Idiodes apicata

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

publication ID 10.11646/zootaxa.1264.1.1

publication LSID

persistent identifier

treatment provided by


scientific name

Idiodes apicata


Idiodes apicata   , Corula geometroides   and Conosara castanaea  

This clade was poorly supported by bootstrap analysis. The sequence divergence percentage between the lithinine I. apicata   and the other two species was 7.6% (28S D2). The Lithinini   is one of the most widespread ennomine tribes and occurs on every continent ( Weintraub et al. 1995). Idiodes   is one of the most species rich lithinine genera and consists of a total of nine Australian species and possibly a number of undescribed species ( Holloway 1987). It is a widespread genus that extends from southern Australia through Melanesia to the Philippines but appears to be most diverse in southeastern Australia. I. apicata   is also widely distributed in Australia from tropical Queensland to most of southern Australia ( Common 1993). Adults are moderately large moths. Both forewings and hindwings are similarly coloured and patterned and are usually an ochreous brown with a darker oblique line although variations are common. Wings are spread widely and are appressed to the substrate at rest. Lithinine caterpillars are fern­feeders and, typically, Idiodes Guenée   larvae feed on Pteridium esculentum Forst. (Bracken Fern)   (Pteridophyta).

I. apicata   shares the following features with the two nacophorines:

—rounded, non­protuberant frons ( C. geometroides   only); short labial palps ( C. geometroides   only); frons basal shelf absent; small projection dorsad to antenna; nonfoveate forewing; A3 pecten without swollen hind­tibia ( C. castanaea   only); simple, acute uncus; socii; large V­shaped gnathos; articulated processes of the anellus (Fig. 109); several discrete cornuti attached to the vesica (Fig. 110); antrum; large corpus bursae; signum ( C. geometroides   only) (Fig. 111).

Differences in adult morphology between I. apicata   and the two nacophorines are as follows:

—ciliate antennae; areolate forewing; relatively long epiphysis; relatively long hindtibia; hair­pencil and groove in hind­tibia; uncus relatively long; modified cucullus (Fig. 109); sclerotised ductus bursae (Fig. 111).

The long hind­tibia in I. apicata   was distinctive among all species surveyed in this study and may be an apomorphy for the genus. It is not known whether this limb elongation is characteristic of other Lithinini   .

The eggs of I. apicata   are very similar to those of Amelora leucaniata   , nebulosa and zophopasta (Young, in press). Shared characteristics are:

—loose or loosely attached; domed aeropyles, large openings present on all surfaces; double­ridged cell walls (Fig. 112).

Idiodes Guenée   eggs also exemplify the more typical lithinine characteristics as described by Salkeld (1983). The eggs of this species closely resemble those of two Nearctic lithinine species described by Salkeld, Petrophora subaequaria Walker   and Homochlodes fritillaria Guenée. Common   features are: narrow, rather elongated eggs with a markedly truncated anterior pole; marked all over by quadrate, elongated, concave cells with moderately broad, double­ridged and elevated walls; prominent longitudinal ribs; elevated aeropyles with large to very large openings; rough chorion (Fig. 112).

Larval and pupal material for C. castanaea   were unavailable; however larval features in common between I. apicata   and C. geometroides   are as follows:

—short spinneret; SV1, SV3 and V1 on A 1 in vertical alignment; no extra prolegs.

However there were also some important differences in larval morphology between the two species. The crochet arrangement in the mature larvae of C. geometroides   is a uniordinal uninterrupted mesoseries whereas in I. apicata   the more common biordinal, incompletely interrupted mesoseries is present. Uniordinal crochets are unusual in mature geometrid larvae however they were also noted in the geometrine H. percomptaria   , the larentiine Euphyia   nr. severata, the oenochromines s. l. Dichromodes   and N. curtaria   and the sterrhine Scopula perlata   . L3, SV1 and V1 on A3–5 are in vertical alignment in I. apicata   but not in C. geometroides   . Six lateral setae are present on the A6 proleg of I. apicata   whereas only four are present in C. geometroides   . Interestingly, this number of A6 lateral setae unites the Amelora   group i.e. A. sparsularia   , Androchela milvaria   , Cassythaphaga macarta   and D. amblopa (McQuillan 1996)   and also the robust­bodied genus, Capusa   .The crochet arrangement in the first instar larva of I. apicata   is also an unusual uniordinal penellipse broken laterally instead of the more common interrrupted mesoseries found in this study. This configuration was also present in the Australian nacophorines Melanodes anthracitaria   and Capusa cuculloides   . Thus I. apicata   also shares two unusual larval features with Capusa   : six A6 lateral setae and the crochet arrangement in the first instar larva.

Shared pupal features were as follows:

—smooth cuticle; exposed labium; concealed meta­tibia; pro­thoracic spiracle present, only well­developed in C. geometroides   ; punctures small, deep, dense, randomly distributed, on meta dorsum and A 1–7 in I. apicata   , but on A 1–8 in C. geometroides   ; dorsal groove, deep, well­developed.

Fore­femora are exposed and the lateral groove developed only in I. apicata   . Instead of the bifurcate cremaster present in Corula Walker   , I. apicata   has four pairs of cremastral setae. In this latter aspect I. apicata   is distinct from the Amelora   group (McQuillan 1996) despite sharing egg characteristics, absence of extra larval prolegs and six lateral setae on the larval A6 proleg