Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Figures from Holldobler and Wilson 1992:
Minor worker, face and lateral views (high resolution gif)
Minor worker, face (low resolution gif)
Minor worker, lateral view (low resolution gif)
Major worker, face and lateral views (high resolution gif)
Major worker, face (low resolution gif)
Major worker, lateral view (low resolution gif)
Identification
Minor worker: head length 0.56mm, head width 0.50mm, scape length 0.53mm, Webers length 0.69mm (n=1). Head rounded behind; promesonotum evenly arched, mesonotal suture absent; propodeal spines short, sharp, upturned; face smooth and shining; pronotum with small humeral bosses; sides of pronotum smooth and shining, rest of mesosoma foveolate; gaster smooth and shining; dorsal pilosity moderately abundant, long, flexuous, swept forward on mesosoma; color yellow brown.
Major worker: head length 0.84mm, head width 0.85mm, scape length 0.51mm (n=1). Face longitudinally rugose foveolate on anterior half between frontal carinae, anterior third between frontal carinae and eyes; remainder of face to vertex lobes smooth and shining; hypostomal margin not visible on types (obscured by mounting media); dorsal pilosity abundant; head with abundant setae projecting from sides of head in face view; face two-toned, with anterior sculptured portion red brown, smooth vertex lobes yellow brown.
Range
Costa Rica (La Selva).
Natural History
Holldobler and Wilson (1992) report the following observations of the single known collection of this species:
The type colony was found nesting in a round mass of dried, thatch-like vegetation about 1.5 meters up in the moderately dense foliage of a small tree, which was located at the edge of a second-growth forest bordering the open experimental fields of the la Selva station. When the nest was disturbed, more than a hundred major and minor workers of P. nasutoides rushed out and ran in erratic looping patterns to form a spreading wave away from the nest. The resemblance of the majors to Nasutitermes nasute soldiers under similar circumstances was remarkable. In particular, the mask of the Pheidole majors is roughly shaped like that of the nasute termites and contrasts with the light remainder of the body in the same way. The illusion was heightened when the ants were in motion, creating a Nasutitermes-like gestalt. Holldobler, who discovered the nest, in fact first thought that the ants were Nasutitermes and nearly passed them by. During the brief time the colony was observed live in the laboratory, the resemblance remained close. Otherwise, the colony seemed typical for a species of Pheidole. Adult males were present, but neither alate nor dealate queens were recovered.
We remain puzzled by our failure to locate other P. nasutoides nests despite prolonged effort in the La Selva area. It is possible that the species is simply very rare, existing in extremely sparse populations. Alternatively, it may be normally a dweller of the high canopy, a zone we did not explore. The nest found was at the edge of a disturbed forest patch, and might have fallen from a higher location.
In spite of additional intensive collecting of ants at La Selva by Longino and Project ALAS, this species has not been subsequently collected.
Literature Cited
Holldobler, B., and E. O. Wilson. 1992. Pheidole nasutoides, a new species of Costa Rican ant that apparently mimics termites. Psyche 99:15-22.
Page authors:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
Stefan Cover, Museum of Comparative Zoology, Harvard University, Cambridge MA 02138 USA. scover@oeb.harvard.edu
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