Research Article |
Corresponding author: Bruno Massa ( bruno.massa@unipa.it ) Academic editor: Netta Dorchin
© 2016 Marcela Skuhravá, Bruno Massa, Giuliano Cerasa.
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:
Skuhravá M, Massa B, Cerasa G (2016) Rediscovery and identity of Pumilomyia protrahenda De Stefani (Diptera, Cecidomyiidae) in Sicily with redescription and reassessment of its taxonomic position. ZooKeys 617: 129-137. https://doi.org/10.3897/zookeys.617.9850
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A population of the gall midge Pumilomyia protrahenda De Stefani, 1919 causing galls on Artemisia arborescens (Asteraceae) was discovered near Palermo (Sicily) in 2008. This species had not been found since 1918. Detailed study of morphological characters of adults, larvae and pupae revealed that P. protrahenda belongs to the genus Rhopalomyia Rübsaamen, 1892, tribe Rhopalomyiini. The monotypic genus Pumilomyia De Stefani, 1919 is therefore synonymized under Rhopalomyia Rübsaamen, 1892. Rhopalomyia protrahenda comb. n. is redescribed, with important morphological characters illustrated. Adults have one-segmented palpi, antennae with 12–13 short flagellomeres and long legs with simple tarsal claws. A neotype is designated in the present paper because the type of this species is lost. The host plant has a circum-Mediterranean distribution but the gall midge is currently known only from Sicily, where it completes several generations between January and May.
Rhopalomyia protrahenda , gall midge, Artemisia arborescens , Italy
Remarkably, this species was known only from De Stefani’s original description in 1919 more than 90 years ago. In recent years we have searched for the galls of this species at its type locality in the Botanical Garden in Palermo, where De Stefani found galls and also in its surroundings but without success. In March 2008 we discovered galls of P. protrahenda on leaves of Artemisia arborescens at Mt. Raffo Rosso (Sicily), west of Palermo.
This recent find of larvae, pupae and adults is important because the De Stefani’s collection, including many type specimens of species described by him, is considered to be lost (V. Caleca, pers. comm.). We take this opportunity to redescribe the species and designate a neotype.
Material for this study was collected at three localities in the area of Palermo (Sicily) in 2008, 2012, 2015 and 2016. Branches of Artemisia arborescens with galls attributed to P. protrahenda were transferred to the laboratory at the Palermo University and placed in rearing cages where they were maintained at ambient temperature to obtain adults. In the field we bagged branches of Artemisia arborescens including galls with fine mesh tulle. Adults which emerged from galls and immature stages that were dissected from galls were preserved in 70% ethanol for subsequent morphological studies. Specimens were examined through a stereomicroscope Wild-Heerbrugg M8. A series of images was taken using a Leica DM2500 compound microscope and a Leica DFC450C mounted camera with Leica Application Suite software. Some galls were photographed with a Canon 7D digital camera provided with a Canon MP-E 65 mm macrolens and photos were integrated using the freeware CombineZP (
Pumilomyia
protrahenda
Pulmilomyia
artemisiae
Pumilomyia
artemisiae
Female (Figs
Rhopalomyia protrahenda comb. n. 1 Females wing 2 female, fifth flagellomere 3 female, two apical flagellomeres 4 female, head 5 male, fifth flagellomere 6 male, two apical flagellomeres 7 female, mouthparts 8 fifth tarsomere with simple claw and empodium 9 terminal part of ovipositor 10 pupal head, lateral view 11 male terminalia.
Thorax. Wing with R5 joining costa at wing apex, well visible only in basal two thirds; Cu barely visible; anterior wing margin with shorter setae, posterior wing margin with long setae; wing surface covered with short setae. Legs long, covered with short hairs. All legs with simple claws, empodia as long as claws.
Abdomen: Second to sixth segments broad, seventh segment narrow; 8th tergite entire. Ovipositor protrusible, cerci fused, ovoid, setose and setulose; hypoproct small, rounded, setulose, visible only in dorsoventral view.
Male (Figs
Antennae: scape obconical, pedicel globular, usually 13 flagellomeres, 1st and 2nd connate; each flagellomere composed of basal node and distal neck; neck about one half of node. Of three males, one male had 12 and two males had 13 flagellomeres.
Terminalia: gonocoxites thick, completely setulose, with several long setae; gonostyli ovoid, short and thick, completely setulose, covered with setae, at the tip with large, brown, beak–formed curved tooth; cerci broad, lobes rounded, deeply separated, setulose; hypoproct slender, incised; mediobasal lobes setulose, apically with several long setae; aedeagus rounded at tip, as long as cerci.
Other morphological characters as in female.
Larva. Body size: 1.2–1.8 mm long, 0.39–0.55 mm broad, cream colored; integument covered densely with very small spiculae; without spatula sternalis, without apparent papillae on ninth abdominal segment.
Pupa (Figs
20 Artemisia arborescens covered with galls 21 female of Rhopalomyia protrahenda next to apical leaves of the host plant covered with reddish mass of eggs 22 galls, detail 23 dissected gall showing a pupa 24 exuviae protruding from a gall 25 adult emergence hole 26 detail of a leaf gall showing the chamber and thin wall 27 pupa, lateral view 28 pupa frontal view 29 female emerging from gall.
(Figs
The neotype of Rhopalomyia protrahenda is designated here: female, Italy, Sicily, Raffo Rosso, reared from small leaf gall on Artemisia arborescens, 18.III.2008, leg. G. Cerasa, microscope slide number 9571, in the collection of National Museum, Prague, Czech Republic (coll. Marcela Skuhravá).
5♀, 3♂, Italy, Sicily, Palermo, locality Raffo Rosso, galls on Artemisia arborescens 3.III.2008, emerged 10–25.III.2008; 3♀, 2♂ same data, emerged 13.II.2012, leg. G. Cerasa; 4♀, 3♂, Italy, Sicily, Cinisi, locality Costa del Furi (Palermo), galls on Artemisia arborescens 11.III.2015, emerged 14–16.III.2015, leg. G. Cerasa; 5♀, 3♂, Italy, Sicily, Palermo, locality Raffo Rosso, galls on Artemisia arborescens 15.II.2016, emerged 16–25.II.2016, leg. G. Cerasa (in ethanol, BMUP); 2♂, 2♀ (neotype included) mounted (on microscope slides in Canada Balsam, coll. Skuhravà,
The host plant Artemisia arborescens is native to the Mediterranean. It is an erect evergreen perennial, with masses of finely–divided aromatic, silvery–white leaves and single–sided sprays of yellow flowers. The plant occurs from the Iberian Peninsula to Israel, the Italian Peninsula, Sicily, the Balkan Peninsula, Turkey and North Africa, and is naturalized in France. Rhopalomyia protrahenda has been found only in Sicily.
Detailed study of morphological characters of larvae, pupae and adults obtained from galls on Artemisia arborescens, found not far from the type locality in Palermo where De Stefani collected galls in the past, revealed that the causer of these galls, described as Pumilomyia protrahenda by
The female of R. protrahenda has mostly 12 antennal flagellomeres as is typical for all species of Asphondylia but the female flagellomeres of R. protrahenda are oval and not cylindrical as in females of Asphondylia. The female of R. protrahenda has the terminal part of ovipositor slender ending with soft, fused cerci, not aciculate and strongly sclerotized as in females of Asphondylia.
The genus Rhopalomyia Rübsaamen, 1892 is characterized by the combination of the following characters: reduced mouthparts with 1 or 2 segmented palpi, rarely 3; 12-25 flagellomeres; male flagellomeres with long necks, female flagellomeres with short necks; wing with R5 reaching Costa nearly at wing apex; simple or toothed tarsal claws; male genitalia with stout gonocoxites and short, completely setulose gonostyli, with large claw; mediobasal lobes sheath aedeagus, cerci broad, hypoproct slender; female 8th tergite entire; ovipositor long, soft, not distinctly sclerotized; cerci fused. Larvae of most species do not have a spatula sternalis and their papillae are barely visible; pupae usually have strongly developed antennal horns.
The genus Rhopalomyia includes 267 species worldwide (
Rhopalomyia is relatively species–rich in central, southeast and western Europe, where it contains 38 species. The number of species decreases markedly towards the south. No species were found in the islands of the Mediterranean Sea (other than Sicily) in the past. It is interesting that Rhopalomyia protrahenda is the only species of the genus Rhopalomyia occurring on a Mediterranean island (Sicily). Many Rhopalomyia species have been found to occur in Central Asia, mainly in Kazakhstan (
We thank Dr Keith Murray Harris (Ripley, Woking, Surrey, UK) for valuable comments on the manuscript and for improvements of the English text. We also thank Raymond Gagné (Systematic Entomology Laboratory