Crematogaster rochai Forel

Longino, J. T., 2003, The Crematogaster (Hymenoptera, Formicidae, Myrmicinae) of Costa Rica., Zootaxa 151, pp. 1-150: 102-103

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Crematogaster rochai Forel


Crematogaster rochai Forel   HNS   1903 REVISED STATUS

Crematogaster rochai Forel   HNS   , 1903:255. Syntype worker, queen, male: Brazil, Ceara (Diaz da Rocha) [ MHNG]   (examined). Emery, 1922:134: combination in C. (Orthocrema)   HNS   . Forel, 1912:213; Gallardo, 1934:21: race/subspecies of brevispinosa   HNS   .


Widespread in Neotropics from southern Mexico to Argentina.

Description of worker (Costa Rica)

Differing from crinosa   HNS   and torosa   HNS   by the following combination of characters: dorsal and posterior face of propodeum in nearly the same plane, such that the propodeal suture appears very shallow with no posterior wall, the propodeum forming a single declivity from the propodeal suture to the petiolar insertion (very large workers have a short dorsal face that drops to propodeal suture); promesonotum strongly arched, not flattened; anteroventral petiolar tooth long, sharply acute, triangular to spine-like; fourth abdominal tergite completely lacking erect setae.


HL 0.851, 0.519, 1.139; HW 0.915, 0.535, 1.238; HC 0.905, 0.509, 1.207; SL 0.559, 0.375, 0.681; EL 0.198, 0.114, 0.257; A11L 0.247; A11W 0.123; A10L 0.110; A10W 0.104; A09L 0.062; A09W 0.078; A08L 0.045; A08W 0.060; WL 0.913, 0.500, 1.259; SPL 0.098, 0.069, 0.158; PTH 0.200, 0.121, 0.265; PTL 0.271, 0.158, 0.407; PTW 0.279, 0.166, 0.343; PPL 0.232, 0.128, 0.286; PPW 0.262, 0.167, 0.352; CI 108, 103, 109; OI 23, 22, 23; SI 66, 72, 60; PTHI 74, 77, 65; PTWI 103, 105, 84; PPI 113, 130, 123; SPI 11, 14, 13; ACI 0.57.

Queen (Costa Rica)

A normal queen (dorsal face of propodeum drops steeply from postscutellum and much of propodeum appears ventral to scutellum and postscutellum, Fig. 1) with general shape, sculpture, and pilosity characters of the worker; size characters as in Figures 4 and 5.


Crematogaster rochai   HNS   has a biology very similar to crinosa   HNS   and torosa   HNS   . It occurs primarily in open, seasonally dry areas, highly disturbed areas, pasture edges, and beach margins. It occasionally occurs in mangroves, although crinosa   HNS   is the more common mangrove inhabitant. I have never collected it in rainforest areas.

Nests are large, polydomous, and distributed in a wide variety of plant cavities. Dead branches and knots in living trees are most often used. In Guanacaste Province in Costa Rica colonies may occupy ant acacias and may invade acacias occupied by Pseudomyrmex   HNS   . I have seen workers distributed in small chambers scattered in the corky bark of Tabebuia   trees (Bignoniaceae) and Erythrina   trees (Fabaceae). Workers often construct small carton baffles to restrict nest entrances and small carton pavilions that shelter Homoptera on surrounding vegetation.

Foraging is primarily diurnal. Workers are generalized scavengers and they frequently visit extrafloral nectaries. Often columns of workers move between nests.

I often find cockroach egg cases scattered in the nest chambers of C. rochai   HNS   , at a much higher density than in the environment generally. The nature of the relationship between cockroaches and the crinosa   HNS   group would be worth investigation.


This is a member of the crinosa   HNS   complex and may not always be distinguishable from crinosa   HNS   and torosa   HNS   . See under crinosa   HNS   for further discussion. In Costa Rica rochai   HNS   always has the fourth abdominal tergite completely devoid of erect setae, and the anteroventral petiolar process is long and sharp. Costa Rican material also lacks a differentiated dorsal face of the propodeum, but material from central and southern South America develops a stronger propodeal suture, thus approaching the condition in other crinosa   HNS   group material. Also, southern material often has one to five erect setae on the anterolateral portions of the fourth abdominal tergite.


Switzerland, Geneva, Museum d'Histoire Naturelle