Gigantiops destructor

Frederick Smith (1858) added his own remarks to a communication he had with Bates in regards to Gigantiops desctructor: This is a very remarkable insect; for, independent of the enormously developed eyes and produced clypeus, the palpi are elongated to half the length of the thorax, the maxillary are six-, and the labial four-jointed. Mr. Bates says, "This curious solitary ant is never seen by more than one at a time, prowling about fallen leaves, etc. in the forest; I have never seen its Formicarium, and, from its solitary habits, have no clue to guide me in looking for it." Subsequent researchers have been able to find their nests and there and a variety of details about their biology that are now known.

Identification
In full face view the eyes of the worker extend from the clypeal border to the posterior margin. The large eyes of this ant make it distinctive among all ants in the subfamily Formicinae.

Distribution
Northern South America.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, Venezuela.

Biology
Beugnon et al. (2001) summarized some of what was known about these ants: "Workers forage solitarily on the ground, or sometimes among the branches of trees, leaping from twig to twig. They run and jump away when pursued by human observers (Smith 1858; Emery, 1893; Mann, 1916; Wheeler, 1922; Tobin, 1989; Hölldobler and Wilson, 1990). As a result, it is rather difficult to follow workers returning to their nests, so that early attempts to localize them were unsuccessful. Wheeler (1922) found only two queenless nests in British Guyana, Tobin (1989) found two nests, one queenless and the other queenright, in eastern Venezuela and a total of six nests in the Manu Biosphere Reserve in Peru. Other attempts to capture entire colonies were unsuccessful and, consequently, males were described only in the second half of the twentieth century (Kempf and Lenko, 1968). For all these reasons, this formicine ant species still merits investigation. In addition, because this species presents impressive forward jumping abilities and has the largest and most prominent eyes of all known ant species to date, it has recently attracted the interest of neuroanatomists (Jaffe and Perez, 1989; Tautz et al., 1994; Gronenberg and Hölldobler, 1999)."

From Beugnon et al. (2001): "Monogynous and polydomous colonies of G. destructor from French Guiana are distributed along the rainforest edges or along streams with a nest density of about 300 nests/ha. The species presents rudimentary nesting habits, as most nests are found in pre-existing cavities in the ground, but some can be found in the hollowed internodes of Cecropia trees fallen onto the ground. A worker, sometimes hidden in a separate “sentry box”, might guard the nest entrance. Colony size can reach several hundreds of workers. The foraging activity of the workers is strictly diurnal with a peak between 9:30 and 11:30. This largest-eyed of all known ant species has remarkable leaping abilities even more impressive than in other jumping ants. Workers are generalist solitary foragers. They collect extrafloral nectar from different plant species and prey on various small live arthropods that they detect visually before tracking and jumping on them. The same individual can forage both on prey and sugary sources during a single foraging trip. Foragers can eat their prey on site and never recruit nestmates in the field or even after a starvation period in the laboratory. They feed larvae with chewed prey. The complete lack of cooperation between foraging workers that can also fight for a prey with a nestmate, combined with the absence of any recruitment for large food sources, constitute a cluster of individualist traits rather unusual for an eusocial insect."

Gigantiops destructor have huge eyes that cover much of the sides of the head. Gigantiops workers are difficult to catch because they see approaching human observers from several meters away and flee by swiftly running and jumping away. Workers of large-eyed ants generally do not respond to prey insects that are standing still, but run toward them as soon as they begin to move. (Hölldobler and Wilson 1990)

Excavations of two nests in the Utariti area showed that full grown colonies number over 1000 individuals. Nuptial flight, at least south of the Amazon river, takes place in spring, i.e., October or November. Completely unexpected was the discovery of parabiosis between G. destructor and Paraponera clavata, the highly feared and gigantic stinging ant of the American tropics. In fact, both species were found in a state of mutual toleration, which has reached the point of G. destructor occupying part of the nest of Paraponera davata. Although this association does not seem to be obligatory, where both species live side by side, there seems to exist, nevertheless, a natural tendency toward it. Gigantiops destructor was seen feeding on small Diptera of families Chironomidae, Drosophilidae, Phoridae, Dolichopodidae and also on termite workers. Collecting of caterpillar droppings and resin secreted on leafaxils of trees of family Guttiferae was also observed. Contrary to its companion, Paraponera clavata, G. destructor never seems to show any aggressiveness always seeking its only defence by hiding and running away. As regards symbiotic arthropods, small apterous cockroaches and several free-living acari were found in the nests of Gigantiops destructor. (Kempf and Lenko 1968)

Nomenclature

 *  destructor. Formica destructor Fabricius, 1804: 402 (w.) SOUTH AMERICA. Wheeler, G.C. & Wheeler, J. 1953c: 170 (l.). Combination in Gigantiops: Roger, 1863b: 11. Senior synonym of solitaria: Roger, 1862c: 287. See also: Wheeler, W.M. 1922b: 185; Wheeler, G.C. & Wheeler, J. 1968: 215.
 * solitaria. Formica solitaria Smith, F. 1858b: 45, pl.13, figs. 4, 5 (w.q.) BRAZIL. Junior synonym of destructor: Roger, 1862c: 287.

Worker
Smith (1858) - Length 4-1/4 lines.-Opake-black, with eight or nine of the apical joints of the antennre of a palish yellow; the mandibles and claws of the tarsi rufo-piceous. Head very large, wider than the thorax or abdomen; eyes occupying the whole of the sides of the head, very convex and prominent; the clypeus very large, much produced and truncate at the apex, with a central longitudinal carina, and covered with a thin grey pile; mandibles large, stout, shining, and having their inner margin finely serrated ; the head emarginate behind ; the ocelli prominent on the vertex. Thorax elongate, narrow and compressed behind; the divisions of the thorax not very strongly marked; legs elongate and slender; the tibiae with a few fine scattered spines or hairs. Abdomen ovate, with a few pale hairs at the apex; the scale of the petiole incrassate, and, viewed sideways, wedge-shaped.

Queen
Smith (1858) - Length 5 lines - Very closely resembles the worker, differing only in the form of the thorax, which is of a more ovate form, as in the majority of species, and in having wings, the neuration of which is the same as in F. ligniperda; the antennae are elongate and slender, as in the worker.