Corresponding author: Hossein Rajaei ( firstname.lastname@example.org )
Academic editor: Sven Erlacher
© 2017 Hossein Rajaei, Michael Leipnitz, Siegfried Ortner.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Rajaei H, Leipnitz M, Ortner S (2017) The biology and preimaginal morphology of Italian endemic species Isturgia sparsaria (Hübner, 1809) (Lepidoptera, Geometridae). Nota Lepidopterologica 40(1): 25-29. https://doi.org/10.3897/nl.40.10865
The geometrid species Isturgia sparsaria (Hübner, 1809) is restricted to Italy and its biology is unknown. Recently, several individuals of this species have been successfully reared in captivity. Experiments with various potential host plants are reported. The larva was reared successfully on Genista tinctoria L. and Ulex europaeus L. (both from family Fabaceae). Adult insects, as well as ovum, larva, and pupa are illustrated and/or briefly described.
Genus Isturgia Hübner, 1823, with around 60 species, is mainly distributed in the Palaearctic, Afrotropical and Oriental Regions, and in Australia (
Isturgia sparsaria (Figs
1–6. Isturgia sparsaria. 1. Male (Italy, Marche, Bolognola, 1100 m, Valle Fargno, 2.viii.2010, leg. Teobaldelli, in coll. M. Leipnitz). 2. Female (Italy, Abruzzo, Majella, 450 m, Fara S. Martino, Valle del Fossato, 26.vi.2009, leg. N. Zahm, in coll. M. Leipnitz). 3. Fifth instar larva (L5). 4. Pre-pupal stage. 5. Pupa. 6–7. Pupal cremaster of male (6) and female (7). 8. Habitat of Isturgia sparsaria, where female specimen was collected: Acuto (Italy, Prov. Frosinone, altitude 770 m). Scale-bar for Figs 1, 2: 1 cm.
On 7 June 2016, the third author collected a female specimen of Isturgia sparsaria in central Italy (Prov. Frosinone, ca. 1 km NW of Acuto, altitude 770 m, 13°09’57.97”E, 41°48’00.11”N).
A single female was attracted to a black light. It laid a total of 71 eggs in a small plastic box, with the bottom covered by toilet paper. Each egg was laid separately. During his holidays in Sardinia, the second author received the eggs from the third author in a plastic box. They were placed in a refrigerator (2°C) for five days to retard their development until he reached home and could start his experiments. Most of the eggs were then kept in the refrigerator (2°C), but three were allowed to hatch at room temperature (22°C) in order to conduct experiments on host-plant preferences before allowing the remainder to hatch.
The tiny first instar larvae were housed in a small Polyethylene box (7.0×4.5×3.0 cm). They were offered a variety of food plants to see which plants were being accepted (this examination took eight days). Then, the larvae were transferred to the food plant. The first instar larva could always be recognised by the bigger head capsule in comparison with the body. After second–third ecdysis, the breeding was continued successfully in a cage (12×12×25 cm), which was covered with a screen-printing mesh, with the food plant in a small jar of water.
Food plants and preimaginal stages. The second author successfully reared the larvae, after many experiments on food preferences (see below).
Food plant. Nearly all species of Isturgia feed on species of Fabaceae (
Isturgia sparsaria (Hübner, 1809): larval reactions to plants (listed by family) offered under captive conditions (botanic nomenclature according to The Euro+Med Plant Base: http://www.emplantbase.org/home.html).
|Family: Plant species||Larval reaction|
|Lathyrus pratensis L.|
|Ononis spinosa subsp. procurrens (Wallr.) Briq. (= Ononis repens L.)|
|Cytisus scoparius (L.) Link (= Sarothamnus scoparius (L.) W. D. J. Koch)|
|Chamaecytisus purpureus (Scop.) Link|
|Genista sagittalis L. (= Genistella sagittalis (L.) Gams)|
|Medicago sativa L.|
|Trifolium campestre Schreb.|
|Dorycnium pentaphyllum subsp. germanicum (Gremli) Gams (= Dorycnium germanicum (Gremli) Rikli)||Rejected|
|Lotus corniculatus L.|
|Astragalus alpinus L.|
|Securigera varia (L.) Lassen (= Coronilla varia L.)|
|Vicia sepium L.|
|Vicia sativa subsp. nigra (L.) Ehrh. (= Vicia angustifolia L.)|
|Vicia cracca L.|
|Fabaceae: Genista tinctoria L.||Accepted (Flowers, young soft leaves)|
|Fabaceae: Ulex europaeus L.||Accepted (Flowers and young soft spines)|
|Salicaceae: Salix purpurea L.||Rejected|
|Fagaceae: Quercus robur L.||Rejected|
|Rosaceae: Prunus spinosa L.||Rejected|
|Apiaceae: Bupleurum falcatum L.||Rejected|
|Lamiaceae: Thymus vulgaris L.||Rejected|
|Caprifoliaceae: Lonicera tatarica L.||Rejected|
|Compositae: Artemisia alba Turra (= A. camphorata Vill.)||Rejected|
Ovum. Elliptical, length about 0.75 mm, breadth about 0.45 mm. Freshly laid eggs dark grey-green, becoming violet-brown after two or three days. The eggs were attached dorso-ventrally to the substrate.
Larva. The first and second instar larva (L1 and L2) are more or less grey-green, without any characteristic colour pattern. The colour pattern appears gradually from L3 towards L5 (see below). The fifth instar (L5) (Fig.
Pupa. In total six larvae completed their development to the pupal stage. Pupa 10–11 mm long, fairly scabrous, red-brown in colour; wing case dark-green directly after pupation, gradually becoming dark-brown; punctures visible on 1st–8th abdominal segment (Fig.
Results of this study indicate that the larvae feed largely on flowers or young soft leaves of Genista tinctoria and flowers or young soft spines of Ulex europaeus in captivity. It is likely that the hostplant of Isturgia sparsaria in the wild is also a species of Fabaceae. In the locality where the specimens were collected, Spartium junceum (Fabaceae) is quite common and is regarded as a potential hostplant of I. sparsaria in the wild, but this suggestion needs further study. According to
It is also quite possible that the larvae of this species are polyphagous on other plants which occur in its habitat. In captivity, the larvae accepted two different genera of Fabaceae, but further field studies are necessary to confirm how host specific the larvae of this species are in the wild.
As the adult specimens of Isturgia sparsaria were observed on an oak, Quercus sp. (
Our special thanks go to Dr. Norbert Zahm (Schmelz-Huttersberg) for his useful advice and comments on different literature related to this study and for his help with our bibliographical research. The authors are grateful to Claudio Flamigni and Gary Edward King for their constructive comments to the manuscript.