Geometrinae (Ferguson, 1985)

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

The Geometrinae and Oenochrominae s. str. as closely related groups

The Oenochrominae were originally erected by Guenée in 1857 and initially included the genera Monoctenia Guenée , Oenochroma Guenée , Arhodia Guenée , Phallaria Guenée , Gastrophora Guenée , Sarcinodes Guenée and Hypographa Guenée. Subsequently many genera, the so­called slender­bodied oenochromines that could not be placed into other subfamilies, were placed into the Oenochrominae based predominantly on shared wing venational characters. In order to resolve the uncertain coherence of the group Scoble and Edwards (1990) proposed the term Oenochrominae s. str. for the robust­bodied genera based around Oenochroma and the balance of oenochromine taxa as the Oenochrominae s. l.

The Oenochrominae s. str. is a predominantly Australasian group and most species are found in southern Australia, a geographical distribution similar to that of the robust­bodied Geometrinae . These oenochromines resemble each other superficially and have general morphological similarities in genitalia and wing venation, but Scoble and Edwards (1990) were unable to define synapomorphies for the group. Nonetheless they are characterised by the following features: robust bodies, well developed uncus and gnathos, broad valvae that sometimes bear various sclerotisations and a well­developed anellus. In most taxa the fultura superior fuses with the transtilla to form a rigid plate ( Scoble & Edwards 1990). Food plants are from the Proteaceae and Myrtaceae (especially Eucalyptus ) although Phallaria has also been recorded feeding on Acacia P. Mill. (Leguminosae) and Dodonaea L. ( Sapindaceae ) ( McFarland 1988). The antennae of Proteaceae feeders are generally unipectinate and Myrtaceae feeders bipectinate ( Holloway 2003); although an exception is the male of the eucalypt feeding Monoctenia smerintheria Felder & Rogenhofer , which has unipectinate antennae. Larvae often have an extra pair of vestigial prolegs on A5 [an exception is Phallaria ophiusaria Guenée ( Anderson 1902) ]. The pupae usually have only a single apical pair of robust and divergent cremastral setae ( McFarland 1988).

In the 28S D2 analysis the oenochromine M. falernaria was linked as a sister species to the pseudoterpnine H. electrica and the oenochromine O. vinaria as a sister taxon to these two species, with low bootstrap support (Fig. 10). In the combined gene analysis O. vinaria was supported as a sister species to the Geometrinae (Fig. 15). Similarly the Geometrinae and Oenochrominae s. str. form a monophyletic clade in a morphological analysis based on 112 characters (Fig. 16), but with low bootstrap support. All outcomes indicate a close relationship between these two subfamilies.

Morphologically, the oenochromines s. str. and geometrines in this study show some interesting similarities. Both the pseudoterpnines and oenochromines s. str. are strong flying, robust­bodied insects. At least one species, Parepisparis lutosaria Felder & Rogenhofer has greenish colouration in the adult ( McFarland 1988) and other species such as Onychodes traumataria Guenée , Oenochroma vinaria and Monoctenia have yellowish colouration that is present in many Geometrinae e.g. Mixochroa gratiosata , Dysphania and Heliothea Boisduval. The females of A. lasiocamparia and M. falernaria have complex antennae; the former is bipectinate and the latter dentate. Similarly the female of H. percomptaria has dentate antennae. Unipectinate antennae, although rare in the Geometridae , are characteristic of Proteaceae feeding oenochrominaes. Significantly, this attribute has been noted in an undescribed grey geometrine possibly related to Sterictopsis occurring in northern Western Australia (unpubl. data).

Wing characters also unite the two groups. A. lasiocamparia and M. falernaria and also Onychodes traumataria have the classical geometrine hind­wing venational character of M 2 situated closer to M 1 than M 3; however the more typical geometrid character is present in O. vinaria . All four of these oenochromines also possess two wing venational characters usually present in Geometrinae (see above): R separate from Rs and anastomosing with Sc for a short distance in the forewing and R 2–5 stalked in the forewing. The frenulum is also moderately reduced and associated with an expanded humeral lobe and the typical geometrine tympanal morphology is present in all four species. However the frenulum is not reduced in Parepisparis Bethune­Baker ( Scoble & Edwards 1990) .

As discussed above, under Geometrinae , some Pseudoterpnini have rather atypical ansal structure that more resembles the ansal morphology found in the Oenochrominae , providing further evidence that the two subfamilies are closely related. This characteristic tapering ansa is also found in A. lasiocamparia and M. falernaria ; however in O. vinaria the ansa is more similar to the geometrine type i.e. narrow at the base, widening mesally and again tapering apically. This feature further supports a sister species placement for O. vinaria to the Oenochrominae s. str.

Certain aspects of the male genitalia are also similar. The aedeagi of O. vinaria (Fig. 36) and M. falernaria (Fig. 37) are rather geometrine­like. As described above for the Geometrinae , the caecum of the aedeagus is long, slender and tapered and the cornuti are not discrete spines and rods but are rather ridges or folds in the sclerotised outer tube and are not attached to the vesica. However the aedeagi of A. lasiocamparia (Fig. 38), Parepisparis ( Scoble & Edwards 1990) and Onychodes traumataria lack the long and slender caecum but have poorly defined cornuti. This reduction in the cornuti and corresponding rugosity of the tubular sheath was also a feature of the Australian boarmiines, caberines and macariines examined in this study (Appendices 2–5). On the other hand, the elongated caecum was almost exclusively a feature of the Geometrinae and Oenochrominae (Figs 31, 32, 34, 36, 37, 38). Superficially the male genitalia of all species of oenochromines s. str. and geometrines examined were similar with a simple uncus, relatively simple valvae and a small juxta. All species also have a very well developed gnathos (Figs 25, 26, 27, 33, 39, 40, 41); however the male genitalia in Parepisparis are unusual in possessing divided valvae ( Scoble & Edwards 1990).

The immature stages also share common features. Eggs are similar in general shape and form. Most are laid flat [ A. lasiocamparia is a notable exception (Fig. 42)] and have rounded sides with little surface sculpturing (Fig. 42). The larvae of Arhodia lasiocamparia Guenée and M. falernaria also share several typical geometrine features: a papillate integument, bifid head ( Ferguson 1985) and blunt setae. This combination of characters was also recorded for the Australian boarmiine Scioglyptis sp. and the Australian nacophorines, Stibaroma melanotoxa and Mochlotona phasmatias ; although the granulated integument of these taxa is probably not homologous to the more pronounced, regularly papillate eipidermis of the geometrines and oenochromines. These features were not present in O. vinaria . Interestingly this species is differentiated from the other two by being a Proteaceae and not Eucalyptus (Myrtaceae) feeder, having nongeometrine wing venation, possessing bipectinate antennae with simple terminal segments (typically a feature of Boarmiini and Caberini ) possessing a geometrine­like ansa and is separated in the DNA analysis (28S D2) as a sister taxon to ( M. falernaria + H. electrica ), although with a low bootostrap percentage. Furthermore the mature larvae of O. vinaria is exceptional among other geometrids examined in this study by possessing a trisetose SV setae on A1 (Fig. 43), although this putatively primitive condition is also found in Epirrhanthis Hübner and the New Zealand representatives of the oenochromines s. l., Dichromodes and Samana Walker ( Dugdale 1961) . Other robust­bodied oenochromines with bifid heads are Parespisparis lutosaria , Phallaria ophuisaria Guenée and Monoctenia smerintheria ( McFarland 1988) . The SV1, SV3 and V1 setae on the first abdominal segment of all geometrine and oenochromine larvae in this study were unaligned and not vertically aligned as in most ennomine larvae. However this attribute is also characteristic of the Larentiinae and Sterrhinae and is possibly correlated with body shape. In addition, all geometrines and oenochomines s. str. examined and Parepisparis virgatus Scoble & E. D. Edwards ( Scoble and Edwards 1990) presented only three lateral setae on the A6 proleg. This feature is considered characteristic of the Geometrinae ( Holloway 1996) but was also present in the outgroup species (three noctuids and one drepanid).

The first instar larvae of both subfamilies also show some similarity. The setae of the first instar larvae of the Australian green geometrines Chlorocoma vertumnaria , C. externa Walker , C. melochrossa Meyrick and E. fugitivaria Guenée are all relatively very short and clubbed. These are also features of A. lasiocamparia , M. falernaria and O. vinaria except that, yet again, the setae of O. vinaria are not clubbed. These attributes were also noted in the boarmiine Gastrinodes bitaenaria , the Tasmanian Archiearinae and the Australian asthenine Poecilasthena in this study. As mentioned above, the first instar larva of Hypobapta has been recorded as having vestigial prolegs on A5 ( Common 1993), a typically oenochromine character, although this was not seen in H. percomptaria in this study.

Only the pupae of H. percomptaria , Euloxia fugitivaria , A. lasiocamparia , M. falernaria and O. vinaria were available for detailed examination. All were superficially similar and shared the following characteristics:

­ stout pupae, except slender in E. fugitivaria ; fore­femur not visible; spiracles present on A2–8; punctation on A1–6, small, shallow and randomly distributed, absent in E. fugitivaria ; well­developed pro­thoracic spiracle present, but weak in H. percomptaria ; deep dorsal groove and shallow lateral groove present, but both weak in the geometrines.

The bifurcate cremastral spines, punctation, dorsal and lateral grooves and mesothoracic spiracles described in the oenochromines here were also noted in the oenochromines Dinophalus drakei L. B. Prout , Hypographa Guenée , Monoctenia smerintheria , Parespisparis lutosaria and Phallaria ophuisaria by McFarland (1988). The most notable difference between the geometrine and the oenochromine pupae was the presence of four pairs of hooked, cremastral setae in the geometrines whereas in the oenochromines the cremaster terminated in long, robust, hamate setae, that diverged apically. The presence of four pairs of setae is characteristic of the Geometrinae ; however, as discussed above, the pseudoterpnines show some variation in this character with multiple and also bifurcate setae occurring in some genera. Geometrine pupae are also noted for their characteristic variegation in colour compared to the more typical unicolorous geometrid pupa. However, again, unicolorous pupae occur in some pseudoterpnines e.g. Sterictopsis .

The Indoaustralian geometrine genus Dysphania also shares features with the robust oenochromines. This genus was placed into a separate tribe by Holloway (1996) on the basis of a number of unique features. These geometrine moths are also large and stout, many have coremata originating in the anellifer, as in Oenochroma and Monoctenia (Figs 39, 40), the valvae are unusually wide for the Geometrinae and possess some ornamentation as in the Oenochrominae s. str. In particular the socii are vestigial and the uncus correspondingly well developed, as in the Oenochrominae . The larvae of D. militaris Linnaeus have not been fully described but lack the typically geometrine pronouncedly bifid head; however the pupae are variegated as is typical for the Geometrinae ( Mohn 2003) .

The uniting of the Geometrinae and the Oenochrominae s. str. is strongly corroborated by morphological characters and molecular data although the latter has low support apart from in the combined gene analysis where O. vinaria is given weak support as a sister species to the Geometrinae (Fig. 15). The two groups are united by the following synapomorphies:

Adult

M 2 originating closer to M 1 than M 3 in forewing; frenulum reduced with corresponding expansion of the humeral lobe; long and slender anterior caecum in aedeagus; reduced cornuti.

Larvae

Very short and clubbed setae in first instars; papillate integument; blunt setae in mature larvae; three lateral setae on A6 proleg.

More detailed study of both the Pseudoterpnini and the Oenochrominae s. str. should elucidate the preliminary findings of this study; however the evidence presented here gathered from three independent datasets appears sufficient to provide validity to a close relationship between the two Geometrinae and the Oenochrominae s. str.