Biology, images, analysis, design...
|"It has long been an axiom of mine that the little things are infinitely the most important" |
Green maple periphyllus aphidOn this page: Identification & Distribution Biology & Ecology Other aphids on the same host Damage & Control
Identification & Distribution
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 (see the fourth image below) 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 micrographs below show (1) an adult vivipara dorsal (2) the hairs on the base of antennal segment VI, and (3) an ovipara dorsal of Periphyllus hirticornis in isopropyl alcohol.
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.
Biology & Ecology
We have not found Periphyllus hirticornis to be generally common, but when and where it does occur, it can be abundant. Stroyan (1977) notes the species may be locally common but is little recorded.
Their eggs hatch early in spring to give the fundatrices. The body of the fundatrix (see pictures below) is pinky brown, quite unlike the bright green offspring that the fundatrix will produce (Toros, 1982). The siphunculi, cauda and legs are lighter than the body, and the eyes are bright red. The body is coated with long coarse hairs on dark sclerites. The fundatrix is larger than viviparous apterae, with an adult body length up to 3.3 mm.
The fundatrices give birth viviparously to large numbers of young nymphs. The pictures below show (first) a first instar fundatrigenia in April, and (second) a developing colony of Periphyllus hirticornis on field maple in April.
These mature to bright green adult apterae (see pictures below) which reproduce parthenogenetically to rapidly increase the population density.
Some nymphs produced in late spring aestivate rather than develop immediately. Aestivating nymphs, shown below, are light green with leaf-like marginal hairs and red eyes.
The image below shows normal nymphs in late June.
In autumn Periphyllus hirticornis produce sexuales. The males are green and alate, with a strong abdominal sclerotic pattern comprising a black dorsal bar on each segment. The secondary rhinaria on the antennae are in a dense and irregular arrangement.
The oviparae are more variable in colour than the viviparae, mostly ranging in colour from green to brown (see pictures below). After mating, the oviparae lay their eggs on the stems of field maples.
Unusual colour forms may arise more often in aphids in the Drepanosiphinae than in other subfamilies - see for example the golden-yellow colour form of Chaitophorus populeti.
Other aphids on same host:
Periphyllus hirticornis has been recorded from 2 Acer species (Acer campestre, Acer monspessulanum).
Blackman & Eastop list 22 species of aphid as feeding on field maple (Acer campestre) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 17 as occurring in Britain (Show British list).
Damage and control
Since field maple is not grown for wood, the green maple periphyllus aphid is seldom considered a pest. However in gardens and urban streets it can cause aesthetic damage because of honeydew production (Pons et al., 2003).