Haplothrips biroi (Priesner, 1928)

Balcerčík, Jozef, Kucharczyk, Halina, Mešková, Michaela, Zvaríková, Martina, Masarovič, Rudolf & Fedor, Peter, 2025, Distribution, host plant association, and morphological diagnosis of adults and larvae of Haplothrips biroi (Thysanoptera: Phlaeothripidae), Zootaxa 5693 (1), pp. 32-40 : 33-37

Diagnosis of Haplothrips biroi

( Figures 1–9 )

Both sexes fully winged; body brown to dark brown; all femora dark brown, fore tibiae yellow, middle and hind tibiae dark brown with yellow apices (approximately the distal fifth of their length); all tarsi yellow. Forewings pale with basal shadings ( Fig. 1 ). Antennal segment I dark, II mostly dark but often narrowly brightened distally, III– V yellow, VI brown apically, VII–VIII brown.

Antennae 8-segmented, segment III with two sense cones, IV with four ( Fig. 6 ). Head approximately 1.1 times longer than wide, genae slightly widened ( Fig. 2 ). Maxillary stylets 0.4–0.6 times the head width apart, retracted almost to level of postocular setae; maxillary bridge well developed, mouth cone pointed but relatively short ( Fig. 2 ).

Fore tarsal tooth absent in females ( Fig. 9b ) but sometimes reduced or stunted ( Fig. 9c ); males always with small fore tarsal tooth ( Fig. 9a ). Pronotum with five pairs of major setae ( Fig. 3 ); anteromarginal and anteroangular setae prominent but shorter than midlateral and posteroangulars setae; epimeral seta typically slightly longer. All major body setae blunt. Forewing medially constricted, typically with four to eight duplicated cilia, most commonly six or seven ( Fig. 7 ); sub-basal wing setae bases arranged in a line ( Fig. 8 ); forewing distal cilia with surface smooth. Pelta bell-shaped ( Fig. 5 ); tergite VII campaniform sensilla wide apart, distance between them approximately 0.8– 1.0 times that of tergite VIII sensilla; tergite IX setae S1 shorter than tube, approximately 60% length of tube; tube at least 2.5 times its basal width.

Measurements (in µm; see Table 1 ): Postocular setae approximately 70 ( 62 in males); compound eye length 72 in females, 69 in males). Epimeral setae 84 in females, 70 in males; posteroangular setae 83 in females, 68 in males.

Diagnosis of first larval instar

( Figures 10–11 )

Body pale creamy, thorax without sclerotisation, legs slightly darker, end of abdomen: segments IX (in distal part) and X light brown; antennae short with segments I, III– V wider than long, III– V tapering towards the apex, and II, VI, VII longer than wide. Segment I in the body colour, but II darker at base, III–VII brown ( Fig. 10 ).

Cuticle of dorsal and ventral sides of thorax and abdomen with clear, dense and lumpy sculpture without microtrichia, ventral setae acute at apex, dorsal acute or slightly blunt ( Fig. 11 ).

Diagnosis of second larval instar

( Figures 12–17 )

Body pale creamy, antennal segments III (at the distal part)-VII darker than I–II (first the lightest), distal part of segment X brown ( Fig. 13 ), apex of the mouth cone and maxillary palpi slightly darker, sclerotised plates on pronotum and spots on meso- and metanotum light brown ( Fig. 12 ).

Head longer than wide, smooth without sclerotised plates, with three pigmented stemmata. Dorsal setae D1 situated below the hind margin of stemmata and D2 below their front margin, in the line with a pair of microsetae. Seta D1 (postocular) acute and D2 blunt at the apex, setae on ventral side of head acute at apex, maxillary palpi twosegmented with three long setae at apex.Antenna seven-segmented, segments I and II rectangular, III–VI elongated, wider at the distal part, VII rounded at the apex, and III the longest ( Fig. 13 ).

Thorax: Pronotum with two sclerotised plates, cuticle smooth without sculpture and microtrichia. Pronotum with seven pairs of setae; setae D1–D7 knobbed or expanded at the apex except for D2 (blunt) and D3 (acute). Setae D1–D5 situated on sclerotised plates, D6 and D7 located laterally of the plates. Mesonotum with two pairs of sclerotised spots, the front one elongated and aligned with spiracles, and the distal one round; setae surrounded by brown sclerotised plates at their bases; cuticle smooth. Mesonotum with six pairs of long setae with narrow spoon shaped apices. One pair of micro setae situated in front of elongated spots. Metanotum with one pair of sclerotised spots and five pairs of long setae with the apices similar with mesonotum ones. Metanotum cuticle smooth. Thoracic ventral setae longer than these dorsal ones and acute at apex ( Fig. 14 ).

Abdomen: Segments I–VIII with smooth cuticle without sculpture and microtrichia. Setae D1-D3 long and knobbed (spoon shaped) at the apex except for IX D1 and D2, which are elongated and needle shaped at apex, D1 on tergite IX in the same length or a little longer than the tube; distance between CS wider than between D1 setae, and situated above D2 setae bases ( Figs 15, 16 ). Apices of setae on the ventral side of the body slightly blunt or acute, V 2 on sternite IX fork-shaped ( Fig. 17a, b ).

Measurements (in µm): body length 1300–1550; head dorsal setae: D1 (postocular) 42,5–50.Antennal segment length/width (at the apex): III 50/25, IV 50/20, V 40/20, VI 30/15, VII 25; maxillary palpus length 30. Length of pronotal setae: D1 40–45, D2 30–35, D4 60–65, D6 70–85; length of mesonotal setae D1 42,5–50, D2 30–37,5; length of metanotal setae D1 50–55, D2 45–47,5, D3 42,5–45, D4 45–50, D5 80–90. Length of abdominal setae: VIII D1 40, D2 40, V 1 80–87,5, V 2 55, IX D1 75–90, D2 35–40; distance D1–D1 30. Distance between CS on tergite VIII 75–82,5, IX 45; length/width of segment IX 100/130, X 90/70. Length/width of spiracles on mesonotum 20/30, abdominal segment II 17,5/22,5 and VIII 15/15, facets of spiracles without pores.

Distinction of H. biroi and Neohegeeria dalmatica larvae

Both H. biroi and N. dalmatica develop on hosts belong to the Lamiaceae family, Ballota nigra and Stachys spp. , respectively. The larval body is pale creamy in both species, but in H. biroi , the third antennal segment is darker than in N. dalmatica larva II. The main characteristic that differentiates the larvae of H. biroi and N. dalmatica is the sculpture of their cuticle. The first larval instar of the former species exhibits a distinct, lumpy sculpture devoid of microtrichia, whereas the latter species is covered with dense microtrichia. The second larval instar’s cuticle is smooth in H. biroi and covered by microtrichia in N. dalmatica . Sclerotisation of the body is similar in both analysed species. Setae on the dorsal and ventral sides of the body are shorter in H. biroi than in N. dalmatica . Most of the longest dorsal setae of the thorax and abdomen are expanded or knobbed at the apices in N. dalmatica ; thoracal setae in H. biroi are expanded or knobbed on pronotum and long spoon shaped at apices on meso- and metanotum, and are similar with those on tergites. Setae D1 on tergite IX are a little shorter than the segment length in H. biroi , and longer in N. dalmatica . In both species, setae V2 on segment IX have a forked shape; however, they are much longer in N. dalmatica ( Kucharczyk et al., 2024) .

Figures

FIGURES 1–6. Haplothrips biroi adult. (1) outline of adult female body; (2) head; (3) pronotum; (4) male pseudovirga; (5) pelta; (6) detail of sense cones on antennal III (2 sense cones) and IV (4 sense cones).

FIGURES 7–9. Haplothrips biroi adult. (7) forewing duplicated cilia; (8) sub-basal wing setae; (9a–c) fore tarsal tooth variation (a – male; b – absent in female; c – stunted in female).

FIGURES 10–13. Haplothrips biroi first (L1) and second larval (L2) instars. (10) antenna of L1; (11) body sculpture of L1; (12) L2 mesonotum middle and left side; (13) L2 antenna.

FIGURES 14–17. Haplothrips biroi second larval (L2) instar. (14) thoracic ventral seta; (15) tergite IX D1 and D2 setae and position of campaniform sensilla; (16) tergite VIII D1 and D2 setae; (17a,b) sternite IX setae (a – position of setae V1 and V2; b – fork-shaped V2 seta).