Formica paralugubris

A mountain wood ant that is a sister species to Formica lugubris.

Identification
A sibling species of Formica lugubris, these two species can be separated using queen pilosity characters and morphometrics (tables and discriminant functions to separate these two species and Formica aquilonia are provided by Seifert 1996).

Distribution based on Regional Taxon Lists
Nearctic Region: Canada. Palaearctic Region: Albania, Andorra, Austria, Germany, Iberian Peninsula, Spain, Switzerland.

Biology
Siefert (1996), in his description of this cryptic species provides rational for why this ant is distinct from its sibling species. This also suggests why our understanding of its biology, while studied, is entangled with studies of Formica lugubris.

During the last 18 years, a lot of biological investigations were performed on big polycalic colonies of Formica lugubris in the Swiss Jura mountains (e.g. Gris and Cherix 1977, Cherix and Rosengren 1979, Rosengren and Cherix 1980, Rosengren and Cherix 1981, Cherix 1983, Passera et al 1990, Cherix et al 1991, Cherix et al 1993, Walter et al, 1993). Extensive studies on allozyme variation (Pamilo et al 1992) gave clear evidence that there were two genetically distinct, sympatric species in the Swiss Jura mountains, where these species occur even syntopically. A clear exchange of genetic material between the two forms named 'type A' and 'type B' could not be demonstrated. In fact they behave like different species and show a clear preference for non-nestmate pupae of their own genetic type in a behavioural choice test (Rosengren et al 1994).

Nomenclature

 *  paralugubris. Formica paralugubris Seifert, 1996a: 199, figs. 4, 5 (w.q.) SWITZERLAND.

Worker


Whole surface of head (except of genae), mesosoma, gaster, coxae, femora, and tibiae with numerous erect setae which are on average shorter than in Formica lugubris. Dorsal plane of scape frequently with several short and semierect hairs. Eyes with numerous erect hairs the longest of which measure 22-40 mm. Frons of head less matt than Formica pratensis, comparable to situation in Formica rufa. Scape shorter and thicker than in F. pratensis: the ratio scape length/maximum midpoint scape diameter is <9.60. Median area of clypeus, frons and back of head, antennae, coxae, femora, tibiae and gaster more or less blackish. Dorsum of promesonotum with a dark patch, which is less well defined than in pratensis. Remaining parts of head and mesosoma yellowish red. For morphometric data and distinction from F. lugubris see tables 1 and 2.

Queen
Occipital margin of head with 20-75 erect setae, which are normally 40-80 11m long. Dorsal plane of scape frequently with a number of shorter, semierect setae. Eyes with numerous erect hairs of 22--45 11m length. Standing setae on pronotum, mesonotum, scutellum, lateral mesopleuron, ventrolateral propodeum, lateral metapleuron, hind tibia, and frontal face of gaster definitely shorter than in lugubris. In contrast to this situation, the standing setae on the whole surface of all gaster sternites are very long (250-350 11m). Clypeus more shining than dorsum of head and genae. Mesonotum and scutellum mildly shining, but less than in rufa. Dorsum of gaster shining. Dorsum of first gaster tergite with very fine transversal microsculpture and closely set microfoveae of 9-13 mm diameter and 15-30 mm midpoint distance. The microfoveae are the basis for the pubescence hairs (Fig. 4). Median area of clypeus, frontal and occipital parts of head, upper pronotum, mesonotum, scutellum, gaster, and tibiae usually blackish. Genae, underside of head, coxae, femora, lower pronotum, lateral sclerites of mesosoma, and petiole yellowish red. For morphometric data and differences to lugubris and aquilonia see Tab. 3.

Type Material
Nest No. G5 near the Chalet a Roch field station, 5 km SSW Le Brassus in the Swiss Jura mountains. Holotype (a queen) and 10 paratypes (4 queens and 6 workers). The workers were collected on 5 May 1993 and the queens in June 1994. The labelling is "CH: Jura, 5.5. 1993, Chalet a Roch, nest G5" in the workers and "CH: Jura, 6. 1994, Chalet a Roch, nest G5" in case of queens. Another 24 worker paratypes originate from the nests G 1-G4, which belong to the same polycalic nest system as the holotype nest and were collected on 5 May 1993.