Acalyptris staticis

Van, Erik J., 2007, Acalyptris Meyrick: revision of the platani and staticis groups in Europe and the Mediterranean (Lepidoptera: Nepticulidae), Zootaxa 1436, pp. 1-48 : 17-18

The Acalyptris staticis group

This species group is established here for the Plumbaginaceae-feeding species and A. pyrenaica . There are no representatives known outside Europe and the Mediterranean region.

These species differ considerably from most other Acalyptris , the most important shared character being the generic apomorphy: the venation with the closed cell in forewing shifted towards base. In contrast to most other Acalyptris , the transverse bar of the transtilla is present as a sclerotized bar (the plesiomorphic condition). The male genitalia are otherwise rather uniform, the vesica being reduced, without any structure, and the aedeagus relatively short. The female genitalia are characterised by a reduced corpus bursae and the absence of sclerotisations, a condition very similar to that in the genus Parafomoria (see van Nieukerken 1983). The reduced bursa and absence of cornuti in the aedeagus are probably related characters. Externally the males lack androconial scaling.

Adult. Head: collar small, comprising hair-scales. Forewing pale, often with fascia, or uniform; cilia-line normally present, often indistinct. Forewing underside without subdorsal retinaculum. Hindwing with costal bristles in male and female. Venation as in platani group (Fig. 19). No androconial scales present. Male with anal tufts on T8, female sometimes with tufts on T7. Sternite 2 with 2A broadly triangular, almost as wide as long ( Fig. 60 ).

Male genitalia. Vinculum invisibly fused with tegumen, forming complete ring; ventral plate rounded, with posterior process joined to ventral carina. Tegumen forming variably shaped prominent pseuduncus. Uncus with single medial process. Gnathos with single medial element. Valva elongate, with a dense group of thick setae terminally on dorsal face. Transtilla with transverse bar present. Aedeagus with bifurcate ventral carina and a pair of curved lateral carinae, curving dorsad; vesica without any structure, no cornuti, but also no cathrema (the striate thickening around base of ductus ejaculatorius). Aedeagus relatively short, ratio aedeagus: capsule 0.6 to 0.8 ( Table 3 ).

Female genitalia. Terminalia blunt. T8 single narrow plate, with single setae or groups of setae. T9 comprising distinct pair of anal papillae, often with many setae. S 7 in some species also with dense group of long setae. Corpus bursae hardly developed, without any sclerotisation or signa; as such no measurements of bursa presented. Ductus spermathecae inconspicuous, with ca 2–3 coils.

Immature stages. Number of instars unknown. Final instar larva. Body yellow. Headcapsule ( Fig. 88 ) wider than long. Frontoclypeus narrowing posteriorly, slightly stirrup-shaped. Anterior tentorial arms long, approximately twice as long as posterior arms. Labrum with medial and lateral setae. Labial palpi with two short segments and long apical seta. Antenna with sensilla not placed cross-wise (Van Nieukerken 1986a).

Prothorax with elongate, narrow, ventral sclerite and narrow paired dorsal sclerites. Pro-, meso- and metathorax respectively with 11, 7 and 7 pairs of setae. A1–8 with 6, A9 with 2 and A10 with 3 pairs of setae. Most setae relatively short, ventral setae longest. Reduction on meso- and metathorax affects the dorsal and lateral setae groups, SV1 and the three more ventral setae are all present. Anal rods almost straight, posteriorly ending in 3 pointed tips ( Fig. 90 ). Spinosity of thorax and abdomen reduced, microspines scattered, hardly visible at a magnification of 400×. Earlier instars not studied.

Pupa (studied from exuviae). Head: clypeus transverse; frons not completely detached at emergence, smooth; labial palpi slightly longer than maxillae. A2–8 dorsally with many relatively short spines, arranged in about 3–4 indistinct transverse rows per segment; cremaster comprising two widely separate spines ( Fig. 92 ).

Biology. Hostplants. Five of the six known species feed on Plumbaginaceae , and four of these on Limonium species (Sea lavenders) along the sea coast. Only A. pyrenaica apparently is feeding on a different host family, because it was found in localities where this plant family is absent. Limonium is a very diverse plant genus in the Mediterranean region. Identification of Limonium is problematic and usually only possible when flowers are present. Previous records of Limonium vulgare as a host in the Adriatic and Aegean area (A. & Z. Laštůvka 1997; Z. & A. Laštůvka 1998) are possibly correct, but should be confirmed on flowering individuals because there are several very similar species.

Phylogenetically the Plumbaginaceae belong to the Caryophyllales , a basal clade in the Core Eudicots in the sense of the APG II classification ( Bremer et al. 2003), and are considered sister to the Polygonaceae .

This group contains the only Nepticulidae found so far that have adapted to halophytic plants and live in a coastal habitat. The larvae make gallery mines, and the cocoons are spun on the leaves, probably as an adaptation to avoid lengthy submersion by sea water.

The mines of all Limonium-feeding species are very similar, usually starting with a more or less spirally arranged gallery, with a thin line of frass. Larva feeds in mine with ventral side uppermost.

Figures

FIGURES 55 – 61. 55 – 59. Acalyptris staticis group: terminal abdominal segments and female genitalia (as far as visible), in dorsal view and dorsally focussed, in 58 more ventrally focussed, showing sternite. 55, 56, A. maritima, slide 3530, Italy, Portogruaro; 57 – 59, A. lesbia, slide 3642, paratype, Greece, Lesvos. 60 – 61. Acalyptris species, female, second abdominal segment from ventral, showing shape of s 2 a. 60, A. limoniastri, slide BM 22615, Algeria, Biskra, Paratype; 61, A. minimella, slide 3415, Portugal (Algarve), Serra de Monte Figo.

FIGURES 84 – 93. Acalyptris species, details of immatures. 84 – 88, Headcapsule of final instar larva and part of prothorax with sclerites. 89, 90, Last abdominal segment (s) with anal rods. 91 – 93, Pupal exuviae, details of abdomen with abdominal spines (91, 92) and detached frons with conical projection (93). 84, 89, A. platani, Greece, Evvoia, Dhírfis Oros; 85, A. minimella, Tunisia, Tabarka; 86, A. pistaciae, slide RMNH 11892, Turkey, Antalya, Selimiye; 87, A. loranthella, Greece, Evvoia, Dhírfis Oros; 88, 90, A. lesbia, RMNH 12393, Greece, Lesvos, paratype; 91, A. loranthella, slide 3647, Greece, Evvoia, Dhírfis Oros; 92, A. lesbia, slide 3643, Greece, Lesvos; 93, A. platani, slide 3646, Italy, Trieste.