Gonioctena (Spartoxena) variabilis Olivier, 1790

Baselga, Andres, 2010, The mature larva of Gonioctena variabilis (Olivier, 1790) Coleoptera, Chrysomelidae, Chrysomelinae) and key to the larvae of the subgenus Spartoxena, ZooKeys 33 (33), pp. 19-27 : 20-25

Gonioctena (Spartoxena) variabilis Olivier , mature larva

Figs 1–3, 10

Material examined. SPAIN. Madrid, Perales de Tajuña (lat: 40.232; long: -3.888), 575 m asl, 2 June 2007, 8 mature larvae .

Description. Length: 8.0–9.5 mm. Body eruciform (Fig. 1), convex and slightly arched in preserved specimens. Inter-tubercular plates pale yellow-brown, tubercles pale brown in dorsal and ventral regions, dark brown in dorsolateral region.

Head. Hypognathous, well sclerotized. Great part of vertex and frons dark brown coloured, the anterior part of frons, clypeus and mouth parts, paler. Epicranial suture

Figure Į. Habitus of Gonioctena variabilis , mature larva from Perales de Tajuña. Length = 9.0 mm.

well developed and long, frontal arms distinct, V-shaped and almost straight. Endocarina present, extending almost to clypeus. Vertex bearing 5 large primary setae (v1, v3, v4, v5, v6) along with many shorter ones on each side. Frons with 5 primary setae (f1, f2, f3, f4, f6) and 8–10 slightly shorter ones on each side. Antennae very short and well

Figures 2–9. Gonioctena spp. 2 Labrum of G. variabilis , dorsal view. In the right side the setae were removed and the microtrichia of epipharynx are shown by transparency 3 Tarsal claw of G. variabilis , lateral view 4 Labrum of G. aegrota , dorsal view 5 Tarsal claw of G. aegrota , lateral view 6 Labrum of G. pseudogobanzi , dorsal view 7 Tarsal claw of G. pseudogobanzi , lateral view 8 Labrum of G. leprieuri , dorsal view 9 Tarsal claw of G. leprieuri , lateral view. Scale bars = 0.1 mm.

sclerotized, three-segmented: first joint highly transverse; second joint almost as long as wide, bearing a conical membranous sensillum, 3 minute setae and 1 placoid sensillum; distal joint narrow, subconical, with membranous apex bearing 5 highly minute setae and 1 placoid sensillum. Stemmata arranged in two groups, 1 pair located below the base of antenna and 2 pairs behind the antenna. Clypeus with 3 pairs of setae.

Mouthparts. Labrum (Fig. 2) bearing 2 pairs of setae and 1 pair of placoid sensilla on upper surface, anterior border with a wide V-shaped notch and 6–7 stout setae on each side. Epipharynx with 2 bands of microtrichia situated laterally to anterior notch (Fig. 2), microtrichia completely isolated through the lateral margin but fused together to form groups of 2–3 denticles near central notch. Mandibles symmetrical, 5-toothed, bearing 2 setae on external face and 1 placoid sensillum on dorsal side. Maxillae: cardo transverse, with 1 seta in external border; stipes elongate, with 2 large setae near base of maxillary palp; mala bearing 13–15 setae on internal margin and apex, basal setae longer than apical ones, maxillary palpi 4-segmented, first joint slightly wider than long, bearing 2 long setae basally and another minute seta apically on external margin, second joint highly transverse, third joint longer than wide with 2 setae on internal face and 1 on external side, and fourth joint conical with 1 minute seta on internal face and membranous apex bearing 11–13 highly minute setae. Labium with postmentum membranous, bearing 3 pairs of setae, anterolateral one very short; prementum with 4 pairs of minute setae, 1 pair posterior and 3 pairs anterior to labial palpi along with 1 pair of placoid sensilla; palpi two-segmented, first joint transverse, distal joint conical with membranous apex bearing 10–11 highly minute setae.

Thorax. All tubercles multisetose (Fig. 10). Prothorax with tubercles D (dorsal), DL (dorsolateral) and EP (epipleural) fused together in a pronotal sclerite, pronotum (D-DL-EP) bearing 10 pairs of primary setae along with many other slightly shorter ones; tubercle P (pleural) with 4–6 setae; ventral region with slightly sclerotized tubercles, tubercle SS (sternellar) reduced to 3–4 sclerotized spots bearing 1 seta, midventral tubercle ES (eusternal) bearing 3 pairs of setae. Meso- and metathorax with 6 tubercles on each side of dorsal region: Dai (dorsal anterior interior, with 6–8 setae), Dae (dorsal anterior exterior, 6–8 setae), Dpi-Dpe (dorsal posterior interior and dorsal posterior exterior fused together, 8–10 setae), DLai (dorsolateral anterior interior, 2–4 setae), DLpi (dorsolateral posterior interior, 11–15 setae), DLae-DLpe (dorsolateral anterior exterior and dorsolateral posterior exterior fused together, 13–18 setae); epipleural region with 2 tubercles, EPa (epipleural anterior, 11–14 setae) and EPp (epipleural posterior, 5–8 setae); mesothoracic spiracle isolated from EPa tubercle, located in front of DLae-DLpe one; P tubercle bearing 4–6 setae; SS and ES tubercles reduced to numerous sclerotized dots bearing isolated setae.

Legs. All pairs similar in size; trochantin located in front of P tubercle (Fig. 10), bearing 1 minute setae in anterior half; prothoracic trochantin also with a larger seta in postero-ventral angle; coxa almost twice longer than wide in lateral view, with 10–11 large setae on dorsal face and 3–5 shorter ones in each lateral declivity; trochanter triangular in lateral view, with 2 large setae on each side, 1 minute seta and 4 placoid sensilla near coxal articulation on anterior side, and 2 placoid sensilla on posterior side; femur wider apically than basally in lateral view, with 2 large and 1 small setae dorsally, 3 large setae and 1 placoid sensillum on anterior side, and 2 large setae on posterior side; tibio-tarsus twice longer than wide, bearing 3 large and 1 minute setae dorsally and 4 ventrally; unguis wide basally, curved apically, with an extremely weak tooth and seta on lower side (Fig. 3).

Abdomen. All tubercles multisetose (Fig. 10). Segments 1–6 with 6 tubercles on each side of dorsal region: Dai (4–6 setae), Dae (6–7 setae), Dpi (6–9 setae), Dpe (7–9 setae),

Figure Į0. Gonioctena variabilis : location of tubercles and body chaetotaxy, right side. Pr prothorax Ms mesothorax Mt metathorax AĮ–AĮ0 abdominal segments 1–10. See text for definition of tubercles abbreviations. Scale bar = 1.0 mm.

DLai-DLae (4–6 setae) and DLpi-DLpe (6–9 setae); epipleural region with tubercle EP bearing 11–12 setae; spiracle isolated from EP tubercle, located in front of DLpi- DLpe one; P tubercle with 6–9 setae; sternal region presents the following tubercles: PS (parasternal, 2–5 setae), slightly reduced in segment 1, but always present and bearing 2 setae; SS (4–6 setae); ES separated in two halves, each one with 2–3 setae. Segment 7 with tubercle Dai fused to Dae, and Dpi to Dpe; segment 8 and 9 with all dorsal and dorsolateral tubercles fused together, ventral ones also fused in segment 9; segment 10 forming anal pseudopod, without dorsal tubercles, ventral ones fused together.

Distribution and ecology. G. variabilis is distributed in the east half of Spain and south France. In Spain it is distributed southwards to Madrid in the westernmost area and to Alicante in the easternmost range ( Kippenberg 2001; Baselga 2007). Its host plant is Genista scorpius (L.) DC. [ Fabaceae ] ( Kippenberg 2001). The larvae described in this paper were collected on the same plant [field identification]. Genista scorpius is known from the Iberian Peninsula but also from southern France and northern Morocco. Its Iberian range includes almost the whole peninsula, excepting the western third ( Talavera 1999). Hence the distribution range of G. variabilis , seems closely related to that of its host plant, although it does not reach the western and southernmost regions where G. scorpius is present. This pattern could be real, as phytophagous insects usually have narrower distribution ranges than their hosts ( Gaston 2003), but further research is needed to clarify to which extent southern and western limits of G. variabilis differ of those of its host plant.