Myrmecia pyriformis

Myrmecia pyriformis is a nocturnal forager whose activity outside the nest is largely restricted to night. Most foragers make only one foraging journey per night, leaving the nest individually at dusk to forage on nest-specific Eucalyptus trees. The majority of foragers return to the nest in the morning twilight, but individuals who capture prey often make multiple trips during the night. Foragers imbibe liquid food while abroad and likely share these resources via trophallaxis once within the nest. (Reid et al., 2013; Narendra et al., 2013)

Colonies can have either a normal, dealate queen or survive without a morphological queen (Dietemann et al., 2004). When the queen is absent a few mated workers are able to reproduce and maintain the colony (i.e. (gamergates). A colony collected without a queen continued to produce workers for the next three years (Sanetra, 2011). Queens generally mate with multiple males, estimated to be 2.6 on average. When gamergates are present, there are generally more than one (Sanetra, 2011).

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Biology
Myrmecia pyriformis is a nocturnal forager. Most foragers make only one foraging journey per night, leaving the nest individually in a narrow light-window in the evening twilight to forage on nest-specific Eucalyptus trees. The majority of foragers return to the nest in the morning twilight, while few attempt to return to the nest throughout the night (mainly those that are returning with prey). Activity during the night varies with moon illumination, likely due to changes in light levels which influence navigation to and from the nest. As light levels drop, ants pause for longer, walk more slowly, the success in finding the nest is reduced and their paths became less straight. In both bright and dark conditions ants rely predominantly on visual landmark information for navigation and landmark guidance becomes less reliable at low light conditions. It is likely that poor navigational efficiency at low light levels cause the majority of foragers to restrict navigational tasks to the twilight periods, where sufficient navigational information is available (Reid et al., 2013; Narendra et al., 2013)

Colony life history
Wheeler (1916) described a mating flight near Armidale in New South Wales: "As soon as a male (and there were hundreds of males to every female) captured a female on a bush, other males surrounded the couple till there was a struggling mass of ants forming a ball as large as one's fist. As many as half a dozen of these balls would keep forming on every little bush and this went on throughout the morning". After mating, young winged queens found colonies independently in a non claustral manner (Life History). Colonies can grow up to a few thousand workers (Sanetra, 2011).

Castes
Myrmecia pyriformis workers are markedly polymorphic in size; minor workers are almost half the size of majors. All workers have a spermatheca, and three gamergates (intermediate in body size) were found in one orphaned colony (Dietemann et al. 2004). This is the only record of gamergates in subfamily Myrmeciinae, and they apparently function as replacement reproductives, after death of the founding queen. In a colony collected from Calga, NSW, queens had 33.3±2.1 (n=5) ovarioles, workers had 21.4±5.4 (n=82)(Dietemann et al. 2004). In a colony collected from the campus of Flinders University in Adelaide, one queen had 30 ovarioles, workers had 8-12 (C. Peeters unpublished). This difference in ovariole numbers may indicate that these populations 1200km distant are genetically differentiated.



Nomenclature

 *  pyriformis. Myrmecia pyriformis Smith, F. 1858b: 144, pl. 10, figs. 1-6 (w.q.m.) AUSTRALIA. Wheeler, G.C. & Wheeler, J. 1971d: 252 (l.); Imai, Crozier & Taylor, 1977: 345 (k.). Subspecies of forficata: Forel, 1910b: 2. Revived status as species: Clark, 1927: 36. Senior synonym of sanguinea: Brown, 1953j: 9. See also: Crawley, 1926: 377; Clark, 1951: 99.
 * sanguinea. Myrmecia sanguinea Smith, F. 1858b: 148 (w.) AUSTRALIA (Tasmania). Mayr, 1876: 94 (q.); Forel, 1910b: 3 (m.); Wheeler, G.C. & Wheeler, J. 1952a: 112 (l.). Junior synonym of forficata: Clark, 1951: 93; of pyriformis: Brown, 1953j: 9. See also: Crawley, 1926: 378.

References based on Global Ant Biodiversity Informatics

 * Andersen A. N., B. A. Myers, and K. M. Buckingham. 1991. The ant fauna of a Mallee outlier near Melton, Victoria. Proceedings of the Royal Society of Victoria 103(1): 1-6.
 * Andersen A. N., T. D. Penman, N. Debas, and M. Houadria. 2009. Ant community responses to experimental fire and logging in a Eucalypt forest of south-eastern Australia. Forest Ecology and Management 258: 188-197.
 * Crawley W. C. 1926. A revision of some old types of Formicidae. Transactions of the Entomological Society of London 1925: 373-393.
 * Emery C. 1911. Hymenoptera. Fam. Formicidae. Subfam. Ponerinae. Genera Insectorum 118: 1-125.
 * Emery, C. "Catalogo delle formiche esistenti nelle collezioni del Museo Civico di Genova. Parte terza. Formiche della regione Indo-Malese e dell'Australia (continuazione e fine)." Annali del Museo Civico di Storia Naturale Giacomo Doria (Genova) (2) 5, no. 25 (1887): 427-473.
 * Imai H. T., R. H. Crozier, and R. W. Taylor. 1977. Karyotype evolution in Australian ants. Chromosoma 59: 341-393.
 * Taylor R. W. 1987. A checklist of the ants of Australia, New Caledonia and New Zealand (Hymenoptera: Formicidae). CSIRO (Commonwealth Scientific and Industrial Research Organization) Division of Entomology Report 41: 1-92.
 * Taylor R. W., and D. R. Brown. 1985. Formicoidea. Zoological Catalogue of Australia 2: 1-149.
 * Ward P. S., and D. A. Downie. 2005. The ant subfamily Pseudomyrmecinae: phylogeny and evolution of big-eyed arboreal ants. Systematic Entomology 30: 310-335.