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Research article
A new oak-feeding species of Lachnus Burmeister and some remarks on the taxonomic status of L. chosoni Szelegiewicz (Hemiptera, Aphididae, Lachninae)
expand article infoMariusz Kanturski, Karina Wieczorek, Łukasz Junkiert
† University of Silesia, Katowice, Poland
Open Access

Abstract

A new species, Lachnus pseudonudus Kanturski & Wieczorek, sp. n., associated with Quercus ithaburensis subsp. macrolepis is described and figured in detail from specimens collected in Turkey. The lectotype and paralectotypes of L. crassicornis, a species associated with Quercus ithaburensis subsp. ithaburensis, are designated. The taxonomic position of L. chosoni, a poorly known species from Korea previously treated as a synonym of L. pallipes, is discussed. Morphological and biometric characters of the studied species are given. An identification key to species belonging to the “pallipes” group is provided.

Key Words

Aphids, Lachninae, Quercus spp., taxonomy

Introduction

The genus Lachnus Burmeister, 1835 comprises about 20 species associated with deciduous trees from the genera Castanea, Castanopsis, Fagus, Quercus (Fagaceae), Hippophae (Eleagnaceae), Salix (Salicaceae), Ficus (Moraceae) and Casuarina (Casuarinaceae) and living on the bark of tree trunks, branches or main roots (Heie 1995; Binazzi and Remaudière 2010). Aphids from this genus are characterised by medium to large body size, long hind legs and pigmented wings in alatae. Key morphological features of Lachnus include also the terminal process of the antenna with 2–7 subapical setae, and primary rhinaria with a sclerotic rosette. The apical segment of the rostrum is short and with a button-shaped apical part (Szelegiewicz 1978; Blackman and Eastop 1994). Among representatives of the genus Lachnus, most species are Fagaceae-feeders, associated mostly with oaks (Quercus spp.). According to Binazzi and Remaudière (2010), this group of species living on the Fagaceae can be divided into subgroups with or without distinct mesosternal tubercles in apterous viviparous females. The group lacking these tubercles comprises L. crassicornis Hille Ris Lambers, 1948, L. longirostris (Mordvilko, 1901) and L. pallipes (Hartig, 1841) (the “pallipes” group) and is characterised also by very long setae on the apical part of the hind tibiae in addition to the normal ones. Among the above mentioned species the status of L. longirostris is questionable; i.e. this species is treated as a synonym of L. pallipes (Szelegiewicz 1975; Blackman and Eastop 1994), which has been confirmed by recent molecular studies (Mróz et al. 2013). Moreover, the species L. chosoni Szelegiewicz, 1975 seems to be closely related to this group, also treated by some authors as a synonym of L. pallipes (Blackman and Eastop 1994, 2014; Remaudière and Remaudière 1997). In addition, Blackman and Eastop (1994, 2014) suggested that in the collection of the Natural History Museum, London, UK (BMNH) specimens determined as L. crassicornis but most probably belonging to an undescribed species related to the “pallipes” group are present.

The aim of this paper is to define the taxonomic status of the species belonging to the “pallipes” group. On the basis of the material deposited in the BMNH a new, hitherto unknown species is described. The lectotype and paralectotypes of L. crassicornis are designated. Based on a reinvestigation of the type material of L. chosoni deposited in the Zoological Institute, Polish Academy of Sciences, Warsaw, Poland (ZMPA) the status of this species is discussed. An identification key to species belonging to the “pallipes” group is provided.

Material and methods

Material examined.

L. chosoni. Holotype: one apterous viviparous female, KOREA, Myohyang-san Mts. 05.VIII.1959, Quercus sp., no APH-4704 B. Pisarski & J. Prószyński leg. ZMPA. Paratypes. Same locality as holotype: two apterous viviparous females, no APH-4705, ZMPA.

L. crassicornis. Lectotype: one apterous viviparous female marked as 1, ISRAEL, Daphne, 28.IV.1945, Quercus ithaburensis (Univ. Jerusalem), no BM 1984-340a (present designation) BMNH. Paralectotypes. Same locality as lectotype: three apterous viviparous females marked as 2, 3, 4, no BM 1984-340a; four apterous viviparous females marked as 1, 2, 3, 4 no BM 1984-340b (present designation) BMNH.

L. pallipes. Three apterous viviparous females POLAND, Międzyzdroje, 10.VIII.1965, Fagus sylvatica, no R 2316, 2718, H. Szelegiewicz leg. (ZMPA), seven apterous viviparous females, POLAND, Borne Sulinowo, 26.VI.2012, Q. robur, no Ł56, Ł. Depa leg., four apterous viviparous females, SLOVAKIA, Palcmanska Masa, 02.VIII.2012, F. sylvatica, no L470, Ł. Depa leg. Department of Zoology, University of Silesia, Poland (UŚ)

The specimens were examined using the light microscope Nikon Ni-U. Drawings were made with a camera lucida. Measurements are given in mm (Table 1 and 2). Measurements and ratios of the first segment of hind tarsus (HT I) were made according to Szelegiewicz (1978) and Heie (1995).

Measurements (in mm) of apterous viviparous females (n = 8) Lachnus pseudonudus Kanturski & Wieczorek, sp. n. from the type material. Measurements of the holotype bolded.

Character Apterous viviparous females
Length of body 3.60 3.20 3.05 3.00 2.62 2.87 2.87 2.95
Maximal width of body 2.25 1.77 1.65 1.52 1.40 1.50 1.55 1.55
Head width across compound eyes 0.81 0.75 0.76 0.74 0.72 0.73 0.73 0.72
Length of antennae 1.60 1.51 1.52 1.36 1.35 1.40 1.43 1.33
Length of antennal segment III 0.64 0.60 0.58 0.53 0.50 0.54 0.51 0.56
segment IV 0.27 0.26 0.27 0.22 0.22 0.25 0.21 0.24
segment V 0.31 0.27 0.30 0.25 0.27 0.26 0.25 0.26
segment VIa 0.13 0.11 0.12 0.11 0.12 0.11 0.11 0.12
segment VIb 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03
Length of rostrum 1.50 1.60 1.60 1.65 1.50 1.62 1.80 1.90
Length of apical segment of rostrum 0.25 0.25 0.24 0.26 0.26 0.25 0.24 0.25
Length of hind femora 1.35 1.30 1.35 1.25 1.15 1.20 1.15 1.25
Length of hind tibiae 2.55 2.47 2.50 2.30 2.17 2.27 2.20 2.37
Length of hind tarsi segm. I 0.11 0.12 0.11 0.11 0.10 0.12 0.11 0.12
Length of hind tarsi segm. II 0.23 0.23 0.23 0.22 0.22 0.22 0.23 0.22
Siphuncular sclerite diameter 0.18 0.21 0.18 0.18 0.19 0.20 0.22 0.18
Siphuncular cone diameter 0.10 0.10 0.10 0.09 0.11 0.10 0.09 0.10
Subgenital plate length 0.29 0.28 0.26 0.25 0.24 0.26 0.26 0.27
Subgenital plate width 0.53 0.50 0.52 0.47 0.45 0.46 0.42 0.48

The main morphological and biometric differences among Lachnus crassicornis and L. pseudonudus Kanturski & Wieczorek, sp. n. BL – body length, HLL – hind leg length, AL – antennae length, ANT VI – antennal segment VI length, ANT III – antennal segment III length, HT I – first segment of hind tarsus length, HT II – second segment of hind tarsus length.

Character Lachnus crassicornis Lachnus pseudonudus Kanturski & Wieczorek, sp. n.
Dorsal chaetotaxy Thorax and abdomen very densely covered by very thin, fine and pointed setae, 0.037–0.050 mm long Thorax and abdomen covered by very short, inconspicuous setae, arranged in 3–4 rows on each segment with blunt, capitate, spatulate or club-shaped apices, 0.010–0.020 mm long
Head setae As long as setae on antennae, fine with pointed apices Shorter than setae on antennae, slightly thick and forked
Antennae Antennal segments swollen Antennal segments not swollen
Siphunculi Siphuncular sclerites very low, siphunculi almost poriform, with little-developed flange with 2–3 rows of polygonal reticulation Siphuncular sclerites well-developed, with very well-developed flange with 8–10 rows of polygonal reticulation
Abdominal cuticle Smooth Wrinkled or reticulated
Hind tibiae chaetotaxy Some setae on distal part of tibiae 3–4 times longer than other setae, 0.14–0.15 mm long Some setae on distal part of tibiae 4–5 times longer than other setae, 0.17– 0.22 mm long
HT I setae 12 14
HLL/BL 1.47–1.68 1.18–1.45
AL/BL 0.57–0.64 0.44–0.53
ANT VI/ANT III 0.19–0.25 0.25–0.31
HT II/ANT III 0.27–0.36 0.36–0.45

The holotype and paratypes of the new species are deposited in the Natural History Museum London, UK, (BMNH). Paratypes will be also deposited in the aphids collection of the Department of Zoology, University of Silesia, Poland (UŚ).

Results

Lachnus pseudonudus Kanturski & Wieczorek, sp. n.

Figures 1, 2, 3; Table 1, 2

Description

Apterous viviparous female. Colour in life unknown. Pigmentation of mounted specimens: head, pronotum and mesonotum sclerotised, covered by light brown sclerotic shield. Antennal segments light brown. Fore and middle femora light brown, hind femora brown with pale proximal area to about ¼ length. Tibiae from proximal part to about ½ length and on distal parts brown, otherwise yellowish (Fig. 3a). Tarsi brown. Abdomen pale. Siphuncular sclerites pale to light brown. Subgenital and anal plate brown. Body large, egg-shaped (Fig. 1). Head densely covered by short, thick and forked setae, shorter than setae on antennal segments. Frons flat. Head width 0.49–0.57 times length of antennae. Antennae 6-segmented (Fig. 2a), 0.44–0.53 times length of body. Ant. segm. III slightly shorter than ant. segm. IV+V+VI, with 0–1 secondary rhinarium. Ant. segm. IV slightly shorter than, or as well as long as ant. segm. V, with 0–3 secondary rhinaria. Ant. segm. V always longer than ant. segm. VI with 1 primary and 1–2 accessory rhinaria. Ant. segm. VI base (IVa) longer than terminal process (IVb), with 1 big primary rhinarium with sclerotised rosette and 6–7 small accessory rhinaria, adjoining each other (Fig. 2b). IVb 0.24–0.33 times length of VIa with 3 apical and 5–7 subapical setae, which are shorter and slightly thicker than basal setae. Other antennal ratios: VI:III 0.25–0.31; V:III 0.44–0.54; IV:III 0.37–0.48; IV:V 0.80–1.03. Ant. segm. I–VIa densely covered with very thin, hair-like, pointed setae. Longest seta on ant. segm. III 1.10–1.66 times basal articular diameter of this segment. Rostrum long, reaching siphunculi or genital plate (in some specimens reaching only hind coxae). Apical segment of rostrum (ARS) pointed, 0.38–0.50 times ant. segm. III and 1.00–1.19 times second segment of hind tarsus (HT II), with 4 primary and 18 accessory setae (Fig. 2c). Mesosternal tubercles absent. Hind legs long, 1.18–1.45 times length of body. Some setae on hind tibiae 4–5 times longer than other setae, hair-like, 0.17–0.22 mm long (Figs 2d, 3a). First segment of hind tarsus (HT I) with 14 ventral setae (Fig. 2d). HT II 0.36–0.45 times ant. segm. III and 1.37–1.50 times ant. segm. VI. Abdomen membranous, cuticle with very densely wrinkled surface in transverse rows. Siphuncular sclerites well-developed, usually slightly oval, around pore a very well-developed flange with 8–10 rows of polygonal reticulation (Figs 2e, 3e). Dorsal abdominal segments covered with 3–4 rows of very short, blunt, capitate, spatulate or club-shaped setae, 0.010–0.020 mm long, arising from dark brown ring-like bases (Fig. 2f). Each abdominal segment with 3 pairs of brown, rounded sclerites. Subgenital plate well-developed, with indentation from posterior side. Cauda circular or semicircular with 22–24 long and pointed setae which are longer and thicker than those on legs. Anal plate well-developed, sclerotised.

Figure 1.

Lachnus pseudonudus Kanturski & Wieczorek, sp. n. – apterous viviparous female: general view.

Figure 2.

Lachnus pseudonudus Kanturski & Wieczorek, sp. n. – apterous viviparous female: (a) antenna, (b) antennal segment V and VI, (c) apical segment of rostrum, (d) distal part of hind tibia and tarsus, (e) siphunculus, (f) dorsal abdominal setae.

Figure 3.

Main differences in pigmentation and chaetotaxy of hind tibiae and size of siphuncular sclerites among apterous viviparous females of the “pallipes” group: (a, e) Lachnus pseudonudus Kanturski & Wieczorek, sp. n., (b, f) L. crassicornis, (c, g) L. pallipes, (d, h) L. chosoni, (i) small mesosternal tubercles of L. chosoni.

Diagnosis

The new species can be distinguished from L. crassicornis as well as from the other Lachnus species by the sparse dorsal chaetotaxy and extremely short, inconspicuous setae with blunt, slightly spatulate, capitate or club-shaped apices. The new species is also characterised by siphunculi with a very well-developed and almost transparent flange with 8–10 rows of polygonal reticulation. Main morphological and biometric differences between L. pseudonudus Kanturski & Wieczorek, sp. n. and L. crassicornis are given in Table 2.

Etymology

The name of the new species is derived from characteristically short and inconspicuous setae on the dorsal part of the thorax and the abdomen.

Biology and host plant

The species live on branches and shoots of Q. ithaburensis subsp. macrolepis (Kotschy) Hedge & Yalt. (= Q. aegilops) and is visited by the ant species Liometopum microcephalum (Panzer, 1798) (Canakçioglu 1975).

Distribution

Turkey, Uşak-Eşme.

Material examined

Holotype: one apterous viviparous female marked as 1. TURKEY, Uşak-Eşme, 850 m, 10.VI.1964, no 731/64, 45a1, M. Canakçioglu leg. BMNH.

Paratypes. Same locality as holotype: one apterous viviparous female marked as 2, no 731/64, 45a1; four apterous viviparous female marked as 1, 2, 3, 4, no 731/64, 45a2 BMHN; four apterous viviparous female marked as 1, 2, 3, 4, no 731/64, 45a3 UŚ.

Other material examined: 22 apterous viviparous females, same locality as holotype: no 731/64, 45a4–45a9 BMHN.

Key to apterous viviparous females of the “pallipes” group of the genus Lachnus

1 Siphunculi almost poriform with almost invisible sclerites (Fig. 3f). Dorsum covered with thin, long, hair-like and pointed setae, which are almost similar to ventral setae Lachnus crassicornis Hille Ris Lambers
Siphunculi with well-developed sclerites (Fig. 3e, g, h). Dorsal setae variable but always different from setae on ventral side 2
2 Dorsal abdominal setae short and inconspicuous (max 0.02 mm) with blunt, capitate or club-shaped apices, and arising from large, ring-like bases (Fig. 2f) Lachnus pseudonudus Kanturski & Wieczorek, sp. n.
Setae on dorsal side of abdomen always longer than 0.037 mm and pointed, not arising from large, ring-like bases 3
3 Hind tibiae brown on distal and proximal parts with pale area for about 1/3 of length (Fig. 3c). Ant. segm. IV/ant. segm. V 0.78–0.96, ARS/ant. segm. VI 1.26–1.38, ARS/HT II 0.96–1.00 Lachnus pallipes Hartig
Hind tibiae with distal part uniformly dark brown and proximal part paler (Fig. 3d). Ant. segm. IV/ant. segm. V 1.00–1.10, ARS/ant. segm. VI 1.00–1.06, ARS/HT II 0.79–0.84 Lachnus chosoni Szelegiewicz

Discussion

The Fagaceae-feeding species of the genus Lachnus form morphologically related groups (Binazzi and Remaudière 2010). The “pallipes” group is characterised by the lack of mesosternal tubercles and two types of setae on the hind tibiae: setae as long as or slightly longer than the diameter of the middle part of the tibiae, and some which are distinctly longer. In this group of species L. pallipes is characterised by the longest tibial setae situated not only on the posterior part of the tibiae but usually also distributed individually along almost the whole length of the tibiae. In that species, the body is also covered with numerous setae, but contrary to L. crassicornis and L. pseudonudus Kanturski & Wieczorek, sp. n. the setae of L. pallipes are much thicker and with brown pigmentation. On the other hand, the chaetotaxy of the body and the form and shape of the siphunculi clearly distinguish L. crassicornis from other Lachnus species. All setae of L. crassicornis are very thin and hair-like with pointed apices. Only the setae on the posterior parts of tibiae are slightly thicker and much longer than others. The setae on the dorsal part of the abdomen are almost identical with the setae on the ventral side. Probably the long, hair-like and pointed setae on the ventral side of the abdomen and the same host plant were the reasons why the slides of L. pseudonudus sp. n. were wrongly determined by Canakçioglu as L. crassicornis and the latter was listed in the aphidofauna of Turkey by the author (Canakçioglu 1966, 1967, 1975). Dorsal setae of L. pseudonudus sp. n. are extremely short and inconspicuous, so they probably were overlooked during the examination of the material. However, the shape of the siphunculi, as well as the very well-developed flange with reticulation and other distinctive morphological and biometric features (see Table 2) give the new species a clear and separate taxonomic position within the genus Lachnus. Both L. crassicornis and L. pseudonudus sp. n. are known from single localities. L. crassicornis was recorded only from two localities in Israel, Daphne and Hotshat (Binazzi and Remaudière 2010; the record of this species from Q. robur in Romania reported by Holman and Pintera 1981 needs confirmation) whereas L. pseudonudus sp. n. is only known from its type locality in Turkey. The available material confirms the same host plant for both species: Q. ithaburensis (Decne). The Tabor oak includes two subspecies – Q. ithaburensis subsp. macrolepis (Kotschy) Hedge & Yalt. and Q. ithaburensis Decne. subsp. ithaburensis. These two subspecies of the Tabor oak occur separately in two Mediterranean subregions i.e. Q. ithaburensis subsp. ithaburensis is known only from Israel and north-western Jordan, whereas Q. ithaburensis subsp. macrolepis occurs in the western part of Turkey and in an enclaved region eastward to Ankara (Drufour-Dror and Ertas 2004). As the two subspecies of the Tabor oak do not overlap in their occurence it is argued that L. crassicornis is associated with Q. ithaburensis subsp. ithaburensis, and L. pseudonudus sp. n. with Q. ithaburensis subsp. macrolepis, which additionally corroborates the separateness of those two species.

Similarly, L. chosoni is a rare aphid species, which is known only from the type locality in Myohyang-san (Korea) and all material, including the types, comprises three apterous viviparous females. Although Szelegiewicz (1975) provided a detailed description and drawings of this species, its taxonomic position was undermined and it was treated as a synonym of L. pallipes (Blackman and Eastop 1994, 2014; Remaudière and Remaudière 1997). On the other hand, Binazzi and Remaudière (2010) gave L. chosoni full species status. However, the authors underlined that it was keyed only on the basis of the data from the original Szelegiewicz’s description without studying the type material and still there were doubts about the possible synonymy of these species. A comparison of the type material of L. chosoni and L. pallipes from various localities, biometric ratios of the lengths of antennal segments, the apical segment of the rostrum and the hind tarsus clearly show differences between those species (see Table 3). Moreover, L. chosoni is characterised by the larger siphuncular sclerite diameter, different colouration of the hind tibiae and, most conspicuously, very small mesosternal tubercles (Figs 3c, g, i). Species belonging to the “pallipes” group, including L. pseudonudus sp. n., are characterised by the absence of those structures, unlike the remaining Fagaceae-feeding species of the genus Lachnus (especially the Quercus spp. habitants, Özdemir et al. 2005), which have prominent mesosternal tubercles. However, the presence of longer and shorter setae on hind tibiae, which is also a unique character of the “pallipes” group, indicates a close relation of L. chosoni with this group of species.

The main morphological and biometric differences among Lachnus chosoni and L. pallipes. BL – body length, HLL – hind leg length, ARS – apical rostrum segment, HT II – second segment of hind tarsus, HT I – first segment of hind tarsus.

Character Lachnus chosoni Lachnus pallipes
ant. segm. VI/ant. segm. III 0.25–0.31 0.21–0.24
ant. segm.V/ant. segm. III 0.34–0.40 0.40–0.41
ant. segm. IV/ant. segm. V 1.00 -1.10 0.78–0.96
BL/HLL 0.65–0.68 0.74–0.83
HLL/BL 1.45–1.52 1.19–1.34
ARS/HT II 0.79–0.84 0.96–1.00
ARS/ant. segm. VI 1.00–1.06 1.26–1.38
Siphuncular sclerite diameter 0.24–0.24 0.15–0.20
HT I basal/HT I ventral 0.29–0.33 0.33–0.40
HT I basal/HT I intersegmental 0.50–0.52 0.60–0.66
HT II/ant. segm. III 0.34–0.37 0.30–0.33
Hind tibiae setae length 0.12–0.14 0.15–0.16
Mesosternal tubercles Present but very small Absent
Hind tibiae Uniformly dark brown with paler proximal part Brown on distal and proximal parts with pale area for about 1/3 of length

Acknowledgements

The authors are sincerely grateful to Roger L. Blackman, Diana M. Percy and Paul A. Brown, Natural History Museum, London for their kindly help during the visit in the collection. We are very grateful to the Reviewers and the Editor for all valuable suggestions and comments that have improved the manuscript.

References

  • Binazzi A, Remaudière G (2010) The Palearctic – Oriental Fagaceae – feeding species of Lachnus Burmeister (Hemiptera Aphididae Lachninae). Redia XCIII: 45–73.
  • Blackman RL, Eastop VF (1994) Aphids on the World’s Trees. CAB International, Wallingford, 987 pp.
  • Çanakçioğlu H (1966) Türkiye’ de orman ağaçlarına arız olan bitki bitleri (Aphidoidea) üzerine araştırmalar (A study of the forest Aphidoidea of Turkey). Istanbul Üniversitesi Orman Fakültesi Deregisi, Seri A, Cilt XVI (2): 90–131.
  • Çanakçioğlu H (1967) Türkiye’ de orman ağaçlarına arız olan bitki bitleri (Aphidoidea) üzerine araştırmalar. T.C. Tarım Bakanlığı, Orman Genel Müd. Yayınları Sıra 466, Seri No: 22, VIII, 151 pp.
  • Çanakçioğlu H (1975) The Aphidoidea of Turkey - Istanbul Univ. Orman Fak. Yayinlari, Nà 1751, 309 pp.
  • Drufour-Dror JM, Ertas A (2004) Bioclimatic perspectives in the distribution of Quercus ithaburensis Decne. subspecies in Turkey and Levant. Journal of Biogeography 31: 461–474. doi: 10.1046/j.0305-0270.2003.01036.x
  • Heie OE (1995) The Aphidoidea of Fennoscandia and Denmark VI. Aphidinae. Part 3 of Macrosiphini and Lachnidae. Fauna entomologica scandinavica 31, 222 pp.
  • Holman J, Pintera A (1981) Übersicht der Blattläuse (Homoptera, Aphidoidea) der Romänischen Sozialistischen Republik. Studie CSAV (Prague) 15: 1–125.
  • Mróz E, Trela J, Depa Ł (2013) Molecular and morphological differentiation of Lachnus pallipes (Hartig) and L. roboris (L.). 9th International Symposium on Aphids, Beijing, China, 2nd-6th June 2013. Abstracts book, 37.
  • Özdemir I, Remaudière G, Toros S, Kilinçer N (2005) New Aphid Records from Turkey including the description of a new Lachnus Species (Hemiptera Aphididae). Revue française d’Entomologie (N.S.) 27(3): 97–102.
  • Remaudière G, Remaudière M (1997) Catalogue des Aphididae du monde Homoptera Aphidoidea. Institut national de la Recherche scientifique, Paris, France, 474 pp.
  • Szelegiewicz H (1975) Two new Lachnid species (Homoptera, Lachnidae) from Korea. Polskie Pismo Entomologiczne 45: 575–581.
  • Szelegiewicz H (1978) Klucze do oznaczania owadów Polski. XVII, Homoptera, 5a, Mszyce – Aphidodea, 1, Lachnidae, 107 pp.