Artículos

Contribution to an understanding of the biology and larval morphology of two taxa in the genus Scopula Schrank, 1802, subgenus Glossotrophia Prout, 1913 (Lepidoptera: Geometridae)

Contribución al conocimiento de la morfología y la biología larvaria de dos taxones del género Scopula Schrank, 1802, subgénero Glossotrophia Prout, 1913 (Lepidoptera: Geometridae)

Introduction

The erstwhile genus Glossotrophia Prout, 1913 was downgraded to sub-genus status (SIHVONEN, 2005) within the sterrhine genus Scopula Schrank, 1802 which consists of 24 taxa in the Iberian Peninsula (REDONDO et al., 2009, modifications according to SIHVONEN 2005). SIHVONEN & KAILA (2004) established three synapomorphies of the genus which include: uncus on the male genitalia absent; 8º sternite with cerata and mappa which is often polymorphic (HAUSMANN, 1999); corpus bursae ovoid with signum made up of small, flat spinules (HAUSMANN, 2004). In terms of biology, the Iberian taxa are generally univoltine with the first generation before the onset of the summer drought period (ASCHMANN, 1984). The larvae tend to be oligophagous or monophagous in lower plants, for example, the labiates (WILTSHIRE, 1962; SORIA, 1987; HAUSMANN, 2004). Larval ethology includes the fact that fully-grown examples often perch in the vicinity of the food-plant rather than directly on it (EBERT & STEINER, 2001; KING & GONZÁLEZ-ESTÉBANEZ, 2015).

Scopula (Glossotrophia) rufomixtaria (Graslin, 1863)

Corology: Western Mediterranean with a distributional focus in meso-Mediterranean and thermoMediterranean Spain eastwards to southern France and the Franco-Italian Maritime Alps southwestwards to the Maghreb (nominotypical subspecies in Morocco); in Algeria and Tunisia is found the subspecies: S. (G.) rufomixtaria sahariensisHausmann, 1993 (HAUSMANN, 1993; 2004).

Phenology: The species is univoltine or bivoltine according to latitude or altitude (HAUSMANN, 2004); in the lowlands (Madrid, for example) it is bivoltine with the first generation end of May-end of July, with a probable third generation (KING & VIEJO-MONTESINOS, 2010) already alluded to by HAUSMANN (2004). In the mid-Ebro valley (NE Spain) S. (G.) rufomixtaria emerges earlier at the end of April flying until end of September (REDONDO & GASTÓN, 1999; REDONDO et al., 2001). The larva (Fig. 1) is associated with the carnations (Caryophyllaceae): CHRÉTIEN (1928) cited Silene and Dianthus (Caryophyllaceae); in Spain recent data describe it as monophagous in Gypsophila struthium L. in Loefl. (KING, 2000; REDONDO et al., 2001; KING & VIEJO-MONTESINOS, 2010).

Scopula (Glossotrophia) asellaria dentatolineata Wehrli, 1926

This taxon belongs to a “ring species” complex (MAYR, 1963) with various subspecies focussed on the Mediterranean region (northern and southern shores) and the Canary Islands (Macaronesia): (S. (G.) asellaria gerstbergeriHausmann, 1993; S. (G.) asellarialenzi Hausmann, 1993) (HAUSMANN, 1993; BACALLADO et al., 2005). The nominotypical subspecies S. (G.) asellaria asellaria (HerrichSchäffer, 1847) is found in Corsica and Sardinia. In the Iberian Peninsula itself there are two subspecies: S. (G.) asellaria dentatolineata Wehrli, 1926 in central and southern regions and S. (G.) asellaria isabellaria Millière, 1868 in the north-east to south-west France; the subspecies S. (G.) asellaria romanaria Millière, 1869 is distributed disjunctively in Sicily, western Italy, the southern Swiss valleys, Malta and Greece. In the Maghreb there fly three subspecies: S. (G.) asellaria lenziHausmann, 1993 (Great Atlas, Morocco); S. (G.) asellaria philipparia Prout, 1913 (northern Algeria, Tunisia); S. (G.) asellaria tripolitanaTurati, 1929 (Libya, southern Tunisia, eastern Algeria) (HAUSMANN, 1993; 2004).

More recent data suggests that the two Iberian subspecies: S. (G.) asellaria dentatolineata Wehrli, 1926 and S. (G.) asellaria isabellaria (Millière, 1868) fly sympatrically in the south-eastern Spanish province of Murcia it being pointed out by the authors that it would be a “contact zone” between the two taxa (CALLE et al., 2000; ORTIZ et al., 2009).

Phenology: HAUSMANN (2004) indicates two generations from the end of March-May, with a second generation from the end of September-early October with an absence of data at low altitudes in the summer months. Limited data from the Ebro valley (NE Spain) REDONDO & GASTÓN (1999) suggest that it is bi-voltine: early April and then in September. ORTIZ et al. (2009) include data from January to May, June, July to early September suggesting that it flies throughout the year. In terms of larval food-plants, it would appear to be polyphagous in the Scrophulariaceae, Zygophyllaceae and Lamiaceae (MILLIÈRE, 1869-1874; CHRÉTIEN, 1917) with snapdragon Antirrhinummajus L. (Scrophulariaceae) cited in central Spain (KING & ROMERA, 2004; KING & VIEJO-MONTESINOS, 2010). The ovum and oviposition strategy of S. (G.)asellaria dentatolineata are described in KING & VIEJO-MONTESINOS (2016).

SHAW (2010) cites Homolobus truncator Say, 1828 (Hymenoptera: Braconidae; Homolobinae) as a larval parasitoid of both S. (G.) asellaria dentatolineata and S. (G.) rufomixtaria.

General morphological information of European Scopula larvae can be found in EBERT & STEINER (2001). SINGH (1951) deals with the chaetotaxy of three European sterrhine genera: Problepsis Lederer, 1853, Scopula and Idaea Treitschke, 1825 with Scopula larvae being diagnosed as follows: cephalic capsule granular; vertex almost rounded; frontal setae situated above level of pores; seta O2 alongside ocellus 1 (within complex of stemmata); O1 very near ocellus 3; lengthened abdomen (urites A1-10), granular cuticule; setae short; MD setae are microscopic; A1-A9; SD1 anterior to spiracles A1-A7; L1 posterior to spiracle and below it A1-A5; A6 and A8 at same level; anal shield (A10) is round, L1 next to L2, D1, L3 in a line; spiracles oval shaped; on A6 are bigger than those in T1; A7 and A8 are of a different size.

The aim of this present paper is to provide data on the biology of these two taxa which includes undocumented parasitoid data (Hymenoptera: Ichneumonidae, Braconidae) and to give a more detailed overview of the larva which includes larval chaetotaxy.

Materials and methods

Study Area

The locality which formed the basis for the collection of imagines and of larvae in the Tagus Valley (Madrid; 590-600 m) was Ciempozuelos (Cerros de Palomera) (N40º 09’09.1 W003º 36’27.1).

The Miocenic and Triassic gypsyferous soils are relatively frequent in the Iberian Peninsula in the Tagus and Ebro basins, and the south-east Peninsular (FERRANDIS etal., 2005). The climate is MesoMediterranean, with important drought conditions from June to September. The little rain that falls does so in the spring (March to May), and in the autumn (September to November). In the winter, conditions of thermic inversion tend to prevail (IZCO, 1984). The general lack of precipitation and the corresponding aridity ensures that the influence of the gypsum soils is a constant, with a consequential effect on the vegetation which is generally understood to be included in the botanic order Gypsophiletalia.