Rhytidoponera metallica (Fr. smith 1858)

Compiled by Warwick Don & Richard Harris 2005

Biostatus: Introduced

Classification

Family:	Formicidae
Subfamily:	Ectatomminae
Tribe:	Melophorini
Genus:	Rhytidoponera
Species:	metallica

Common name(s)

Metallic pony ants (Andersen 2002)

Synonyms (WWW5)

Chalcoponera pulchra Clark, Ponera metallica Smith, Rhytidoponera (Chalcoponera) caeciliae Viehmeyer, Rhytidoponera (Chalcoponera) metallica var. purpurascens Wheeler, Rhytidoponera (Chalcoponera) metallica var. varians Crawley

Origin

Rhytidoponera is a large genus with 104 described species, 76 of which occur in Australia (Shattuck 1999). One species is definitely established in New Zealand, R. chalybaea , a recent arrival from Australia. Intercepted on several occasions (associated with imported poles and sawn timber), this species probably became established here during the 1950s. A second species, R. metallica , is probably established, with several recent collections in Napier.

Distribution

R. metallica is likely to be established in Napier, at least temporarily, with recent collections there in 2001 and 2003 (PANZ) well away from the port. Earlier collections were made in Penrose, Auckland (1958; NZAC), again in Penrose in 1959 (Taylor 1961), and in Mt Manganui (1961; FRI), but no further specimens have been encountered at these locations.

General Description

Identification

The genus Rhytidoponera is distinguished by means of a tooth on the leading edge of the pronotum, pointing downward just above the front legs. The node of the petiole has distinct front, top and rear faces. The tips of the tibiae of the hind legs each have either a single small, simple comb-like spur, or two spurs, one large and comb-like and one small and simple.

Diagnostic features of the worker

Length about 6.5 mm; mesosomal profile is evenly convex (cf. chalybaea ); the subpetiolar spine has a broad base, which has an "angled"/bluntly pointed posterior profile (P. Holder, NPPRL); has a metallic green appearance.

[Rhytidoponera metallica] head. Image: April Nobile (Specimen code: CASENT0172345). www.antweb.org Image — Rhytidoponera metallica head. Image: April Nobile (Specimen code: CASENT0172345). www.antweb.org

Rhytidoponera metallica profile ANTWEB

[Rhytidoponera metallica] dorsal view. Image: April Nobile (Specimen code: CASENT0172345). www.antweb.org Image — Rhytidoponera metallica dorsal view. Image: April Nobile (Specimen code: CASENT0172345). www.antweb.org

Biology

In Australia, R. metallica lives mainly in moderately wooded or open areas. It is even abundant in lawns and gardens in some cities. Taylor (1961) notes it "constructs small, rather loosely integrated nests, usually among grass roots or beneath logs or stones." This species, Taylor observes, forages during the day on a wide variety of insects and other small arthropods.

Pest Status

A large species by New Zealand ant standards. As a consequence can cause concern when discovered in urban situations. Possesses a powerful sting and allergic reactions to the venom have been recorded (Solley et al. 2002).