Calosoma (Castrida) alternans (Fabricius, 1792)

Calosoma (Castrida) alternans alternans (Fabricius, 1792)

Carabus alternans Fabricius, 1792: 146 (type: "Americae insulis"; Zoologischen Museums der Universität Kopenhagen)
Calosoma laterale Dejean, 1826: 199 (preoccupied by Calosoma laterale Kirby, 1818) (type: Brésil; Muséum National d'Histoire Naturelle, Paris)
Calosoma granulatum Perty, 1830: 9 (type: Brésil)
Calosoma brullei Blanchard, 1843: 42
Calamata coxalis Motschulsky, 1865: 307
Calamata rugata Motschulsky, 1865: 308
Calosoma (Callistriga) alternans Breuning, 1927: 192
Calosoma (Callistriga) granulatum Breuning, 1927: 195
Caminara (Callistriga) alternans Lapouge, 1932: 417
Castrida alternans Jeannel, 1940: 95
Castrida alternans ssp granulatum Jeannel, 1940: 96
Calosoma (Castrida) alternans Gidaspow, 1959: 241
Calosoma (Castrida) alternans granulatum Gidaspow, 1963: 300
Calosoma (Castrida) alternans Erwin, 2007: 86

Length 24-30 mm. C. alternans differs from C. sayi, which is the only other species of Castrida with elytral, sculpture of heterodynamic type, because, while the primary intervals are of the same width than the secondary ones, the tertiary intervals are markedly reduced in size and elevation.
C. alternans occupies the southern part of Central America and most of South America up to northern Argentina. In this species we find two morphotypes. One consists of dark brown individuals superficially similar to C. sayi, with males having, in general, only one or two articles of the basal anterior tarsi with scarce hairy pads on the ventral side, on the apical part only. This morphotype is dominant in the populations of northward spreading area: Lesser Antilles (Dominica, Martinique, Trinidad), Panama, Colombia, Venezuela, Guyana, Peru and northern Brazil. The other morphotype is characterized by brightly metallic upper side of the body, with the pronotum slightly more transverse and males having three articles of the anterior tarsi with thick hairy pads, as it is the rule in the species of Castrida. This second morphotype tends to be dominant in the populations of the central western part of South America: central southern Brazil, Bolivia, Paraguay, Uruguay, Argentina . These populations were regarded by Breuning (1927: 195) as pertaining to a distinct species (Calosoma (Callistriga) granulatum), but were considered by Jeannel (1940: 96), and by later authors, rather as constituting a southern subspecies of C. alternans. However, considering the mingling of individuals of one type or another inside the same population, more recent authors (Erwin, 1999: 20) prefer to consider the infraspecific subdivision unnecessary.

Examined specimens and literature’s data
Argentina. Misiones: Panambi (SB); Entre Rios: Pronunciamiento (EM); Bahia Blanca, Buenos Aires (Gidaspow, 1963: 300)
Bolivia: Santa Cruz (Gidaspow, 1963: 300)
Brazil. Rio de Janeiro: Rio Bonito (SB); Bahia: Villa Victoria (SB); Santa Catarina: Florianopolis (EM), Nova Teutonia (SB); Mato Grosso: Uirapuru (SB); Brasilia (AMNH); Amazonas: Manaus; São Paulo (Breuning, 1927: 196); Manicoré, Santarem, Marañhão, Jaguariba river, Recife, Rio Grande do Sul: Porto Alegre; Minas Gerais: Lavras; Paranà: Rolândia (Gidaspow, 1963: 300)
Colombia. Guainía, La Coruna (SB), La Garita (Breuning, 1927: 197)
Curação. (Breuning, 1927: 196)
Dominica. (AMNH)
Guyana: Georgetown (AMNH), Upper Rupununi (Gidaspow, 1963: 298)
Honduras: Choluteca (Erwin, 1991: 22)
Martinique (France): La Trinité; St Barthélemy (Breuning, 1927: 197 sub granulatum coxale)
Nicaragua. (Erwin, 2007: 86)
Panama: Chiriqui (Breuning, 1927: 197); Margarita, Madden Dam, Altos de Maje, Diablo, Anton, Rio Hato, La Sabanas (Erwin, 1991: 22)
Paraguay. San Pedro: Nova Germania (SB), Cororo (SB); Caaguazu (SB); Alto Paranà (Gidaspow, 1963: 300)
Peru. Ica: Nazca 590 m (SB), Tumbez (Breuning, 1927: 197)
Uruguay. Canelones: Las Piedras (EM, SB)
Trinidad and Tobago (Erwin, 2007: 86)
Venezuela. Araqua: Palo Negro (SB); Caracas, Maracaibo (Breuning, 1927: 197); Cabimas, San Fernando de Apure, Monagas, Caripito, Bolivar (Gidaspow, 1963: 298)

Notes: Winged. It is attracted to the light at night. Adults and larvae may be caught using pitfall traps.
It lives in a variety of habitat from evergreen forests to pastures and plantations. In Bolivia it has been noted as a possible auxiliary to agriculture because of predation of caterpillars injurious to cotton plantations such as Alabama argillacea and Spodoptera frugiperda (Allen, 1977: 74).
Active individuals were captured mostly in the rainy season, from October to April.

Calosoma (Castrida) alternans
(Fabricius, 1775)
Perù, Ica prov., Nazca 590m., 9-11.3.1988, Czadek lg.
Calosoma (Castrida) alternans
(Fabricius, 1775)
Argentina, Misiones, Panambi, XII.57, Walz lg.
Calosoma (Castrida) alternans granulatum
Perty, 1830
Paraguay, San Pedro prov., 6km NW Nova Germania, 8-11.II.2008, Halada lg.
Calosoma (Castrida) alternans granulatum
Perty, 1830
Brazil, Bahia, Villa Victoria, Ch Pujol 1890
Calosoma (Castrida) alternans granulatum
Perty, 1830
Brésil (holotype of Calosoma laterale Dejean, 1826)
(coll. Muséum National d'Histoire Naturelle, Paris)