Biology, images, analysis, design...
|"It has long been an axiom of mine that the little things are infinitely the most important" |
Maple periphyllus aphidOn this page: Identification & Distribution Biology & Ecology Other aphids on the same host Damage & Control
Identification & Distribution:
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.
Biology & Ecology:
Overwintering eggs of Periphyllus aceris hatch in early spring and the fundatrices settle the buds and lignified shoots of maple. The fundatrices vary in colour from a dirty green to a reddish brown as shown below.
The offspring of these fundatrices initially feed on the young stems with the parent fundatrix as shown below.
Periphyllus aceris is not usually attended by ants, but it appears that they may be early in the year when there are doubtless very few aphid species producing honeydew in any quantity. In May they move to the leaves.
These develop into both apterae and alates which in turn produce a generation of diapausing nymphs. The picture below is a close up of large group of aestivating nymphs of Periphyllus aceris on the underside of the leaf. They are creamy in colour and very hairy, much like the aestivating nymphs of Periphyllus acericola, although there are minor differences in the shape of some hairs on the tarsal segments.
Mackos (2008) reports these nymphs form the gatherings immediately after birth. Several gatherings may be found on one leaf with about 40-50 larvae in each. Their heads are turned towards the middle of the circle. He records how in situations of danger such as the approach of coccinellids they may disperse on the leaf, only re-aggregating when danger has passed.
The first image shows the distribution of groups of aestivating nymphs on a leaf of Acer platanoides (Norway Maple). They appear to be concentrated around the edge of leaf, possibly because there are fewer risks of a predator attack (although also fewer options of escape). A few of the nymphs at the edges of the groups are much darker than the others - these are shown in close up in the second image. They appear to have been killed by a fungus which contributes to the mortality of nymphs during aestivation. Furuta (1985) recorded a very high (99.9 %) mortality rate of a related American species during aestivation, mainly resulting from predation.
The aestivating nymphs resume development in late summer and mature to oviparae shown in the picture below.
Other aphids on same host:
Periphyllus aceris has been recorded from 7 Acer species.
Damage and control
Norway Maple is widely used as an urban street and shade tree due to its tolerance of poor soils and urban pollution. As such, when aphid populations are high, deposits of honeydew may reach nuisance levels. The aphids also presumably reduce tree growth, although no studies have specifically addressed this for Periphyllus aceris.