Ficusacalles, 2010

Stüben, Peter E. & Astrin, Jonas J., 2010, Molecular phylogeny in endemic weevils: revision of the genera of Macaronesian Cryptorhynchinae (Coleoptera: Curculionidae), Zoological Journal of the Linnean Society 160 (1), pp. 40-87 : 68-69

FICUSACALLES STÜBEN & ASTRIN GEN. NOV.

( FIG. 13A–E )

Type species: Acalles senilis Wollaston, 1864

Wollaston, 1864, 1865; de Marseul, 1875; Roudier, 1954; Franz, 1996; Arechavaleta, Zurita & Oromí, 2000: 93; Behne, 2000; Sprick & Stüben, 2000; Stüben, 2000a, 2007b, 2008a; Stüben et al., 2003; Stüben & Germann, 2005.

Compilation of the species of the genus

Ficusacalles

Ficusacalles senilis senilis ( Wollaston, 1864) comb. nov. (formerly: Acalles ) – El Hierro (including type locality), Tenerife, northern La Palma

Ficusacalles senilis ficvorator (Stüben, 2007) comb. nov. (formerly: Acalles ) – southern La Palma (including type locality)

Ficusacalles senilis oceanicus (Stüben, 2002) comb. nov. (formerly: Acalles ) – Selvagens (including type locality)

Description

Size: 3.30–5.50 mm (without rostrum).

The species of the new genus are very variable regarding habitus and colouring.

Pronotum: As long as wide or slightly wider; widest behind the middle, outline towards base only slightly rounded, narrowed in a straight line or rounded long oval to ‘bellied’; with a slight depression next to the front margin. Contrastingly coloured as for the elytra in recently emerged specimens. Often with slender mid-groove or wide and shallow depression. Disc of pronotum sometimes with an aggregation of bristles on both sides of the mid-groove.

Elytra: 1.35–1.45¥ as long as wide; widest anterior to the middle, c. at the end of the second fifth (from the base); from the middle towards the apex of elytra almost lineally narrowed or rounded long oval, apex of elytra protruding ‘beak-like’, flanks with depression in the range of second and third sternite; elytra without shoulders; disc of elytra anterior to the middle with light (beige) scales covering the first and second interval; the first three intervals near the middle with a triangular mark of dense black scales. Slope of elytra with light (beige) scales forming either a broad fascia or covering the entire slope. With a falciform, white fascia on each elytron going from the basal edges to the second interval directly in front of the middle. Elytra with pit-shaped punctures becoming deeper towards the flanks. Intervals clearly wider than punctured stripes; scutellar stripe with a black, elongated aggregation of bristles in the middle of elytra; second interval with a predominantly light, elongated aggregation of bristles next to the base and a shortly oval aggregation of bristles directly behind the middle; third interval with a small, oval, bristled hump anterior to the middle; fourth interval again with an elongated, even aggregation of bristles. Humps are present primarily in the nominotypic taxon Acalles senilis senilis (type locality: El Hierro). These structures are conspicuously more flat in the other subspecies and the aggregation of the bristles are often abraded in older specimens.

Legs: Front femur reaching the front margin of eyes, hind femur ending far from the apex of elytra. Legs sparsely covered with short, predominantly light bristles that are close-fitting at the femur and erect at the tibia.

Head: Eyes slightly oval, rounded towards the front and tapering towards the underside of rostrum. Rostrum of ♂ dark brown, short, at most 3.80¥ as long as wide, with dense and fine punctures next to the apex (mid-line without punctures) and with a dense cover of light scales between base and insertion of antenna; rostrum of ♀ longer, brighter, narrower between the insertions of antenna, with scales only next to the base and finer and more spacious punctures at the apex.

Venter: Second abdominal sternite as long as sternites 3 and 4 combined; second sternite covered with light, rounded scales partly overlapping like tiles and in addition with a few short and slender bristles.

Aedeagus: With a conspicuous, big, long, and parallel balk-shaped structure of the internal sac ( Fig. 13B ).

Differential diagnosis: This new genus is characterized by the conspicuously big, parallel, balk-shaped structure of the internal sac of the aedeagus (cf. Fig. 13B ) and therefore the genus can be easily distinguished from all other species of Macaronesian Cryptorhynchinae . See also the ‘Key to the genera and subgenera of Macaronesian Cryptorhynchinae’.

Biology and ecology: Specimens of F. senilis senilis and F. senilis ficvorator have been collected by beating dead twigs of Ficus carica L. on the western islands of the Canarian archipelago (cf. Fig. 13C ). The biology and ecology of F. senilis ficvorator of La Palma as well as rearing studies using twigs of the genus Ficus , a typical cultivated plant of the Canary Islands, have been described in detail ( Stüben, 2007b: 218–220). On Tenerife and El Hierro F. senilis senilis lives predominantly on Foeniculum vulgare Mill. , which is a common shrub on fallow land. In these habitats one can beat numerous specimens from the lower dead stalks of robust plants at night. The development takes place in these dead stalks. The species of this new genus seem to be extraordinarily oligophagous to polyphagous. On El Hierro F. senilis senilis is ‘omnipresent’, living – amongst other woody perennials – on Carlina salicifolia , Sonchus hierrensis , Tolpis proustii , and Chamaecytisus proliferus . Therefore, it is not a big surprise that even the endemic Euphorbia anachoreta Svent. of the spurge family ( Euphorbiaceae ) has been reported as host plant for F. senilis oceanicus of the Selvagens (cf. Stüben, 2000a: 132).

The variability of F. senilis correlates with the high number of host plants. There are contrastingly black and white coloured specimens as well as unicoloured white or grey individuals. Stüben (2008a: 324) attributed this variability primarily to the differences in nutrition, especially to the influence of several phytochemicals during larval development (not only to the ‘ageing’ of the integument). Thus phenotypically, the species of this genus cannot be easily discriminated. The only reliable morphological character is the endophallus.

Etymology: The name Ficusacalles refers to the hostplant relation of the Canarian species of this genus, which can be beaten from savaged plants of the Mediterranean fig tree ( Ficus carica ) at night.

Distribution: Only known from the western Canary Islands Tenerife, La Palma, and El Hierro as well as from the Selvagens.

Figures

Figures 2–22. Morphological, biological, and ecological comparison of the genera and subgenera of Macaronesian Cryptorhynchinae along with the respective sections of the tree; (TS) = type species. Figures 4E and 5E show a section of the tree that results when 16S sequences for Aeoniacalles aeonisimilis* and Dendroacalles euphorbiacus* are excluded.