Anochetus orchidicola

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Anochetus orchidicola
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Anochetus
Species: A. orchidicola
Binomial name
Anochetus orchidicola
Brown, 1978

Anochetus orchidicola casent0260503 p 1 high.jpg

Anochetus orchidicola casent0260503 d 1 high.jpg

Specimen Labels

A. orchidicola lives in montane wet forest, nesting beneath epiphytes in the low arboreal zone. Workers have also been collected in Winkler samples from the forest floor (Longino)

Identification

Brown (1978) - This interesting species apparently is closest to Anochetus altisquamis, but it is smaller and differs in sculpture, in the sharper apical margin of the petiolar node, and in having smaller eyes. The small size of the eyes invites comparison with Anochetus minans, but minans is a less robust species with even smaller eyes; thicker, apically bicuspid petiolar node; trunk less convex, much as in Anochetus mayri; and conical subapical mandibular teeth. Also, the mandibles in A. minans are slightly more than half the head length (HL > 50), and the antennal scapes are longer, very slightly overreaching posterior borders of occipital lobes as seen in perfect full-face view. A. minans is more extensively and opaquely sculptured on vertex and sides of pronotum and anterior mesopleura, and especially sides of metanotum and propodeum, which are finely and densely reticulo-punctulate, The propodeal teeth of minans, while low and blunt, are much more dentiform than are the rounded angles of orchidicola.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Costa Rica, Honduras, Mexico (type locality), Nicaragua, Panama.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Not much is known about the the biology of Anochetus orchidicola but we can presume that its biology is similar to other Anochetus species. The following account of Anochetus biology is modified from Brown (1968):

Habitat. The places where Anochetus live are varied. Where they penetrate into the temperate zone, most species excavate nests in the earth. Occasionally the nest is dug under a covering rock. In the tropics, many nests are also dug in the soil, but in moist forested areas, a common site is the soil beneath a rotting log or other large mass of rotting wood, with extensions of the nest into the log itself. Another frequent nesting site in tropical forest is in the humus and leaf litter at the base of large trees, particularly between buttress roots. Anochetus species of medium or small size often nest in small pieces of rotting wood or bark, or even small rotting twigs or seeds and nuts lying in or on the forest litter. Some species tend to choose more arboreal nest sites.

Foraging for living animal prey takes place on the soil surface, within the soil-humus-log mold matrix, or on the trunks, branches and foliage of trees and plants wherever these are available. Fragmentary evidence indicates that most epigaeically foraging tropical Anochetus tend to do their foraging at dusk, at night, or during dawn hours. I found Anochetus africanus walking on tree trunks only at night in the Ivory Coast. Some species, particularly those with red heads or other aposematic coloration, apparently forage in the open more during the day. No systematic comparative study has yet been made of foraging hours for different species.

The food of Anochetus consists principally of living arthropods caught and killed or incapacitated by the ants. The smaller and more delicate species Anochetus inermis has been observed by me in a laboratory nest. The colony came from a piece of rotten wood from the floor of a wet ravine near Bucay in western Ecuador. The colony was fed with small tenebrionid beetle larvae (Tribolium castaneum), comparable in size to the A. inermis workers, and the latter attacked the prey with their mandibles in the familiar snapping manner, but very cautiously and nervously, with stealthy approach, extremely rapid strike, and instant recoil-retreat. After several attacks of this kind, with intervening periods of waiting, during which the beetle larvae fled, rested, or writhed about in distress, an ant would finally attack with its mandibles and hold them closed on the prey for long enough to deliver a quick sting in the intersegmental membrane. After this, the prey appeared to be paralyzed, or at least subdued, and sooner or later was carried off by the ant to the nest, and eventually placed on an ant larva. Frequent delays and excursions before the prey are finally immobilized and brought to the ant larvae in the nest may well have the function of allowing time for protective allomones of the prey to dissipate. Many tenebrionid adults, including Tribofium, possess potent quinonoid defensive allomones, but the larva is not known to possess quinones in this genus.

Nuptial flight. Although males of different species of Anochetus are commonly taken at light, other species are not. Stewart and Jarmila Peck gave me Malaise trap samples taken in western Ecuador that contained males of several species, but Malaise traps capture both day- and night-flying insects.

Defense. When a nest of any of the larger Anochetus species is breached, some of the workers immediately hide beneath leaves or other objects, while other workers rush about with open jaws, which they snap at foreign objects, or even at leaves and twigs, with an audible tick. On human skin or clothing, a worker will snap her jaws and hold fast to the surface with them, at the same time quickly bringing her gaster around to sting. The sting is long and strong, and to me the effect is shocking and quickly painful.

Most of the smaller and medium-sized Anochetus species feign death when disturbed, crouching flat against the surface, or rolling themselves into a ball and remaining still, often for a minute or more. Only when held do they sting. Their stings can be felt in most cases, but the effect is usually trifling.

Castes

Nomenclature

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

  • orchidicola. Anochetus orchidicola Brown, 1978c: 619 (w.) MEXICO.

Description

Worker

Worker, holotype: TL 4.8, HL 1.29, HW 1.11, ML 0.58, WL 1.45, scape L 0.91, eye L 0.12 mm; CI 86, MI 45.

Body short, robust; head almost as broad behind as across eyes (HW across vertex 1.05 mm). Eyes small, with about 22-25 facets, each occupying about 2/3 of an indistinct orbital fossa. Antennal scapes fail to reach posterior borders of «occipital» lobes by about the length of the first funicular segment, or pedicel, which is about 0.17 mm long, distinctly longer than combined funicular segments II + III, which are each almost as broad as long. Apical antennal segment tapered to a very slender, acute point.

Mandibles very short and thick, convex, gradually broadened apicad; shining, finely punctate and sparsely pubescent; inner margins approximately straight, and not excised or sinuate before apex. Apical teeth short; ventral and intercalary teeth subconical, with rounded apices, the ventral tooth slightly longer than the intercalary; dorsal apical (subapical) tooth broad, only slightly longer than broad, and truncate, much as in the Odontomachus rixosus group, or large workers of Odontomachus ruficeps, its apex even with that of intercalary tooth.

Antennal fossae rather deep, indistinctly bounded behind, extending to about cephalic midlength. Center of dorsum of head with a conspicuous fossa or narrow impression, perhaps corresponding to the anterior ocellus in the unknown queen of this species. Posteromedian impression of vertex distinct but narrow, round-bottomed, receiving the rather narrow, but rounded, anterior curve of the nuchal carina. Occipital lobes very broad, rounded posteriad, with gently convex sides.

Head basically smooth and shining; frontal carinae finely striate, the striation extending caudad and fanning out somewhat, sericeous-opaque, but becoming indistinct a short way beyond the central fossa, and then replaced on the vertex by numerous coarse punctures, crowded, but mostly with narrow, shining interspaces, each puncture bearing a fine, short, appressed or decumbent hair, these collectively forming the fairly conspicuous cephalic pubescence. The rest of the body and appendages mostly bear similar pubescence, especially well developed and dense on gastric dorsum, but it is sparser or absent on underside of head, on center of pronotal disc, on sides of trunk, on coxae and on petiolar node.

Sparse, short, fine standing hairs are also found on mandibular apices, on pronotum, on both upper and lower surfaces of gaster (longer at apex), and a single inconspicuous pair on vertex.

Trunk robust, with broadly convex pronotum having a very short cervix and a fine, raised, transversely reticulate-striolate anterior margin. Mesonotal disc moderately convex in both directions, about 1 1/2 times as broad as long, slightly raised above both pronotum and metanotum, its surface sloping, gently caudad; pronotum and mesonotum smooth and shining, with scattered small punctures. Metanotum also convex, subequal in length to mesonotum but only half as wide. It is separated by a distinctly impressed sutural line from mesonotum, and by a deeper and wider saddle from propodeal dorsum; propodeal dorsum short, weakly concave, subequal in length to declivity, into which it rounds as seen from the side; as seen from above, the propodeum is constricted cephalad, the declivity is concave, and the concavity extends cephalad nearly to the metanoto-propodeal suture between blunt, anteriorly-converging ridges that form the dorsolateral margins of the propodeum. Metanotal disc and propodeum transversely striate, very finely in front, but more coarsely behind, especially on declivity. Sides of pronotum, mesopleura and metapleura smooth and shining, except area of metapleural gland and its bulla, which are rugulose. Mesopleura without obliquely transverse suture. Legs weakly to strongly shining, finely punctulate and pubescent, especially toward apices.

Petiolar node strongly axially compressed, cuneiform in side view, with extremely sharp apical rim; as seen from in front, the rim is convex on the sides, entire and rounded above, but with a slight tendency toward flattening at the extreme apex. The anterior slope as seen from the side is feebly sinuate, almost straight, while the posterior slope is weakly convex. Gaster broad and deep, only modestly constricted between first and second segments; second segment slightly longer than first; upper part of anterior face of first gastric segment overhangs receding lower part. Terminal segments of gaster almost wholly retracted into second segment in this specimen, but sting extended.

Legs short and thick, the anterior femora and all 3 pairs of tibiae distinctly incrassate; 2 fine spurs on each mesotibial apex; one large pectinate spur and a smaller spiniform lateral spur on the hind tibial apex.

Color castaneous (dull orange-brown); trunk and legs perhaps a trifle lighter than head and gaster; mandibles darker, more brownish.

Type Material

Holotype worker (National Museum of Natural History) a unique intercepted in quarantine at Laredo, Texas, 20 June 1944, «with orchid root» originating at Orizaba, Veracruz, Mexico. The Laredo quarantine number is 33930, and the «Lot No.» is 44-15848. Queen and male unknown

References

  • Brown, W. L., Jr. 1978c. Contributions toward a reclassification of the Formicidae. Part VI. Ponerinae, tribe Ponerini, subtribe Odontomachiti. Section B. Genus Anochetus and bibliography. Stud. Entomol. 20: 549-638 (page 619, worker described)