Termite Food Consumption in North America

23 Oct 2011   | Uncategorized

— This article by Jerry Cates,  first published on 23 October 2001, was last revised on 6 December 2013. © Bugsinthenews Vol. 12:01(03).

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Termite Food Consumption

How much do subterranean termites eat in a day?

Summary: Subterranean termite daily food consumption rates vary, among six species of termites common to the United States, from 0.015mg to 0.2mg, averaging about 0.08mg per termite per day. Formosan termite workers tend to eat slightly less than average, but make up for that with huge colonies. Termite colonies vary in size from only a small number of workers up to, perhaps, an average size of 200,000 workers in our native species, and 500,000 workers for Formosan termite colonies. Thus, an average native subterranean termite colony may eat an average of 16 grams (0.56 ounces) a day, 465 grams (1.07 lbs) a month, or 5,840 grams (12.9 pounds) in a year, while a Formosan termite colony may consume somewhat more than twice that amount. Using these numbers to figure how much cellulose in a termite interceptor, or in a wooden structure, a termite colony might eat over a period of time cannot be recommended, however, because termite colonies do not eat in one or only a few places at a time. How many feeding places the colony uses depends on the availability of different food sources, and termite interceptors–as well as structures that they are feeding in–constitute only a portion of their food supply at any given time. Scroll down to read full text of of article.

Subterranean Termites in the U.S.

The rate of food consumption varies by termite species, the kind of wood consumed, and both the age and the vigor of the termite colony. The vigor of the typical termite colony tends to decline as the colony ages. Throughout most of the United States, six species are responsible for most of the subterranean termite damage to homes and businesses, and a seventh species is poised to enter the fray in the not-too-distant future.

In the east, south, and southwest, the most common species of subterranean termite found infesting structures is Reticulitermes flavipes. Less frequently, R. hageni and R. virginicus infest structures in the same areas. In the west, from southern British Columbia to central California, the structural termite species encountered most often is R. hesperus. In the desert southwest, Heterotermes aureus is the primary subterranean termite found in structures. Food consumption, per termite, for each of these species, varies a little, with workers in the species R. flavipes and R. hesperus consuming slightly more, in general, than the others.

In some areas, notably along the coast of the Gulf of Mexico but also inland, where they have been transported in railroad ties and other materials, a sixth (imported) species, Coptotermes formosanus, better known as the Formosan subterranean termite, causes considerable damage. Formosan termite colonies tend to be larger than those of our native species, and up to 25% of their infestations in Florida are aerial, i.e., with no connection to the soil. Comparable percentages of aerial infestations should be expected in other locales having similar humidity and rainfall levels. Food consumption for this species, per termite worker, is somewhat lower than that of R. flavipes or R. hesperus, but that statistical deficit is more than compensated for by the huge colonies the species produces.

A seventh (also imported) species, Coptotermes gestroi (also known under the junior synonym Coptotermes havilandi), the Asian subterranean termite, became established in Miami, Florida, sometime after its discovery there in 1997. This termite rivals the destructive potential of C. formosanus, and we should expect it to expand its territory beyond Miami in the coming years. It is difficult to distinguish between C. formosanus and C. gestroi in the field, but the latter has been recovered, in Tennessee, from shipping crates imported from East Asia, and it is only a matter of time before the species becomes more widespread in the continental United States.

Average Rates of Food Consumption

I am indebted to Dr. Barbara Thorne for her compilation of food consumption data in the 1998 NPCA report she authored, “Biology of Subterranean Termites of the Genus Reticulitermes,” (which, by the way, also included figures for Coptotermes formosanus). That compilation comprised the base data used to calculate the following figures. Any errors the reader may note in these figures are most likely mine, rather than hers.

For R. flavipes, R. hesperus and C. formosanus, the rate of food consumption varies from 0.004mg to 0.196mg, averaging–at least for R. flavipes and R. hesperus–about 0.08mg per termite per day. As mentioned earlier, C. formosanus workers eat somewhat less (ranging from 0.010mg to 0.185mg per termite per day). For this discussion, we assume that all three species are alike with regard to per-termite daily food consumption.

Termite colonies vary in size from only a small number of workers up to, perhaps, an average size of 200,000 workers in our native species, and 500,000 workers for Formosan termite colonies (these are my rough extrapolations from a covey of data reported from a variety of sources). Using these gross figures, which I hasten to add are only crude estimates, an average native subterranean termite colony may be expected to eat an average of 16 grams (0.56 ounces) a day, 465 grams (1.07 lbs) a month, or 5,840 grams (12.9 pounds) in a year, while a Formosan termite colony may eat slightly less than twice that amount.

Here, caution is in order. Statistics are crude estimates only. Attempts to extrapolate beyond these numbers to estimate how much cellulose in a termite interceptor, or in a wooden structure, a termite colony might eat over a period of time is tricky, for several very important reasons. The vigor of different termite colonies varies by a wide margin, ranging from a low of only one-fifth the average, to a high that can be two and a half times the average. Even more important is the fact that termite colonies do not eat in one place, or in only a few places, at a time. How many feeding places the colony uses depends on the availability of different food sources, and termite interceptors as well as the structures they happen to be feeding in constitute, in general, only a portion of their food supply at any given time.

When I started designing termite interceptors, I kept the above food consumption numbers in mind, but factored in one important caveat:

Termites don’t feed on singular food sources in nature. Instead, they exploit a multitude of food sources at once. Individual termite workers travel a circuit, hiking from one food source to another, spending only enough time at each to ingest a small quantity of food. That food is not immediately available to produce energy, but must be broken down, in the termite’s digestive system (by the termite’s gut fauna), while they hike to the next food source.

It takes much more time for a termite to digest its food than to ingest it, so termites spend more time hiking than feeding. Even laboratory specimens of live termite colonies, feeding on a single food source in a soil substrate, create a labyrinth of tubes throughout the soil, and hike the tubes incessantly. This on-the-go behavior, in natural surroundings, suffices to keep the colony at the peak of health. Laboratory specimens, by comparison, are notoriously weaker and less vigorous, partly because their hiking trails, being confined to small laboratory containers, are shorter and more prone to contamination.

A practical termite interceptor will allow its store of termite food to be replenished with fresh food material after it is serviced. As long as regular inspections are conducted, none of the devices in a given installation should be allowed to run out of food before termite interdiction and inoculation work together to eliminate the termite colony.

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Taxonomy:

  • Kingdom Animalia (ahn-uh-MAYHL-yuh)  — first described in 1758 by the Swedish taxonomist Carolus Linnaeus [23 May 1707 – 10 January 1778], using the Latin word animal = “a living being,” from the Latin word anima = “vital breath”, to refer to multicellular, eukaryotic organisms whose body plans become fixed during development, some of which undergo additional processes of metamorphosis later in their lives; most of which are motile, and thus exhibit spontaneous and independent movements; and all of whom are heterotrophs that feed by ingesting other organisms or their products;
  • Phylum Arthropoda (ahr-THROPP-uh-duh) — first described in 1829 by the French zoologist Pierre André Latreille [November 20, 1762 – February 6, 1833], using the two Greek roots αρθρον (AR-thrawn) = jointed + ποδ (pawd) = foot, in an obvious reference to animals with jointed feet, but in the more narrow context of the invertebrates, which have segmented bodies as well as jointed appendages;
  • Class Insecta (Linnaeus, 1758) — named using the Latin word insectum, a calque of the Greek word ἔντομον ( EN-toh-mawn) = “(that which is) cut into sections”; comprised of arthropods with chitinous external (exo-) skeletons, a three part body composed of a distinct head, thorax, and abdomen, the midmost part having three pairs of jointed legs, and the foremost part having a pair of compound eyes and antennae;
  • Subclass Pterygota (Lang, 1888) — ;
  • Infraclass Neoptera (Wulp 1890) — first described in 1890 by the Dutch zoologist F. M. Van der Wulp, using the Greek words νεος (NEE-ose) = “young, youthful, new, fresh” + πτερον (TARE-on) = “a feather, wing, fin” to distinguish the winged insects in this infraclass — whose wing morphology is more recently evolved and enables them to be folded over the abdomen in such a way that, when at rest, the wings are generally inconspicuous — from the more primitive winged insects in the Paleoptera (an infraclass that appears to be paraphyletic and is now undergoing significant taxonomical scrutiny and revision, not without some attendant controversy) whose wings cannot be so folded and thus remain conspicuous and somewhat encumbering of the resting insect; this infraclass includes most of the winged insects of today, excluding the mayflies, dragonflies, and damselflies;
  • Superorder Dictyoptera — from the Greek words δικτυον (DICK-ty-ohn) = “a net” + πτερον (TARE-on) = “a feather, wing, fin” to refer to insects with membranous, net-like wings; includes three groups of polyneopterous insects, namely the termites, the cockroaches, and the mantids;
  • Order Blattodea — from the Latin term, blatta = “cockroach”; the order, today, includes all cockroaches and all termites, the latter having been transferred from the order Isoptera (of Greek origin, meaning “equal wings”) when modern molecular genetics confirmed the long-held suspicion that termites and cockroaches were intimately related in taxonomical terms;
  • Superfamily Blattoidea [syn. Termitoidea (Latreille, 1802)];
  • Epifamily Termitoidae — from the Latin word, termes = “wood-worm”;
    • Family Mastotermitidae (Froggatt 1897) — the most primitive of all extant termites, comprised of a single genus and species, Mastotermes darwiniensis (Froggatt 1897), and found only in Northern Australia;
    • Family Kalotermitidae (Banks 1919) — drywood termites, consisting of 22 genera and 419 species of termites that infest dry timbers and that do not require a connection to the soil to survive (Mallis 2011);
    • Family Termopsidae (Grassè 1949) — dampwood termites, consisting of 5 genera and 22 extant species of termites that infest moist wood, usually in forest regions where they perform beneficial processes that reduce fallen timbers to soil, but that sometimes infest structures due to excessive moisture and wood-to-ground contact (Mallis 2011);
    • Family Hodotermitidae — rottenwood termites, comprised of 3 genera and 19 species that, like the Termopsidae, infest damp, rotten wood;
    • Family Rhinotermitidae (Froggatt 1897) — subterranean termites, comprised of 345 species that generally require a connection to soil to thrive, but including several genera, e.g., Coptotermes, that do not absolutely require a soil connection if moisture conditions in the cellulose they are feeding upon are sufficient;
    • Family Serritermitidae (Hagen and Bates) — a primitive, monotypic termite family that includes a single, small, rare, bizarre species, Serritermes serrifer (Hagen and Bates), known only from three localities in Brazil.
    • Family Termitidae (Latrielle 1802) — higher (more recently evolved) termites, comprised of seven subfamilies;
  • Family Rhinotermitidae (Froggatt, 1897) — first described by the Australian economic entomologist Walter Wilson Froggatt (13 June 1858 – 18 March 1937), who combined the Greek word ρινος “RYE-nos” = skin or hide + the Latin word termes = a wood-worm , to refer to a wood-destructive organism whose colonies reside within a tough outer skin-like structure of their own making; the family includes 16 distinct genera, and approximately 345 known species;
    • Genus Coptotermes — from the Greek word κοπτω (KOPP-toh) = “to strike, smite, cut off” + the Latin word termes = “wood-worm”, a possible reference to the ability of massive numbers of the termites in this genus to cause devastating damage to sound wood by breaking off small pieces of the wood with their mandibles;
      • Species Coptotermes formosanus (Shiraki, 1909) — first described in 1909 by the Japanese entomologist Tokuichi Shiraki, who happened upon the species in the Formosan city of Taipei; the species is native to southern mainland China, and had been introduced to Formosa centuries earlier, possibly by hitching a ride with traders;
    • Genus Reticulitermes — Holmgren, 1913. First described by the Swedish Entomologist Nils Holmgren (1877-1954) in 1913. He combined two Latin words, reticulum = a small net (evidently a reference to the net-like appearance of the wings exhibited by alate reproductives) + termes (a Latin word which refers to the end of life, or goal, which according to Victor Wolfgang von Hagen [Maeterlinck, 1939] was applied first by Linnaeus, who confused the termite with the deathwatch beetle, then afterward by others who propagated that error) = a wood-worm, to form the generic name Reticulitermes.
      • Species: Six phenotypes have been identified from some 21 phylogenetic species and subspecies on three continents, five of which represent, in North America, tbe major cause of termite damage (Austin, et al., 2002). One of these, Reticulitermes flavipes, known as the eastern subterranean termite, is the most common of the five most destructive termite species found in North America (ibid).

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Anatomy: in process

Behavior: in process

Common Names: in process

Distinguishing Characteristics: in process

Distribution: in process

Physiology: in process

Mythology: in process

Similar Families: in process

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References:

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