Megalomyrmex modestus Emery

Longino, John T., 2010, A taxonomic review of the ant genus Megalomyrmex Forel (Hymenoptera: Formicidae) in Central America, Zootaxa 2720, pp. 35-58 : 46-47

Megalomyrmex modestus Emery

Megalomyrmex modestus Emery, 1896: 94 . Lectotype worker (designated by Brandão 1990: 425): Suerre [near Jimenez, Limón Prov.], Costa Rica [MCSN] (examined). Brandão, 1990: 426: description of queen, male.

Measurements. Worker: HW 0.81–0.93, HL 1.00–1.12, SL 1.02–1.12, ML 1.29–1.45 (n=13, from Brandão, 1990).

Geographic range. Costa Rica, Panama, Colombia, Venezuela.

Biology. Forel (1899) reported that the type specimens were collected by A. Alfaro from a rotten log. Kugler collected specimens in Colombia, from a "large nest in rotten log, soil - rocks, under forest" (reported in Brandão 1990).

In Costa Rica, M. modestus is found in mature wet forest of the Atlantic slope. Although it occurs at sea level, it is most abundant at middle elevations, 500– 800 m. Nests are subterranean and very large. From these nests, inconspicuous covered galleries extend large distances up trees and under liana stems, and workers may be found under epiphyte mats in the canopy. Workers tend Coccoidea under the shelters. Workers are occasionally collected at baits on the forest floor, but in general they are not often seen as exposed foragers.

At Refugio Eladio, on the Río Peñas Blancas, I found a nest on the bank of a small stream. An area of excavated soil about 2m across covered the ground. There were hundreds of small entrances, and excavations in the surface soil turned up only scattered workers, and no brood. As I dug deeper into the center of the nest (more than 20cm deep) workers became more dense and I began finding adult males and some brood. At a depth of about arm's length workers were very dense, brood more abundant, and two dealate queens were turned up. The soil was very friable, and I could not discern any gallery or chamber structure. Given that I was digging in only a small part of the colony, and turned up two queens, the colony must have had many queens. Around the periphery of the colony there were abundant Coccoidea ( Pseudococcidae ?) in the soil.

Additional material examined. COSTA RICA: Alajuela: Casa Eladio, Rio Penas Blancas, 10°19'N, 084°43'W, 800 m, 27 Apr 1988 (J. Longino); El Aleman, Rio Penas Blancas, 10°18'N, 084°45'W, 940 m, 18 May 1991 (J. Longino); 10 km E Monteverde, 10°18'32"N, 084°42'59"W, 820 m, isolated clearing in mature wet forest area, open lawn area at edge of building, 3 Mar 2010 (J. Longino); Cartago: 5 km E Turrialba, 09°54'N, 083°38'W, 945 m; Heredia: La Selva Biological Station, 10°24'59"N, 084°01'12"W, 50 m, 26 Jan 2004 (M Molina, H Garcia ); 7 km SW Pto. Viejo, 10°24'14"N, 084°02'22"W, 160 m, 3 Mar 2005 (M Molina/ G Hurtado); 16 km SSW Pto. Viejo, 10°19'03"N, 084°02'56"W, 500 m, 17 Oct 2005 (Marcos M/ Deimer A/ Gilberth H/ Felix C/ Joel A); Cantarrana, 11 km ESE La Virgen, 10°20'43"N, 084°03'28"W, 300 m, 20 Mar 2006 (Marcos M, Gilberth H, Felix C); Casa Plastico, 17 km S Pto. Viejo, 10°18'N, 084°02'W, 550 m, 26 Jan 1989 (J. Longino); 22 km N Volcan Barba, 10°20'N, 084°04'W, 500 m, 7 Mar 1985 (J. Longino); Rara Avis, 17 km S Pto. Viejo, 10°18'N, 084°03'W, 700 m, 11 Sep 1985 (J. Longino); 17 km N Vol. Barba, 10°17'N, 084°05'W, 880 m, 14 Jul 1986 (J. Longino); 11 km ESE La Virgen, 10°21'00"N, 084°03'00"W, 300 m, wet forest, 15 Feb 2004 ( ALAS); 11 km SE La Virgen, 10°20'N, 084°04'W, 500 m, 14 Feb 2003 ( ALAS); Limón: Hitoy Cerere Biol. Reserve, 09°40'N, 083°02'W, 200 m, 29 Aug 1985 (J. Longino); Rio Toro Amarillo, vic. Guapiles, 10°13'N, 083°48'W.