Bactericera lyrata Seljak, Malenovský & Lauterer, 2008

Seljak, Gabrijel & Malenovský, Igor, 2014, Preimaginal stages and biology of Bactericera lyrata (Hemiptera: Psylloidea: Triozidae), Acta Entomologica Musei Nationalis Pragae (suppl.) 54 (1), pp. 35-46 : 38-39

Bactericera lyrata Seljak, Malenovský & Lauterer, 2008

( Figs 1–4 , 6–10 , 12 )

Bactericera lyrata Seljak et al., 2008: 530 .

The following sections complement the original description by SELJAK et al. (2008) by providing details about the coloration of the adults, the morphology of the fifth instar immature, egg, the host plant, and the life cycle.

Adult. Coloration. Seasonally dimorphic. General body colour of specimens of the long day (summer) generation(s) almost uniformly reddish to orange brown with dark brown transversal bands on abdominal tergites. Males usually darker than females, red-brownish ( Figs 1, 2 ). Forewings transparent. Short day specimens (late autumn, overwintering generation) markedly dark: males with thoracic dorsum evenly brownish black ( Fig. 3 ; paler longitudinal stripes only visible in fresh specimens, disappearing later with hardening of cuticle); females dark brown to almost black with more or less distinct paler longitudinal stripes on thoracic dorsum ( Fig. 4 ); forewing membrane light straw-yellowish in mature specimens of both sexes.

Fifth instar immature ( Figs 6 , 12 ). Coloration. Short day immatures (autumn generation) dirty yellowish with diffuse dark brown markings on thorax and abdomen; brown markings concentrated on thorax along midline, in an obtuse V-shaped streak on mesothorax, a less apparent streak on metathorax, and patches on tips of fore- and hindwing-pads; abdomen with diffuse radial brown markings near margins of caudal plate (margins and central area of caudal plate lighter). Apices of tibiae, tarsi and antennae dark brown. Long day (summer) immatures are generally lighter with weakly or hardly pronounced brown markings.

Structure. Body broadly flattened, elliptic ovoid, anterior head and posterior caudal plate margins broadly rounded. Dorsal cuticle densely covered with fine tubercles, caudal plate radially sculptured. Body margin completely bordered with sectasetae present in following numbers: head 58–69; forewing-pad 86–100; hindwing-pad 12–18; abdomen 170–215; poles of all sectasetae truncate, cylindrical, with almost perfectly parallel edges. Head and abdominal sectasetae densely arranged with interspaces of about 0.15 to 0.30 poles width. Forewing-pad sectasetae markedly shorter and more sparsely arranged with interspaces of about 0.5 to 1.1 poles width. Sectasetae completely absent from dorsum. Posterior eye margin with a small lobe lacking sectasetae. Antenna short, three-segmented, apical segment (flagellum) narrowed in middle, indistinctly subdivided, with four rhinaria; terminal setae unequal in length, one truncated at tip, the other seta tapered and almost twice as long as the truncate one. Humeral lobes of forewing-pads large, distinctly surpassing anterior eye margin. Tarsal arolium relatively large (larger than claws), broadly triangular (trapezoidal). Anus situated ventrally, outer circumanal pore ring with one single row of densely arranged elliptic pores.

Measurements and ratios in Table 1.

Egg. Colour. Freshly laid eggs whitish, later becoming orange-yellow, with brownish pedicel.

Structure. Oblong-oval, pedicel straight, about as long as egg or slightly longer ( Fig. 8 ). Eggs are laid on both upper and lower sides of leaves ( Fig. 10 ).

Host plant. Potentilla reptans L. ( Rosaceae ) ( Fig. 11 ) has been confirmed as the host plant of B. lyrata . This plant can support all developmental stages. Rearing was successful in obtaining successive new generations of adults.

Life cycle. Observations from outdoor rearing in Slovenia show that B. lyrata has three generations per year. Light-coloured adults of the presumably first summer generation were collected on the host plant on July 13. Two successive generations developed in the captivity. The phenology of the second and third generations is shown in Table 2. Adults of the second generation appeared at the very beginning of October in rearing (2013), which is about the same time when they were collected in the field (end of September, 2012). The fifth instar immatures of the third (short day) generation appeared in the last decade of November and the first adults of this generation were found at the beginning of December. At that time, the majority of immatures were still in the third, fourth and fifth instars. In our rearing conditions the mortality of immature stages of the third generation was relatively high, apparently due to a strong competition of co-occurring aphids ( Aphis sp.) and mites ( Tetranychus urticae Koch, 1836 ). However, it was observed that at least the later immature instars were able to move from badly damaged leaves to fresh or less damaged ones. Even the late season immatures can achieve the adult stage, which was confirmed also by a finding in the field: several overwintering adults of B. lyrata (7 33and 5 ♀♀) were swept on the type locality on January 1, 2014 from the partly wilted leaves of Potentilla reptans . It remains unknown whether the adults of the overwintering generation migrate to shelter plants and when they return to the primary host in spring.

Figures

Figs 1–5. Bactericera lyrata Seljak, Malenovský & Lauterer, 2008. 1 – adult male of the summer genera- tion; 2 – adult female of the summer generation; 3 – adult male of the overwintering generation; 4 – adult female of the overwintering gene- ration; 5 – abandoned field near Vogrsko village, Vipava Valley, western Slovenia: the type locality of B. lyrata.

Figs 6–11. Bactericera lyrata Seljak, Malenovský & Lauterer, 2008. 6 – fifth instar immature; 7 – fourth instar immature; 8 – egg; 9 – freshly hatched first instar immature; 10 – adult female and eggs on a leaf of Potentilla reptans; 11 – Potentilla reptans, the host plant.

Fig. 12. Fifth instar immature of Bactericera lyrata Seljak, Malenovský & Lauterer, 2008 with details of sectasetae, the circumanal pore ring and tarsal arolium.