= Pheidole JTL-027
Suggested synonym:
= Pheidole humida Wilson 2003
Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Range
Costa Rica: Volcan Barva, Monteverde.
Identification
Minor worker: head length 0.57mm, head width 0.54mm, scape length 0.54mm, Webers length 0.72mm (n=1). Head flattened behind, with median excavation; promesonotal suture weakly impressed; metanotal groove well impressed; propodeal spines of moderate length, upturned; face and most of mesosoma shallowly foveolate-aereolate; sides of pronotum and medial portion of katepisternum smooth and shining; gaster smooth and shining; mesosomal dorsum with moderately abundant, long flexuous setae; color yellow.
Major worker: head length 0.97mm, head width 0.96mm, scape length 0.59mm (n=1). Most of face shallowly foveolate-aereolate, overlain with longitudinal rugae; vertex lobes smooth and shining; hypostomal margin flat, with pair of stout teeth 1/3 distance from midline to small recessed teeth flanking mandibles, no median tooth; mesosomal dorsum and gaster with moderately abundant, flexuous setae; abundant short suberect setae projecting from sides of head in face view.
Natural History
This species is a montane cloud forest specialist. In the tropics ant abundance declines dramatically between 1500 and 2000m and ants are very difficult to find above 2000m. Pheidole boltoni occurs in a narrow band at the very upper edge of of ants' natural occurrence.
Pheidole boltoni was first collected in 1979 by Phil Ward in Monteverde cloud forest. He collected a nest series (Ward #3450) in a rotten log. A specimen from this collection is the holotype of Pheidole humida Wilson 2003. In 1986 I collected three nest series (Longino #1329, #1330, #1336) at 1850m elevation on the Volcan Barva transect in Braulio Carrillo National Park. All three nests were under epiphyte mats in treefalls and branchfalls. One nest was observed with definite seed caches (perhaps melastome seeds). I used the morphospecies code name JTL-027 for this species, and a specimen from one of these collections is the holotye of P. boltoni Wilson 2003. I recently collected the species again during the Project ALAS expedition to the 2000m Vara Blanca site along the Volcan Barva transect. The site is cloud forest, with heavy epiphyte loads on all the larger trees. Nests of Pheidole boltoni were found beneath epiphytes in a fresh treefall in mature forest.
Judging from images of the P. humida holotype, P. humida and P. boltoni are synonyms.
It is notable that Pheidole boltoni has not been collected in Monteverde since Ward's original collection, in spite of abundant collecting in the area by Longino and Cover. Perhaps climate change has driven it out of Monteverde, along with the golden toads.
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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