Camponotus senex

In Costa Rica, C. senex is very common in lowland wet forest habitats. It can occur in both mature forest and highly disturbed areas. For example, workers are very common in canopy fogging samples from mature forest at La Selva Biological Station, yet I have also found them on the landscaping around the Juan Santa Maria airport near San Jose. Foragers are diurnal. Nests occur in highly insolated areas such as upper forest canopy, open scrubby or second growth vegetation, roadsides, and agricultural land. The species is an opportunistic cavity nester. Nests are in dead branches, ranging from narrow vine stems to relatively large branches. In surveys of Cecropia trees, I often find nests in internodes of saplings, or in mature trees abandoned by Azteca, or in peripheral portions of trees that have a dominant Azteca colony elsewhere in the crown. Importantly, they never make silk nests among leaves. (Longino 2006)

Identification
Longino (2006) - The subgenus Myrmobrachys of Camponotus is characterized by workers with a somewhat box-like propodeum that has a broad, subrectangular dorsal face. Within this group there is a confusing set of morphologically similar species that vary in details of shape, surface sculpture, and pilosity. In Costa Rica extensive faunal inventory work has resulted in an improved understanding of species boundaries. The species I identify as C. senex is all black, the side of the mesosoma is densely punctate, there are abundant short erect setae projecting from the sides of the head in full face view, the mesosomal dorsum is abundantly setose, the gastral dorsum is abundantly setose with an underlying pubescence that is sparse. Some species, such as the common Camponotus planatus and the silk-making Camponotus textor, have dense appressed pubescence on the gaster that nearly obscures the underlying cuticle and gives the gaster a yellow to white color. In contrast, the black cuticle of C. senex is easily seen beneath the dilute pubescence and the gaster appears black. There is strong worker polymorphism: the major worker is relatively large compared to minor workers. This contrasts with C. textor, which has major workers that are little larger than minor workers.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Colombia, Costa Rica, Ecuador, Honduras, Mexico, Panama, Peru, Trinidad and Tobago.

Biology
De Oliveira et al. (2015), studying ant occupancy of Cecropia trees in southwest Bahia, Brazil, found three colonies of  opportunistically nesting in Cecropia pachystachya trees.

Koch et al. (2018) sampled this species in Caryocar barsiliense trees, in southeastern Brazil cerrado, as part of a study examining species interactions in ant-plants.

Passos and Leal (2019) - This species was found attending extrafloral nectaries of the plant Turnera subulata in northeastern Brazil Caatinga vegetation. Camponotus senex, classified as a subordinate species, was a common attendant at the extrafloral nectaries.

Nomenclature

 *  senex. Formica senex Smith, F. 1858b: 47 (w.q.) BRAZIL. Mayr, 1878: 868 (m.); Forel, 1879a: 96 (s.); Wheeler, G.C. & Wheeler, J. 1953e: 194 (l.). Combination in Camponotus: Mayr, 1862: 676; in C. (Myrmobrachys): Forel, 1912i: 91. Senior synonym of tomentosa: Emery, 1892b: 167. See also: Longino, 2006b: 133.
 * tomentosa. Tapinoma tomentosa Norton, 1868a: 60, pl. 2, fig. 2 (w.) MEXICO. Combination in Camponotus: Norton, 1868c: 3. Junior synonym of senex: Emery, 1892b: 167.

Longino (2006) - Camponotus senex was described in 1858 from material collected in Brazil. I have not made extensive examinations of C. senex from museum collections, but in my own collecting experience I have identified as C. senex material from Costa Rica, Panama, Venezuela, and Guyana. The range of the species based on published identifications is Mexico to Brazil. Alex Wild examined a syntype of C. senex and provided a high-resolution image. It differs from the Costa Rican material in having red instead of black legs, but this is a character that appears intraspecifically variable in many species of Camponotus. The syntype is also similar to a montane form of C. textor found in Costa Rica, and I cannot easily distinguish the two. However, the montane form of C. textor is more likely to be a local endemic species or geographic variant of C. textor. Type specimens from Brazil are more likely to be conspecific with the widespread generalized cavity nester that I recognize in Central America and northern South America.

Through an early misidentification by Forel, it has been thought that C. senex builds silk nests. There is no mention of the nest of C. senex in Smith's original description nor in Mayr's (1878) redescription. Forel (1879) reviewed the Camponotus species related to C. senex and identified a collection from Cordoba, Mexico, as C. senex. The Mexican collection was from a “paper nest among branches,” and Forel noted the similarity to the silk nests of Camponotus chartifex and Camponotus nitidior (subgenus Dendromyrmex). Forel (1899) described the subspecies C. senex textor, based on material that Tonduz collected in Costa Rica, from a carton nest on leaves. Forel later (1905) identified Brazilian material as C. senex and reported Göldi’s observations that the larvae are used to spin silk for the nest. Wheeler (1915) reviewed use of larval silk for nest construction by ants, perpetuating the association of C. senex with carton nests. This was followed by Wheeler and Wheeler (1953), Schremmer (1979), and Holldobler and Wilson (1983). The name C. senex should be disassociated from the silk-spinning Camponotus and C. textor applied instead.

Given the lack of dense gastral pubescence on C. senex, it is unlikely that Norton’s Camponotus tomentosa is actually a synonym of C. senex. However, given the unavailability of types for the old Norton names, it can rest in oblivion under C. senex.

Type Material
Longino (2006) - Syntype worker, queen: Brazil, RJ, Constancia (Rev. H. Clark) (image examined).

References based on Global Ant Biodiversity Informatics

 * Adams B. J., S. A. Schnitzer, and S. P. Yanoviak. 2019. Connectivity explains local ant community structure in a Neotropical forest canopy: a large-scale experimental approach. Ecology 100(6): e02673.
 * Andrade-Silva J., E. K. C. Pereira, O. Silva, C. L. C. Santos, J. H. C. Delabie, and J. M. M. Rebelo. 2015. Ants (Hymenoptera: Formicidae) associated with pig carcasses in an urban area. Sociobiology 62(4): 527-532.
 * Antoniazzi R., R. N. S. L. Garoo, W. Dattilo, S. P. Ribeiro, and F. S. Neves. 2019. Ant species richness and interactions in canopies of two distinct successional stages in a tropical dry forest. The Science of Nature 106: 20
 * Armbrecht, I., and I. Perfecto. 2003. Litter-twig dwelling ant species richness and predation potential within a forest fragment and neighboring coffee plantations of contrasting habitat quality in Mexico. Agriculture, Ecosystems & Environment 97: 107-115.
 * Boer P. 2019. Ants of Curacao, species list. Accessed on January 22 2019 at http://www.nlmieren.nl/websitepages/SPECIES%20LIST%20CURACAO.html
 * Boscardin J., E. C. Costa, J. H. C. Delabie. 2014. Relation between ant communities and environmental quality in Eucalyptus grandis submitted to different weedy species control in the south of Brazil. Entomotropica29(3): 173-182.
 * Camarota F., S. Powell, A. S. Melo, G. Priest, R. J. Marquis, and H. L. Vasconcelos. 2016. Co-occurrence patterns in a diverse arboreal ant community are explained more by competition than habitat requirements. Ecology and Evolution DOI: 10.1002/ece3.2606
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Dejean A., B. Corbara, J. Orivel, R. R. Snelling, J. H. C. Delabie, and M. Belin-Depoux. 2000. The importance of ant gardens in the pioneer vegetal formations of French Guiana (Hymenoptera: Formicidae). Sociobiology 35(3): 425-439.
 * Emery C. 1890. Studii sulle formiche della fauna neotropica. Bull. Soc. Entomol. Ital. 22: 38-8
 * Emery C. 1894. Estudios sobre las hormigas de Costa Rica. Anales del Museo Nacional de Costa Rica 1888-1889: 45-64.
 * Escalante Gutiérrez J. A. 1993. Especies de hormigas conocidas del Perú (Hymenoptera: Formicidae). Revista Peruana de Entomología 34:1-13.
 * Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
 * Forel A. 1908. Ameisen aus Sao Paulo (Brasilien), Paraguay etc. gesammelt von Prof. Herm. v. Ihering, Dr. Lutz, Dr. Fiebrig, etc. Verhandlungen der Kaiserlich-Königlichen Zoologisch-Botanischen Gesellschaft in Wien 58: 340-418.
 * Franco W., N. Ladino, J. H. C. Delabie, A. Dejean, J. Orivel, M. Fichaux, S. Groc, M. Leponce, and R. M. Feitosa. 2019. First checklist of the ants (Hymenoptera: Formicidae) of French Guiana. Zootaxa 4674(5): 509-543.
 * Herrera H.W., and L. Roque-Albelo. 2007. Lista anotada de las hormigas de las Islas Galapagos, Ecuador. Fundación Charles Darwin. 13 pp
 * INBio Collection (via Gbif)
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Longino J. T. 2006. New species and nomenclatural changes for the Costa Rican ant fauna (Hymenoptera: Formicidae). Myrmecologische Nachrichten 8: 131-143.
 * Longino J. T. 2013. Ants of Nicargua. Consulted on 18 Jan 2013. https://sites.google.com/site/longinollama/reports/ants-of-nicaragua
 * Longino J. T., J. Coddington, and R. K. Colwell. 2002. The ant fauna of a tropical rain forest: estimating species richness three different ways. Ecology 83: 689-702.
 * Longino J. et al. ADMAC project. Accessed on March 24th 2017 at https://sites.google.com/site/admacsite/
 * Luederwaldt H. 1918. Notas myrmecologicas. Rev. Mus. Paul. 10: 29-64.
 * Maes, J.-M. and W.P. MacKay. 1993. Catalogo de las hormigas (Hymenoptera: Formicidae) de Nicaragua. Revista Nicaraguense de Entomologia 23.
 * Maravalhas J., and H. L. Vasconcelos. 2014. Revisiting the pyrodiversitybiodiversity hypothesis: long-term fire regimes and the structure of ant communities in a Neotropical savanna hotspot. Journal of Applied Ecology 51: 1661-1668.
 * Miranda P. N., F. B. Baccaro, E. F. Morato, M. A. Oliveira. J. H. C. Delabie. 2017. Limited effects of low-intensity forest management on ant assemblages in southwestern Amazonian forests. Biodivers. Conserv. DOI 10.1007/s10531-017-1368-y
 * Neves F. S., K. S. Queiroz-Dantas, W. D. da Rocha, and J. H. C. Delabie. 2013. Ants of Three Adjacent Habitats of a Transition Region Between the Cerrado and Caatinga Biomes: The Effects of Heterogeneity and Variation in Canopy Cover. Neotrop Entomol 42: 258268.
 * Philpott, S. M. 2005. Changes in arboreal ant populations following pruning of coffee shade-trees in Chiapas, Mexico. Agroforestry Systems 64: 219-224.
 * Philpott, S. M. 2006. Ant patchiness: a spatially quantitative test in coffee agroecosystems. Naturwissenschaften 93: 386-392.
 * Philpott, S.M. and P.F. Foster. 2005. Nest-site limitation in coffee agroecosytems: Artificial nests maintain diversity of arboreal ants. Ecological Applications 15(4):1478-1485
 * Pires de Prado L., R. M. Feitosa, S. Pinzon Triana, J. A. Munoz Gutierrez, G. X. Rousseau, R. Alves Silva, G. M. Siqueira, C. L. Caldas dos Santos, F. Veras Silva, T. Sanches Ranzani da Silva, A. Casadei-Ferreira, R. Rosa da Silva, and J. Andrade-Silva. 2019. An overview of the ant fauna (Hymenoptera: Formicidae) of the state of Maranhao, Brazil. Pap. Avulsos Zool. 59: e20195938.
 * Reis P. C. J., W. D. Darocha, L. Falcao, T. J. Guerra, and F. S. Neves. 2013. Ant Fauna on Cecropia pachystachya Trécul (Urticaceae) Trees in an Atlantic Forest Area, Southeastern Brazil. Sociobiology 60(3): 222-228.
 * Ribeiro L. F., R. R. C. Solar, T. G. Sobrinho, D. C. Muscardi, J. H. Schoereder, and A. N. Andersen. 2019. Different trophic groups of arboreal ants show differential responses to resource supplementation in a neotropical savanna. Oecologia 190(2): 433-443.
 * Ribeiro S. P., N. B. Espirito Santo, J. H. C. Delabie, and J. D. Majer. 2013. Competition, resources and the ant (Hymenoptera: Formicidae) mosaic: a comparison of upper and lower canopy. Myrmecological News 18: 113-120.
 * Ryder Wilkie K.T., A. L. Mertl, and J. F. A. Traniello. 2010. Species Diversity and Distribution Patterns of the Ants of Amazonian Ecuador. PLoS ONE 5(10): e13146.doi:10.1371/journal.pone.0013146
 * Siqueira de Castro F., A. B. Gontijo, W. Duarte da Rocha, and S. Pontes Ribeiro. 2011. As comunidades de formigas de serapilheira nas florestas semidecíduas do Parque Estadual do Rio Doce, Minas Gerais. MG.BIOTA, Belo Horizonte 3(5): 5-24.
 * Smith M. A., W. Hallwachs, D. H. Janzen. 2014. Diversity and phylogenetic community structure of ants along a Costa Rican elevational gradient. Ecography 37(8): 720-731.
 * Suguituru S. S., M. Santina de Castro Morini, R. M. Feitosa, and R. Rosa da Silva. 2015. Formigas do Alto Tiete. Canal 6 Editora 458 pages
 * Vittar, F., and F. Cuezzo. "Hormigas (Hymenoptera: Formicidae) de la provincia de Santa Fe, Argentina." Revista de la Sociedad Entomológica Argentina (versión On-line ISSN 1851-7471) 67, no. 1-2 (2008).
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * Wheeler W. M. 1916. Ants collected in British Guiana by the expedition of the American Museum of Natural History during 1911. Bulletin of the American Museum of Natural History 35: 1-14.
 * Wheeler W. M. 1922. The ants of Trinidad. American Museum Novitates 45: 1-16.
 * Yanoviak S. P., and M. Kaspari. 2000. Community structure and the habitat templet: ants in the tropical forest canopy and litter. Oikos 89: 259-266.