Agriopis aurantiaria

Young, Catherine J., 2006, Molecular relationships of the Australian Ennominae (Lepidoptera: Geometridae) and implications for the phylogeny of the Geometridae from molecular and morphological data, Zootaxa 1264 (1), pp. 1-147 : 1-147

Agriopis aurantiaria and Alsophila aescularia

The strong association shown between these species in this study is also supported by the combined data analysis from Abraham et al. (2001) and Abraham (2002). The sequence divergence between the two taxa is only 1.0% (Appendix 6) (28S D2).

A. aurantiaria (Spring Usher, Scarce Umber) is a common boarmiine that is widespread through Europe and Asia Minor. This species inhabits deciduous forests and remnant woodlands and males fly in October and November. The females are brachypterous.

The genus Alsophila (winter moths), a group of slender­bodied Palaearctic geometrids, was placed into the Oenochrominae s. l. by Inoue (1982), Seven (1991) and Müller (1996). Holloway (1996) decided to assign this genus to the Alsophilinae on the basis of the recognised polyphyly of the Oenochrominae s. l. and its distinctiveness as a taxon. The definition of this subfamily which comprises 26 species in four genera in the Palaearctic and one Nearctic species is weakly based on wing venational characters which have some exceptions in the eastern Palaearctic fauna ( Hausmann 2001).

However several morphological characters warrant Alsophila’s placement in the Boarmiini . Nakamura (1987) placed Alsophila into the Ennominae on the basis of pupal characteristics and in particular pupal chaetotaxy and the possession of a bifid cremaster (a typically boarmiine feature). Patočka and Zach (1994) also commented that the pupa of Alsophila ( A. aceraria Denis & Schiffermüller and A. aescularia ) greatly resembled that of the boarmiine genus Theria Hübner. Other typical boarmiine features present in Alsophila are: a weak M 2 vein, a short and broad uncus, absence of socii, modified incised valvae, well­developed juxta, extended ventro­posteriorly and with no lateral processes and a straight aedeagus with few or no cornuti. The females of Alsophila are apterous similar to the females of A. aurantiaria .

Alsophila does possess some anomalous characters that appear to contradict its placement in the Boarmiini . Eggs are unusual in their upright orientation and almost unmarked chorion and the females cover their eggs with corethogyne ( Salkeld 1983; Patočka & Zach 1994; Hausmann 2001). By contrast boarmiine eggs are relatively uniform in structure, are usually narrow and elongated with cells arranged regularly in longitudinal rows and the chorion is often soft ( Salkeld 1983). The caterpillars of Alsophila are also unusual in posessing an extra pair of prolegs on A5, a characteristic more typical of the Oenochrominae ( Scoble & Edwards 1990) . Larvae also have eight lateral setae on the A6 proleg whereas most boarmiines have only four at this position ( Sato 1984). However multiple lateral setae occur in many ennomines, in particular the American Nacophorini and Azelinini ( Heitzman 1985; Poole 1987).

In the hind wing, Sc + R 1 and Rs are fused for more than ¼ the length of the cell, a feature characteristic of the Larentiinae and the forewings lack foveae. Hind­tibiae are relatively short. In the male genitalia the gnathos is absent but typically boarmiine features such as a Y­shaped prominent juxta (e.g. Alcis complex sensu Sato) and incised valvae are present ( Sato 1984). Correlated with their aptery and consequent lack of mobility, females lack tympana. However given molecular support and collaboration from some important morphological features, Alsophila is probably a derived boarmiine with some unusual features that are likely adaptations to an extreme environment. The upright orientation, clutch sizes and massing of the eggs of Alsophila are probably, as observed in some Australian Nacophorini , correlated with synchronous hatching and very active first instar larval dispersal ( McFarland 1973), behaviour most likely to be an adaptation to a hostile environment.