Phyllocnistis triandricola Voith, Aarvik & Berggren, 2023

Phyllocnistis triandricola Voith, Aarvik & Berggren View in CoL sp. n. Figures 6–8 View FIGURES 6–11 , 12–15 View FIGURES 12–17

Type material. Holotype ♀, NORWAY: Innlandet , Lillehammer : Graverberget, 61.1579°N 10.3888°E, 11.VII.2020, leg. R. Voith, BOLD sample ID: NLON807-20 , coll. NHMO GoogleMaps . Paratypes, 3♀♀, same data as holotype, genitalia slide RVO 3360 GoogleMaps ; 4♂♂, 9♀♀, same locality as holotype, 20.VII.2020, genitalia slides RVO GoogleMaps ♀ 3354, 3359, 2♀♀ ex pupa Salix triandra , 4♂♂ 6♀♀ coll. NHMO , 2♀♀ coll. RVO, 1♀ coll. ZMUC ; 9♂♂ 7♀♀, NORWAY, Innlandet, Lillehammer: Bronsøya, 61.1571°N 10.3978°E, 6–9.VII.2020, BOLD GoogleMaps sample ID: NLON808-20 , genitalia slides ♂ RVO 3229, 3232, 3233, 3234, 3235, genitalia slides RVO ♀ 3230, 3231, 8♂♂ 7♀♀ coll. NHMO , 1♂ coll. RVO; 3♀♀, 12. VIII.2020, 2♀♀ coll. NHMO , 1♀ coll. RVO; 1♀, 29.VIII.2020, genitalia slide RVO 3358 coll. NHMO , 1♂ coll. ZMUC ; 4♀♀, 18. V .2021, genitalia slides RVO 3701, 3702, 3703, 3704; 1♀, 17.VIII.2021, genitalia slide RVO 3671; 2♂♂ 3♀♀, ex pupa Salix triandra , 28. VI .2022, hatched 1–6.VII.2022; 1♀, NORWAY, Innlandet, Lillehammer: Søre Jørstad, 61.1580°N 10.3867°E, 14.VII.2019, in pheromone trap, BOLD GoogleMaps sample ID: NLON264- 19 , coll. RVO; 4♂♂ 7♀♀, NORWAY: Innlandet, Elverum: Prestøya, 60.8696°N 11.5519°E, 21.VII.2020, genitalia slides GoogleMaps ♂ RVO 3237, 3356, genitalia slides RVO ♀ 3353, 3355, 3357, coll. NHMO ); 1♂ 2♀♀, same locality, 23.VIII.2020 , 2♀♀ ex pupa Salix triandra , 1♂, 2♀♀ coll. NHMO , 2♀♀ coll. RVO; 1♂, NORWAY, Innlandet, Hamar: Åkersvika NR, Vikingskipet, 60.7915°N 11.0989°E, 19. V GoogleMaps .2022, genitalia slide RVO 3700, coll. RVO; 2♀♀, NORWAY, Innlandet, Alvdal: Holmen, 62.0925983°N E 10.6467847°E, 30. V GoogleMaps .2022 coll. RVO; 4♀♀, NORWAY, Innlandet, Stor Elvdal: Koppang, Søndre Bakken, 61.5496118°N 11.0453668°E, 30. V GoogleMaps .2022, genitalia slides RVO 3807, 3809 coll. RVO. All paratypes from Innlandet collected by R . Voith.

Additional material: 1♂, NORWAY: Viken , Lillestrøm : Sørum, Nordre Hammaren 59.9904434°N 11.2091675°E, 11.VI.2022, ex pupa Salix triandra , leg. P.K. Slagsvold GoogleMaps ; 1♀, same locality, 20.VI.2022, ex pupa Salix triandra , leg GoogleMaps .

L.Aarvik (both NHMO) ; 1♀, AUSTRIA, Kärnten, Tiebelmündung , 2.VII.2018, KLM Lep 14420 , BOLD sample ID: LEASV209-19 , genitalia slide RVO 3743, leg. & coll. C. Wieser

Diagnosis. The most obvious differences between Ph. triandricola sp. n. ( Figures 6–8 View FIGURES 6–11 ) and other members of the complex are the length of the longitudinal fascia and the curvature of the transverse fasciae 1 and 2. The longitudinal fascia in Ph. triandricola sp. n. is well defined and comparatively shorter than in the other species, usually just reaching the middle of the wing and usually not to the transverse fascia 1. If it reaches the transverse fascia 1, this is only with a few dark scales. In Ph. saligna , Ph. ramulicola and Ph. asiatica the longitudinal fascia is longer, reaching nearly to two-thirds of the wing, and it will usually reach the transverse fascia 1. In Ph. triandricola sp. n. transverse fasciae 1 and 2 normally merge, forming a broad angulate band. In Ph. saligna and Ph. asiatica fascia 1 is reduced in the dorsal half and fascia 2 is slightly curved. In Ph. ramulicola fascia 1 is represented by a short oblique streak from the costa and fascia 2 forms an angled band, at 90–130 degrees, extending a short distance along the dorsum. The latter species is smaller than Ph. triandricola sp. n., wingspan 5.7–7.0 mm., whereas Ph. triandricola sp. n. measures 7.5–8.0 mm. Ph. asiatica has a defined seasonal dimorphism whereas this is not the case with Ph. triandricola sp. n., where no seasonal dimorphism has been noted. Adults of Ph. saligna and Ph. ramulicola are illustrated by Laštůvka & Laštůvka (2014), and adults of Ph. saligna , Ph. ramulicola and Ph. asiatica are illustrated by Laštůvka et al. (2018).

In the male genitalia ( Figures 12–13 View FIGURES 12–17 ) no significant character separating Ph. triandricola sp. n. from the other species of the complex has been found.

In the female genitalia ( Figs 14–15 View FIGURES 12–17 ) Ph. ramulicola differs from Ph. triandricola sp. n., as well as Ph. saligna and Ph. asiatica , by having two signa of unequal size. In the latter three species the two signa are of equal size. According to the photograph in Gomboc & Kirichenko (2022) the female of Ph. valentinensis also has signa of unequal size. In the ovipositor there are two parallel sclerites in Ph. triandricola sp. n., Ph. saligna and Ph. asiatica (we have not checked for this character in other species). The sclerites are of different size and shape in the three species. In Ph. triandricola sp. n. ( Figures 14–15 View FIGURES 12–17 ) the sclerites are flat and become less sclerotized towards the broader dorsal end. In Ph. saligna ( Fig. 16 View FIGURES 12–17 ) and Ph. asiatica ( Figure 17 View FIGURES 12–17 ) the sclerites are more three dimensional and curved. The length of the sclerites in Ph. triandricola sp. n. is 81–103 μm (n = 12); in Ph. asiatica they are 98–122 μm (n = 4) and in Ph. saligna (58–70 μm, n = 5). In Ph. saligna the sclerites are banana-shaped, slender and pointed in both ends. In Ph. asiatica the sclerites are wider and usually banana-shaped, but they may also be more irregular, approaching the shape of an ‘s’. The sclerites in both these species are three dimensional and may change shape from pressure from the cover glass during preparation.

12 15

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300 μm

Molecular diagnosis. Phyllocnistis triandricola sp. n., with BIN: BOLD:ABW1114, is separate from its nearest neighbour Ph. asiatica , with BIN: BOLD:AAL5482, by a p-distance of 5.84 %. Ph. saligna is almost equally close to Ph. triandricola sp. n. Intraspecific variability in Ph. triandricola is 0.33 %. In the Maximum Likelihood tree ( Figure 18 View FIGURE 18 ), Ph. triandricola forms a well-supported (BS=99) cluster and forms a sister group to Ph. saligna + Ph. asiatica .

Description. Wingspan 7.5–8.0 mm. Head, thorax and tegulae cream-white, shiny; face and palp whitish, palp length twice the diameter of eye; scape of antenna covered with silvery, shining scales, antenna dark fuscous, greyish white on underside, 60–70 % length of forewing. Forewing cream-white, glossy, with ochreous hue particularly dorsad to longitudinal fascia; base of costa narrowly edged blackish; dorsum basally with small, oblique, brownish patch; a broad brown longitudinal fascia edged fuscous reaches to about middle of wing, not touching transverse fascia 1, ground colour visible between apex of longitudinal fascia and transverse fascia 1; transverse fasciae 1 and 2 merge, forming a broad angulate band partly ochreous within, narrower and more distinct dorsally; transverse fasciae 3 and 4 form two coastal strigulae reaching to middle of wing, inwardly edged ochreous; three fuscous apical strigulae emerge from black dot; transverse fascia 4 continued dorsally as an oblique, fuscous cilia line inwardly edged ochreous; cilia – apart from strigulae – white. The upper side forewing pattern is reflected on the underside. Hindwing grey, shining; cilia grey at costa, apically and dorsally white.

Male genitalia ( Figures 12–13 View FIGURES 12–17 ). Valva long and slender, medially narrower, terminally spoonshaped, with triangular process, basally with two finger-like processes, lower edge of lower «finger» with membranous extension; phallus tubular, gradually narrowing, cornutus long and slender. Valvae three-dimensional, and their shape on the genitalia slides varies according to the position; also, position and visibility of the triangular process vary according to the position in which the genitalia are fixed.

Female genitalia ( Figures 14–15 View FIGURES 12–17 ). Margin of papillae anales with row of strong setae, apophyses posteriores short, strong, eighth segment short; apophyses anteriores very broad, horn-shaped; within ovipositor two slender sclerites, widened at dorsal end, slightly resembling a spatula, relatively weakly sclerotised and gradually membranous towards dorsum; ductus bursae membranous, narrow; corpus bursae with numerous denticles and two large signa of equal size, signa banana-shaped with one strong spine in middle.

Variation. The ground colour of the forewing varies from creamy ochreous white to shining silky white. Head, thorax and tegulae vary in the same way as the forewing, but may contrast with the ground colour of the forewing. The longitudinal fascia may be almost unicolorous blackish brown or ochreous with blackish brown margins. It may nearly reach the transverse fascia, but in such cases only with single dark scales. The transverse fascia 1 might occasionally extend a little basad along dorsum, resembling the fascia of Ph. ramulicola . In a few cases the transverse fasciae 1 and 2 are separate, making the forewing pattern resemble that of Ph. saligna and Ph. asiatica .

Biology. According to information in the BOLD database (accessed 28.10.2022) bred from Salix babylonica var. matsudana Koidz and S. euxina V.I. Belyaeva in the Czech Republic. In Norway the only observed host-pIant is Salix triandra ( Figures 19–21 View FIGURES 19–21 ). Oviposition takes place on the underside of the leaf. The newly hatched larva enters the leaf and starts to form a tiny mine, always on the underside. The mine is extended, directly or with some sinuosity, to the main vein of the leaf which it then follows to the petiole and hence into the stem. The mine continues in the stem usually downwards for 5–10 cm, normally either to the first or second petiole before it turns 180 degrees and continues upwards for some 10–20 cm, either to the third or fourth petiole. Then the larva will enter a new leaf via the petiole where it makes a fairly straight mine in the middle up to two thirds or three quarters of the leaf’s length. From there it will either mine straight to the margin to pupate, or cross over to the opposite side of the leaf where it makes a fold at the margin in which it forms a chamber under the epidermis and spins a loose white cocoon where the pupation takes place. The cigar-shaped fold with the cocoon is on the underside of the leaf. The fresh mine is more or less of the same colour as the stem ( Figure 21 View FIGURES 19–21 ) but turns whitish after some days and is then easy to see. After some weeks the mine within the leaf will turn darker as the frass in the mine decomposes and it becomes quite conspicuous. Due to their snail-track appearance the mines are obvious on the underside ( Figure 20 View FIGURES 19–21 ). The larvae of Ph. saligna and Ph. asiatica mine more in the leaves than does Ph. triandricola sp. n., which is predominantly a stem-miner.

The young larva is almost translucent, maggotlike with a broad head capsule and with a greenish hue. Fully grown it becomes more yellowish.

The pupa is dark brown – black and with a conspicuous process on the head for cutting through the cocoon. The duration of the pupal stage is not known, but moths have emerged between one and eight days after the pupae were collected. Cocoons with pupae were found – not more than one per leaf – in July and the beginning of August. Mines and exuviae have been found as late as the beginning of October. Hibernating adults occur from mid-May, and the imagines of the first generation appear from approximately 20 June, depending on the weather. Then there will be a continuous flight in two overlapping generations until the end of August. The moths gradually disappear in late August and are completely absent by mid-September. The species hibernates as an adult. If their hibernating habitat is not covered with snow, they will have to be able to withstand winter temperatures dropping regularly down to -30°C degrees and occasionally even -40°C.

Ecology. In Norway the species is local and occurs exclusively where Salix triandra grows ( Figures 23–24 View FIGURE 23 View FIGURE 24 ). A few specimens can occasionally be found on nearby trees and bushes, but almost all were observed on 2–5 m high bushes of S. triandra growing on riverbanks. The flight time indicates that the moth completes its first generation during the flood season when its food-plant is, at least partly, submerged in water. The type locality is a riverbank which is flooded annually in early summer, normally with about one metre of water; in extreme cases with up to two metres of water and strong currents. It seems possible that larvae are mining under water during the flood.

Distribution. In Norway present along the rivers Glomma and Lågen ( Figure 25 View FIGURE 25 ), most northerly in the Sel and Alvdal municipalities in the foothills of the Dovre Mountains. These two rivers run in a southerly direction and meet just north of 60 oN. The total distance with localities along the two rivers is approximately 450 km, and the moth has up to 2022 been found in 17 localities. It has been searched for along other rivers in South Norway, but this has not been successful. Phyllocnistis saligna was recorded new to Norway by Aarvik et al. (2013). The record was based on a male specimen collected at Elverum in 1980 and which had remained misidentified as Ph. labyrinthella (Bjerkander, 1790) for many years. This specimen belongs to Ph. triandricola sp. n.

Otherwise known from the Czech Republic (data in BOLD) and Austria. Probably confused with its relatives and more widespread than current data indicates.

Voith et al.: Taxonomy of the Phyllocnistris saligna complex

Etymology. The species name, triandricola , is from Salix triandra , the scientific name for ‘almond willow’, and the feminine form of incolus, inhabitant. Phyllocnistis triandricola , the Phyllocnistis living on Salix triandra .