Fig 1.
Parthenogenetic morphs of Adelges laricis exules on Larix decidua.
(A) ‘Crawler’– 1st instar nymph after hatching. The arrow points to the crawler. (B) ‘Wooly’ nymphs and females. (C-D) Wax-covered ‘spheres’ of accumulated honeydew. The ‘sphere’ is covered with wax and it often adheres to the insect and the egg clusters. Olympus DP-Soft binocular (10 x 6.3), Sony camera − Exwave HAD (1600 x 1200).
Table 1.
Characteristics and suggested meaning of EPG-recorded waveforms generated by Adelges laricis during probing on Larix decidua.
Fig 2.
Pathway phase ‘AC’ waveforms generated by Adelges laricis during EPG-recorded probing on Larix decidua.
(A) Compressed view of AC waveforms; arrows show the transition points; 100 s trace 2.5V resolution. (B) Non-probing and the transition to waveform AC1(arrow); 60 s trace, 2.5V resolution. (C) Waveform AC2; arrows indicate the beginning and the end of ‘short Apd1’ series; 100 s trace, 2.5V resolution. (D) ‘Short’ potential drops Apd1 –detail; 30 s trace, 2.5V resolution. (E) ‘Standard aphid-like’ potential drop Apd2; phases of Apd2 − I, II, III; sub-phases of Apd2 − II-1, II-2, II-3; 30 s trace, 2.5V resolution. (F) Waveform AC3, 100 s trace, 2.5V resolution.
Fig 3.
Assessment of the R and emf components contribution to each waveform by plant voltage adjustments, positive (+), zero (0) and negative (−).
Adjustments of the plant voltage during recording. (A) Waveform AC1; 30 s traces, resolution 2.5V. (B) Waveform AC2; 60 s traces, resolution 2.5V. (C) Waveform AE1; 60 s traces, resolution 1V. (D) Waveform AE2; 60 s traces, resolution 1V. (E) Waveform AE3; 10 s traces, resolution 1V. (F) Waveform AE3; 30 s traces, resolution 1V. (G) Waveform AG; 30 s traces, resolution 1V.
Table 2.
Frequency and duration of individual EPG-recorded waveforms generated by Adelges laricis during probing on Larix decidua.
Table 3.
Potential drops during AC phase stylet activities of Adelges laricis on Larix decidua.
Fig 4.
Phloem phase ‘AE’ waveforms generated by Adelges laricis during EPG-recorded probing on Larix decidua.
(A) Transitions from AC to AE1, then AE1 to AE2 and AE2 to AE3; arrows show the transition points; 60 s trace, 2.5V resolution. (B) Compressed view of AE waveforms; arrows show the transition points; 30 s trace, 2.5V resolution. (C) Waveform AE1; 30 s trace, 1V resolution. (D) Waveform AE2; 10 s trace, 2.5V resolution. (E) and (F) Different representations of waveform AE2; 30 s traces, 1V resolution. (G) Waveform AE3; 30 s trace, 1V resolution.
Fig 5.
Xylem phase ‘AG’ waveforms generated by Adelges laricis during EPG-recorded probing on Larix decidua.
(A) Transition from AC1 to AG; arrow shows the transition point; 60 s trace, 5V resolution. (B) Waveform AG; 30 s trace, 2.5V resolution. (C) Waveform AG; 10 s trace, 2.5V resolution. (D) Different representations of waveform AG; arrow shows the transition point; 30 s traces, 2.5V resolution. (E)–(H) Different representations of waveform AG; 30 s traces, 1V resolution.
Fig 6.
Waveform patterns AC-d generated by Adelges laricis on sucrose diets.
(A) Equipment for EPG registration on sucrose diets, 1 –aphid electrode, 2 –diet chamber, 3 –diet electrode; (B) the mobile crawler of A. laricis (C)–(D) representative traces of waveform AC-d; 30 s traces, resolution 1V.
Fig 7.
Scanning electron microscope images showing exulis morph of Adelges laricis on Larix decidua needles.
(A) Crawler at the larch needle, lateral view; arrow points at the mouthparts’ stylets. (B) Crawler at the larch needle, ventral view; arrows point at the rostrum and the stylets. (C) Wingless sessile female with most of the wax removed on the larch needle, dorsal view; arrow points at the stylets. (D) Stylets of the female inserted near the stomata of larch needle; arrow points at the stylets. (E) Stylets of the female inserted near a stoma and between epidermal cells of the larch needle; asterisk indicates the stoma. (F) Ventral view at rostrum and stylets of the female; arrow points at the stylets. (G)–(H) Stylets inserted between epidermal cells of the larch needle; different resolutions.
Fig 8.
Sequential changes in the probing behavior of Adelges laricis on Larix decidua.
The graphs represent the proportion of time devoted to a given activity at the end of each hour of the 8-hour continuous EPG monitoring. (A) Image based on all replications (n = 84). (B) Image based on recordings that started with either any of AC or AG waveform patterns (n = 24). (C) Image based on recordings that started with any of AE waveform patterns (n = 57). Anp–non-probing. AC1, AC2, AC3 –variants of pathway phase AC. AE1, AE2, AE3 –variants of phloem phase AE. AG–xylem phase.
Fig 9.
Proportion (%) of various non-probing and probing activities during the 8 h EPG-recordings of Adelges laricis on Larix decidua.
Anp–non-probing. AC1, AC2, AC3 –variants of pathway phase AC. AE1, AE2, AE3 –variants of phloem phase AE. AG–xylem phase.
Fig 10.
Kinetogram of behavior during stylet penetration of Adelges laricis on Larix decidua.
The values near the arrowheads indicate the occurrence (%) of transitions from one waveform to the next that occurred in all (n = 84) EPG recordings. Anp–non-probing (black labels). AC1, AC2, AC3 –variants of pathway phase AC (green labels). AE1, AE2, AE3 –variants of phloem phase AE (blue labels). AG–xylem phase (purple label).