Biology, images, analysis, design...
|"It has long been an axiom of mine that the little things are infinitely the most important" |
Periphyllus AphidsOn this page: Periphyllus acericola aceris californiensis hirticornis lyropictus negundinis obscurus testudinaceus
Periphyllus are medium-sized to large elongate oval or pear-shaped aphids which may be winged or wingless. The dorsum is mainly membranous (unsclerotized) but there are many small hair-bearing plates. The siphunculi are stump-shaped with a pronounced flange. The cauda at the tip of the abdomen is either rounded or tongue-shaped with a slight constriction. Antennal hairs are usually long and conspicuous.
There are about 42 species of Periphyllus aphids mostly living on maples and sycamore (Acer spp) in the Aceraceae. They have a sexual stage in the life cycle, but do not host alternate. Some species are usually ant-attended. They show seasonal polymorphism to cope with physiological changes in the host with several species having an aestivating nymphal stage which is often flattened and hairy.
Periphyllus acericola (Sycamore periphyllus aphid)
Adult Periphyllus acericola apterae are pale green or yellowish green, with darker green flecks and sometimes with dorsal brownish markings (see first picture below). The tips of the antennal segments are dark and the terminal process is 2.3 - 3.0 times longer than the base of the last antennal segment. The longer of the two hairs on the base of antennal segment VI is more than half as long as the base of antennal segment VI (cf. Periphyllus testudinaceus and Periphyllus californiensis
which have the longer of the two hairs on the base of antennal segment VI less than half as long as the base of antennal segment VI) . The head and pronotum are pale as are the legs and the siphunculi. The siphunculi are stump shaped, their lengths a little less than their basal diameters. The width of the base of the cauda is more than twice the length of the cauda. The adult Periphyllus acericola aptera body length is 2.4-3.5 mm.
Periphyllus acericola alates (see second picture above) have broad dark dorsal abdominal cross-bars scarcely separated between segments. The pterostigmata of the wings are very black and darker than the marginal sclerites (cf. Periphyllus testudinaceus which has the pterostigma of the wing paler than the marginal sclerites). The adult alate body length is 3.0-3.5 mm. The Periphyllus acericola fundatrix is greenish-brown and strongly hairy with numerous black tubercles. It is unusually large, with a body length of up to 4.5 mm.
The sycamore periphyllus aphid is found on the undersides of leaves, petioles and young shoots of Sycamore (Acer pseudoplatanus). It is sometimes attended by ants. Periphyllus acericola is found through most of Europe.
Periphyllus aceris (Maple periphyllus aphid)
Periphyllus aceris apterae are yellow with green flecks dorsally (see first picture below). The head, pronotum and legs (except tarsi) are pale (cf. Periphyllus testudinaceus which has the hind tibia with a pale middle region contrasting with a dark base and distal section). The antennae have a terminal process that is 2.2-2.7 times as long as the last antennal segment. The siphunculi are pale and short - about 2.1 - 2.5 times as long as the cauda. The cauda is broadly rounded and distinctly shorter than the width of its base (cf. Periphyllus lyropictus which has a tongue-shaped cauda, about as long as broad). The body length is 1.5-3.7 mm.
Periphyllus species are most readily differentiated using characters on the alates. Periphyllus aceris alates (see second picture above) have widely separated dorsal cross-bands (cf. Periphyllus acericola alates which have broad dark dorsal abdominal cross-bars scarcely separated between segments). The marginal sclerites and the pterostigma are equally dark (cf. Periphyllus testudinaceus which has the cross-bands and marginal sclerites darker than the light brown pterostigma of the wing). The alate body length is 3.2-4.5 mm.
Periphyllus aceris lives on the undersides of leaves, petioles and growing shoots of Acer species, especially Acer platanoides (Norway maple). It is not usually attended by ants. The species is found throughout most of Europe, but has apparently not so far established itself in North America.
Periphyllus californiensis (Californian maple aphid)
Periphyllus californiensis apterae (see first picture below) are reddish brown to dark olive-green. The length of the antennae is about 0.6 times the body length, with the terminal process about twice as long as the last antennal segment.The broken dorsal cross bands are dark as are the head, pronotum, and siphunculi. The siphunculi are about as long as the second hind tarsal segment. The hind femur and tibia are uniformly dark (cf. Periphyllus testudinaceus where the tibiae have a very pale middle section which contrasts with their dark base and tip). The cauda is broadly rounded with 8-12 hairs. The body length is 2-3 mm.
The Californian maple aphid is not indigenous to Europe (nor to California), but is from East Asia. Periphyllus californiensis has proved highly invasive and has spread to Europe, North America, Australia and New Zealand on planted Asian ornamental maples such as smooth Japanese maple (Acer palmatum) and downy Japanese maple (Acer japonicum).
Periphyllus hirticornis (Green maple periphyllus aphid)
Periphyllus hirticornis apterae are light green or yellow-green with red eyes and no dark markings. The antennae are 0.7 times the body length, and have a terminal process that is 5 times as long as the base of the last antennal segment. The two hairs on the base of antennal segment 6 are very unequal in length with the longer hair more than 4 times as long as the shorter (cf. Periphyllus obscurus which has the two hairs on the base of antennal segment 6 both long and fine, the longer one being 1.3-3.0 times the shorter). Some dorsal hairs have forked apices. The siphunculi are pale, longer than the second hind tarsal segment and strongly flared at the apex (cf. Periphyllus aceris, Periphyllus acericola, Periphyllus obscurus and Periphyllus testudinaceus, which do not have the siphunculi strongly flared at the apex). The cauda is knobbed with 6-8 hairs, and is more than half as long as its basal width. The body length is 2-3 mm.
Periphyllus hirticornis alates are bright green with variably developed marginal plates, no dorsal cross bands, and brownish siphunculi and cauda.
The green maple periphyllus aphid lives on the undersides of young leaves, leaf petioles and developing seeds of field maple (Acer campestre). Colonies are often attended by ants. Aestivating nymphs with foliate (=leaf-like) marginal hairs are present in summer. oviparae and alate males are produced in October-November. Periphyllus hirticornis is widely distributed in Europe.
Periphyllus lyropictus (Norway maple periphyllus aphid)
Periphyllus lyropictus apterae (see first picture below) are yellowish with brown dorsal markings, usually comprising a broad spinal stripe on head and thorax and a large V-shaped mark on the dorsal abdomen. The terminal process of the sixth antennal segment is 4.5-6.0 times longer than the base of that segment. The antennal and dorsal hairs are acute and fine pointed. The siphunculi of the Periphyllus lyropictus aptera are pale to dusky, conical, and about as long as their basal widths. The cauda is tongue shaped, about as long as broad, and often with a slight constriction (cf. Periphyllus testudinaceus where the cauda is clearly shorter than its basal width). The body length is 1.9-3.0 mm.
Periphyllus lyropictus alatae (see second picture above) have dark marginal sclerites, but other dorsal sclerotization is limited to the spinal area, not forming cross-bands. The shorter hair on the basal part of the sixth antennal segment is 0.025-0.04 mm long (cf. Periphyllus hirticornis which has this hair 0.019-0.025 mm long). The siphunculi are 0.17-0.23 mm long (cf. Periphyllus hirticornis where the siphunculi are 0.21-0.28 mm long).
The Norway maple aphid lives on the undersides of leaves of Norway maple (Acer platanoides). They often form large colonies producing much honeydew and are visited by ants and other insects. Periphyllus lyropictus does not produce aestivating nymphs. Oviparae and alate males are produced in October-November. The Norway maple periphyllus is native to Europe, but it was introduced on Norway maple to North America, where it is now also widespread.
Periphyllus negundinis (Boxelder aphid)
Adult apterae of Periphyllus negundinis (see right in first picture below) are pale yellow-green to apple-green with a darker green stripe on each side of the dorsum, but with no clear pattern of dorsal dark markings (cf. Periphyllus californiensis, which has a clear pattern of dorsal dark markings, either bars or paired spots). The antennal terminal process is 2.5-3.0 times the length of the base of antennal segment IV. The longest hair on the base of antennal segment VI is always less than half as long as the base of that segment (cf. Periphyllus californiensis, which has the longest hair on base of antennal segment VI usually more than half as long as base of that segment). The tibiae are rather uniformly pigmented, dusky or dark (cf. Periphyllus testudinaceus, which has the tibiae with the middle part much paler than the base or distal section). The siphunculi are short and pale.
Both images above by permission, copyright Claude Pilon, all rights reserved.
Alatae (see second picture above) have the head and thorax brown, and rather variable dark green dorsal abdominal markings, but no distinct cross-bands. They have 3-10 secondary rhinaria on antennal segment III. The short siphunculi of the alatae are dusky.
Periphyllus negundinis is monophagous on boxelder (Acer negundo), feeding on young growth in or near fruit clusters in spring, and later on the undersides of leaves. Aestivating nymphs have foliate (=leaf-shaped) marginal hairs. Dark green apterous males and mottled green oviparae are reported to occur in October-November (see picture of ovipara in AphidTrek). They are commonly attended by ants (see picture above). It has been noted that at times this "plant louse becomes so abundant on boxelder in Illinois that it is exceedingly obnoxious, for the honeydew covers the sidewalks beneath infested trees." Periphyllus negundinis is widely distributed in North America including Mexico.
Periphyllus obscurus (Dark periphyllus aphid)
The adult aptera of Periphyllus obscurus is rather small and blackish green. The terminal process of the antenna is 3.2-6.9 times the length of the base of the last antennal segment. The hind tibiae are more or less pale throughout (cf. Periphyllus testudinaceus which has tibiae with a contrasting dark base and distal section). The siphunculi are dark and only about as long as the basal width. The cauda is rounded with a constriction near its base and is more than half as long as its basal width. The body length is 1.8-2.6 mm.
The dark periphyllus aphid is found on young shoots, leaf petioles and undersides of leaves of field maple (Acer campestre). Aestivating nymphs are not produced, and all stages are present through the summer (cf. Periphyllus testudinaceus which spends mid-summer as aestivating nymphs). Colonies are usually attended by ants. Oviparous females and males are produced in the autumn. Periphyllus obscurus is found in central and western Europe.
Periphyllus testudinaceus (Common periphyllus aphid)
Periphyllus testudinaceus apterae are dirty dark green to dark brown or blackish and have a clear pattern of dark abdominal sclerites (see first picture below). The antennae have a terminal process that is 2.5-3.7 times as long as the last antennal segment. The siphunculi are brown and short. The tibiae have a very pale middle section which contrasts with their dark base and tip (cf. Periphyllus obscurus which has tibiae which are are more or less pale throughout). The cauda is twice as broad as long. The body length of Periphyllus testudinaceus is 2.0-3.7 mm.
Periphyllus testudinaceus alates (see second picture above) have dark dorsal abdominal cross-bands and marginal sclerites, which are darker than the light brown pterostigma of the wing (see second picture above).
The common periphyllus aphid is found on the young growth, leaves and leaf petioles of various Maple species (Aceraceae) including Field Maple (Acer campestre), Norway Maple (Acer platanoides) and Sycamore (Acer pseudoplanatus) as well as sometimes on Horse Chestnut (Aesculus hippocastaneum). It is often attended by ants. Periphyllus testudinaceus is found throughout Europe and has been introduced to other parts of the world including New Zealand and North America.