View Image Gallery of Family Castniidae

The most recent general review of the Castniidae, focusing on the Neotropical Castniinae, is that of Miller (1986[9]), though shorter accounts of the family may be found in Holloway, Bradley & Carter (1987), Common (1990) and Scoble (1992). Miller placed S.E. Asian castniids in a subfamily Tascininae, sister to the Castniinae which include the diverse neotropical representation as sister to the Australian ones (as subtribes Castniidi and Synemonidi of tribe Castniini, equivalent to the Castniinae). Hampson (1895) erected the family Neocastniidae for the Oriental taxa but later (Hampson, 1918) changed this to Tascinidae without comment. The former family-group name should strictly have priority. Heppner (1993[6]) recognised three subfamilies: Castniinae, Synemoninae and Neocastniinae. Edwards et al. (in press) recognise two: Castniinae, with tribes Castniini and Synemonini; Tascininae. This last arrangement is followed here.

All castniids are robust with clubbed antennae and are day-flying, usually brightly coloured. The antennal club usually has an apiculus. The Australian taxa are somewhat more delicate than the rest, with wings somewhat less deep. All have a rather characteristic venation with the M-stem present in the cells of both fore- and hindwings, and very much closer to CuA than to Rs, forming a narrow sub-cell that gives rise to M2, M3, CuA1 and CuA2 in a quadrifid arrangement (Holloway, 1986a, Fig 1).

Figure 1. Phylogeny of the Macrolepidoptera as suggested by Minet (1991) and Kristensen & Skalski (in press). Superfamilies are indicated in capitals. Groups treated in this work are indicated in bold.

The forewing usually has an areole within the radial system in the Castniinae but not in the Tascininae. The terminal bifurcation of the radial system is R3 + R4 in the Castniini, R4 + R5 in the Synemonini and in the Tascininae. The Tascininae have lost discocellular cross-veins in fore- and hindwings, including that between M and CuA in the latter: CuP is also absent from both. The Tascininae have an unusual branching system for the forewing radial veins and M1: R1, (R2, R3), ((R4, R5) M1) in typical Tascina Westwood with (R1 (R2, R3)) in the type species of Neocastnia Hampson. A chorda is sometimes present. The frenulum is strongly developed. The tongue is present in the Castniinae, absent in the Tascininae. Ocelli are present but chaetosemata are absent.

The male genitalia in the Castniinae have the uncus divided or bifurcate, but generally variable in structure. The gnathus is present. The saccus is broadly and sharply bifurcate. The aedeagus is recurved, more strongly so in Neotropical taxa. The valve is broad but simple. The genitalia of Tascina Westwood are described below: the saccus is entire, the aedeagus simple, not recurved.

In the castniine female the ovipositor and apodemes are elongated, the lobes of the former sometimes acute, blade-like, for insertion of eggs into roughened plant surfaces or soil. The development of the ductus bursae varies. There may be one or two spiny signa in the bursa. The genitalia of the tascinine female are described below.

The eggs of Castniinae are spindle-shaped, laid flat, with four longitudinal ribs in Synemonini, five in Castniini, and with numerous transverse striae between them.

The larva has a prognathous head, partially retracted into the prothorax, where there is a sclerotised, prothoracic shield. There are small dorsal sclerotised areas on segments T2 to A2 in Synemonini, and the cuticle is generally spinulose. Primary setae are in pinacula. The prolegs are short, broad, with few crochets, uniordinal in two transverse bands: in Castniini these are progressively lost through succeeding instars, being replaced by numerous microspicules surrounding a T-shaped ampullar lobe (Miller, 1986[9]). Miller gave details of larval chaetotaxy and noted that later instars of Castniini produce a reddish brown exudate from a prothoracic gland, and secondary setae develop in later instars of Synemonini.

In the Neotropics the larval hosts are monocotyledons in the families Bromeliaceae, Gramineae, Marantaceae, Musaceae, Orchidaceae and Palmae (Miller 1986[9]; Edwards et al., in press). The larvae feed endogenously, excavating a tunnel within the host, e.g. in a palm leaf rachis. The Australian Synemonini feed initially in the tillers and butt of their host-plants (Cyperaceae, Ecdeiocoleaceae, Gramineae and Lomandraceae), with later instars feeding on rhizomes from a silk-lined tunnel in the soil: pupation occurs in a chimney extending upwards from this tunnel (Common, 1990). The life cycle in Synemonini requires at least two years but is shorter in Castniini. Nothing is known of the biology of Tascininae: even the adults are extremely rare, with specimens in collections probably numbering no more than about twenty.

Miller discussed the biogeography of the family, suggesting it established its current range prior to the break-up of Gondawanaland, and was possibly well represented in Antarctica at that time. The vicariance of the Tascininae is unclear: they could have separated from the Castniinae with India in the late (120Ma) Cretaceous (Hall, 1998), subsequently following more humid tropical conditions to Sundaland, or they could have separated earlier on Gondwanan components of South-east Asia, perhaps in the late Jurassic (separating at about 165Ma) and early Cretaceous on continental terranes now attached to western Burma and (Woyla terranes) Sumatra (Metcalf, 1996, 1998). The Gondwanan biogeography of the Castniidae is also reviewed by Holloway & Hall (1998).

The higher classificatory position is still subject to some disagreement. Common (1990), Scoble (1992), Heppner (1993[6]) and Nielsen, Edwards & Rangsi (1996) place the family on its own in the superfamily Castnioidea, whereas Minet (1986, 1991) included the family in the Sesioidea on the basis of three apomorphic features: the ocular diaphragm is more heavily pigmented anteriorly; large patagia; the condition of the metafurcal apophyses. This latter arrangement is supported by Edwards et al. (in press).

There is more general agreement about the relationship of the Sesioidea to the Cossoidea, possibly with the Zygaenoidea more distantly related (e.g. Minet, 1991; Edwards et al., in press). Miller (1986 [9]) noted the condition of the basal abdominal tergites, including an ovoid, scaleless area on each side of the second tergite, as being shared with the Cossidae, and she suggested general larval and pupal features also supported this affinity. Minet (1991) referred to two specific larval features: an oblique dark stripe between the dorsal setae of the larval pronotum; irregularly distributed spinules on the integument.

Scoble (1992) noted the presence of flavonoid pigments in Castniidae in common with sphingids, noctuids and butterflies, but did not indicate this to be of any higher classificatory significance.

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