Myzus mumecola (Matsumura, 1917)

Tomić, Mihajlo, Jovičić, Ivana & Petrović-Obradović, Olivera, 2024, Description of fundatrix and sexual morphs of the Asian apricot aphid, Myzus mumecola (Matsumura, 1917) (Hemiptera: Aphididae), Zootaxa 5537 (3), pp. 395-406 : 397-403

Descriptions of fundatrix and sexual morphs of Myzus mumecola

Fundatrix ( Figs 1a , 2 , 5a , Table 1 ) (n=10)

Color of live specimens: Dark red with dusky spinal longitudinal stripe and two lateral rows of small dusky transverse stripes. Antennae and legs mostly pale in color with dark apices and siphunculi and cauda pale. Pigmentation of slide-mounted specimens: head and pronotum brown, mesonotum with irregular light brown spots, metanotum, and abdominal tergites I–VI mostly pale with brown spinal, pleural, and marginal intersegmental muscle sclerites, abdominal tergites VII and VIII light brown. Antennal segment I brown, concolorous with the head, segment II light brown, segment III pale, sometimes dusky at the apex, and segments V and VI dark brown. Legs mostly pale, except for the distal halves of the middle and hind femora and the apices of tibiae and tarsi which are brown. Siphunculi pale. Other morphological characters: Body broadly oval, 2.03–2.77 mm long and 1.27–1.60 as long as it’s wide. Head spiculose with (0-) 2 median frontal setae (mode 2) and 7–8 dorsal setae (mode 8). Antennal tubercles weakly developed. Antennae imbricated, short, 5-segmented, or rarely 4-segmented (antennal segments III and IV are fused), 0.34–0.49 times body length. Antennal segments I, II, III, IV and V respectively with 3, 0–3, 1–8, 2–4, 0–8 short and blunt setae (0-3 setae on base of antennal segment V, 0–1 setae on base of terminal process and 0–4 setae on top). Longest setae on antennal segment III 0.17–0.31 times the basal diameter of antennal segment III. Terminal process 0.59–1.40 times the length of base, which has 5–6 accessory rhinaria around the primary rhinarium. Legs shorter than in later generations, 0.40–0.52 times body length. First tarsal segment formula 3:3:2. Rostrum reaches hind coxae. Ultimate rostral segment with (2-) 3–5 accessory setae and 3 pairs of subapical primary setae, 1.24–1.45 times the length of second hind tarsal segment. Pronotum with 6 setae. Tergum wrinkled. Setae on abdominal tergites I–VI short and blunt, on abdominal tergites VII and VIII longer and pointed. Abdominal tergites III, VI, VII and VIII respectively with 9–14, 9–10, 2–4 and 3–4 hairs. Longest setae on abdominal tergite III 0.19–0.39 times the length of basal diameter of the segment. Genital plate spinulose with 11–20 setae on posterior margin and 2–5 setae on anterior half. Siphunculi imbricated, tapering, or slightly swollen on the inner side, curved outwards, 0.19–0.25 times body length, 2.31–3.04 times cauda length, 0.84–1.05 times head width across eyes, 3.00–3.93 times as long as their basal widths; the diameter of the swollen distal part is 1.03–1.09 times the diameter of the narrowest basal part. Cauda short, triangular, 0.75–1.18 times its basal width, 0.07–0.10 times body length with 6 setae.

Oviparous female ( Figs 1b , 3 , 5b , 6a, b, c , Table 1 ) (n=12)

Color of live specimens: Dark red or pink, mottled with greyish-pink patches. Antennae mostly pale with blackish apices. Legs mostly pale, except the distal parts of the middle and hind femora and apices of tibiae and tarsi which are black. Siphunculi gradually darken from base to apex, cauda blackish. Pigmentation of slide-mounted specimens: head and pronotum blackish. Mesonotum, metanotum, and abdominal tergites I–VI pale. Abdominal tergites VII and VIII have brown transverse spinopleural sclerites. Genital plate brown. Antennal segment I concolorous with head, antennal segment II light brown, antennal segment III pale, and antennal segments V and VI dusky. Legs mostly pale, except for the distal parts of the middle and hind femora and apices of tibiae and tarsi which are brown. Siphunculi brown, darkening gradually from base to apex, cauda brown, except at the base. Other morphological characters: body oval, 1.53–2.02 mm long, 1.25–1.95 as long as wide. Head spiculose with 0–2 median frontal and 8 dorsal setae. Antennal tubercles well-developed with 3–4 blunt setae, the longest of them 0.61–0.93 times the basal diameter of antennal segment III. Antennae imbricated, 6-segmented, 0.68–0.90 times as long as body length. Antennal segments I, II, III, IV, V and VI respectively with 6–9, 3–4, 10–18, 6–11, 5–10, 3–11 short, blunt or bluntly pointed setae (2–6 setae on base of antennal segment V, 0–1 setae on base of terminal process and 1–4 setae on top). Longest setae on antennal segment III 0.17–0.31 times as long as the basal diameter of antennal segment III. Terminal process 2.30–2.95 times the length of the base of antennal segment VI, which has 5–6 accessory rhinaria around the primary rhinarium. Hind tibiae swollen, 0.44–0.60 times body length, with 39–162 pseudorhinaria. First tarsal segment formula 3:3:2. Rostrum reaches hind coxae. Ultimate rostral segment with 3–5 accessory setae and 3 pairs of subapical primary setae and is 1.30–1.47 times the length of second hind tarsal segment. Pronotum with 6 hairs. Tergum wrinkled. Setae on abdominal tergites I–VI short and blunt, on abdominal tergites VII and VIII are longer and pointed. Abdominal tergites III, VI, VII and VIII respectively with 9–12, 6–10, 2–9 and 5–8 hairs. Longest setae on abdominal tergite III 0.26–0.56 times the length of basal diameter of the segment and longest setae on abdominal tergite VIII measuring 0.027 –0.037 mm. Genital plate transversely oval with spinulose imbrications and 26–35 setae on posterior margin and 18–35 on anterior half. Siphunculi imbricated, slightly swollen on inner side, markedly tapering subapically before well-developed flange, curved outwards, 0.23–0.30 times body length, 2.81–3.42 times cauda length, 0.94–1.19 times head width across eyes, 4.01–5.94 times as long as their basal widths, the diameter of the swollen distal part is 1.03–1.30 times the diameter of the narrowest basal part. Cauda short, triangular, 0.87–1.07 times its basal width, 0.08–0.10 times body length with 6–8 setae.

Alate male ( Figs 4 , 5c , Table 1 ) (n=10)

Color of live specimens:Unknown. Pigmentation of slide-mounted specimens: Head, thorax and antennae dark brown. The distal parts of fore femora dark brown, and middle femora and hind femora mostly dusky, except the base.Apices of tibiae and tarsi dark brown. Abdomen with large round, marginal, and post-siphuncular sclerites and large central patch on abdominal tergites III–VI with 3–4 windows. The patch is more broken than in alate viviparous female, which has a more compact patch with 1–2 windows. Other segments with brown transverse sclerites. Ventral side of abdomen has 4 pairs of large transverse pleural sclerites. Siphunculi and cauda dark brown. Other morphological characters: body is 1.78–2.26 mm long, 2.00–3.15 times as long as wide. Media twice branched. Head is nearly smooth with 2 median frontal setae and 7–11 dorsal setae (mode 8). Antennal tubercles well developed with 3–5 pointed setae, the longest of them 0.77–1.12 times the basal diameter of antennal segment III. Antennae long, imbricated, 6-segmented, 1.13–1.50 times body length. Setae on antennae pointed. Antennal segments I, II, III, IV, V and VI respectively with 8–12, 2–5, 14–19, 8–14, 4–10, 1–7 pointed setae (1–3 setae on base of antennal segment V, 0–1 setae on base of terminal process and 0–3 setae on top). Antennal segments III, IV and V respectively with 55–108, 39–65, 16–29 secondary rhinaria and 5–6 ciliated accessory rhinaria around the ciliated primary rhinarium on antennal segment VI. Terminal process 3.12–4.59 times as long as the base of antennal segment VI. Longest setae on antennal segment III 0.52–0.68 times as long as the basal diameter of antennal segment III. Legs long, hind tibiae 0.62–0.86 times body length. First tarsal segment formula 3:3:2. Rostrum reaches middle coxae. Ultimate rostral segment with 3–5 accessory setae and 3 pairs of subapical primary setae, 1.11–1.50 times the length of second hind tarsal segment. Pronotum with 6 hairs. Abdominal tergites III, VI, VII and VIII respectively with 10–18, 6–9, 4–6 and 2–4 pointed setae. Longest setae on abdominal tergite III 0.68–1.20 times the length of basal diameter of the segment and longest setae on abdominal tergite VIII measuring 0.033 –0.046 mm. Siphunculi imbricated, slightly to moderately swollen on the inner side, 0.18–0.24 times body length, 2.97–3.85 times cauda length, 0.87–1.04 times head width across eyes, 4.83–9.10 times as long as their basal widths; the diameter of the swollen distal part is 1.13–1.74 the diameter of the narrowest basal part. Cauda short, triangular, 0.88–1.26 times its basal diameter and 0.06–0.07 times body length with 6 (7) setae.

Molecular identification

The morphological identification of the sexual morphs of M. mumecola was confirmed by DNA sequence analysis.

The COI barcodes of two M. mumecola individuals (one male and one oviparous female) were sequenced and subsequently deposited in the NCBI GenBank. The DNA sequences of the oviparous female (accession number PP779927.1) collected in Zemun in Serbia, spanned 619 nucleotides, and the DNA sequences of the male (accession number PP795382.1) collected in Surčin in Serbia, spanned 685 nucleotides. The DNA sequences obtained from the Serbian aphid samples (sexual morph) were compared with those available in NCBI GenBank (www.ncbi.nlm. nih.gov) and Bold Systems (http://boldsystems.org/). BLAST analyses of sequences obtained during this research showed full nucleotide similarity (100%) to those sequences of M. mumecola originating from Hungary (accession numbers MT635054.1, MT635055.1, MT635056.1, MT635057.1, MT635058.1, MT635059.1) in NCBI.

Biology

In Serbia, Myzus mumecola is heteroecious, holocyclic on Prunus armeniaca . The fundatrices hatch from eggs ( Fig. 1c ) in February and March. The fundatrigeniae and their progeny cause the curling of leaves on Prunus armeniaca , and spring migrant alate migrate to unknown secondary host(s) in May and June. Autumn migrant alate (gynopara) and alate males return in November.

Figures

FIGURE 1. Myzus mumecola on Prunus armeniaca: a—fundatrix, b—oviparous female, c—egg

FIGURE 2. Illustration of the fundatrix of Myzus mumecola

FIGURE 3. Illustration of the oviparous female of Myzus mumecola

FIGURE 4. Illustration of the alate male of Myzus mumecola

FIGURE 5. Photographs of clarified slide mounts of Myzus mumecola: a—fundatrix, b—oviparous female, c—alate male, d—alate gynopara

FIGURE 6. Tarsi of the oviparous female of Myzus mumecola: a—fore tarsus, b—middle tarsus, c—hind tarsus