Nesting architecture and population structure of the fungus-growing antCyphomyrmex transversus(Formicidae: Myrmicinae: Attini) in the Brazilian coastal zone of Ilhéus, Bahia

Abstract

Abstract. The present study provides valuable information about the nesting biology and demographics of Cyphomyrmex transversus (Formicidae: Myrmicinae: Attini). This species has been observed nesting under and inside dry coconuts on the forest ground in the Brazilian coastal zone of Ilhéus, state of Bahia. To investigate the association between C. transversus and coconuts, we surveyed 153 coconuts. Of the surveyed ones, 62 (40.5%) exhibited associated colonies of Cyphomyrmex transversus (one colony per coconut): 53 (85.5%) of the 62 colonies nested under the coconut, and nine (14.5%) nested inside. Distributed among 57 of the coconuts, 17 other ant species were found. The ants most frequently found were Paratrechina longicornis and Camponotus atriceps. Nests of C. transversus were structurally simple, with one principal chamber with small depressions located on the base. Inside the nest cavities, yeast-like fungi formed in polygonal masses. More than one dealate queen was observed in several C. transversus colonies. The population of C. transversus individuals per colony increased according the coconut size. We conclude that the use by the ants of coconut pieces as a part of their nest structure and the occurrence of multiple dealate queens per colony show adaptive fl exibility in C. transversus. It may confer a greater capacity for colonization and maintenance of competitive nest densities in the harsh environmental conditions of Brazilian coastal zones. Further studies should consider the social organization of all ant species that nest in coconuts and its effect on colony survival rates and competitive relationships.Résumé. Architecture du nid et structure des populations chez la fourmi champignonniste Cyphomyrmex transversus (Formicidae : Myrmicinae) dans la zone brésilienne côtière de Ilhéus, Bahia. Cette étude présente des données inédites sur la nidifi cation et la démographie de Cyphomyrmex transversus (Formicidae : Myrmicinae : Attini). Les nids de cette espèce ont été rencontrés sous et à l'intérieur de noix de coco sèches tombées sur le sol dans la zone littorale de la région d'Ilhéus, dans l'état de Bahia au Brésil. Pour étudier les modalités de cette nidifi cation particulière, 153 noix de coco ont été collectées. 62 (40.5%) d'entre elles, abritaient des colonies de Cyphomyrmex transversus avec une colonie par noix. Parmi celles-ci, 53 colonies (85.5%) étaient établies sous la noix tandis que neuf (14.5%) étaient à l'intérieur. Parmi 57 de ces noix de coco, 17 autres espèces de fourmis ont été rencontrées. Les plus fréquemment rencontrées ont été Paratrechina longicornis et Camponotus atriceps. Les nids de C. transversus sont structurellement simples, avec une chambre principale et quelques petites dépressions à la base. A l'intérieur de la cavité du nid, un champignon du type levure forme des masses polygonales. Plusieurs reines sans ailes ont été observées dans diverses colonies de C. transversus. Le nombre d'individus dans les colonies de C. transversus augmente en fonction de la taille de la no...

Nest Biology and Demography of the Fungus-Growing Ant Cyphomyrmex lectus Forel (Myrmicinae; Attini) at a Disturbed Area Located in Rio Claro, SP, Brazil

“…Leal et al, 2011;Ramos-Lacau et al, 2012) when compared to Atta and Acromyrmex genera (Wirth et al, 2003;Silva Junior et al, 2013). Here, one single circular nest-entrance hole without a well-formed nest mound was observed in C. lectus.…”

“…Colonies with multiple dealate queens are frequently observed among Attines (Delabie, 1989;Leal et al, 2011;Ramos-Lacau et al, 2012), where the colonies can be both haplometrotic and pleometrotic (Fernández-Marín et al, 2004). Regarding the absence of alates in our study, it is possible that this occurred simply because the majority of colonies (five) were sampled in June, during the middle of the dry and cold season.…”

“…For example, in Costa Rica, on Atlantic slopes, Adams Contrasting with another Cyphomyrmex species (rimosus group) described by Leal et al (2011), the fungus garden in C. lectus was well-defined (yeast-like fungi formed a sponge mass) and arranged at the bottom of the chambers. This pattern has been also illustrated for C. transversus (Ramos-Lacau et al, 2012). According to Leal et al (2011), the fungus garden in Cyphomyrmex colonies was usually characterized by yeast nodules scattered among the superficial soil and leaf litter, in Brazilian savanna (Cerrado).…”

“…However, other Cyphomyrmex species (e.g. C. transversus and C. cornutus) present a highly distinctive nesting biology compared to C. lectus, C. strigatus and C. rimosus (Adams & Longino, 2007;Ramos-Lacau et al, 2012). For example, in Costa Rica, on Atlantic slopes, Adams Contrasting with another Cyphomyrmex species (rimosus group) described by Leal et al (2011), the fungus garden in C. lectus was well-defined (yeast-like fungi formed a sponge mass) and arranged at the bottom of the chambers.…”

Locating, collecting, and maintaining colonies of fungus-farming ants (Hymenoptera: Myrmicinae: Attini)

“…Mound of craters, >1000 nest entrances (Autuori, 1942;Moreira et al, 2004;Weber, 1941Weber, , 1945Weber, , 1946Weber, , 1947Weber, , 1966Weber, , 1969bWeber, , 1972bWeber, , 1982Wheeler, 1907 (Adams and Longino, 2007;Dejean and Olmsted, 1997;Klingenberg et al, 2007;Mueller and Wcislo, 1998;Ramos-Lacau et al, 2012;Schultz et al, 2002;Weber, 1941Weber, , 1945Weber, , 1946Weber, , 1947Weber, , 1969bWeber, , 1972bWeber, , 1982Wheeler, 1907) (Bucher, 1974;Diehl-Fleig and Diehl, 2007;Klingenberg and Brandão, 2009;Klingenberg et al, 2007;Weber, 1941Weber, , 1945Weber, , 1969bWeber, , 1982Wheeler, 1907) Mycetosoritis x x x -Underground. 1 to 2 chambers Small mound, single entrance (Mueller et al, 2010;Wheeler, 1907) AJ, TRS, JSC unpublished.…”