Simopelta JTL-003 Longino ms

Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia


worker face view

worker lateral view

Additional images:
Worker, sem of face (large, small); mandible (large, small); head, lateral view (large, small); lateral view (small, large); mesosoma, lateral view (large, small; petiole, lateral view (large, small; petiole, dorsal view (large, small; line drawing of face (large, small).

Range

Costa Rica, Panama. Costa Rica: Montane areas from Cordillera de Tilarán southward, 800-1500m.

Identification

Mandible with two apical teeth and large basal tooth, basal tooth thick and blunt (unlike JTL-002); eye relatively small (unlike oculata); sculpture on face with large confluent puncta underlain by granular microsculpture; anteromedian clypeal projection broadly triangular to somewhat rounded, not strongly projecting; head relatively broad, head width/head length greater than 0.8.

Natural History

All Simopelta species are nomadic group raiders, convergent with Ecitoninae. See additional information under genus account.

I have seen seven collections of this species from various localities in the Cordilleras de Tilarán, Volcanica Central, and Talamanca, and from the Bocas del Toro region of Panama. Collections have all been from mid-elevation wet forest sites, 800-1700m.

For one collection (JTL1374) in Braulio Carrillo National Park I watched a raid on a Pheidole browni colony. A column of Simopelta workers extended from the leaf litter on one side of the trail, across the trail to a spot on the opposite bank. There the column ended where workers clustered. I think the column had just arrived. There was no superstructure to the Pheidole nest, and at first I saw no reason for the aggregation. After a few minutes, an alate Pheidole queen was pulled from a small hole and attacked. Soon thereafter, several other queens emerged, and some minor workers. Later a major worker appeared. All were attacked. For about 5 minutes the captive adults were pinned near the entrance to the nest. Rather suddenly, Simopelta workers began extracting brood from the nest, and the raiding column began to return. Brood, workers, and the alates were all carried away. The column disappeared into the leaf litter about 1m from the Pheidole nest, and I could not trace it beyond that point. The habitat was dense, shaded second growth, mostly Cephaelis-type Psychotria, along a stream bank.

In another instance (JTL2469) in the San Luis Valley near Monteverde I observed a column crossing a trail carrying single-size brood.


Page author:

John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu

Last modified: 21 July 2005.


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