THE APHIDS

 

 

         SYSTEMATIC TREATMENT OF APHID GENERA

        (in alphabetical order)

 

 

O

 

Obtusicauda

Oedisiphum

Oestlundiella

Olegia

Ossiannilssonia

Ovatomyzus

Ovatus

 

Obtusicauda Soliman

Aphidinae: Macrosiphini

About 10 species occurring in  North America and Asia, feeding exclusively on Compositae-Artemisiinae.  They are probably most closely related to Macrosiphoniella, although some features such as the stiletto-shaped R IV+V may be due to convergent evolution on the same host plants. Holman & Szelegiewicz (1979) revised the palaearctic species, and the nearctic species were reviewed by Robinson & Halbert (1989). For colour photos of some unidentified (or unidentifiable) North American species see aphidtrek.org. Most earlier accounts placed the species in other genera (Macrosiphum, Macrosiphoniella, Narzykulovia).

Obtusicauda anomella (Knowlton & Allen)    Appearance in life is unrecorded; BL of aptera 1.4-2.0 mm. On Artemisia tridentata in Utah (original description), and recently fundatrices identified as this species have been collected on this host plant in Idaho (A. Jensen, aphidtrek.org). Alatae are unknown.

Obtusicauda artemisiphila (Knowlton & Allen)    Colour of apterae in life is not recorded; BL 1.7-2.1 mm. Alatae are green to blackish green. Described from Artemisia tridentata in Utah, and also found in Idaho, Oregon, Nevada and Montana.

Obtusicauda coweni (Hunter)  Plate 28b   Apterae are dark olive brown to greenish black, with a metallic lustre; BL 1.2-2.3 mm. On leaves and shoot tips of Artemisia and Seriphidium spp. in western North America.  We follow Robinson & Halbert (1989) who synonymized several species under the name coweni in recognizing a single, variable species.  Siphuncular length is particularly variable, even within a population, but more reliable features are the long antennal terminal process and the rounded, pigmented scleroites at the bases of many dorsal abdominal hairs.  O. zerothermum may also be a synonym. The Asian species O. moldavica seems remarkably similar and also shows wide morphological variation. Monoecious holocyclic; oviparae and alate males occur in late October-November (BMNH collection). 2n=12.

Obtusicauda dolychosiphon (Umarov)    Apterae are shining brownish black, BL 1.8-2.9 mm. Described from Artemisia persica in Tajikistan, and similar aphids have been found in Kazakhstan (on A. pauciflora; described as a subspecies, O. dolychosiphon ssp. praecellens Smailova), Uzbekistan, Kyrgyzstan, Iran and Pakistan (on various Artemisia spp.).  Holman & Szelegiewicz (1979) tabulated morphometric data and reviewed the host plant range and distribution.

Obtusicauda filifoliae (Gillette & Palmer)    Apterae are are cinnamon brown to yellowish brown, tinged laterally with yellow ochre; BL 1.7-2.3.  On leaves and shoot tips of Artemisia filifolia and A. tridentata in western USA.  Monoecious holocyclic; Robinson & Halbert (1989) examined type specimens of two Knowlton & Allen species collected in April-May and considered them both to be fundatrices of  filifoliae.

Obtusicauda frigidae (Oestlund)    Apterae are shining dark metallic green; BL 1.8-2.3 mm. On leaves and young growth of Artemisia spp. in western North America, and there are also records from eastern Canada (New Brunswick, Nova Scotia; Smith & Parron 1978). Monoecious holocyclic; oviparae and apterous males occur in late September-November, fundatrices in late May (Palmer 1952).

Obtusicauda moldavica (Bozhko)    Apterae are blackish, BL 1.95-3.0 mm. On terminal parts of  Artemisia spp. and Seriphidium spp., forming dense colonies of rather immobile, “dead-looking” aphids that produce copious honeydew (Holman & Szelegiewicz 1979).  In Moldavia, Hungary, Crimea and Kazakhstan. Aphids from an Artemisia sp. in Tajikistan were described as a new species (O. crassitubia) by Narzikulov & Umarov (1969), but this was placed as a subspecies of  moldavica by Holman & Szelgiewicz (1979), who tabulated morphometric data for this group and reviewed host plants and distribution. The latter authors assigned a single aptera from Pakistan to ssp. crassituba. O. nilkaensis on Artemisia capillaris in Xinjiang, China (Zhang et al. 1999, described as Uroleucon nilkaense) is closely related and a possible synonym, as is O. longicauda Zhang, described from ‘Gramineae’ in Tibet (Zhang & Zhong 1981).

Obtusicauda mongolica Holman & Szelgiewicz    Apterae are shining black, slightly wax-powdered; BL 1.6-2.2 mm. On Artemisia frigida in Mongolia.

 

Oedisiphum          van der Goot

Aphidinae: Macrosiphini

One or two species in east Asia resembling Brachycaudus but with reniform spiracular apertures, and with a long R IV+V adapted for feeding on Compositae/Asteraceae-Gnaphalieae. Medda & Chakrabarti (1998) provided a key couplet distinguishing the alatae.

Oedisiphum compositarum van der Goot  Plate 10b  Apterae are brownish green with black siphunculi; BL 1.4-1.8 mm. Alatae have numerous secondary rhinaria on ANT III-V and an extensive black dorsal abdominal patch. On flower-stalks and flowers of a Gnaphalium species in Java (original description), and subsequently (1951) collected from Gnaphalium (= Helichrysum) luteoalbum and G. japonicum (BMNH collection, leg. F.W. Rappard), and also from Anaphalis spp. in north-west India (Medda & Chakrabarti 1998).

Oedisiphum soureni A.N. Basu   (= indicum A.K. Ghosh)    Apterae are pale brown (probably sometimes darker), BL 1.3-1.7 mm.  Feeding on undersides of leaves and inflorescences of Anaphalis spp., without causing noticeable injury, in West Bengal, and also recorded from Gnaphalium (= Helichrysum) luteoalbum in Uttar Pradesh (India). Medda & Chakrabarti (1998) described the alata. 2n=8.

 

Oestlundiella Granovsky

Calaphidinae: Calaphidini

One North American species on Alnus, related to Euceraphis.

Oestlundiella flava (Davidson)  All viviparae are alate, delicate, lemon yellow with plumes of bluish white wax developing on antennae and legs; BL 2.4-3.4 mm.  On undersides of leaves of Alnus spp., tending to aggregate on certain leaves and feed along either side of the mid-rib.  Widely distributed in North America (except the south-east).  Apterous oviparae and alate males occur in October.  2n=8.

  

Olegia Shaposhnikov

Phylloxeridae

 

One species with one-segmented tarsi, forming galls on leaves of Japanese elm.

Olegia ulmifoliae (Aoki)  Aptera (fundatrix?) in gall is yellowish, broadly pear-shaped; BL 1.0-1.7 mm.  In small galls (fig. 134A and Stoetzel 1993) on the mid-ribs of leaves of Ulmus japonica in Japan (Hokkaido, Aoki 1973, as Aphanostigma) and east Siberia (Pashchenko 1988a).  The fundatrix is remarkably fecund; Shaposhnikov (1979b) counted over 1500 eggs and first instar larvae around one female in a gall in July.  Alatae are unknown, dispersal being by wind-blown first instars.  Monoecious holocyclic, sexuales mating either in the gall or on the leaf surface (Stoetzel 1993).

 

Ossiannilssonia Hille Ris Lambers

Aphidinae: Macrosiphini

One palaearctic species on Galium with paired spinal protruberances on abdominal tergites 3-5 and unpaired cauda-like processes on abdominal tergites 6, 7 and 8. The siphunculi are short, curved and flangeless as in certain other genera associated with Galium.

Ossiannilssonia oelandica Hille Ris Lambers  Plate 14c  (Fig.29g)   Apterae are greenish to lemon yellow with mainly pale appendages; BL 1.7-2.0 mm. On Galium boreale, especially in sunny locations, in Sweden, Finland (Heikinheimo 1997, describing alatae) and Germany. Monoecious holocyclic, with oviparae and alate males in late August-Septembr (Ossiannilsson 1959b, Heie 1992).

 

Ovatomyzus Hille Ris Lambers

Aphidinae: Macrosiphini

Three European species similar to Myzus but the head is not spiculose and alatae have numerous secondary rhinaria on ANT III-V as in Ovatus. Only anholocyclic populations are known, feeding mainly on Lamiaceae and Boraginaceae. Blackman (2010) reviewed the genus.

Ovatomyzus boraginacearum Eastop  Plate 18a   Apterae are whitish to pale greenish yellow (see influentialpoints.com/Gallery; but brownish yellow to orange in overwintering populations); BL 0.9-1.6 mm. Alatae have a black dorsal abdominal patch and secondary rhinaria distributed III 19-30, IV 7-17, V 1-7.  Living scattered on the undersides of leaves of its host plants, which are mainly Boraginaceae (Anchusa, Pulmonaria, Symphytum), and less commonly Salvia spp. (Lamiaceae); also recorded from Geum urbanum (Rosaceae) and Knautia arvensis (Dipsacaceae) (Eastop 1987).  Specimens from Eupatorium cannabinum (Compositae/Asteraceae) described by Theobald (1926) as Myzus eupatorii also seem to be this species. In Europe (England, Germany, Netherlands, Sweden, Czech Republic), Iran and Kazakhstan (Kadyrbekov 2012a). Apparently entirely anholocyclic, with a specialised hibernating apterous morph (Müller 1969a, as calaminthae).  2n=12.

Ovatomyzus chamaedrys (Passerini)  (Fig.50e)   Apterae are yellowish white to whitish green (darker at colder temperatures); BL 0.8-1.5 mm. Alatae have a black dorsal abdominal patch and secondary rhinaria distributed III 31-36, IV 11-15, V 0-4. On undersides of leaves of  certain labiates, especially Clinopodium vulgare and Teucrium spp., and also recorded from Scabiosa columbaria (Dipsacaceae) and Lithodora diffusa (Boraginaceae); the same plant families as O. boraginacearum, but with different preferred hosts. There are records from England, Wales, Denmark, France, Spain, Italy, Germany, Austria, Turkey, and it is also reported from Kazakhstan (Kadyrbekov 2009a, 2012a). Apparently there is no sexual phase.

Ovatomyzus stachyos Hille Ris Lambers  (Fig.50d)   Apterae are pale greenish white; BL 1.0-1.5 mm. Alatae have a dark dorsal abdominal patch and secondary rhinaria distributed III 26-44, IV 10-23, V 0-8. On Stachys spp., living dispersed on undersides of older leaves, often hidden under hairs. In western Europe (Denmark, Sweden, UK, France, Netherlands, Portugal). Apparently there is no sexual phase. [Apterae collected from an unidentified climbing plant in China, with 4-segmented antennae and capitate hairs on head and eighth abdominal tergite, were identified as fundatrices of O. stachyos by Su & Qiao (2012), but the identity of these aphids needs further confirmation, for example by biological studies.] 2n=12.

 

Ovatus van der Goot

Aphidinae: Macrosiphini

About ten palearctic species of Myzus-like aphids, three of which host-alternate between Pyroideae and Lamiaceae, while the others live all-year-round on the former secondary hosts. The alatae usually have more rhinaria than Myzus, and have no black central abdominal patch.  There are accounts for Europe (Heinze 1960, Müller 1969b), Fennoscandia and Denmark (Heie 1994), UK and Ireland (Blackman 2010), Japan (Miyazaki 1971) and Korea (Lee et al. 2002). The native American species previously placed in Ovatus have been transferred to a new genus, Abstrusomyzus (Jensen & Stoetzel, 1999). For the economically important species see Blackman & Eastop 2000, p.314-5.

Ovatus archangelskajae Kadyrbekov   Apterae are whitish, with reddish eyes; BL 1.4-1.6 mm. Alatae are undescribed. On leaves of Mentha longifolia in south-east Kazakhstan (Kadyrbekov 2008).

Ovatus crataegarius (Walker)  Plate 17i   Apterae in spring colonies are yellowish green to mid- or darkish green (see influentialpoints.com/Gallery); BL 1.4-2.4 mm. They feed on the undersides of young leaves of Pyroidea (Crataegus, Cydonia or Malus), without causing leaf deformation. Alatae have secondary rhinaria distributed III 11-52, IV 2-24, V 0-9. They migrate to found colonies on the undersides of leaves of Mentha and some other Lamiaceae (Melissa, Nepeta). Apterae on secondary hosts are yellowish green, mid- to pale green or greenish white, BL 1.0-1.9 mm. Colonies may also persist into the summer months on the primary host, e.g. on pruned hawthorn hedges. The return migration to Crataegus occurs in September. Anholocyclic overwintering occurs on secondary hosts where climatic conditions permit. Presumably European in origin, O. crataegarius is now almost world-wide. However, in Japan, and possibly also in Korea, similar aphids occur on Cydonia, Malus and Chaenomeles sinensis, but not on Crataegus and Mentha, so could be a separate taxon, for which the name malicolens Hori is available. 2n=12.

Ovatus glechomae Hille Ris Lambers    Apterae are rather dark, dirty brown or brownish green, usually darker laterally; BL 1.4-2.0 mm. Alatae have secondary rhinaria distributed III 10-14, IV 5-9, V 2-5.  Living in small colonies at soil level on etiolated stems and runners of  Glechoma hederacea, usually under stones. In north-west Europe (Netherlands, England, northern Germany, Sweden). Monoecious holocyclic, with  oviparae and apterous males in September-October.

Ovatus insitus (Walker)    Apterae in spring colonies are greenish-white, paler than O. crataegarius, rather shiny; BL 1.6-2.6 mm. They are found on undersides of young leaves of Crataegus spp. or Mespilus germanica, sometimes on Cydonia, Pyrus or Sorbus.  Alatae have secondary rhinaria distributed III 25-83, IV 9-57, V 1-24. Migration occurs in June to stem bases or rhizomes of Lycopus spp., especially L. europaeus. Apterae on Lycopus are shining green or greenish white, with later generations in August becoming mottled brown with dark siphunculi; BL 0.9-1.8 mm. In Europe, south-west and central Asia, and Siberia. The relationship between the very closely related O. insitus and O. crataegarius was studied by Müller & Hubert-Dahl (1979) and Müller (1980); there appears to be little or no gene flow between them although they sometimes form mixed colonies on the same primary host plant. O. lycopi (Nevsky) is closely related and possibly a synonym. 2n=12.

Ovatus (Ovatoides) inulae (Walker)  (Fig.34d,e)  Apterae are yellow to lemon yellow or pale green; BL 1.0-1.6 mm. On undersides of leaves, shoot apices and flowers of Pulicaria  dysenterica and Inula spp., and also recorded from several other composite genera (Adenostyles, Galactites, Helichrysum). Widely distributed in Europe (England, Belgium, France, Germany, Portugal, Italy, Yugoslavia, Russia), in North Africa (Tunisia; Boukhris-Bouhachem et al. 2007), eastward to Turkey and Central Asia. Monoecious holocyclic, with alate males (Schouteden 1900). Alate males and small pale yellow oviparae occur in England in October.

Ovatus malisuctus (Matsumura)  Apterae are dark yellowish brown to brownish green with black siphunculi and distal halves of femora; BL 1.0-1.7 mm.  Immatures are shiny yellow (Moritsu 1983).  Curling young leaves of Malus spp. (baccata, domestica, halliana, sieboldii) and Chaenomeles japonica.  In China, Japan, Korea, Taiwan, and also recorded from Georgia (as Myzus chaenomelis Dzhibladze).  There is no host alternation.  Population ecology and control have been studied in Japan and Korea (e.g. Takeda 1979, Kim et al., 1986), including interactions with predators (Hukusima 1963).  2n=12 (Chen & Zhang 1985b).

Ovatus mentharius (van der Goot)    Apterae are greenish white or pale green with darker green markings (see influentialpoints.com/Gallery); BL 1.2-1.8 mm. Alatae have secondary rhinaria distributed III 12-21, IV 7-11, V 0-5. On undersides of leaves of Mentha spp.  Monoecious holocyclic with alate males. In Europe and the Middle East; it has also been identified to occur in the United States where samples on Mentha dating back to 1935 had previously been recorded as O. crataegarius, but possibly without establishment except in glasshouse situations (G.L. Miller et al. 2007)..

Ovatus minutus (van der Goot)    Apterae are bright yellow; BL c.1.3 mm. In curled top leaves, probably of Coleus aromaticus (= Plectranthus amboinicus), in Java. [Aphids from Leonurus sibiricus in Meghalaya, India, provisionally identified as minutus (A.K. Ghosh & Raychaudhuri 1972), were probably Myzus ornatus.]

Ovatus nipponicus Takahashi    Apterae are yellow; BL c.1.7-1.9 mm. On Mentha sp(p). in Japan, and also collected in Korea on Mentha canadensis (BMNH collection, leg. W.H. Paik). Apparently this species is at least partially anholocyclic; viviparae occurred in December and March, and an ovipara was found in late March (original description).