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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 Ta-
vares, 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 sa-
malla 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 löytö-
hetkellä ollut karjaa.
Janetiella glechomae elää vain maahumalalla (Glechoma hederacea). Lajin toukat aiheuttavat äkämän maahuma-
lan kypsyvään lohkohedelmään. Yhden tai kahden toukan asuttama yksittäinen lohko (merikarppi) paisuu voi-
makkaasti 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 Hollan-
nin 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: hhbruun@bio.ku.dk
Jyrki Torniainen, Jyväskylä University Museum, Natural History section, University of Jyväskylä, Ihantolantie 5,
40100 University of Jyväskylä, Finland, e-mail: jyrki.torniainen@jyu.
The gall midge fauna of Europe is reasonably well known over-
all, 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 to-
Fig. 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 longitudi-
nal section, with one larva.
Janetiella glechomae-äkämäsääsken äkämä maahumalalla.
Osa verhiöstä on poistettu äkämän paljastamiseksi. Normaali
maahumalan lohkohedelmä koostuu neljästä tummanruske-
asta lohkosta, jotka ovat paljon äkämää pienempiä. Pikkuku-
vassa 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, Micromyi-
nae, Winnertziinae and Porricondylinae), have sub-
stantially added to the gall midge checklist for Fin-
land, which now comprises 356 species (Jaschhof,
Skuhravá & Penttinen 2014). However, only three
new plant-galling species of the subfamily Cecid-
omyiinae have been added since 1980 (Huldén 2003,
Jaschhof, Skuhravá & Penttinen 2014). This calls for
increased focus on basic faunistics of this group of in-
sects, and so does the following report of a haphazard
nding of Janetiella glechomae Tavares, 1930 (Ceci-
domyiidae: Cecidomyiinae).
19
Sahlbergia 22.2 (2016), 18-19
On June 18, HHB went on a short eld-trip with Dr. Anna
Oldén after her successful PhD defence the day before. We
visited some of the wood pastures that she had been study-
ing for her thesis. At one of the sites, we came across larvae
of the gall midge Janetiella glechomae Tavares, 1930 liv-
ing 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 en-
larged to a degree where it protrudes out of the persistent
calyx. The gall is whitish at rst, but turns brown. Inside
the galled fruit are 1–2 larvae, at rst whitish, but c. 3 mm
long and dull orange when mature.
Janetiella glechomae was described in 1930 by the Portu-
guese 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 Car-
bonelle 2015). Subsequently, several ndings of the spe-
cies have been made in the Netherlands and Belgium. HHB
found the species at two Danish sites just a week prior to
the nding in Finland.
The occurrence of J. glechomae in Finland was not directly
expected from its hitherto known distribution in Central Eu-
rope. However, it indicates that large holes in the knowl-
edge of the Finnish gall midge fauna remain to be lled.
A specimen of two galls (in ethanol), one opened contain-
ing 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 Med-
edelingen 44: 47–167.
Skuhravá, M. & Skuhravý, V. (2009) Species richness of gall midg-
es (Diptera: Cecidomyiidae) in Europe (West Palaearctic): bi-
ogeography and coevolution with host plants. Acta Societatis
Zoologica Bohemoslovaca 73: 87–156.
Tavares, J. S. (1930) Quelques cécidies du centre de la France. An-
nales de la Société Linnéenne de Lyon 75: 145–167.
