Larentiinae (Holloway, 1994)

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

Larentiinae

Monophyly of the Larentiinae

The larentiines in this analysis are represented by 5 species from four tribes: Xanthorhoini , Hydriomenini , Cidariini and Operophterini . Two of the species ( A. pauper and Euphyia nr. severata) are Australian and the other three Palaearctic. The monophyly and the basally diverged position of the group are supported by the 28S D2 analysis (Fig. 10). The Larentiinae (represented by one taxon only) was placed in a basal polytomy with the outgroup noctuid in both the EF­1 (Figs 12–14) and the combined molecular analysis (Fig. 15).

However the monophyly of the Larentiinae as a subfamily is only weakly supported by the following wing characters: discal spot present on both forewings and hindwings, forewings usually with numerous fine transverse fasciae often arranged in multiple groups and in the hindwing, Sc + R 1 usually fusing with Rs for at least ½ the length of the cell. The group is defined more strongly by the absence of seta SV3 on abdominal segments in the larvae ( Singh 1953; Dugdale 1961). Given the strong support for a monophyletic clade of four tribes from this analysis and also the studies of Abraham et al. (2001) and Abraham (2002) (3 tribes) from molecular data, the security of this subfamily seems more assured. However this hypothesis needs to be tested further with more extensive sampling. Other, less definitive, morphological characters of the larentiines are as follows (from Scoble 1995; Minet & Scoble 1999):

Adult

—vein M 2 fully developed; wings much reduced in females of a few species; one or two areoles present in the forewing; coremata between A8 and genitalia often present; octavals on A8 often present; labides often present; hammer­headed ansa, also present in Cosymbiini (Sterrhinae) and also rarely occurs in the Ennominae ( Cook & Scoble 1992) .

Eggs

—very variable in morphology ( Salkeld 1983) but are generally laid flat and many are unattached to the substrate (common in herbaceous feeders) ( McFarland 1988).

Pupae

—distinct coronal suture separating frons and vertex; metanotum with rounded or obtuse frontolateral processes ( Patočka & Zach 1994).

The Larentiinae in a basally diverged position within the Geometridae

The position of the Larentiinae as a basal group within the Geometridae is supported by molecular data in this analysis and also the studies by Abraham et al. (2001) and Abraham (2002). This contradicts the traditionally held belief that the Archiearinae are the sister group to the rest of the Geometridae as reviewed by Holloway (1998). In fact, morphological characters only weakly support the basal position usually assigned to the Archiearinae .

Several characters have been used to corroborate a primitive phylogenetic position for the Archiearinae . Unlike most geometrids, Holarctic archiearines lack an accessory tympanum and have a very narrow fenestra media ( Minet 1983). Accessory tympana are typically present in moth families such as the Geometridae and Noctuidae in which the tympana are not isolated from the moving parts of the insect, and are therefore necessary to supplement hearing during flight to escape the predation of bats. Holarctic archiearines are diurnal and appear to utilize hearing when sitting on the ground where they are easily disturbed and difficult to intercept ( Surlykke & Skals 1998). In these species, a thick cuticle occupies the usual site of the accessory tympanum. Accessory tympana are also absent in moths that possess an abdominal tympanum in which the tympanal air sac is enclosed and buffered in a rigid capsule, as in the Pyralidae and Uraniidae , or in which the primary function of the tympanum is altered, as in the Drepanidae ( Hasenfuss 2000) . The lack of an accessory tympanum in the Archiearinae may, therefore, be a secondary adaptation to a diurnal habit and not a primitive character.

A large noctuoid­type exposed labial palpus in the pupa of Archiearis Hübner was also noted by Nakamura (1987) as a possible primitive feature but this character is variable within the genus and was not illustrated or noted by Patočka & Zach (1994) in their study of A. parthenias , A. notha and A. puella , nor was it noted in the arctic archiearine Leucobrephos brephoides ( Gibson & Criddle 1916; Forbes 1945, 1948). Furthermore Minet (1991) suggested that the inconsistent occurrence of noctuoid palps in Archiearis was most likely a malformation and that concealed labial palps also occur in the Noctuoidea. However Patočka and Zach (1994) further noted that the Archiearis pupa resembled drepanoid pupae because the metathoracic wings do not become concealed under the mesothoracic wings as in other Geometridae , but are visible as a narrow strip along the outer margin of the wings. The pupal cremaster in Archiearis ( A. parthenias and A. notha ) is distinctively T­shaped, the setae being two­segmented (illustrated by Nakamura 1987). Again, however, apart from a bifurcate cremaster, there is no mention of these features in L. brephoides ( Gibson & Criddle 1916; Forbes 1945, 1948). The unusual structure of the cremastral setae may differentiate Archiearis from the many other groups that have a bifurcate pupal cremaster, but, otherwise, this character is widespread through the Ennominae , Alsophilinae , some Scopulini and some Larentiinae ( Holloway 1994) . Pupation of Archiearis occurs in a small hole bored into rotten wood ( Patočka & Zach 1994). This combination of unusual features, diurnal habit, absence of secondary tympanum and pupal autapomorphies may indicate that Holarctic archiearines, rather than being a sister group to the Geometridae is a derived group within the family.

It is also interesting to map the occurrence of a chemical found in high concentrations in the Geometrinae , the green pigment geoverdin, with regard to the hypothesized basal positioning of the Larentiinae . According to a study by Cook et al. (1994), this chemical is present in trace quantities in the Noctuidae , is absent in Drepanidae , present again in trace quantities in Larentiinae and Sterrhinae , absent in Archiearis and present in large quantities in the Geometrinae . Cook et al. (1994) proposed from their study that this chemical was not a ground plan character in the Geometridae because of its absence in the Archiearinae . If the phylogeny proposed from this study is correct, the presence of this chemical, albeit in small quantities, in the Noctuidae , Larentiinae and Sterrhinae may well provide evidence for its inclusion in the geometrid ground plan. A stumbling block for this theory is the apparent absence of the pigment in the Drepanidae . On that account, it would be instructive to survey more genera and tribes from this family for both geoverdin and molecular data. The position of A. parthenias as a sister group to the ( Geometrinae + Oenochrominae s. str.) is not supported by bootstrapping and so does not necessarily compromise this proposed evolutionary pathway of geoverdin.

The putative basal position of the Larentiinae is also interesting from a broader phylogenetic perspective in the Macrolepidoptera. The Geometroidea were proposed as a sister group to the Hedyloidea, Hesperioidea and Papilionoidea on molecular evidence by Weller and Pashley (1995). They used a larentiine, Disclisioprocta stellata Guenée (Xanthorhoini) , as an exemplar geometrid and suggested that the common ancestor of the two groups may be a slight­bodied moth, possibly weak­flying and with crepuscular as well as nocturnal activity. These are all characteristics of the Larentiinae . However, as Scoble (1996) indicated, a more extensive analysis using exemplars from the other members of Geometroidea ( Uraniidae , Drepanidae and Sematuridae ) and possibly less derived members of the Noctuidae and Notodontidae is needed to provide more convincing evidence of relationships between the moths and butterflies.

The cosmopolitan distribution and high morphological diversity [including egg structure ( Salkeld 1983)] of the Larentiinae and its colonization of many diverse habitats (e.g. Brehm & Fiedler 2003) may also indicate an ancient origin. Some larentiine larvae also have the unusual (for Geometridae ) habit of concealing themselves by making nests from silk­tied or folded leaves ( McFarland 1988) and a few Chloroclystis Hübner are internal feeders of the reproductive structures of plants. It is believed, from fossil evidence, that both homoneurous and heteroneurous ancestors of modern­day Lepidopoteran groups were present and widely­distributed in Gondwana ( Gall & Tiffney 1983; Common 1993). Furthermore the discovery of part of a fossil lepidopteran resembling part of the sacculus of a larentiine male from the late Cretaceous in New Zealand provided evidence that the ancestors of this group may have existed in Gondwana before rifting began ( Harris & Raine 2002).

The Trichopterygini appear to be rather distinct within the Larentiinae because of the possession of many attributes that are present in the ground plan of the Geometridae but not present in other larentiine tribes. The following characteristics, present in the Trichopterygini , are absent from most larentiines:

—A3 transverse ventral setal comb [in Ennominae and Geometrinae and also the Noreia Walker / Celerena Walker group of the Oenochrominae ( Holloway 1994) ].

—hair­pencil in the hind­tibia (e.g. Phthonoloba Warren ).

—socii.

—gnathos.

—processes of the anellus, also absent in Boarmiini , Oenochrominae , Geometrinae .

—chiefly arboreal larvae.

Interestingly, an arboreal habit is most likely a ground­plan attribute of the Geometridae as it is also present in the Drepanidae .

Holloway (1998) commented on other features that differentiated this tribe. The forewing fasciae tend to be more spread out and evenly spaced across the wing and in many species the forewing postmedial is not angled as in other tribes. Lack of fusion of Sc + R 1 and Rs in the hindwing is also seen in many trichopterygines but also in some hydriomenines. Trichopterygines also lack modifications to abdominal segment 7 unlike the Eupithecini, Larentiini and Hydriomenini (J. Dugdale pers. comm.). The tribe is further distinguished by the presence of a lobe or lappet in the anal area of the male hindwing ( Dugdale 1980). The corpus bursae is also often studded with numerous, minute, inwardly directed spicules ( Dayong 1992).

Information on trichopterygine larvae is sparse but the chaetotaxy and crochet arrangement in seven Japanese taxa, Episteira eupena Prout , E. nigrilinearia nigrilinearia Leech , Otoplecta frigida Butler , Esakiopteryx volitans Butler , Trichopteryx misera Butler , Trichopterigia consobrinaria Leech and T. costipunctaria Leech are typically larentiine except that SD1 appears to be missing on the prothorax ( Hashimoto 1982, 1985, 1991). Further the crochet arrangement on the ventral proleg of T. costipunctaria is in the form of a broken multiserial circle instead of the more typical biordinal mesoseries. A very reduced number of crochets (1–2) is also atypically found on the ventral proleg of E. n. nigrilinearia . The former anomaly appears to demonstrate some interspecific variability in this character. Interestingly the larvae of Episteira Warren feed on Podocarpus macrophyllus (Thunb.) Lanb. (Podocarpaceae) , similar to the conifer­feeding New Zealand genus Tatosoma Butler ( Holloway & Hall 1998) . Holloway & Hall (1998) suggested that, due to this hostplant affinity, Episteira may be a possible sister genus of Tatosoma . However the distribution of Episteira is more widespread with relatively greater Oriental diversity and some representation in Africa and therefore may be an Indian Gondwanan vicariant of Tympanota Warren ( Holloway & Hall 1998) . The description of the larvae of Indian species of the large Indoaustralian genus Sauris Guenée given by Singh (1953, 1955) is also typically larentiine.

Descriptions of the pupae of the Trichopterygini are also few. However Hashimoto (1982, 1985, 1991) included pupae in his descriptions of the above species. These descriptions reveal much variability in pupal characters ranging from four pairs of cremastral setae in Otoplecta Warren and Episteira to a bifid cremaster in Esakiopteryx Inoue and Trichopteryx Hübner. The labium is exposed or concealed and the cocoon can be suspended in the food plant as in Episteira or earthern as in Esakiopteryx and Trichopteryx . This heterogeneity in pupal characteristics is possible further evidence of the early derived status of the tribe.

The Trichopterygini occur in all biogeographical regions. There is a rich fauna in New Zealand, all assigned to the endemic genus Tatosoma , which may be related to Neotropical taxa although this relationship is weakly based on the presence of two pairs of spurs on the hindleg ( Dugdale 1980). Some of these species feed on conifers, e.g. Agathis Salisb. (Araucariaceae) , and one species T. tipulata Walker , which feeds on angiosperms, now includes an exotic member of the Cupressaceae as a hostplant (J. Dugdale pers. comm.). The apparent capture of conifers as food plants by moths previously feeding on angiosperms is not unusual, however, as a study on British moths found that the colonization of conifers more often occurs in species that feed on a wide range of angiosperm hosts and that these original hosts are likely to be woody shrubs or trees ( Fraser & Lawton 1994).

Australian trichopterygines are mainly of tropical and Asian derivation ( McQuillan 1986) indicating either an ancient, pre­Gondwanan origin or derivation from a more recent dispersal event. A southern Australian member of the tribe includes the alpine Tympanota perophora podocarpi Dugdale that feeds on Podocarpus lawrencii Hook. f. ( Dugdale 1980). From this evidence, the Trichopterygini are promising candidate for a primitive group within the Larentiinae as proposed by Holloway (1998) in his tentative phylogeny for the Geometridae . Further studies should include exemplars from this tribe.