top of page

Grupo programa-asi

Público·237 miembros
Montrell Reid
Montrell Reid


Similar to ants and some bees and wasps from the separate order Hymenoptera, most termites have an analogous 'worker' and 'soldier' caste system consisting of mostly sterile individuals which are morphologically and behaviorally distinct. Unlike ants, most colonies begin from reproductively mature individuals called a "king" and "queen" which form a lifelong monogamous pair. Also unlike ants, which undergo a complete metamorphosis, termites undergo an incomplete metamorphosis that proceeds through egg, nymph, and adult stages. Termite colonies are commonly described as superorganisms due to the collective behaviors of the individuals which form a self-governing entity: the colony itself.[5] Their colonies range in size from a few hundred individuals to enormous societies with several million individuals. Most species are rarely seen, having a cryptic life-history where they remain hidden within the galleries and tunnels of their nests for most of their lives.


Download Zip:

The infraorder name Isoptera is derived from the Greek words iso (equal) and ptera (winged), which refers to the nearly equal size of the fore and hind wings.[13] "Termite" derives from the Latin and Late Latin word termes ("woodworm, white ant"), altered by the influence of Latin terere ("to rub, wear, erode") from the earlier word tarmes. A termite nest is also known as a termitary or termitarium (plural termitaria or termitariums).[14] In earlier English, termites were known as "wood ants" or "white ants".[15] The modern term was first used in 1781.[16]

Termites were formerly placed in the order Isoptera. As early as 1934 suggestions were made that they were closely related to wood-eating cockroaches (genus Cryptocercus, the woodroach) based on the similarity of their symbiotic gut flagellates.[17] In the 1960s additional evidence supporting that hypothesis emerged when F. A. McKittrick noted similar morphological characteristics between some termites and Cryptocercus nymphs.[18] In 2008 DNA analysis from 16S rRNA sequences[19] supported the position of termites being nested within the evolutionary tree containing the order Blattodea, which included the cockroaches.[20][21] The cockroach genus Cryptocercus shares the strongest phylogenetical similarity with termites and is considered to be a sister-group to termites.[22][23] Termites and Cryptocercus share similar morphological and social features: for example, most cockroaches do not exhibit social characteristics, but Cryptocercus takes care of its young and exhibits other social behaviour such as trophallaxis and allogrooming.[24] Termites are thought to be the descendants of the genus Cryptocercus.[20][25] Some researchers have suggested a more conservative measure of retaining the termites as the Termitoidae, an epifamily within the cockroach order, which preserves the classification of termites at family level and below.[26] Termites have long been accepted to be closely related to cockroaches and mantids, and they are classified in the same superorder (Dictyoptera).[27][28]

The oldest unambiguous termite fossils date to the early Cretaceous, but given the diversity of Cretaceous termites and early fossil records showing mutualism between microorganisms and these insects, they possibly originated earlier in the Jurassic or Triassic.[29][30][31] Possible evidence of a Jurassic origin is the assumption that the extinct Fruitafossor consumed termites, judging from its morphological similarity to modern termite-eating mammals.[32] The oldest termite nest discovered is believed to be from the Upper Cretaceous in West Texas, where the oldest known faecal pellets were also discovered.[33] Claims that termites emerged earlier have faced controversy. For example, F. M. Weesner indicated that the Mastotermitidae termites may go back to the Late Permian, 251 million years ago,[34] and fossil wings that have a close resemblance to the wings of Mastotermes of the Mastotermitidae, the most primitive living termite, have been discovered in the Permian layers in Kansas.[35] It is even possible that the first termites emerged during the Carboniferous.[36] The folded wings of the fossil wood roach Pycnoblattina, arranged in a convex pattern between segments 1a and 2a, resemble those seen in Mastotermes, the only living insect with the same pattern.[35] Krishna et al., though, consider that all of the Paleozoic and Triassic insects tentatively classified as termites are in fact unrelated to termites and should be excluded from the Isoptera.[37] Other studies suggest that the origin of termites is more recent, having diverged from Cryptocercus sometime during the Early Cretaceous.[4]

The primitive giant northern termite (Mastotermes darwiniensis) exhibits numerous cockroach-like characteristics that are not shared with other termites, such as laying its eggs in rafts and having anal lobes on the wings.[38] It has been proposed that the Isoptera and Cryptocercidae be grouped in the clade "Xylophagodea".[39] Termites are sometimes called "white ants", but the only resemblance to the ants is due to their sociality which is due to convergent evolution[40][41] with termites being the first social insects to evolve a caste system more than 100 million years ago.[42] Termite genomes are generally relatively large compared to those of other insects; the first fully sequenced termite genome, of Zootermopsis nevadensis, which was published in the journal Nature Communications, consists of roughly 500Mb,[43] while two subsequently published genomes, Macrotermes natalensis and Cryptotermes secundus, are considerably larger at around 1.3Gb.[44][41]

The Neoisoptera, literally meaning "newer termites" (in an evolutionary sense), are a recently coined clade that include families commonly referred-to as "higher termites", although some authorities only apply this term to the largest family Termitidae. The latter characteristically do not have pseudergates except in some taxa (such as in Serritermitidae: see below). All Neoisopterans have a fontanelle, which appears as a circular or series of pores in a depressed region within the middle of the head. The fontanelle connects to the frontal gland which evolved to excrete toxic chemicals for defense, and so is typically most developed in the soldier caste.[49] Cellulose digestion in "higher termites" has co-evolved with eukaryotic gut microbiota[50] and many genera have symbiotic relationships with fungi such as Termitomyces; in contrast, "lower termites" typically have flagellates and prokaryotes in their hindguts. Five families are now included here:

Termites are found on all continents except Antarctica. The diversity of termite species is low in North America and Europe (10 species known in Europe and 50 in North America), but is high in South America, where over 400 species are known.[51] Of the 2,972 termite species currently classified, 1,000 are found in Africa, where mounds are extremely abundant in certain regions. Approximately 1.1 million active termite mounds can be found in the northern Kruger National Park alone.[52] In Asia, there are 435 species of termites, which are mainly distributed in China. Within China, termite species are restricted to mild tropical and subtropical habitats south of the Yangtze River.[51] In Australia, all ecological groups of termites (dampwood, drywood, subterranean) are endemic to the country, with over 360 classified species.[51] Because termites are highly social and abundant, they represent a disproportionate amount of the world's insect biomass. Termites and ants comprise about 1% of insect species, but represent more than 50% of insect biomass.[53]

Due to their soft cuticles, termites do not inhabit cool or cold habitats.[54] There are three ecological groups of termites: dampwood, drywood and subterranean. Dampwood termites are found only in coniferous forests, and drywood termites are found in hardwood forests; subterranean termites live in widely diverse areas.[51] One species in the drywood group is the West Indian drywood termite (Cryptotermes brevis), which is an invasive species in Australia.[55]

Most worker and soldier termites are completely blind as they do not have a pair of eyes. However, some species, such as Hodotermes mossambicus, have compound eyes which they use for orientation and to distinguish sunlight from moonlight.[58] The alates (winged males and females) have eyes along with lateral ocelli. Lateral ocelli, however, are not found in all termites, absent in the families Hodotermitidae, Termopsidae, and Archotermopsidae.[59][60] Like other insects, termites have a small tongue-shaped labrum and a clypeus; the clypeus is divided into a postclypeus and anteclypeus. Termite antennae have a number of functions such as the sensing of touch, taste, odours (including pheromones), heat and vibration. The three basic segments of a termite antenna include a scape, a pedicel (typically shorter than the scape), and the flagellum (all segments beyond the scape and pedicel).[60] The mouth parts contain a maxillae, a labium, and a set of mandibles. The maxillae and labium have palps that help termites sense food and handling.[60] The cuticle of all castes except the imago is typically soft, unpigmented and unsclerotized, especially of the abdomen which appears translucent. Pigmentation and sclerotization of the cuticle varies, with species that forage out in the open tending to be more sclerotized.

Termites have a ten-segmented abdomen with two plates, the tergites and the sternites.[62] The tenth abdominal segment has a pair of short cerci.[63] There are ten tergites, of which nine are wide and one is elongated.[64] The reproductive organs are similar to those in cockroaches but are more simplified. For example, the intromittent organ is not present in male alates, and the sperm is either immotile or aflagellate. However, Mastotermitidae termites have multiflagellate sperm with limited motility.[65] The genitals in females are also simplified. Unlike in other termites, Mastotermitidae females have an ovipositor, a feature strikingly similar to that in female cockroaches.[66] 041b061a72

Acerca de

¡Te damos la bienvenida al grupo! Puedes conectarte con otro...


bottom of page