Colobopsis imitans

Relatively thermophilous; occurring in Sicily from a few meters above sea level to at least 1015 m elevation, ascending up to 1290 m a.s.l. in Morocco, and so far known from coastal lowland areas in Spain. Probably common but also heavily under-recorded due to its cryptic arboreal lifestyle, low colony population (most-likely monogynous), effective mimicry and long periods of inactivity during the most arid and coldest times of the year. Workers and soldiers are unlikely to descend to the ground but were observed to do so at least once, following a sparsely populated Crematogaster scutellaris trail. Soldiers, in general, are difﬁcult to find outside the nest and are usually seen acting as gatekeepers of the nest entrance. Founding queens were observed to do the same. Nests are hidden in minute holes on the dead parts of arboreal trunks, where C. imitans often seems to act as secondary user of cavities excavated by xylophagous insects. It exploits Andricus quercustozae (Bosc, 1792) oak galls as nests [occupying about 15% of galls collected in Bosco della Ficuzza (Sicily) in a recent survey, authors’ unpublished data], in a similar way to Colobopsis truncata (see: Giannetti et al., 2019, 2021; Fürjes-Mikó et al., 2020). Polydomy appears probable due to repeated ﬁndings of groups of workers with no queen within oak-galls. Nesting observed on several diverse plant species, including at least: Citrus reticulata Blanco, ''Ci. sinensis (L.) Osbeck, Laurus nobilis L., Olea europaea L., Quercus ilex L., Q. pubescens-group, Q. suber L., Pyrus communis L. and Pittosporum tobira'' (Thunb.) W.T.Aiton. Dense populations appear to have been found in old Citrus orchards, relatively sparse cork oak (Q. suber) woods and also in deciduous oak forests. However, C. imitans occurs in a broad range of habitats, from cities to agricultural lands to natural forest habitats, but information available has so far been insufﬁcient to depict a satisfactory picture of habitat preferences. Despite the earlier claim by Carpintero et al. (2005), there is currently no evidence backing the fascinating hypothesis that C. imitans foundress queens prefer trees hosting Crematogaster scutellaris to found their colonies. A focused investigation on this topic would be interesting. Nuptial flights for C. imitans occur approximately in the same period as C. truncata (alates in Sicily observed from June 30 to July 13, N = 5, see Supporting Information, File S1). Winged queens and males were repeatedly seen to be attracted by artificial light at night.

Identification
Generally easy to determine on the basis of worker material due to strong chromatic differentiation from Colobopsis truncata and allopatric distribution (although further investigation is required for possible contact regions in southern Iberia and southern Italy). Some small worker specimens may appear almost completely black, therefore lacking the typical chromatic pattern; workers with entirely red mesosoma seldom observed. Tentative identiﬁcations of isolated soldier or queen specimens should be much more cautious, although their chromatic appearance may sometimes appear to be explicit. The low number of males and the lack of particularly evident distinctive characters from C. truncata do not allow a safe species-level identiﬁcation of this caste based on morphology. As for workers, the morphometric linear discriminant function provided in the Results section should help with dubious cases, including decoloured specimens. Finally, DNA barcoding, which can be used for the same purpose and can also be employed on the other castes, shows relatively low error rate but may present risks due to the polyphyletic pattern that we observed.

Distribution based on Regional Taxon Lists
Palaearctic Region: Algeria, Italy, Morocco, Portugal, Spain.

Nomenclature

 * . Colobopsis imitans Schifani et al., 2021: 11, figs. 10-12 (w.s.q.m.) ITALY.

Type Material

 * Holotype worker from Mondello, Sicily (Italy), 38.1953, 13.3354, 5m, 14.X.2018, E. Schifani, (Hungarian Natural History Museum collection)
 * 14 paratype workers, same data as holotype.