Fig 1.
Scanning electron micrographs of the head of Pyrrhocoris sibiricus.
(A) Anterior view. (B) Lateral view. (C) Dorsal view showing four-segmented labium (I–IV). Lg, labial groove; Sf, stylet fascicle; Lm, labrum; Lb, labium; Ls, longitudinal suture.
Fig 2.
SEM of first labial segment and labrum of Pyrrhocoris sibiricus.
(A) Anterior view of labrum and first labial segment. (B) Lateral view of labrum. (C) Enlarged view of sensilla trichodea I (St I). (D) Enlarged view of outlined box in (B), showing the tip of labrum. (E) Enlarged view of surface in (B) (black arrow). (F) Enlarged view of cuticular pores (Cpo). (G) Enlarged view of triquetrous cuticular processes (Tcp).
Fig 3.
Diagrams of different types of sensilla and cuticular processes on mouthparts of female Pyrrhocoris sibiricus.
St I, sensilla trichodea I; St II, sensilla trichodea II; St III, sensilla trichodea III; Sb I, sensilla basiconica I; Sb II, sensilla basiconica II; Sb III, sensilla basiconica III; Sb IV-2, No. 2 of sensilla basiconica IV; Sb IV-9, No. 9 of sensilla basiconica IV; Sb IV-10, No. 10 of sensilla basiconica IV; Sca, sensilla campaniformia; Spl, sensilla placodea; Tcp, triangular cuticular processes.
Table 1.
Morphometric data (mean ± SE) for various sensilla of adult P. sibiricus except for peg-like sensilla basiconica IV.
Fig 4.
SEM of second labial segment of Pyrrhocoris sibiricus.
(A) Anterior view. (B) Lateral view. (C) Dorsal view. (D) Enlarged view of outlined box of (A) showing sensilla trichodea I (St I), sensilla campaniformia (Sca) and sensilla basiconica II (Sb II). (E) Enlarged view of outlined box of (B) showing sensilla trichodea I (St I) and sensilla basiconica I (Sb I). (F) Enlarged view of sensilla basiconica I (Sb I). (G) Enlarged view of sensilla basiconica II (Sb II). (H) Enlarged view of sensilla campaniformia (Sca). Bars: (A), (B) and (C) = 500 μm; (D) = 100 μm; (E) = 200 μm; (F) = 10 μm; (G) = 5 μm; (H) = 10 μm.
Table 2.
Measurements of labrum, labium and stylets (mean ± SE) obtained from scanning electron microscopy.
Fig 5.
SEM of third labial segment of Pyrrhocoris sibiricus.
(A) Anterior view. (B) Dorsal view. (C) Lateral view. (D) Enlarged view of outlined box in (C) showing sensilla trichodea I (StI). E. Enlarged view of outlined box in (D) showing sensilla basiconica III (SbIII). Bars: (A) (B) and (C) = 400 μm; (D) = 100 μm; (E) = 10 μm.
Fig 6.
SEM of the fouth labial segment of Pyrrhocoris sibiricus.
(A) Anterior view. (B) Lateral view. (C) Dorsal view. (D) Enlarged view of sensilla trichodea II(StII). (E) Enlarged view of sensilla trichodea III(StIII). (F) Enlarged view of sensilla placodea (Spl).
Fig 7.
Distribution of sensilla on tip of labium of Pyrrhocoris sibiricus.
A. Dorsal view of labial tip showing the cactoid apical plate (Ap); B. Anterior view of labial tip showing two lateral lobes; C. Vertical view of labial tip showing distribution of sensilla; D. Enlarged view of No.9 of sensilla basiconica IV; E. Enlarged view of right side of labial tip showing 12 sensilla basiconica IV; F. Enlarged view of No.10.of sensilla basiconica IV.
Fig 8.
SEM of the inner surface of labium of Pyrrhocoris sibiricus.
(A) Internal view. (B) Enlarged view of outlined box in (A) showing piliform cuticular processes. (C) Internal view. (D) Enlarged view of outlined box in (C) showing cuticular processes.
Table 3.
Mean±SE lengths (n = 15) of peg-like sensilla basiconica IV at labial tip of P. sibiricus.
Fig 9.
SEM of stylet fascicle and mandibular stylets of Pyrrhocoris sibiricus.
(A) Stylet fascicle showing mandibular (Md) and maxillary stylets (Mx). (B) Anterior view of stylet fascicle. (C) External view. (D) Lateral view of mandibular stylet (Md) showing three central teeth (black arrow) and two pairs of lateral teeth (white arrow). (E) Interior view of mandibular stylet (Md) showing squamous texture (black arrow). (F) Lateral view. (G) Enlarged view of outlined box of (F).
Fig 10.
SEM of maxillary stylets of Pyrrhocoris sibiricus.
(A) Apex of right maxillary stylet (RMx) showing food canal (Fc) and salivary canal (Sc). (B) Apex of left maxillary stylet (LMx) showing food canal (Fc) and salivary canal (Sc). (C) Apices of interlocked maxillary stylets showing inner surface of right maxillary stylet (RMx), outer surface of left maxillary stylet (LMx) and process (black arrow). (D) Apex of right maxillary stylet (RMx) showing process (white arrow). (E) Apex of right maxillary stylet (RMx). (F) External view of left maxillary stylet (LMx). (G) Lateral view of left maxillary stylet (LMx). (H) Lateral view of left maxillary stylet (LMx).
Fig 11.
Cross-section of stylet fascicle of Pyrrhocoris sibiricus.
(A) and (B) Cross-section of stylet fascicle through middle of second segment and third segment showing shapes of mandibular stylets (Md), maxillary stylets (Mx), food canal (Fc), salivary canal (Sc) and dendritic canal (black arrow). (C) Diagram of cross-section of stylet fascicle. LMd, left mandibular stylet; RMd, right mandibular stylet; LMx, left maxillary stylet; RMx, right maxillary stylet; Fc, food canal; Sc, salivary canal; Ic, interlocking canal; CN, dendritic canal; RPr, Right process of the maxilla; A, Straight upper right process of dorsal lock; A’, Hooked upper left process of dorsal lock; B, Hooked lower right process of dorsal lock; B’, Straight lower left process of dorsal lock; C, Straight upper right process of middle lock; C’, Hooked upper left process of middle lock; D, T-shaped lower right process of middle lock; D’, Hooked lower left process of middle lock; E, Hooked lower right process of the ventral lock; E’, Hooked upper left process of ventral lock; F, Straight lower left process of ventral lock.
Fig 12.
Feeding stages on mature seeds and young stalks in adult Pyrrhocoris sibiricus showing positions of the mouthparts.
(A) Location of suitable feeding position by the labium. (B) Puncture of seed by stylet fascicle showing elbow-like fold of proximal and second rostral segments and stylet penetration. (C) Start of feeding showing puncture of epidermis by stylets and labium withdrawn below the ventral side of the head and thorax. (D) Feeding on seed. (E) Termination of feeding showing retraction of stylets. (F) Use of forelegs to return stylet fascicle to labial groove. (G) penetration of green stalk. (H) Feeding on green stalk. Lm, labrum; Lb, labium; Sf, stylet fascicle.