Simopelta oculata Gotwald and Brown 1967

Ponerinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia


worker face view

worker lateral view

Additional images:
Worker, lateral view of head showing eye (small, large); sem of face (large, small); mandible (large, small); clypeus (large, small); lateral view of head (small, large); mesosoma, lateral view (large, small; line drawing of face (large, small).
Queen, face view (small, large); lateral view (small, large); line drawings from Gotwald and Brown (1967) (large).

Range

Costa Rica: various middle elevation sites on the Atlantic slope.

Identification

Eye relatively larger than any other species; mandible with two apical teeth and large basal tooth, basal tooth relatively sharp; anteromedian clypeal border triangular, strongly projecting, without spine; face largely punctate; head relatively narrow, head width/head length less than 0.8.

Similar species: JTL-002.

Natural History

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

I know this species from seven different collections, not including the collection on which Gotwald and Brown's original description was based. Collections have all been from mid-elevation Atlantic slope: 600-1000m in the Cordillera de Tilarán, 400-1500m in the Cordillera Volcanica Central, and 1300m in the Tapantí area.

Gotwald and Brown (1967) thoroughly described the ecitonine-like behavior of this species, based on a nest collection from near Guapiles, Costa Rica. A foraging column led to a nest in a vertical dead stick suspended in low vegetation. The raiding column was returning with Pheidole brood as prey. At the time of collection the nest contained 361 workers (not including the estimated several hundred workers in the observed foraging column) and one queen.

Selected Records

JTL5Jul84/0830: Wet forest; raiding column at 0830hrs. I followed the leading edge of the column. They were carrying booty so I presume they were returning. At first the column followed a route of several meters without hesitation; suddenly it became very hesitant, bunching up at the front, exploratory columns extending out in several directions. The column very slowly proceeded in this fashion for 2-3 meters, then I quit watching them. Later note: in the container, in addition to Simopelta workers, were 2 Pheidole truncula soldiers and 1 minor worker (and a few small brood). I presume these were being carried by the raiding Simopelta workers when I collected them.

JTL5516: cloud forest; at 1550hrs I saw a column of workers. The column was only about a meter long, with perhaps a hundred workers. Some of the workers were carrying tiny ant brood, and one worker was carrying an adult Stenamma felixi worker. I followed the column as it wound through the forest, usually on low sticks and vines, elevated just off the surface. They rarely traveled directly on the leaf litter. The column came to a dead and rotten section of aroid stem propped against a tree buttress. Workers were going into this rotten section. I collected the entire section into a plastic bag for later dissection. The point where I first saw the raiding column was 7m from the nest. The total nest population was one queen, 1942 workers, and 100-200 larvae. The larvae were of a relatively uniform, intermediate size. There were no eggs, small brood, or pupae.


Page author:

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


Date of this version: 21 July 2005.
Previous versions of this page: 11 June 1997, 17 May 1999.
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