Cephalotes hirsutus

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Cephalotes hirsutus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. hirsutus
Binomial name
Cephalotes hirsutus
De Andrade, 1999

De Andrade 1999 Cephalotes OCR - Copy-592 Cephalotes-hirsutus.jpg

Nothing is known about the biology of Cephalotes hirsutus.

Identification

A member of the wheeleri clade the worker of which differs from all the other species of the clade for possessing the following autapomorphy: body with dense, thick, long, appressed hairs with golden reflexes. C. hirsutus and Cephalotes insularis both share the postpetiolar spines subequal in length to the postpetiole and the border of the first gastral tergite yellowish and transparent. (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Mexico (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

The biology of many Cephalotes species is not known. Ants in this genus are common in the New World tropics and subtropics and are especially abundant and diverse in the canopies of Neotropical forests. The majority of species are arboreal. Species that live in other strata inhabit smaller trees, bushes or grass stems. These noon-arboreal species, due to their accessibility, are among the better studied members of the genus. There are also species that can be found in downed wood but it is likely the wood housed the colony before it fell to the ground. Soil nests are not known for any species nor do most species appear to extensively excavate plant tissue. They nest instead in preformed cavities. Overall, ants in the genus utilize a wide range of plants. Some species are predictable in their plant use but none appear to have evolved specialized mutualisms with particular plant species.

Worker castes typically include two forms, a worker and soldier, but there are a few species that are monomorphic. The larger soldier caste typically has an enlarged head disk. In some species the head of the soldier is very different from the worker while in others these differences are less pronounced. Queens and soldiers tend to share similar head morphology. Soldiers use their heads to plug the nest entrance. This can be very effective in excluding potential intruders. Other morphological differences between the worker castes are present but these differences have not been studied as well as head moprhology.

The behavioral repertoire of Cephalotes varians has been examined in great detail (ethograms from Wilson 1976, Cole 1980 and Cole 1983). Soldiers do little else besides defend the nest. This specialized soldier behavior is presumed to be the norm for most species. An especially interesting behavior occurs when workers are dislodged from trees: they "fly" towards the tree, often grabbing the trunk well above the ground (video).

Mature nest size varies, by species, from less than a hundred to many thousands of workers. Available evidence suggests most species are monogynous. Queens may mate with multiple males.

The proventriculus of the Cephalotes is peculiar relative to other ants. The morphology of the structure suggests it serves as a powerful pump and filter. This does not appear to lead these ants to have a highly specialized diet as most species appear to be general scavengers. Foragers have been observed feeding on carrion, bird feces, extrafloral nectaries and even tending membracids. Pollen feeding has been observed in some species, and this is somewhat specialized for ants, but it is not evident that any species restricts its diet to this resource in any significant way. Evidence for pollen feeding in Cephalotes has accumulated, in part, via finding digested pollen grains seen in infrabucal pellets. It has been suggested that the morphology of the proventriculus is a specialization for processing pollen.

More research examining all aspects of the biology of Cephalotes is needed. Our present understanding of these ants is largely based on species that live in locations other than the forest canopy, which is where Cephalotes are most common and diverse.

Castes

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • hirsutus. Cephalotes hirsutus De Andrade, in De Andrade & Baroni Urbani, 1999: 589, fig. 274 (w.) MEXICO.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Vertexal angles round, with superficially crenulate border. Vertexal border straight and not marginate medially. Hypostoma not connected by a bridge. Cheeks feebly marginate dorsally. Frontal carinae with a superficial incision over the eyes. Antennal scrobes reaching the antero-ventral border of the eyes. Clypeal border concave. Mandibles with superficial lateral carinae.

Mesosoma convex in profile. Pronotum in dorsal view with the anterior border not marginate and convex. Scapular angles absent or not visible in dorsal view. Pronotum with three pairs of lateral teeth, the first, humeral, short and pointed, followed by another pair subequal in length or smaller, variably pointed and by a third, shorter, broad, obtuse or round pair close to the mesonotum. Sides of the mesonotum converging posteriorly and unarmed. Promesonotal and propodeal sutures superficially marked only on the sides in dorsal view. Propodeum continuously sloping posteriorly, without distinctly differentiated basal and declivous faces, with a pair of pointed, thin spines directed laterally and slightly upwards at midlength.

Petiole anteriorly truncate; its anterior border marked by a transversal carina variably impressed. Petiolar spines on the middle of the petiolar sides, ca. half as long as the petiole, thin, and pointing backwards. Postpetiole broader than petiole, with thin, pointed spines slightly shorter than the postpetiole, arising anterolaterally and curved backwards at the base.

Gaster oval, without crest, lobe or lateral margin.

Hind and mid femora without angle or denticles; mid and hind basitarsi long and without flat and broad base.

Sculpture. Head dorsum reticulate, with dense, irregular foveae divided by thick, reticulation, sometimes forming longitudinal, irregular rugosities. Frontal carinae superficially reticulate. Ventral face of the head reticulate and irregularly striato-rugose. Mesosoma and pedicel reticulate, with foveae separated by irregular, longitudinal striae and rugae. Sides of the mesosoma with the same sculpture as the dorsum, but with rare foveae. Upper metapleurae with or without striae on the. First gastral tergite and sides of the first gastral sternite with longitudinal, thin rugosities, more superficial and irregular posteriorly in some specimens Anterolateral borders of the first gastral tergite and central part of the first sternite superficially reticulate and shining. Legs reticulate, with slightly shining femora. Outer face of the tibiae with oval and superficial foveae.

Pilosity. Body with four types of hairs: (1) sparse, long, erect and truncate on the head, on the mesosoma, on the pedicel, on the gastral tergites and on the legs; (2) similar to type (1) but thinner and shorter on the gastral sternites; (3) canaliculate, long, appressed, thick and dense, on the head, on the dorsum of the mesosoma, on the pedicel, on the first gastral tergite and on the extensor face of the legs; (4) similar to the type (3) but thinner and shorter on the middle of the first gastral tergite, on the first gastral sternite and on the anterior and posterior faces of the legs.

Colour. Black. Frontal carinae yellowish orange and semi-transparent. Fore legs with tibiae and tarsi ferruginous. Femora and tarsi of the mid and hind legs black. Tibiae and tarsomeres of the mid and hind legs dark ferruginous with the tarsomeres lighter. Border of the first gastral tergite yellowish and transparent. Some specimens with the antero lateral border of the first gastric tergite with a pair of oval, orange-reddish spots. Golden reflexes due to the pilosity on most of the body including the appendages.

Measurements (in mm) and indices: TL 4.58-4.92; HL 1.08-1.14; HW 1.18-1.26; EL 0.32-0.34; PW 0.96-1.08; PeW 0.53-0.57; PpW 0.68-0.68; HBaL 0.52; HBaW 0.11; CI 109.0-110.5 PI 116.7-122.9; PPeI 181.1-1 89.5; PPpI 143.3-158.8; HBaI 21.1.

Type Material

Holotype worker from 4.6 mi E of Chupaderos, Sinaloa, Mexico, 22.8.1964, E. I. Schlinger; paratypes 3 workers, same data as the holotype, all in Los Angeles County Museum of Natural History.

Etymology

Hirsutus in Latin means hairy, referred to the abundant pilosity of this species.

References

  • de Andrade, M. L.; Baroni Urbani, C. 1999. Diversity and adaptation in the ant genus Cephalotes, past and present. Stuttgarter Beitrage zur Naturkunde Series B (Geolgie and Palaontologie). 271:1-889. (page 589, fig. 274 worker described)