Japananus hyalinus, a new species of leafhopper in Britain

Japananus hyalinus, often called the Japanese Maple Leafhopper, is a species of (relatively) large leafhoppers of the family Cicadellidae. Believed to be native to eastern Asia, it has been carried with the trade in cultivated maples and is now widely found in Europe, North America and Australia. Entirely accidentally, I seem to have been the first person to find one of the species in the wild in Britain. This page is a commemoration of that event and an appeal for observers to watch out for it and report any further sightings.

Original naming

The species was first described (as Platymetopius hyalinus) by Herbert Osborn in 1900, from specimens taken in Washington, D.C. He considered it improbable that there could be an undescribed native species as distinctive as this, and suggested it had been introduced to the USA with exotic plants. A second independent description, as Platymetopius cinctus, was published by Shōnen Matsumura in 1914 based on specimens from Hokkaido, Honshu and Kyushu, and in 1931 Paul Oman answered Osborn's conjecture by realising these two species were identical. Virtually at the same time Elmer Ball reallocated all supposed American Platymetopius species, and designated hyalinus as the type (and, at the time, only) species of a new genus Japananus. Since then a further five species have been placed in this genus, which are all native to mainland Asia and show no tendency to major range expansions.

Increase in Range

Whether it was from the United States or directly from the far east, the species eventually reached Europe. The first European records, from Austria and Romania, were published in 1961, followed by reports from Germany, the former Czechoslovakia and Yugoslavia (1987), Bulgaria and Hungary (1989), France, Spain and Northern Italy (1994), Slovenia (2002), Serbia and Southern Russia (2003), Luxembourg (2010) and Poland (2012). It was reported from Australia in 1997.

Discovery in the wild in Britain

First sighting

First sighting

On 28th August 2014 I noticed a leafhopper in my garden in Cambridge which I hadn't seen before. It was somewhat awkwardly placed among some michaelmas daisies, so I was only able to photograph it from one angle, but it looked sufficiently distinctive that I thought it would be easy to identify from the gallery in British Bugs.

However I couldn't find it there, and a post on iSpot elicted no response. In the end I posted it to the UK Hoppers Group on Flickr as "Unknown species" and assumed it would remain a mystery to me.

Imagine my surprise, therefore, just a few days later to receive this message from user "hnickel1"*:

"Japananus hyalinus. If it is from UK it should be new."

So I emailed the Auchenorrhyncha Recording Scheme and received the following reply:

"This is an excellent find — the first one recorded in Britain as far as I am aware, although we have been 'looking out for it' for some time."

I subsequently discovered that the claim of the first sighting needs to be qualified slightly. As far back as 1999 two specimens were found during inspection of imported Acer palmatum stock from Korea. This is therefore only claimed as the first sighting in the wild. Just as it seemed unlikely to Osborn in 1900 that he had discovered a native species, it seems highly unlikely to me that I discovered the ONLY J. hyalinus in Britain. I am not aware of any new maple planting in the immediate vicinity which might introduce it, so I am confident that there is a population out there quietly tapping into the maple syrup and waiting to be discovered. The first specimen was found directly underneath a long-established Acer palmatum, which I assumed was its real home (subsequently confirmed by the finding of a nymph, see below).

I had rather expected that this might be a one-off sighting, but not so. I found another one in the same part of the garden in late September, and another in mid-October. There seem to me to be definite differences in the markings in each set, so I think they are three different insects - although I suppose it is possible that markings change somewhat over an insect's life. The third sighting was unintentionally photographed with the camera stopped down, hence the rather darker appearance.

Second sighting 22nd September 2014. Third sighting 19th October 2014.

* I later realised this must be Dr Herbert Nickel of the University of Göttingen, co-author of ''The Auchenorrhyncha of Central Europe''. The Internet is a wonderful thing, sometimes!

2015 - Survival

The winter of 2014/5 was exceptionally mild in Cambridge, and it seemed that if the species had bred there was likely to be a good survival rate. I therefore observed the leaves of the Acer palmatum frequently during the following summer, and on the 8th August was rewarded by the sight of a tiny curved scrap of yellow which proved to be a hyalinus nymph. The species is therefore established as having bred in Britain at least once. Another was spotted the next day, I think a different insect as it was noticeably larger (around 4mm). Nymphs were found until nearly the end of August.

Nymph, 8th August 2015. 9th August 2015. 27th August 2015.

Then, also on the 9th August, I found a new season adult tucked away among the leaves. This one is less heavily marked and only 4mm long, so is probably a male (see description below). A further sighting on 20th August was of another male on which a yellow tinge to the forewings was clearly visible through the viewfinder, and looking at the 9th August photo again the yellow tinge is visible here as well. Further observations followed, the last being in early September.

9th August 2015. 20th August 2015. 27th August 2015.

2016 - Still hanging on.

Following the even milder winter of 2015/6 the discovery site was monitored again throughout the summer. The first, and so far only sighting, was a single adult found on 11th September.

11th September 2016.

Description

The females are 5.5mm long (or even a little more), the males smaller 4.25mm. The head comes to an acute point, this and the prothorax are greenish yellow (some photos, perhaps teneral insects, show bluish silver). The forewings (hemelyta) are translucent (this may look silvery-grey from some angles) with reddish veins, the males being paler (the photo above from August 2015 is noticeably paler so this may be the male).

In the resting position three major narrow beaded bands of purplish-brown colour run more or less straight across the wings, incorporating some portions of the veins, and some other cross-veins are also thickened. The scutellum is yellow and often has thin dark markings resembling the "frowny" emoticon.

The nymphs are around 3-4mm long, sharply pointed at both head and abdomen; sometimes yellowish all over, sometimes nearly white; slightly hairly with quite long twin dark anal appendages. They frequently adopt a head-up "star-gazey" posture.

The food-plants are maple species. In its Asian home range it utilises Acer japonicum and A. palmatum. In Europe it is mainly found on field maple, but also Norway maple, sycamore (as understood in Europe, Acer pseudoplatanus), and others.

Sexual dimorphism

Female Male
6mm long or more 5mm long or less
Angle of vertex acute Angle of vertex a right angle
Veins in elytra orange-red Veins in elytra hardly visible
Elytra always neutral in colour Elytra sometimes suffused with yellow

Original descriptions by Authors

Original description as Platymetopius hyalinus by Osborn: Elytra hyaline with dark points and fuscous bands arranged, one sub-basal, one median and one sub-apical. Face bright sulphur yellow, vertex, pronotum and scutellum yellow with some infuscation or greenish washes. Length ♀ 5.5 mm.; ♂ 4.25 mm. Vertex acute, nearly twice as long as width at base, slightly less acute and produced in male, anteriorly depressed and with a conspicuous median impressed line running from base to tip. Front narrow, clypeus widening to apex, lorae almost a half-circle, genae evenly rounded. Prothorax of usual form, sides short, posterior edge very slightly emarginate at center. Elytra hyaline, without veinlets or narrow lines, the nerves conspicuous, but one transverse vein between second and third sector.

Color: vertex yellow, more or less infuscated, the females showing a yellow wedge anteriorly, the males with deeper infuscation but having a marginal and anterior median stripe lighter. Face clear yellow with a marginal fuscous line just beneath margin of vertex, the margin of cheeks becoming somewhat greenish. Prothorax greenish yellow with slight trace of fuscous anteriorly in ♀ and faint milky irrorations in ♂. Elytral nervures fulvous in ♀, paler in ♂. Three fairly distinct transverse bands of fuscuous spots, one, midway on clavus and including first transverse vein consists of transverse fuscous spots behind which to tip of cell is a smoky patch. The middle band includes a distinct black point at tip of clavus and on the nodal vein. The subapical band includes the anteapical transverse veins, the inner and outer of which are black, the fuscous points appearing in outer and middle anteapical cells in proximal part of three apical cells, those in the outer and middle apical cells forming a broken circle. Pectus black with yellow borders on coxal and pleural pieces. Abdomen above black on disk in female, with yellow border and apex, in male black with marginal yellow spots. Beneath light yellow in female, black in male. Legs yellow with black points at base of spines.

Description as Platymetopius cinctus by Matsumura:

German original: Beim ♂ blassgelb, beim ♂* schmutziggelb. Scheitel spitzdreieckig, bein ♀ deutlich länger als der Abstand zwischen den Augen, in der Mitte ausgehöhlt. Schenkellinie und ein Längsfleck an der Spitze gelblich, eine mittlere Längsfurche bräunlich; am Uebergange zur Stirn mit einem Λ-förmliche, schwarzen Flecke. Stirn gelblich, sich in der Mitte der Länge nach etwas kielartig erhebt; am Gipfel mit einem undeutlichen, bräunlichen Querstreifen. Pronotum und Scutellum fast ohne Zeichnung. Elytren hyalin, schmutzigweiss getrübt, die Nerven beim ♂ gelblich, beim ♀ rötlich; nahe der Wurzel in einer Querreihe drei dunkle Flecke, 2 dunkle Fleckchen nahe der Spitze der inneren Clavuszelle, die Umgebung dieser Fleckchen hellbräunlich gefärbt; in der Mitte eine hellbräunliche Querbinde, darauf in einer Querreihe 4 dunkle Fleckchen, von welchen ein an der Spitze des Clavus sich befindlicher Fleck am grössten ist; nahe der Spitze ein weit ausgedehnter, bräunlicher Fleck, darauf 5 hellere Fleckchen sich befinden; beim ♀, die Querstreifen der Elytren nich so deutlich wie beim ♂. Unterseite beim ♂ schwarz, beim ♀ blassgelblich, hie und da schwärzlich gefleckt. Beine blassgelblich, beim ♂ die Schenkel mit bräunlichen Längsstreifen, beim ♀ Coxen, Trochanter und Femora vorwiegend schwarz; Hintertibien je an der Innenseite schwärzlich, an den Aussenseite mit einer Reihe von schwarzen Punkten. (* one of these must be wrong, I think the second should be ♀)

Attempted translation: The ♂ pale yellow, the ♀ dirty yellow. Vertex pointed triangular, in the ♀ significantly longer than the distance between the eyes, hollowed out in the middle. Side line and a longitudinal stain at the top yellow, a central longitudinal furrow brownish; on the crossing to the forehead black stains making a Λ-shape. Face yellowish, in the middle of the length something like a keel rises; with at the highest point a faint, brownish horizontal stripe. Pronotum and scutellum almost without markings. Elytra hyaline, clouded with dirty white, the veins yellowish in the ♂, reddish in the ♀; near the wing root a transverse band of three dark marks, with 2 dark spots near the top of the inner clavus cell, the neighbourhood of these spot tinted light brown; in the middle a light brown cross band on which are 4 dark spots in a transverse row, of which the one at the tip of the clavus is largest; near the wing tip a widely extended, brownish stain on which are 5 lighter spots; in the ♀, the stripes of the elytra are not so prominent as in the ♂. The underside black in the ♂, pale yellowish in the ♀ strewn with blackish spots. Legs pale yellowish, in the ♂ the femora with brownish stripes, in the ♀ coxae, trochanters and femora predominantly black; hind tibia always blackish on the inside, on the outside with a series of black dots.

Any drawbacks?

While a new leafhopper species will need to be monitored as a possible vector of virus or phytoplasma diseases, the British and Polish studies reported in the links below are not currently aware of any such connection for J. hyalinus.

Reporting

Records can be notified directly to the Auchenorrhyncha Recording Scheme, or logged on the iRecord site (free registration required). I would like to report the anticipated expansion of the species on this site, so please send me an email - with any photos you are prepared to have published - to

Links on other sites

Japananus on Flickr Apart from my photos and one from Tokyo these are all from the USA. Those with locations given are placed in Massachusetts, North Carolina, New York, New Jersey, Ohio, Pennsylvania and Virginia. These are all eastern states, although Oman in 1920 reported that it had been found in Oregon.

A new leafhopper for Polish fauna (2012) reviews the spread of the species in Europe.

Rapid Pest Risk Analysis (2014) from the Food & Environment Agency, Defra (concludes it is unlikely to be a pest).

The discovery was reported in the Summer 2015 edition of LEDRA, the Newsletter of the Auchenorrhyncha Recording Scheme for Britain & Ireland, on page 4.

My paper describing the discovery was published in the September 2015 issue of the British Journal of Entomology & Natural History.

Other adventive leafhoppers are available

New species of leafhopper are discovered in the UK at a rate of about one a year, and some rapidly become widespread. The two shown here were found in the same garden in Cambridge as J. hyalinus. Sightings of any of these can be reported in the same way.

Orientus ishidae from Japan, and nymph Synophropsis lauri, from south-east Europe

© Keith Edkins 2016. All photos licensed under Creative Commons Attribution-Share Alike 3.0 license.