Research Article |
Corresponding author: Juan L. Hernández-Roldán ( hernandez.roldan@gmail.com ) Academic editor: Zdenek Fric
© 2018 Juan L. Hernández-Roldán, Juan C. Vicente, Roger Vila, Miguel L. Munguira.
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:
Hernández-Roldán JL, Vicente JC, Vila R, Munguira ML (2018) Natural history and immature stage morphology of Spialia Swinhoe, 1912 in the Iberian Peninsula (Lepidoptera, Hesperiidae). Nota Lepidopterologica 41(1): 1-22. https://doi.org/10.3897/nl.41.13539
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We present new data on the ecology, natural history and geographic distribution of the recently described skipper Spialia rosae Hernández-Roldán, Dapporto, Dincă, Vicente & Vila, 2016 and compare its immature stage morphology with the sympatric species S. sertorius (Hoffmannsegg, 1804). Spialia rosae uses species of Rosa L. (Rosaceae) as larval host-plants and prefers montane habitats, while S. sertorius feeds on Sanguisorba minor Scop. (Rosaceae) and inhabits lower altitudes. Rosa corymbifera Borkh. and R. tomentosa Sm. are documented for the first time as foodplants of S. rosae. We report Microgaster australis Thomson, 1895 (Hymenoptera, Braconidae, Microgastrinae) as a larval parasitoid of S. rosae. Details of the immature stages of S. rosae and S. sertorius are shown using scanning electron microscope photographs, confirming the similar immature stage morphology, at least as regards the Iberian S. sertorius. In both species, the egg has high radial ribs, the last instar larva has branched setae covering the head, and the pupa has setae with pointed tips, barrel-like cuticular formations, and hairy mesothoracic tubercles. By extensive sampling of the species of Spialia in the region of Segovia, Central Spain, we extend the previously known geographic distribution of S. rosae to 56 new 100 km2 MGRS squares, which represents a 155 % increase. Spialia rosae is present in the northern part of the interior plateau and in the main mountain systems of the Iberian Peninsula. The main threats to the populations of S. rosae are its limited distribution range and the possible effects of climate change due to its specialization in montane habitats. The conservation status of S. rosae was previously regarded as Data Deficient (DD). With the addition of new data the species can now be evaluated as Least Concern (LC).
The genus Spialia Swinhoe, 1912 (Lepidoptera, Hesperiidae) occurs in the Palaearctic region and Africa, and its larvae are generally monophagous or oligophagous on plants of the family Rosaceae (
Spialia rosae is currently known only from Spain at an elevation range of 860–2640 m, showing a significantly higher altitudinal range than the closely related S. sertorius and S. orbifer. The species occurs in the main mountain systems of the Iberian Peninsula: Sierra Nevada and La Sagra (Betic Mountains), Iberian Mountain System, Cantabrian Mountains, Central Mountain System and the Pyrenees (
Spialia rosae can be distinguished from the most closely related species (S. sertorius, S. orbifer, S. ali and S. therapne) on the basis of the DNA sequence of the mitochondrial gene cytochrome c oxidase subunit I (COI), the composition of the wing cuticular hydrocarbons and the ecology, suggesting that S. rosae represents a case of ecological speciation involving larval host-plant and altitudinal shifts, also apparently associated with a Wolbachia infection (
There are no previous studies on the morphology of the immature stages of the genus Spialia based on scanning electron micrographs but, within the Hesperiidae family, there has been a study of the eggs of the subfamily Pyrginae (Thust 1997). Morevoer, the morphology of eggs, larvae and pupae of the European species of the genus Pyrgus Hübner, [1819] have been extensively studied (
At the European level, the conservation status of Spialia sertorius, S. therapne and S. orbifer has been considered as Least Concern (LC) following IUCN criteria (
The object of the present paper is to describe the biology, distribution and morphological details of the egg, last instar larva and pupa of S. rosae in the Iberian Peninsula and to compare these stages with S. sertorius, that partly overlaps in geographic range, in order to test whether these two species show similar immature stage morphology. The morphological study is based on micrographs taken with scanning electron microscopy. We also aim to evaluate the threats and conservation status of the new species in the study area.
Spialia eggs were collected in the field by following females until oviposition took place. We also searched for eggs on plants of Sanguisorba spp. and Rosa spp. Larvae were collected by searching for larval refugia on the foodplants. We collected samples of rose bushes from several localities in order to determine the species. Also, we have been able to study samples of roses from two localities where S. rosae was cited in the literature (
Rearing took place in the laboratory, using field collected eggs and larvae, and with climatic parameters different from those in the natural habitat. Larvae were provided with the same genus of plants on which they were collected. After emergence of the adults the exuviae were preserved for morphological studies.
Images used to study the morphology of the egg, last instar larva and pupa were obtained using a Hitachi S-3000N scanning electron microscope, with an acceleration voltage of 20 kV. Dried samples were used in the case of the egg and pupa. The eggs were killed with ethyl acetate when the larva had already formed inside the egg to prevent the egg collapsing when dried. For the study of pupae, exuviae were used after the emergence of adults. Larvae were preserved in 70% ethanol and then fixed with 1.5% formaldehyde. For larval dehydration a series of increasing concentrations of ethanol was used, ending with absolute ethanol and then the liquid was removed to produce dried samples with an Emitech K850 Critical Point Dryer. Samples were then coated with a 10 nm layer of gold using an Au-Cr Quorum 150TS Sputter. The microscope and all the other equipment used are located in the Servicio Interdepartamental de Investigación (SIDI) of the Universidad Autónoma of Madrid. A scale bar was added to all images. Egg measurements were performed directly on the images using IMAGEJ.1.43 software (
The new distributional data for S. rosae are based exclusively on immature stages collected on Rosa spp., in order to avoid confusion with S. sertorius. Both species are morphologically similar as adults, but their larvae feed on different plant genera. Some of the samples in this study were previously used by
Terminology for the description of wing characters follows
Spain: 2 Paratype eggs on Rosa sicula, Puerto de La Ragua, Sierra Nevada (Granada), 37°5.48’N, 3°3.38’W, 2090 m, 19.vii.2012, leg. et coll. J.L. H.-R. (JHSEM-C19P09); Paratype larva L5 on Rosa pouzinii, El Vallecillo, Sierra de Albarracín (Teruel), 40°14.25’N, 1°38.88’W, 1525 m, 5.viii.2012, leg. J.L. H.-R., J.C. Vicente, R. Vila and S. Viader, coll. J.L. H.-R. (JHSEM-C20P01 and JHSEM-C20P02), tissues in coll. IBE (RV-12L066); Male paratype, Puerto de El Cubillo, Tragacete (Cuenca), ex larva L3 on Rosa sicula40°19.74’N, 1°45.84’W, 1630 m, 6.viii.2012, leg. J.L. H.-R., J.C.V., R.V. and S.V., coll. J.L. H.-R. (pupal exuviae: JHSEM-C19P12, adult: JH6620), tissues in coll. IBE (RV-12L068); Egg on Rosa sp., Aldeavieja (Ávila), 40°46.59’N, 4°28.88’W, 1235 m, 26.viii.2012, J. C. V. and B. P. leg.; Larva on Rosa sp., Torreiglesias (Segovia), 41°8.51’N, 4°0.77’W, 915 m, 10.viii.2013, J. C. V. and B. P. leg.; Eggs and larvae on Rosa sp., Pajares de Pedraza (Segovia), 41°8.57’N, 3°53.62’W, 1015 m, 26.x.2013, J. C. V. and B. P. leg.; Larva on Rosa sp., Duratón, alrededor del municipio (Segovia), 41°19.48’N, 3°39.43’W, 960 m, 27.x.2013, J. C. V. and B. P. leg.; Eggs and larvae on Rosa sp., Sebúlcor (Segovia), 41°13.97’N, 3°53.70’W, 940 m, 27.x.2013, J. C. V. and B. P. leg.; Larva on Rosa sp., Sepúlveda (Segovia), 41°19.43’N, 3°46.60’W, 930 m, 27.x.2013, J. C. V. and B. P. leg.; Egg on Rosa sp., El Espinar, Estación (Segovia), 40°46.83’N, 4°7.55’W, 1280 m, 08.vi.2014, J. C. V. and B. P. leg.; Eggs and larvae on Rosa sp., Escobar de Polendos (Segovia), 41°3.04’N, 4°7.83’W, 935 m, 21.vi.2014, J. C. V. and B. P. leg.; Eggs and larvae on Rosa sp., Peñasrubias de Pirón (Segovia), 41°8.44’N, 4°7.92’W, 925 m, 21.vi.2014, J. C. V. and B. P. leg.; Larva on Rosa sp., Veganzones (Segovia), 41°13.92’N, 4°0.85’W, 890 m, 04.vii.2014, J. C. V. and B. P. leg.; Larva on Rosa sp., Fuente el Olmo de Fuentidueña (Segovia), 41°24.72’N, 4°1.02’W, 920 m, 10.vii.2014, J. C. V. and B. P. leg.; Larva on Rosa sp., Ojos Albos (Ávila), 40°41.18’N, 4°28.76’W, 1280 m, 11.vii.2014, J. C. V. and B. P. leg.; Larva on Rosa sp., San Rafael, Sierra de Guadarrama (Segovia), 40°41.35’N, 4°14.56’W, 1260 m, 11.vii.2014, J. C. V. and B. P. leg.; Egg on Rosa sp., Aldeanueva de la Serrezuela (Segovia), 41°30.24’N, 3°46.73’W, 1300 m, 15.vii.2014, J. C. V. and B. P. leg.; Larva on Rosa sp., Navares de las Cuevas (Segovia), 41°24.83’N, 3°46.67’W, 1130 m, 15.vii.2014, J. C. V. and B. P. leg.; Larva on Rosa sp., Villacastín (Segovia), 40°46.68’N, 4°21.77’W, 1180 m, 09.viii.2014, J. C. V. and B. P. leg.; Larva on Rosa sp., Campo Azálvaro (Segovia), 40°41.27’N, 4°21.66’W, 1290 m, 09.viii.2014, J. C. V. and B. P. leg.; Eggs and larvae on Rosa sp., Matabuena, Sierra de Guadarrama (Segovia), 41°3.22’N, 3°46.41’W, 1955 m, 23.viii.2014, J. C. V. and B. P. leg.; Larva on Rosa sp., Frumales (Segovia), 41°24.65’N, 4°8.20’W, 865 m, 23.viii.2014, J. C. V. and B. P. leg.; Larva on Rosa sp., Dehesa Mayor (Segovia), 41°24.58’N, 4°15.38’W, 860 m, 23.viii.2014, J. C. V. and B. P. leg.; Larva on Rosa sp., Cuevas de Provanco (Segovia), 41°35.59’N, 3°53.99’W, 915 m, 30.viii.2014, J. C. V. and B. P. leg.; Larva on Rosa sp., Bahabón (Valladolid), 41°29.98’N, 4°15.48’W, 875 m, 30.viii.2014, J. C. V. and B. P. leg.; Larva on Rosa sp., Canalejas de Peñafiel (Valladolid), 41°30.06’N, 4°8.29’W, 835 m, 30.viii.2014, J. C. V. and B. P. leg.; Larva on Rosa sp., La Mata (Segovia), 41°8.62’N, 3°46.47’W, 1180 m, 01.xi.2014, J. C. V. and B. P. leg.; Larva on Rosa sp., Cantalojas, Sierra de Ayllón (Guadalajara), 41°14.16’N, 3°17.90’W, 1320 m, 06.ix.2014, J. C. V. and B. P. leg.; Larva on Rosa sp., Francos, Sierra de Ayllón (Segovia), 41°24.97’N, 3°17.95’W, 1035 m, 06.ix.2014, J. C. V. and B. P. leg.; Eggs and larvae on Rosa sp., Galve de Sorbe (Guadalajara), 41°14.18’N, 3°10.74’W, 1315 m, 06.ix.2014, J. C. V. and B. P. leg.; Eggs and larvae on Rosa sp., Torrecilla del Pinar (Segovia), 41°19.32’N, 4°0.94’W, 875 m, 14.vi.2015, J. C. V. and B. P. leg.; Eggs and larvae on Rosa sp., Castroserna de Abajo (Segovia), 41°14.03’N, 3°46.54’W, 990 m, 06.vii.2015, J. C. V. and B. P. leg.; Larva on Rosa sp., Castrojimeno (Segovia), 41°30.19’N, 3 53.92’W, 1095 m, 13.vii.2015, J. C. V. and B. P. leg.; Larva on Rosa sp., Valle de Tabladillo (Segovia), 41°24.78’N, 3°53.84’W, 1025 m, 13.vii.2015, J. C. V. and B. P. leg.; Eggs and larvae on Rosa sp., Pradales (Segovia), 41°30.28’N, 3°39.54’W, 1140 m, 29.vii.2015, J. C. V. and B. P. leg.; Larva on Rosa sp., Puerto de Malangosto (Madrid), 40°57.76’N, 3 53.48’W, 1930 m, 02.viii.2015, J. C. V. and B. P. leg; Larva on Rosa sp., Palazulelos de Eresma, Sierra de Guadarrama (Segovia), 40°52.30’N, 4°0.52’W, 1620 m, 03.viii.2015, J. C. V. and B. P. leg.; Larva on Rosa sp., Palazuelos de Eresma, Sierra de Guadarrama (Segovia), 40°57.70’N, 4 0.60’W, 1845 m, 03.viii.2015, J. C. V. and B. P. leg.; Larva on Rosa sp., Puerto Alto del León (Madrid), 40°41.43’N, 4°7.46’W, 1525 m, 04.viii.2015, J. C. V. and B. P. leg.; Larva on Rosa sp., El Espinar, Sierra de Guadarrama (Segovia), 40°46.76’N, 4°14.66’W, 1295 m, 04.viii.2015, J. C. V. and B. P. leg; Larva on Rosa sp., Revenga, Sierra de Guadarrama (Segovia), 40°52.23’N, 4°7.64’W, 1185 m, 09.viii.2015, J. C. V. and B. P. leg.; Larva on Rosa sp., Maderuelo (Segovia), 41°30.32’N, 3°32.35’W, 945 m, 16.viii.2015, J. C. V. and B. P. leg.; Eggs and larvae on Rosa sp., Alconada de Maderuelo (Segovia), 41°24.92’N, 3°32.31’W, 935 m, 16.viii.2015, J. C. V. and B. P. leg.; Eggs and larvae on Rosa sp., Aldealengua de Santa María (Segovia), 41°30.35’N, 3°25.16’W, 955 m, 16.viii.2015, J. C. V. and B. P. leg.; Larva on Rosa sp., Barahona del Fresno (Segovia), 41°19.51’N, 3°32.26’W, 1010 m, 16.viii.2015, J. C. V. and B. P. leg.; Larva on Rosa sp., Cuellar (Segovia), 41°24.50’N, 4 22.55’W, 880 m, 22.viii.2015, J. C. V. and B. P. leg.; Larva on Rosa sp., Grado del Pico, Sierra de Ayllón (Segovia), 41°19.58’N, 3°10.75’W, 1355 m, 16.viii.2015, J. C. V. and B. P. leg.; Larva on Rosa sp., Ayllón (Segovia), 41°24.95’N, 3°25.13’W, 1015 m, 19.ix.2015, J. C. V. and B. P. leg.; Larva on Rosa sp., Soto del Real (Madrid), 40°47.00’N, 3°46.22’W, 1025 m, 06.x.2015, J. C. V. leg.; Larva on Rosa sp., Segovia, around the city (Segovia), 40°57.64’N, 4°7.73’W, 955 m, 16.x.2015, J. C. V. and B. P. leg.; Larva on Rosa corymbifera, Urueña (Valladolid), 41°45.32’N, 5°13.51’W, 820 m, 07.vii.2016, J. C. V. and B. P. leg.; Larva on Rosa corymbifera and R. micrantha, La Santa Espina (Valladolid), 41°45.45’N, 5°6.30’W, 815 m, 07.vii.2016, J. C. V. and B. P. leg.; Larva on Rosa sp., Montejo de la Vega de la Serrezuela (Segovia), 41°35.69’N, 3°39.60’W, 925 m, 12.vii.2016, J. C. V. and B. P. leg.; Larva on Rosa sp., Montejo de la Vega de la Serrezuela (Segovia), 41°35.73’N, 3°32.40’W, 905 m, 12.vii.2016, J. C. V. and B. P. leg.; Larva on Rosa tomentosa, San Llorente (Valladolid), 41°40.93’N, 4°1.28’W, 910 m, 28.vii.2016, J. C. V. and B. P. leg.; Larva on Rosa sp., Cuevas de Ayllón (Segovia), 41°24.97’N, 3°17.95’W, 1035 m, 20.viii.2016, J. C. V. and B. P. leg. Larvae on Rosa sp., Sepúlveda (Segovia), 41°19.43’N, 3°46.60’W, 1025 m, 16.x.2016, J. C. V. and B. P. leg.; Eggs on Rosa sp., Renedo de Esgueva (Valladolid), 41°40.52’N, 4°37.31’W, 810 m, 11.vi.2017, J. C. V. leg.; Eggs and larvae (L1) on Rosa sp., Montejo de la Sierra (Madrid), 41°8.70’N, 3°32.17’W, 1280 m, 24.vi.2017, J. C. V. and A. García leg.; Eggs and larvae (L1) on Rosa sp., Montejo de la Sierra (Madrid), 41°3.30’N, 3°32.13’W, 1340 m, 24.vi.2017, J. C. V. and A. G. leg.; Eggs on Rosa sp., La Hiruela (Madrid), 41°3.33’N, 3°24.99’W, 1260 m, 24.vi.2017, J. C. V. and A. G. leg.; Eggs and larvae (L1) on Rosa sp., Puerto de la Hiruela (Madrid), 41°3.33’N, 3°24.99’W, 1470 m, 24.vi.2017, J. C. V. and A. G. leg.; Eggs on Rosa sp., Puebla de la Sierra (Madrid), 40°57.92’N, 3°24.96’W, 1160 m, 24.vi.2017, J. C. V. and A. G. leg.; Eggs on Rosa sp., Berzosa del Lozoya (Madrid), 40°57.89’N, 3°32.09’W, 1025 m, 24.vi.2017, J. C. V. and A. G. leg.
Spain: 1 larva, ex ovum on Sanguisorba minor, Garganta de Vadillo, Losar de la Vera (Cáceres), 40°7.51’N, 5°38.43’W, 480 m, 22.vi.2006, leg. et coll. J. L. H.-R. (JHSEM-C12P11 and JHSEM-C12P12); 1 pupa, ex ovum on Sanguisorba minor, Garganta de Vadillo, Losar de la Vera (Cáceres), 40°7.51’N, 5°38.43’W, 480 m, 22.vi.2006, leg. et coll. J. L. H.-R. (JHSEM-C09P01); 4 eggs on Sanguisorba minor, Vallelado (Segovia), 41°24.50’N, 4°22.55’W, 815 m, 1.vi.2013, leg. J. C. V., coll. J. L. H.-R. (JHSEM-C20P09);
Spain: 2 males, Puerto de La Ragua, Sierra Nevada, 37°5.48’N, 3°3.38’W, 2090 m, ex S. rosae (L5, L4), 19.vii.2012, em. 1.viii.2012, 23.viii.2012, leg. J. L. H.-R., det. M. Shaw, coll. J. L. H.-R. (JH6569) and National Museums of Scotland (1 leg of JH6569: MRS/JFT 0278, MRS/JFT 0247).
Immature stages of S. sertorius were found in the wild on Sanguisorba minor Scop. (Rosaceae). In the case of S. rosae, immature stages were collected on rose bushes. The species of Rosa (Rosaceae) on which S. rosae has been previously cited in the literature (
The habitats of S. rosae in the Iberian Peninsula are located at altitudes ranging from 469 m (Navarra, N Spain) to 2640 m (Sierra Nevada, SE Spain). The type locality of Puerto de la Ragua (Sierra Nevada, Granada, SE Spain, Fig.
Habitats and foodplants of Spialia rosae in the Iberian Peninsula. 1. Habitat in Puerto de la Ragua, 2090 m (Sierra Nevada, Spain, July 2011). 2. Habitat in Pico Yordas, 1700 m (Cantabrian Mountains, Spain, September 2012). 3. Plant of Rosa sicula (July 2013). 4. Flowers of R. sicula (July 2013). 5. Plant of R. pendulina (September 2012).
The habitat of S. rosae in the Pico Yordas (Cantabrian Mountains, León, N Spain, Fig.
The foodplant of S. rosae in Puerto de la Ragua (Granada, SE Spain) is Rosa sicula (Figs
Life cycle of Spialia rosae on Rosa sicula in Puerto de la Ragua, Granada, SE Spain. 6. Egg on the upperside of a leaf of R. sicula and 7. On the underside of the leaf (July 2012). 8. Recently emerged first instar larva on a leaf of R. sicula (note that the epidermis and parenchyma of the leaf have been eaten, July 2012). 9. Third instar larva. 10, 11. Larval shelter made with leaves. 12. Cocoon of the parasitoid Microgaster australis (Hymenoptera), with the remains of a third instar larva of S. rosae on R. sicula. 13. Adult of M. australis bred from S. rosae. Photographs 9–13 were taken in August 2012.
Life cycle of Spialia rosae. 14. Dorsal view of a last instar larva on Rosa sicula in Puerto de la Ragua, Granada, SE Spain (July 2012). 15. Pre-pupa on R. sicula in Puerto de El Cubillo, Cuenca, Central Spain (August 2012). 16, 17. Dorsal and lateral views of a pupa on R. sicula in Puerto de El Cubillo (September 2012). 18, 19. Upperside views of adult male and female in Puerto de la Ragua (July 2013). 20, 21. Side view of adult male and female in Puerto de la Ragua (July 2013).
Egg (Figs
The egg is whitish when laid and turns to pale orange in 24–48 hours. Its form is spherical with depressions in the base and annular areas. The diameter is 0.63–0.69 mm (number of samples examined, n = 2) and its height 0.55–0.57 mm (n = 2). The chorion surface is perforated by pores (Fig.
Scanning electron microscope images of the egg of Spialia rosae (Paratypes from Puerto de la Ragua, Granada, SE Spain). 22. Lateral view of egg on a leaf of Rosa sicula showing the glands of the plant epidermis. 23. Lateral view. 24. Lateral view of the annular area with annular area in the middle. 25. Cells from the lateral zone of the egg formed by radial and transverse ribs. 26. Detail of the radial ribs. 27. View of the annular pole. 28. Annular area with the micropylar rosette. 29. Detail of the micropylar rosette and the micropyle showing six micropylar openings.
Last instar larva (Figs
The surface of the head capsule displays a reticular pattern and is covered with a large number of highly branched setae and a few longer and smooth setae with a pointed tip (Figs
Scanning electron microscope images of a last instar larva of Spialia rosae (Paratype from Sierra de Albarracín, Teruel, Central Spain). 30. Head capsule and collar. 31, 32. Detail of the head capsule setae and sculpture. 33. Cuticular formations on thoracic and abdominal segments. 34. Detail with different types of subdorsal and lateral setae on the first thoracic segment: long and short setae with pointed tips. 35. Cuticular formations on an abdominal segment. 36. Last abdominal spiracle. 37. Last abdominal segments with the anal plate and setae with pointed tips and rounded bases.
Pupa (Figs
The pupa is fusiform, with a smooth cuticle that is dark grey or black. It is covered in wax, giving the pupa a characteristic appearance, with a fine powder on its surface and a light grey colour (Figs
Scanning electron microscope images of a pupa of Spialia rosae (Paratype from Puerto de El Cubillo, Cuenca, Central Spain). 38. Lateral view of the mesothoracic tubercle. 39. Upper view of the mesothoracic tubercle. 40. Detail of the pupal cuticle showing smooth setae with rounded bases. 41. Abdominal spiracle. 42. Detail of the spiny papillae inside the spiracle. 43. Ventral view of the last abdominal segments. 44. Detail of the cremaster. 45. Tips of the cremastral hooks.
Immature stages of S. sertorius do not have significant diagnostic differences from those of S. rosae in the Iberian populations studied.
Egg (Figs
This is similar to the egg of S. rosae. The diameter is 0.61 ± 0.02 mm (n = 4) and its height 0.51 ± 0.01 mm (n = 3). In the equator of the egg the number of radial ribs is 17–21 (n = 4, Fig.
Scanning electron microscope images of an egg of Spialia sertorius from Vallelado, Segovia, Central Spain. 46. Lateral view. 47. Lateral view of the annular area. 48. Detail of the annular area. 49. Cells of the egg equator formed by radial and transverse ribs. 50. Detail of the radial ribs. 51. View of the annular pole. 52. Annular area with the micropylar rosette. 53. Micropylar rosette and micropyle showing six micropylar openings.
Last instar larva (Figs
The larva of S. sertorius (Figs
Scanning electron microscope images of a last instar larva of Spialia sertorius from Losar de la Vera, Cáceres, Central Spain. 54. Head capsule and collar. 55, 56. Detail of the head capsule setae and sculpture. 57. Cuticular formations on thoracic and abdominal segments. 58. Detail with different types of subdorsal and lateral setae on the first thoracic segment: long and short setae with pointed tips. 59. Detail of a barrel-like formation and the cuticular sculpture. 60 Last abdominal spiracle. 61. Last abdominal segments with the anal plate and setae with pointed tips and rounded bases.
Pupa (Figs
The morphology of the pupa of S. sertorius is similar to that of S. rosae (Figs
Scanning electron microscope images of a pupa of Spialia sertorius from Losar de la Vera, Cáceres, Central Spain. 62. Lateral view of the mesothoracic tubercle. 63. Upper view of the mesothoracic tubercle. 64. Detail of the pupal cuticle showing smooth setae with rounded bases. 65. Abdominal spiracle. 66. Detail of the spiny papillae inside the spiracle. 67. Ventral view of the last abdominal segments. 68. Detail of the cremaster 69. Detail of the cremastral hooks.
S. rosae and S. sertorius are morphologically identical externally as adults. The upperside of the wings in both males and females is dark brown, almost black, with chequered fringes. The upperside of the forewing has a white quadrilateral discal spot, a series of white postdiscal spots (spots in E4 and E5 are often missing or very small), and a submarginal series of small dots. The upperside of the hindwing has a white spot in the cell, an incomplete postdiscal series with only two or three white dots distally, and a series of small submarginal dots. The underside of the forewing has pale or reddish costal, apical and marginal areas, while the discal and postdiscal areas are dark grey or brown, with the same dorsal white spots as on the upperside. The colour of the underside of the hindwing is brick red or reddish ochre, with a series of white postdiscal spots that are larger in E7 and E8. The white spot in E8 is displaced towards the base of the wing, giving the series a curved shape. The submarginal series has larger spots in E4, E5 and E7 (according to the original description in
Fig.
The distributions of both species of Spialia are clearly related to the altitudinal zonation where their host-plants occur. In Sierra Nevada, as an example of the Mediterranean biogeographic region, S. sertorius is present in the thermomediterranean (0–600 m), mesomediterranean (600–1500 m) and supramediterranean (1500–1900 m) belts, and is generally absent from the oromediterranean (1900–2900 m) and crio-oromediterranean (>2900 m) belts (terms for mediterranean biogeographic belts follow
In the Cantabrian Mountains, which belong to the Atlantic biogeographical region, S. sertorius is present in the lowest bioclimatic belt (Quercus robur L. (Fagaceae) and Q. ilex L. forests, 0–500 m) and montane belt (Fagus sylvatica (Fagaceae) and other deciduous forests, 500–1700 m), while S. rosae is present in the montane and subalpine belts (heathlands, 1700–2200 m) and probably also in the alpine belt (grasslands above 2200 m). Here, the two species can coexist in the montane belt.
We compared the morphological characters of the immature stages of S. rosae and S. sertorius (which do not present constant diagnostic differences between the two species) with those of the European species of the genus Pyrgus, which have been extensively studied (
Larvae of Spialia in the examined Iberian samples, have highly branched setae on the head capsule, while this type is not found on the head capsule of the last instar larvae of Pyrgus. On the other hand, narrow setae with their tip forming a crown, which are present in Pyrgus, are missing on the last instar larvae of Spialia. In addition, both genera have two characteristic cuticular barrel-like formations on each segment of the thorax, abdomen and on the collar. The inner part of the spiracles in Spialia has branched papillae, while most of the species of Pyrgus, with the exception of P. andromedae (Wallengren, 1853), P. cacaliae (Rambur, 1839), P. malvae (Linnaeus, 1758) and P. malvoides (Elwes & Edwards, 1897), have filiform spiracular papillae.
The pupae of Spialia have the mesothoracic tubercles with an undulated external wall and a hairy surface, features that are found in most species of Pyrgus, except for the external wall of the mesothoracic tubercles, which is smooth in P. malvae and P. malvoides, and the surface of the rest of the tubercle, which is smooth in P. malvoides, covered with spines in P. malvae, and rugose in P. andromedae and P. cacaliae. The pupal spiracles of Spialia have branched papillae in their interior as do most species of Pyrgus, except in P. andromedae, P. cacaliae, P. malvae and P. malvoides, which have unbranched spiracle papillae.
While S. sertorius is widely distributed in the Iberian Peninsula except at the highest altitudes, S. rosae is restricted to mid and high elevations. Thus, their distributions are complementary, with a wide overlap at mid-mountain. Nevertheless, it is important to note that the status of the two species is radically different because:
1) S. sertorius is widely distributed in Western Europe and S. rosae is apparently endemic to the Iberian Peninsula.
2) While S. sertorius is present in all the regions of the Iberian Peninsula, S. rosae seems to be absent in some mountains, for example the Eastern Pyrenees, where it has been searched for without success.
3) The populations of S. sertorius are generally connected through lowland habitat, as this species tolerates anthropogenic effects quite well.
In the case of S. rosae, most populations in mountain systems are fragmented. Nevertheless, the discovery of the existence of this species in the northern part of the interior plateau, and potentially quite widespread, suggests that the populations of the Cantabrian Mountains could be connected to those of the Central Mountain System and Northern Iberian Mountain System. Moreover, the fact that the species has been found in most places in which it was searched for in the Province of Segovia predicts a wider distribution than that shown by our map. It would be very important to assess if S. rosae is indeed widespread in the whole northern part of the interior plateau, as well as testing its potential presence in the southern part of the interior plateau and other parts of the Iberian Peninsula where it has not yet been recorded.
Spialia rosae has an apparently relatively limited and fragmented distribution in the Iberian Peninsula and prefers mountain areas (Fig.
We are grateful to Esperanza Salvador, Enrique Rodríguez and Isidoro Poveda (Laboratory SEM-EDX, SIDI from the Universidad Autónoma of Madrid, Spain), for their help with the scanning electron microscope images. Vlad Dincă (IBE, CSIC-UPF, Barcelona), Antonio García, Beatriz Parra and Santi Viader helped with fieldwork. Mark Shaw (National Museums of Scotland, Edinburgh, UK), kindly identified the parasitoids. Yeray Monasterio provided samples of host- plant roses from Navarra and La Rioja (Northeast of Spain) for identification. The fieldwork of this research was financed by projects CGL2013-48277-P (MINECO) and CGL2016-76322-P (AEI/FEDER, UE), and scanning electron microscope photographs by the Spanish Ministerio de Ciencia e Innovación (project CGL2004-04680-c10-08/BOS). Environmental authorities of the regional governments kindly gave permission to collect butterfly samples for scientific purposes. We thank Patrick Gros, Zdeněk Fric, and an anonymous referee for their valuable suggestions that considerably improved a previous version of this manuscript.
List of the new locations
Data type: specimen data