Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
|
|
|
Image catalog (click here). Includes images of holotype.
Range
Costa Rica.
Identification
Crematogaster jardinero is uniquely characterized by the combination of (1) shiny face with erect setae, (2) subquadrate dorsal face of petiole, (3) erect tibial pilosity, (4) dark coloration, (5) short posteriorly directed propodeal spines, and (6) lack of anteroventral propodeal process. It can be confused with limata and relatives but differs in the more subquadrate, less tapering dorsal face of the petiole. The general habitus of the workers and the small shiny queen with posteriorly produced propodeum suggest a closer relationship to distans, acuta, and other species with "acuta-like" queens.
Description of worker
Color dark red brown to black.
Mandibles striate, shiny; clypeus emarginate anteriorly, flat, shiny; face smooth and shiny; scapes clavate, with apical third distinctly wider than basal two thirds, with abundant long erect setae, longest erect setae longer than width of scape; terminal three segments of antenna enlarged, especially apical two, thus intermediate between a two and three-segmented club; face with abundant long erect amber setae; in full face view abundant setae projecting from posterior margin of head but not from sides.
In lateral view, pronotum rising steeply, curving into flat and more gently sloping posterodorsal face, which smoothly joins flat mesonotal dorsum, which slopes downward to propodeal suture, mesonotum very slightly produced, such that promesonotal suture visible as a very faint impression; propodeal suture broad and shallow, v-shaped; dorsal and posterior faces of propodeum distinct; propodeal spines broad-based but abruptly narrowing to short, narrowly acute spines; side of pronotum and dorsolateral propodeum smooth and shiny; katepisternum and ventrolateral propodeum with faint areolate rugose sculpture, sublucid; promesonotal dorsum and dorsal face of propodeum with faint irregular areolate rugose sculpture and etchings, sublucid, rugulae more pronounced on mesonotum than propodeum; posterior face of propodeum smooth and shiny; pronotum and mesonotum each with an anterior row of long, flexuous, erect, amber setae, pronotal row usually of four setae and mesonotal row usually of two; femora with sparse, long, subdecumbent setae; tibiae with similar subdecumbent setae and several pairs of long erect setae that are longer than width of tibia.
Petiole in side view trapezoidal, with microareolate sculpture; anteroventral tooth well-developed, triangular, acute; dorsal face rectangular, slightly longer than wide, smooth and shiny, with pair of long setae on posterior margin; portion of petiole posterior to dorsal face relatively well developed, forming a distinct cylindrical collar; postpetiole with no ventral tooth; postpetiole in dorsal view subquadrate/globular, about as wide as long, slightly wider anteriorly than posteriorly, posterior margin flat to very weakly convex, dorsum convex; fourth abdominal tergite smooth and shiny; postpetiole and fourth abdominal tergite with abundant long erect flexuous amber setae.
Measurements:
Holotype: HL 0.691, HW 0.727, HC 0.663, SL 0.592, EL 0.154, WL 0.802, SPL 0.144, PTH 0.181, PTL 0.246, PTW 0.196, PPL 0.171, PPW 0.208, CI 105, OI 22, SI 86, PTHI 74, PTWI 80, PPI 122, SPI 18.
Other specimens: HL 0.683, 0.641, 0.717; HW 0.716, 0.692, 0.783; HC 0.666, 0.627, 0.698; SL 0.590, 0.557, 0.629; EL 0.147, 0.152, 0.175; A11L 0.260; A11W 0.111; A10L 0.097; A10W 0.098; A09L 0.069; A09W 0.075; A08L 0.058; A08W 0.056; WL 0.788, 0.758, 0.829; SPL 0.108, 0.098, 0.141; PTH 0.173, 0.169, 0.180; PTL 0.240, 0.233, 0.255; PTW 0.205, 0.192, 0.216; PPL 0.182, 0.172, 0.164; PPW 0.214, 0.205, 0.219; CI 105, 108, 109; OI 22, 24, 24; SI 86, 87, 88; PTHI 72, 73, 71; PTWI 85, 82, 85; PPI 118, 119, 134; SPI 14, 13, 17; ACI 0.24.
Description of Queen
In lateral profile dorsal face of propodeum sloping obliquely from postscutellum, such that most of propodeum is posterior to scutellum (in contrast to normal queens, in which dorsal face of propodeum drops steeply from postscutellum and much of propodeum appears ventral to scutellum and postscutellum); entire body (head, mesosoma, petiole, postpetiole, fourth abdominal tergite, appendages) polished, very smooth and shiny; mandible smooth and shiny; anterior margin of clypeus emarginate; clypeus flat; antennal club three-segmented; scapes clavate as in worker, with abundant long erect setae; face, mesonotum, scutellum, posterior face of petiole, postpetiole, fourth abdominal tergite, femora, and tibiae with moderately abundant long erect amber to whitish setae; dorsal face of pronotum perpendicular, at right angle to anterior collar, but not recessed beneath mesonotum as in raptor, and with anterolateral gibbosities; propodeal spines very long, narrow, parallel-sided, with blunt tips; petiole similar in form to worker but with shorter dorsal face, dorsal face about as wide as long, slightly wider anteriorly than posteriorly; postpetiole with no ventral tooth; postpetiolar dorsum trapezoidal, wider than long, wider anteriorly than posteriorly, with hint of posterior emargination and median sulcus, when viewed at certain angles.
Natural History
Crematogaster jardinero is an ant garden inhabitant that occurs in primary wet forest on the Atlantic slope of Costa Rica. The most extensive observations of this species are from work I carried out with Operation Raleigh in 1985, at a 500m site in the Zona Protectora of Braulio Carrillo National Park. While working in the canopy I discovered an "archipelago" of ant gardens. A larger central garden was in an Inga longispica crown (Fabaceae), and a constellation of smaller gardens was scattered in the same crown and an adjacent crown of Dipholis crotonoides (Sapotaceae). The large nest in the Inga was moss-covered, and looked like the oldest one. All gardens sprouted a diverse assemblage of epiphytes. The most abundant species was an aroid with thick, white, fleshy roots, which seemed to form the scaffolding of most of the nests. There were about 20 epiphyte species total, including Piperaceae, Gesneriaceae, Bromeliaceae, and Orchidaceae. When gardens were removed, the tree stems beneath them were densely clustered with scale insects. No scale insects were visible on any exposed stems; they only occurred where sheltered by the carton material of the gardens.
I dissected ten gardens, including the large central garden, and failed to find any concentrated area of brood or a physogastric queen. Curiously, after I finished the dissections and had returned to camp, I found a physogastric queen and one attending worker on my clothing. I presume she crawled or was shaken onto my clothing during the dissection, and I cannot say from which garden she came. However, the presence of this single physogastric queen after dissections of ten gardens suggests monogyny. Workers, brood, males, and alate queens were dispersed evenly throughout the matrix of each garden. The fact that the larvae were highly dispersed could indicate that they feed on something produced by the garden itself, rather than relying on an external food source that is harvested and delivered to them by workers. The arrangement was reminiscent of nests of the Attini, where larvae are evenly distributed in fungus gardens, rather than the more typical concentration of brood in discrete piles.
The Crematogaster were tolerant of other ant species on their gardens. Small nests of Tapinoma and Pseudomyrmex were found in dead sticks lodged in the garden epiphytes.
A second colony of this species was collected by Bill Haber at Laguna Poco Sol. This site is in the Cordillera de Tilar‡n, about 60km west of the Braulio Carrillo site, at a similar elevation. He collected a small ant garden and delivered it to me in a plastic bag. I found a similar assemblage of epiphytes, and a similarly even dispersion of workers, brood, and alate queens in the nest.
Other collections of the species are from a mixed collection of foraging workers from another site in Braulio Carrillo National Park, where trees were being felled along a road cut, and an old collection from Hamburg Farm, a lowland rainforest site in Limon Province. The latter were collected by F. Nevermann and deposited in the MCZ at Harvard.
Image catalog of garden archipelago found during Operation Raleigh in 1985 (click here).
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
Date of this version: 4 March 2003.
Go back to top