here, they soon shed their wings, 
which may be found in large numbers even after the termites have disappeared. 
56 
