First Fennoscandian record of the gall midge Janetiella glechomae Tavares, 1930 (Diptera: Cecidomyiidae)

This is an electronic reprint of the original article. This reprint may differ from the original in pagination and typographic detail. Author(s): Title: Year: Version: Please cite the original version: All material supplied via JYX is protected by copyright and other intellectual property rights, and duplication or sale of all or part of any of the repository collections is not permitted, except that material may be duplicated by you for your research use or educational purposes in electronic or print form. You must obtain permission for any other use. Electronic or print copies may not be offered, whether for sale or otherwise to anyone who is not an authorised user. First Fennoscandian record of the gall midge Janetiella glechomae Tavares, 1930 (Diptera: Cecidomyiidae) Bruun, Hans Henrik; Torniainen, Jyrki Bruun, H. H., & Torniainen, J. (2016). First Fennoscandian record of the gall midge Janetiella glechomae Tavares, 1930 (Diptera: Cecidomyiidae). Sahlbergia, 22(2), 1819. http://www.luomus.fi/sites/default/files/sahlbergia/sahlbergia_22_2_2016.pdf 2016 18 Sahlbergia 22.2 (2016), 18-19 First Fennoscandian record of the gall midge Janetiella glechomae Tavares, 1930 (Diptera: Cecidomyiidae) Hans Henrik Bruun & Jyrki Torniainen Bruun, H. H. & Torniainen, Jyrki 2016: First Fennoscandian record of the gall midge Janetiella glechomae Tavares, 1930 (Diptera: Cecidomyiidae) [Fennoskandian ensimmäinen havainto Janetiella glechomae Tavares, 1930-äkämäsääskestä]. – Sahlbergia 22(2): 18–19. Janetiella glechomae (Tavares, 1930) -äkämäsääski ilmoitetaan ensimmäisen kerran Suomesta. Havainto on samalla koko Fennoskandian alueelle uusi. Havainnon ja määrityksen teki tanskalainen tutkija, tohtori Hans Henrik Bruun, 18.6.2016 ollessaan vierailemassa vastaväittäjänä Jyväskylän yliopistossa. Varsinainen havaintopaikka sijaitsee ES: Joutsan Taka-Ikolassa. Habitaatti on reheväkasvuinen ja ruohoinen laidun, jolla ei juuri lajin löytöhetkellä ollut karjaa. Janetiella glechomae elää vain maahumalalla (Glechoma hederacea). Lajin toukat aiheuttavat äkämän maahumalan kypsyvään lohkohedelmään. Yhden tai kahden toukan asuttama yksittäinen lohko (merikarppi) paisuu voimakkaasti ja äkämä ulottuu verhiön jäänteiden ulkopuolelle. Äkämä on ensin vaalea, myöhemmin ruskea. Toukat ovat pieninä valkeahkoja, täysikasvuisina n. 3 mm pitkiä ja oranssin sävyisiä. Laji kuvattiin vuonna 1930 Ranskan Normandiasta. Seuraavat havainnot tehtiin 80 vuotta myöhemmin Hollannin Bennekomissa vuonna 2010. H.H. Bruun löysi lajin kahdesta paikasta Tanskalle uutena vain viikkoa ennen Suomen havaintoa. Kaksi äkämää Joutsasta on taltioitu Jyväskylän yliopiston tiedemuseon hyönteiskokoelmiin. Hans Henrik Bruun, Dept of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark, e-mail: [email protected] Jyrki Torniainen, Jyväskylä University Museum, Natural History section, University of Jyväskylä, Ihantolantie 5, 40100 University of Jyväskylä, Finland, e-mail: [email protected] The gall midge fauna of Europe is reasonably well known overall, with more than 1800 named species in 270 genera (Skuhravá & Skuhravý 2008). Finland, however, stands out as a relatively poorly investigated territory. The 1980 checklist comprised a toFig. 1. A gall of Janetiella glechomae in fruit of Glechoma hederacea, collected from Joutseno, Finland. The calyx is partly removed to reveal the brownish outer wall of the gall. The normal fruit consists of four dark brown mericarps, much smaller than the gall. Inset photo shows the gall, in longitudinal section, with one larva. Janetiella glechomae-äkämäsääsken äkämä maahumalalla. Osa verhiöstä on poistettu äkämän paljastamiseksi. Normaali maahumalan lohkohedelmä koostuu neljästä tummanruskeasta lohkosta, jotka ovat paljon äkämää pienempiä. Pikkukuvassa on avattu äkämä toukkineen. tal of 135 species, with 104 belonging to the mainly phytophagous subfamily Cecidomyiinae. Since then, renewed investigations in the fauna of wood midges and allies (i.e. the mainly xylophilous or mycotrophic subfamilies Catotrichinae, Lestremiinae, Micromyinae, Winnertziinae and Porricondylinae), have substantially added to the gall midge checklist for Finland, which now comprises 356 species (Jaschhof, Skuhravá & Penttinen 2014). However, only three new plant-galling species of the subfamily Cecidomyiinae have been added since 1980 (Huldén 2003, Jaschhof, Skuhravá & Penttinen 2014). This calls for increased focus on basic faunistics of this group of insects, and so does the following report of a haphazard finding of Janetiella glechomae Tavares, 1930 (Cecidomyiidae: Cecidomyiinae). 19 Sahlbergia 22.2 (2016), 18-19 On June 18, HHB went on a short field-trip with Dr. Anna Oldén after her successful PhD defence the day before. We visited some of the wood pastures that she had been studying for her thesis. At one of the sites, we came across larvae of the gall midge Janetiella glechomae Tavares, 1930 living in galls on its only host plant Glechoma hederacea L. (Lamiaceae; Finnish name: maahumala). The site is a lush, herb-rich mesic pasture—not grazed at the time—close to a farm house near Taka-Ikola in Joutsa municipality, Central Finland (YKJ: N6874881:E3455033). The galls induced by this species consist of one immature mericarp, strongly enlarged to a degree where it protrudes out of the persistent calyx. The gall is whitish at first, but turns brown. Inside the galled fruit are 1–2 larvae, at first whitish, but c. 3 mm long and dull orange when mature. Janetiella glechomae was described in 1930 by the Portuguese Jesuit and entomologist Joaquim da Silva Tavares (1866–1931) based on material collected in Normandy, France (Tavares 1930). It seems as if the species fell into neglect, as the next recording was as much as 80 years later, in 2010 in Bennekom, the Netherlands (Roskam and Carbonelle 2015). Subsequently, several findings of the species have been made in the Netherlands and Belgium. HHB found the species at two Danish sites just a week prior to the finding in Finland. The occurrence of J. glechomae in Finland was not directly expected from its hitherto known distribution in Central Europe. However, it indicates that large holes in the knowledge of the Finnish gall midge fauna remain to be filled. A specimen of two galls (in ethanol), one opened containing two larvae, of J. glechomae are archived in Jyväskylä University Museum, Natural History section invertebrate collections. References Hackman, W. (1980) A check list of the Finnish Diptera. Notulae Entomologicae 60: 17–48. Huldén, L. (2003) Dasineura pustulans (Rübs.) (Cecidomyiidae) discovered in Finland. Sahlbergia 8: 100. Jaschhof, M., Skuhravá, M. & Penttinen, J. (2014) Checklist of the Cecidomyiidae (Diptera) of Finland. Zookeys 441: 103–118. Roskam, H. & Carbonelle, S. (2015) Annotated checklist of the gall midges from the Netherlands, Belgium and Luxembourg (Diptera: Cecidomyiidae). Nederlandse Faunistische Mededelingen 44: 47–167. Skuhravá, M. & Skuhravý, V. (2009) Species richness of gall midges (Diptera: Cecidomyiidae) in Europe (West Palaearctic): biogeography and coevolution with host plants. Acta Societatis Zoologica Bohemoslovaca 73: 87–156. Tavares, J. S. (1930) Quelques cécidies du centre de la France. 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