MACARIINI, Guenee, 1858

Scoble, Malcolm J. & Krüger, Martin, 2002, A review of the genera of Macariini with a revised classification of the tribe (Geometridae: Ennominae), Zoological Journal of the Linnean Society 134 (3), pp. 257-315 : 259-260

THE MACARIINI : A PERSPECTIVE

Details of macariine structure, both for adults and immature stages, are provided by Krüger (2001) in a work on African species. The introductory component to that study applies across the tribe so just a perspective on macariine biology is presented here.

Macariines typically are medium-sized, ennomine geometrids with a global distribution. Many species live in tropical or subtropical regions, although only 15 described species are listed for Australia ( McQuillan & Edwards, 1996). The group is well represented in North America with 253 species recorded by Hodges et al. (1983). A total of 270 macariine species (previously described or new) are accepted by Krüger (2001) in Africa, Madagascar and Arabia. Macariines also occur in cold regions, as far north, for example, as northern Yukon, Canada ( McGuffin, 1972) and the Kola Peninsula, north-western Russia ( Kozlov & Jalava, 1994).

The tribes probably most closely related to Macariini are Cassymini and Eutoeini (Holloway, [1994]; Krüger, 2001). In all three groups, the pupa has a bifid cremaster and in males the valva is divided. The Boarmiini , which are also related, have a bifid cremaster but the valva is usually undivided (Holloway, [1994]).

Wing pattern varies across the tribe as, to a lesser extent, does wing shape. Nevertheless, one arrangement is of particularly widespread occurrence across genera and geographical regions. Examples are shown in Figs 22,33,188. The purpose of the whole moth figures (colour and black and white) is to illustrate variation across the tribe, so proportionally few moths with this pattern have been illustrated in the present work compared with the number that exists. This phenotype is found, particularly, in Macaria , Chiasmia , Semiothisa and Oxymacaria , making it difficult to assign species with this appearance to the appropriate genus based on external appearance alone. There are two components to this wing form – wing shape and wing pattern. The forewing is angular rather than rounded and notched just below the apex. The hindwing is produced into a short ‘tail’ at M3. In terms of pattern, characteristic elements include a rather faint yet distinct postmedial band or line both on the forewing and the hindwing. This band or line often is sharply angled as it meets the costal edge of the forewing. Typically, a large, conspicuous but somewhat poorly defined, interneural spot lies on the band just above its midpoint. This spot occurs on the forewing and often on the hindwing as well. The moths displaying this widespread pattern have two further bands or lines medially and antemedially. These markings usually run continuously from the costa of the forewing to the posterior edge of the hindwing.

Many species exhibit the wing shape just described, frequently display the transverse lines, but lack the distinctive spots. The situation in genera such as Itame , Digrammia , and many species of Isturgia (in its new expanded sense) is simpler consisting usually of a standard basic line pattern. The small, often ochreous to yellow, members of the Platypepla - group usually display a similar arrangement (e.g. Figs 1–3). In many of these macariines, the wing margins are more rounded.

Patterns found commonly in particular genera are noted under the appropriate generic treatment below.

Distribution

Macariines are particularly well represented in tropical and subtropical areas. Cladistic analysis by Krüger (2001) and biogeographical data suggest a late Gondwanaland origin of the tribe in Africa, with a subsequent spread to other zoogeographic regions. The Afrotropical region today holds the highest number of basal members of the clade. The paucity of Macariini in Australia is consistent with this explanation as Australia separated early in the history of the breakup of the supercontinent.

Foodplants

Legumes are the most frequent foodplants. Legumefeeding, a habit shared with Cassymini , appears to be the primitive condition within Macariini . Dispersal from the Afrotropical region into the Palaearctic and, from there, into the Nearctic, appears to have been accompanied by several shifts in foodplant preference to deciduous trees and conifers. Available records for members of the Platypepla -group indicate a different route of specialization on hemiparasitic plants in the Loranthaceae and Olacaceae .

Immature stages

Immature stages have been described in detail for very few species of Macariini . McGuffin (1972) provided descriptions and illustrations of all stages for several of the Canadian species, and Krüger (2001) has done the same for certain African species. The numbers of observations on immature stages represent such a small proportion of total macariine species that we have been unable to recognize diagnostic characters at the tribal or generic levels.