Megalomyrmex goeldii Forel, 1912

Brandão, Carlos Roberto F., 2003, Further Revisionary Studies On The Ant Genus Megalomyrmex Forel (Hymenoptera: Formicidae: Myrmicinae: Solenopsidini) C R F. B Abstract, Papéis Avulsos de Zoologia (São Paulo) 43 (8), pp. 145-159 : 147-148

Megalomyrmex goeldii Forel, 1912

J. Delabie, sent me from CPDC a sample of M. goeldii , including workers and several “ergatoid” females collected in an old cocoa plantation located at Km 22 of the Itabuna-Ilhéus road (14 48’S, 39°16’W), Bahia state, Brazil. Reproductives are larger and darker than conspecific workers, and retain only the anterior median ocellus (as do ordinary gynes of this species), lacking any vestiges or scars of the lateral ones. Their mesonotuns bear a transverse impression (in side view) and the metanotuns can be clearly differentiated from other sclerites. The dorsal area of the anepisternuns and lateral margins of the katepisternuns bear rugulae .

I failed to notice any difference between workers of this sample and those of queenright colonies workers from southern localities. It is interesting to note that these are the only colonies from which ergatoids are known, and they come from the periphery of the species distribution, northern in this case.

Later on, J. Diniz visited the same locality (but in a specific location called Parque Zoobotânico) and found a Megalomyrmex goeldii colony with several ergatoids (voucher workers at MZSP). Unfortunately, we do not know if all of them were inseminated, as is the case for many other Megalomyrmex species. Queenright colonies from southern localities may have several inseminated dealated gynes (see Brandão, 1990:424). I studied, from the same locality but unfortunately not from the same colony series, seven males collected by P. Terra in March 3, 1988 (# 4587). In these specimens the pronotum is strongly depressed, representing one extreme of the tendency already noticed in southern samples.

Jones et al. (1999) compared the amount of different venom alkaloids present in M. goeldii ergatoid gynes and workers.

In July 1987, I collected 30 foraging workers of M. goeldii on a rotten stump in a dense evergreen primary Atlantic Forest reserve , Parque Municipal Baepi, Ilha de São Sebastião, São Paulo state, Brazil, 500 m of altitude (23°50’S, 45°18’W). Although I failed to locate the nest, this sample helped to confirm that, in workers from the southern end of the species distribution, the epipetiolar carina is not complete over the foramen ( Brandão, 1990:424) .

From the Los Angeles County Museum ( LACM), I received three workers of M. goeldii from “ Brazil ” mounted on one pin, from the U.S. Quarantine at Hobboken, New Jersey, collected in July 16, 1947 by McMaster & Adams in wild Cattleya purpurata (# 47-10233).

I studied three workers of M. goeldii collected by M. Queiroz in a coffee plantation in Viçosa, Minas Gerais state, Brazil, in April 26, 1988 (20°45’S, 42°53’W), deposited in the MZSP. Soares et al. (1998) collected M. goeldii visiting sardine/honey baits set in a secondary growth semideciduous forest in the same locality.

Megalomyrmex goeldii seems to be fairly common in the localities where it has been recorded, but populations seem to be widely scattered. This may be related to the fact that in some populations of this species, the female reproductives are ergatoids, and hence dispersion is severely limited. These ants are easily attracted to baits, so it may be reasonable to conclude that they do not occur in places where they have never been found using baits. However, Yamamoto (1999) surveyed the litter ant fauna in the Estação Biológica de Boracéia, Salesópolis, São Paulo state, Brazil (23°39’26”S, 45°53’36”W), 843 m above sea level, an Atlantic Forest reserve pertaining to the MZSP. The author collected 132 individually sifted 1 m 2 litter samples submitted to Winkler extractors, obtaining a total of 95 ant species in 1304 records (record in this case means a species recorded in a given sample). M. goeldii was recorded 14 times in the survey (1.1% of all records), in a locality previously surveyed by several ant researchers and where specimens of M. goeldii were never found so far. Notwithstanding, M. iheringi (see below) has not been found recently in the E.B. Boracéia, a locality where it was still fairly common in the beginning of the twentieth century.

As part of an ongoing leaf litter ant fauna survey along the Atlantic forest, financed by FAPESP, A.A. Tavares (2002) collected 50 individually sifted 1 m 2 litter samples submitted to Winkler extractors for 48 hours, in Ribeirão Grande, Parque Estadual Intervales, Base Barra Grande, São Paulo state, Brazil, in February 5, 1999. Megalomyrmex goeldii was recorded four times in the survey. In Parque Estadual Serra do Mar, Núcleo Cunha-Indaiá Cunha, São Paulo state, Brazil (23°15’03”S, 45°00’26”W), Tavares repeated the procedure and recorded M. goeldii 20 times. The species seems to be one of the most common litter inhabiting ants in these localities.