Where do eastern subterranean termites come from

Where do eastern subterranean termites come from

Most pest species of subterranean termites in North America belong to the endemic genus Reticulitermes. Reticulitermes species are found in every state in the continental United States except Alaska, but are most common in the warm and humid southeastern region. The eastern subterranean termite, Reticulitermes flavipes (Kollar) is the most widely distributed and is found in the entire eastern region of North America as far north as Ontario, Canada, and south to Key Largo, Florida. Its counterpart, the western subterranean termite, Reticulitermes hesperus Banks, is found along the entire Pacific Coast ranging from southern California to British Columbia. Reticulitermes tibialis Banks occurs in the inter-mountain region of the West. In addition to Reticulitermes flavipes, two other Reticulitermes occur in Florida, Reticulitermes virginicus (Banks), and Reticulitermes hageni Banks.

Figure 1. Indoor swarm of eastern subterranean termite, Reticulitermes flavipes (Kollar). Photograph by T. Myles, University of Toronto.

Description and Identification (Back to Top)

Because of their cryptic nature, structural infestations of subterranean termites are usually not visible. Most people become aware of an infestation when annual flights of winged termites (called alates) occur in structures. The alates of Reticulitermes flavipes and Reticulitermes virginicus are dark brown, while those of Reticulitermes hageni are yellowish brown. Alates of Reticulitermes flavipes are generally larger (approximately 0.4″ long including wings) than those of Reticulitermes virginicus or Reticulitermes hageni (approximately 0.3″ long). Alate wings of Reticulitermes species have two hardened and thickened veins that are visible along the entire front end, but lack the small hairs that are characteristic of the Formosan subterranean termite, Coptotermes formosanus Shiraki. After indoor flights, most alates are found dead near windows or in sinks and bath tubs – usually with their wings still attached.

Figure 2. Alates of eastern subterranean termite, Reticulitermes flavipes (Kollar) (R.f.), and other native subterranean termites, Reticulitermes virginicus (Banks) (R.v.) and Reticulitermes hageni Banks (R.h.). Photograph by Nan-Yao Su and Rudolf H. Scheffrahn, University of Florida.

Figure 3. Wing of Reticulitermes, a subterranean termite genus. Photograph by Nan-Yao Su and Rudolf H. Scheffrahn, University of Florida.

As with other termite species, Reticulitermes colonies contain three primary castes; the reproductives (king, queen, alates, alate nymphs, and supplementary reproductives), soldiers, and workers. Alates and soldiers are used for species identification.

Figure 4. Life cycle of Reticulitermes subterranean species. Graphic by Nan-Yao Su and Rudolf H. Scheffrahn, University of Florida.

Figure 5. Queen (bottom) and soldier (top) castes of the eastern subterranean termite, Reticulitermes flavipes (Kollar). Photograph by Lyle J. Buss, University of Florida.

Figure 6. Queen (top) and worker (bottom) castes of the eastern subterranean termite, Reticulitermes flavipes (Kollar). Photograph by Lyle J. Buss, University of Florida.

Figure 7. Queen (bottom) and soldier (top) castes of Reticulitermes hageni Banks, a U.S. native subterranean termite, surrounded by larvae. Photograph by Lyle J. Buss, University of Florida.

Figure 8. King caste of Reticulitermes hageni Banks, a U.S. native subterranean termite. Photograph by Lyle J. Buss, University of Florida.

Soldiers of subterranean termites (Rhinotermitidae) are distinguished from those of drywood or dampwood termites (Kalotermitidae) by their smaller size and the relative width of the pronotum. In subterranean termites, the pronotum (segment immediately behind the head) is narrower than the head, while in kalotermidis they are equally as wide. Reticulitermes soldiers are further distinguished from those of Coptotermes formosanus by the rectangular-shaped head of the former compared to the oval-shaped head of the latter.

Figure 9. Soldier heads of the Formosan subterranean termite, Coptotermes formosanus (C.f.), and eastern subterranean termites, Reticulitermes flavipes (R.f.). Photograph by Nan-Yao Su and Rudolf H. Scheffrahn, University of Florida.

Figure 10. Soldier caste of Reticulitermes hageni Banks, a U.S. native subterranean termite. Photograph by Lyle J. Buss, University of Florida.

Subterranean termites form a network of interconnected feeding sites beneath or above the soil surface. A single colony of subterranean termites, especially those of Reticulitermes flavipes, may contain 100,000 – 1,000,000 termites and forage up to 150 feet in search of food (Su et al. 1993). When subterranean termites search for food aboveground, they may enter a house through small cracks or joints in the foundation, or by building shelter tubes along the foundation wall. These tubes are highways connecting the underground termite population with aboveground food sources.

Figure 11. Shelter tubes of Reticulitermes, a subterranean termite genus. Photograph by Nan-Yao Su and Rudolf H. Scheffrahn, University of Florida.

Life History (Back to Top)

Flight seasons differ among the three Reticulitermes species in Florida. Reticulitermes hageni alate flights begin in early December and last until early February while Reticulitermes flavipes flights start in early January and end in April. Dispersal flights of Reticulitermes virginicus occur between early February and late May. Swarming by Reticulitermes flavipes and Reticulitermes virginicus occurs during warm, sunny and windless afternoons usually after rain, while Reticulitermes hageni alates swarm at night.

Figure 12. Flight seasons of the three Reticulitermes species in Florida. Graphic by Nan-Yao Su and Rudolf H. Scheffrahn, University of Florida.

Figure 13. Swarm of the eastern subterranean termite, Reticulitermes flavipes (Kollar). Photograph by Lyle J. Buss, University of Florida.

Figure 14. Young alate of Reticulitermes hageni Banks, a U.S. native subterranean termite. Photograph by Lyle J. Buss, University of Florida.

After a brief flight, alates drop to the ground and shed their wings. Females begin to search for potential nesting sites such as moist crevices with wood, and males follow closely behind. The pair forms a royal chamber in a moist site near wood and begin laying eggs, thus starting the life cycle of a subterranean termite colony. Individuals hatched from eggs (called larvae) molt into workers. Some workers may molt into the soldier caste or become alates by molting first into alate nymphs. Some workers or nymphs are capable of becoming supplementary reproductives and take over the role of queen or king if and when a primary reproductive dies or is distanced from part of the colony. It may take five to 10 years for a single pair of alates to form a mature colony that produces alates.

Figure 15. Eggs and larvae of Reticulitermes hageni Banks, a U.S. native subterranean termite. Photograph by Lyle J. Buss, University of Florida.

Damage (Back to Top)

Because termites consume cellulose, the main structural components of plant cells, any wood material in a house is a potential food source, but they may also damage non-wood material in search of food. Termites rarely show themselves in the open, and infestations can be difficult to detect until damage becomes severe. In addition to the presence of alates and shelter tubes, wood material can be probed with a screw driver or ice pick to locate infested wood. The surface of severely damaged wood may appear blistered or peeling, as termites hollow out the wood leaving a paper-thin surface. Reticulitermes tend to cover the wood they feed upon with soil, thus giving wood a more “dirty” appearance than Coptotermes formosanus-infested wood. However, it is not advisable to identify the termite species based solely on damage as there are many exceptions.

Figure 16. Reticulitermes virginicus (Banks), a U.S. native subterranean termite, feeding in broccoli. Photograph by Lyle J. Buss, University of Florida.

Pest Status (Back to Top)

Previously, Reticulitermes flavipes was considered the most common subterranean termite pest of Florida, but our survey indicated that Reticulitermes virginicus is found almost as frequently in structures as Reticulitermes flavipes (Scheffrahn et al. 1988). It is less common to find Reticulitermes hageni infestations. Of the $2.2 billion annually spent for termite control in the United States, subterranean termites account for 80% share, and the majority of this is probably due to Reticulitermes flavipes and Reticulitermes virginicus, and Coptotermes formosanus (Rust and Su 2012)

Management (Back to Top)

Preventive practice: Because subterranean termites forage in soil, it is important to keep structural lumber from direct contact with soil. Keeping the lower foundation walls and siding clear of vegetation or mulch makes it easier to inspect for termite shelter tubes. Subterranean termites need moisture for survival. Leaky plumbing, air conditioning condensate, and any portion of a building and its perimeter that collects excessive amounts of moisture should be corrected to maintain an environment less attractive to subterranean termites.

Soil termiticide barriers: Spraying the soil beneath the foundation with liquid insecticides has been the traditional method for subterranean termite control. The objective is to place a chemical barrier between termites and the structure to be protected. Before the foundation is poured, soil termiticides are applied onto sub-slab soil to form a horizontal barrier. A vertical barrier is applied around the perimeter after the foundation is poured. This pre-construction treatment is mandatory in many of the United States. Post-construction treatment consists of drilling holes through slabs and injecting insecticides under the foundation and by drenching trenches dug along building foundations. Currently available termiticides include permethrin (Dragnet® FT, etc.), cypermethrin (Demon® TC, etc.), bifenthrin (Biflex® FT, etc.), imidacloprid (Premise®, etc.), chlorfenapyr (Phantom®), chlorantraniliprole (Altriset®), and fipronil (Termidor®, etc.). Pyrethroids such as permethrin, cypermethrin, bifenthrin, and fenvalerate repel termites from treatment barriers, while other termiticides prevent termite invasion by lethal contact.

Physical barriers: Mirroring the safety concerns of some soil termiticide barriers, two physical barrier types, uniform-sized particles and stainless steel screening, have been employed as non-chemical controls in recent years. When used as continuous horizontal barriers installed during pre-construction installation, these physical barriers withstood intensive foraging activities of several termite species under field conditions (Su and Scheffrahn 1992, Lenz and Runko 1994). These non-chemical barriers are semi-permanent and can be readily installed during construction. Their physical presence, as opposed to the less visible chemical barriers, also provides ease for verification by regulatory inspectors.

Population control using baits: Because a subterranean termite colony may contain 100,000 – 1,000,000 termites that forage up 150 ft., the soil termiticide application may not impact the overall colony population. In recent years, baits have become available for population control of subterranean termites. One such approach is the monitoring-baiting program that incorporates a bait matrix containing a chitin synthesis inhibitor, hexaflumuron, commercially known as the Sentricon® Termite Colony Elimination System. Stations containing a monitoring device are first installed in the soil around a home. When termites are found in the station, the monitoring device is replaced with a plastic tube containing the hexaflumuron-laced bait. Termites feeding in the stations then carry baits to other members of their colony, leading to the demise of the entire colony population. The recent development for Sentricon® system is a durable bait Recruit® HD that contains noviflumuron. Recruit® HD is weather-resistant, and can be installed in the station without the monitoring phase for up to 12 months. Because the noviflumuron bait is used throughout, it is referred to as the “always active” technology.

Numerous field studies with hexaflumuron baits have demonstrated that baited colonies of subterranean termites were eliminated (Su and Scheffrahn 1998, Grace and Su 2001). Other baits (active ingredients) currently available include Advance® (diflubenzuron), Shatter® (hexaflumuron), Isopthor® (diflubenzuron), Trelona® (novaluron), and Terminate® (hexaflumuron). With the exception of Terminate® that can be purchased by individual homeowners, all baits are applied by trained pest control professionals. The efficacy and claims of these commercial bait products differ from one another, thus it is prudent to read the fine print and ask questions. For a review of some bait products, please refer to:

Selected References (Back to Top)

  • Grace J K, Su N-Y. 2001. Evidence supporting the use of termite baiting systems for long-term structural protection. Sociobiology 37: 301-310.
  • Lenz M, Runko S. 1994. Protection of buildings, other structures and materials in ground contact from attack by subterranean termites (Isoptera) with a physical barrier – a fine mesh of high-grade stainless steel. Sociobiology 24: 1-16.
  • Rust M, Su N-Y. 2012. Managing social insects of urban importance. Annual Review of Entomology 57: 355-75. (doi: 10.1146/annurev-ento-120710-100634)
  • Scheffrahn RH, Mangold JR, Su N-Y. 1988. A survey of structure-infesting termites of peninsular Florida. Florida Entomologist 71: 615-630.
  • Su N-Y, Scheffrahn RH. 1992. Penetration of sized-particle barriers by field populations of subterranean termites (Isoptera: Rhinotermitidae). Journal of Economic Entomology 85: 2275-2278.
  • Su N-Y, Ban PM, Scheffrahn, RH. 1993. Foraging populations and territories of the eastern subterranean termite (Isoptera: Rhinotermitidae) in southeastern Florida. Environmental Entomology 22: 1113-1117.

Authors: Nan-Yao Su and Rudolf H. Scheffrahn, University of Florida
Photographs and Graphics: Nan-Yao Su, Rudolf H. Scheffrahn and Lyle J. Buss, University of Florida, and T.Myles, University of Toronto
Web Design: Don Wasik, Jane Medley
Publication Number: EENY-212
Publication Date: May 2001. Latest revision: April 2016.

An Equal Opportunity Institution
Featured Creatures Editor and Coordinator: Jennifer L. Gillett-Kaufman, University of Florida

entnemdept.ufl.edu

Eastern Subterranean Termites

The workers are the cream-colored caste that consumes cellulose and feeds the colony.

Soldiers

The soldiers are about 1/4 inch-long protectors of the colony. Soldiers are equipped with large jaws that they use to combat colony intruders.

Alates

The alates are winged termites or “swarmers” that leave the colony and establish new colonies. The male and female alates leave the colony in the spring, mate after leaving the colony, construct a new colony, and then become the primary king and queen of this new colony. Fortunately, extremely few alates actually succeed in establishing new colonies.

The reproductive caste is made up of the primary queens and males (kings) that stay within the colony for life. The secondary reproductives are important during times of colony stress or conditions unfavorable to the success of the colony.

Alate queens and kings are black or dark brown, about 3/8 to a half inch long, and have two pairs of wings that are lost after a termite swarm. Generally, the appearance of swarmers or their shed wings is the first sign of a problem with eastern subterranean termites.

How Did I Get Eastern Subterranean Termites?

These termites nest underground and cause expensive problems for homeowners. The pests infest wood touching the soil or piled close to siding. Eastern subterranean termites also build mud tubes, which they use to access untreated walls, doors, or trim to venture deeper into homes.

How Serious Are Eastern Subterranean Termites?

All termite species cause issues, but the Eastern subterranean termite is one of the most destructive. The pests’ feeding weakens buildings, causing issues with a house’s framing that can lead to collapse or costly repairs. Because these termites work inside wood, it may be years before residents suspect an infestation.

Signs of Infestation

Usually a subterranean termite infestation is first discovered when winged termite swarmers are seen in the early or late spring, depending upon the climatic conditions. A good inspection will help you locate and become familiar with the following common signs indicating a termite problem:

  • Finding shed swarmer wings or winged swarmers around windows, patio doors, or other sources of light.
  • The presence of mud tubes.
  • Wood material in the home that appears to be soft, easily penetrated, rippled, peeling, or bubbled.

How Do I Get Rid of Eastern Subterranean Termites?

It’s always advised to call your local pest management professional (PMP) as soon as an infestation is suspected. Common control methods invovle removing termite food sources, fixing or repairing entry points, and reducing moisture around the home are good preventative measures to keep Eastern subterranean termites away. Some other recommended control methods your PMP will suggest include:

  • Secure wood piles: Keep wood piles off the ground and don’t allow any ground contact. Inspect firewood to ensure that termites have not constructed exploratory mud tubes and found your firewood.
  • Avoiding wood-to-ground contact: If possible, replace any construction wood that contacts the soil (deck and fence posts, etc.) with materials that are non-cellulose or pressure treated. Also, never allow any wooden siding to contact the soil surface. Maintain at least six inches or more of space between siding and the ground. Do not put mulch on the ground next to the foundation. If you want to use mulch around the home, be sure to provide a “no mulch” zone that is at least one to two feet wide since mulch allows the soil to hold more moisture.
  • Replacing damaged wood: Replace severely damaged wood with sound construction materials. Use pressure-treated wood at surfaces where wood must be in contact with soil.
  • Cleaning up fallen vegetation: If a tree blows down, grind down the stump and roots; never simply let a stump remain in place. If a shrub dies, dig it out and remove all the woody parts and roots of the dead shrub.
  • Trimming and thinning plants: Do not let landscaping plants touch the siding or get too thick around the foundation. Not only does this make a friendly environment for termites, it also makes it more difficult to inspect for signs of a termite problem.
  • Guarding against moisture: Ensure there are no plumbing leaks, water from air conditioner condensation, leaking gutters, and that downspouts direct water away from the house, not close to the foundation. Provide ventilation and drainage in the crawl spaces under the house.
  • Repairing possible entryways:If you notice a crack in the foundation, repair with concrete or heavy duty, durable caulking materials.

Your local Orkin technician is trained to help manage Eastern subterranean termites and similar pests. Since every building or home is different, your Orkin technician will design a unique program for your situation.

Orkin can provide the right solution to keep Eastern subterranean termites in their place…out of your home, or business.

Behavior, Diet, Habits

Above ground foraging also takes place, and the typical termite mud tube must be constructed when workers forage above ground. The mud tube’s purpose is to protect the workers as they explore for new sources of food or travel back and forth with the cellulose they bring back to nourish the colony members.

Where Do They Live?

Eastern subterranean termites infest damp timber and prefer damp soil because they need moisture to survive. Humid areas of the home, around the home, and water-damaged lumber are perfect habitats.

Geographic Range

There are numerous termite species native to the United States. Eastern subterranean termites are a subterranean species found primarily in the South and on the East Coast. These insects can have a large economic impact on homeowners due to their dense distribution.

Colonies

One colony of Eastern subterranean termites may contain anywhere from 60,000 to nearly one million individuals. Unlike some other insect species, reproductive male termites mate throughout their lives, and males do not die immediately after mating. Eastern subterranean reproductive termites do shed their wings after mating swarms, at which time they go on to found new colonies.

Termite Control

Learn the signs to look for to determine if you might have a termite infestation.

Termites cost Americans more than $5 billion in damage each year and most insurance plans don’t cover the damage.

We’ll determine whether you actually have termites, then discuss a treatment plan including financing that works for you.

Learn what to expect from your Orkin Man and the AIM process.

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