Camponotus macilentus Smith, 1877

Herrera Léon Baert Wouter Dekoninck, Henri W., Causton, Charlotte E., Sevilla, Christian R., Pozo, Paola & Hendrickx, Frederik, 2020, Distribution and habitat preferences of Galápagos ants (Hymenoptera: Formicidae), Belgian Journal of Entomology 93, pp. 1-60 : 13

Camponotus macilentus Smith, 1877

( ANTWEB: CASENT0173216). ( Map 9 )

This endemic and nocturnal species is uncommon in the archipelago. It was collected for the first time by Charles Darwin in 1835 ( SMITH, 1877; WHEELER, 1919; LUBIN, 1984). It is known mainly from dry areas and is rarely found in the humid zones. It is distributed on 13 islands and is known to nest under rocks, and in hollow twigs in dry branches of B. graveolens and M. octogona previously inhabited by termites (WHEELER, 1919, 1924). It has been observed collecting honeydew from scale insects on the trunks and stems of Scalesia gordilloi O. Hamann & Wiumand and it has been reported visiting flowers of C. lutea , C. molle , S. cordata and extrafloral nectaries of O. echios and J. thouarsii ( MEIER, 1994; BOADA, 2005; MCMMULLEN, 2011, 2012). C. macilentus has been collected from mangroves ( Rhizophora mangle L., L. racemosa ), B. graveolens , C. galapageia , under trees of H. mancinella , and in undergrowth (like I. triloba ) and ferns. It has also been collected in areas dominated by Psychotria rufipes Hook. f. , Z. fagara , S. microcephala , C. pyriformis and P. juliflora . Camponotus macilentus apparently is strongly associated with forests of B. graveolens (HWH, pers. obs.).

Recent sampling (on volcanoes Alcedo and Darwin) show that the species is abundant in better conserved areas. Camponotus macilentus could be threatened by invasive species on Baltra, Floreana, Española and Santa Cruz islands. It was collected for the last time on Santa Cruz in the Littoral Zone in 1996 and in the Humid Zone in 2001 and has not been found since then despite intensive collections in all vegetation zones (using a large number of collecting methods) over the last 12 years. LUBIN (1985) suggested a probable displacement of C. macilentus due to the invasion of Tetramorium bicarinatum (Nylander, 1846) during the Niño event of 1982–1983 on Española. Camponotus macilentus is extremely shy and prefers to escape fast when threatened. In natural habitats it is preyed upon by T. stolzmanni , a crab–spider present in littoral, dry and transition zones, especially in shrubs of C. galapageia ( LUBIN, 1983) . Camponotus macilentus is a complex of at least 12 subspecies (WHEELER, 1919, 1924, 1933), that requires further study.

Figures

Map 9. Distribution of Camponotus macilentus Smith, 1877.