Periphyllus californiensis

(Shinji, 1917)

California maple aphid, Japanese maple aphid

Periphyllus californiensis is an native to East Asia (Japan, China, Korea, Taiwan, Russian Far East) that has established in North America, Australia, New Zealand, and Europe. It is a feeder on maple trees (Acer spp.), with documented including Acer palmatum, A. japonicum, A. amoenum, and numerous other maple species. The species exhibits complex phenological synchrony with host trees, producing distinct larval morphs—non-summer- larvae on unexpanded leaves and summer-diapause (aestivating) dimorphs on expanded leaves—based on host plant nutritional quality rather than genetic . High mortality (>99.9%) of summer dimorphs has been observed, with survivors resuming activity in autumn. The species has been recorded in Poland since 2009 and spreads via ornamental maple trade.

Periphyllus californiensis by (c) Bill Keim, some rights reserved (CC BY), uploaded by Bill Keim. Used under a CC-BY license.

Pronunciation

How to pronounce Periphyllus californiensis: //ˌpɛrɪˈfɪləs ˌkælɪˌfɔːrniˈɛnsɪs//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from Periphyllus testudinaceus by uniformly black hind tibiae (P. testudinaceus has pale tibiae with dark apices). Aestivating dimorphs with foliate marginal hairs appear in June. and females described in taxonomic literature; specific morphological characters for -level identification require microscopic examination.

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Habitat

Specialized on maple trees (Acer spp.). Colonies form on undersides of leaves along , typically in small . Spring feeding restricted to buds, growing shoots, and inflorescences. Summer occurs on leaves or key-fruits (samaras). Autumn utilize key-fruits in October, leaves in November, and twigs in December.

Distribution

Native to East Asia: Japan (type locality), China, Russian Far East, Korea, Taiwan, India. Introduced and established in: North America (first described from California, USA), Australia, New Zealand, and Europe (England, Netherlands, Italy, Denmark, Croatia, Germany, Switzerland, Belgium, Poland). In Poland, recorded from the Botanic Garden of the Jagiellonian University, Kraków, in 2009 and 2010.

Seasonality

Active year-round on maple trees. Spring begins with hatching synchronized to budburst; stem mothers lay larvae for approximately 9 days after leaf of Acer palmatum. Winged females appear in spring (laying larvae for ~6 days on A. amoenum leaves, ~8 days on inflorescences) and again in November for autumn . Aestivating dimorphs present in summer (May–September), becoming active in October. Oviparae produced after mid-November.

Diet

Phloem sap from maple leaves (Acer spp.). Feeding success depends on nitrogen content of tissue: unexpanded leaves, inflorescences, and young shoot tips provide high-quality nutrition, while fully expanded leaves are nutritionally inferior and trigger production of aestivating dimorphs.

Host Associations

  • Acer palmatum - primary Stem mothers lay larvae on unfurling leaves for ~9 days after
  • Acer japonicum - primary Documented in native and introduced ranges
  • Acer amoenum - primary Winged females lay larvae on leaves for ~6 days after ; inflorescences used for ~8 days from 3–11 days after emergence
  • Acer campestre -
  • Acer carpinifolium -
  • Acer circinatum -
  • Acer macrophyllum -
  • Acer miyabei -
  • Acer mono -
  • Acer negundo -
  • Acer oblongum -
  • Acer platanoides -
  • Acer pseudosieboldianum -
  • Acer turbinata -
  • Aesculus californica - Anomalous record; possibly erroneous or occasional

Life Cycle

Holocyclic and (complete on single ). Overwinters as . Spring: fundatrices (stem mothers) hatch and reproduce viviparously on new growth. Phenotypically plastic larval production: non-summer- larvae produced on unexpanded leaves with high nitrogen content; summer-diapause (aestivating) dimorphs produced on expanded leaves with low nitrogen content. This morph determination is environmentally cued, not -fixed. Summer: >99.9% mortality of aestivating dimorphs observed; survivors resume activity in October. Autumn: utilizes key-fruits, then leaves, then twigs sequentially; winged females appear in November and disperse. Oviparae (egg-laying females) produced after mid-November, completing cycle.

Behavior

Forms small colonies on leaf undersides along . Exhibits phenotypically plastic reproductive strategy: individuals can switch between producing summer- and non-summer-diapause offspring when moved between expanded and unexpanded leaves. Active by winged females in spring and autumn; autumn dispersal necessary for individuals on trees that shed leaves before mid-November to reach suitable sites for ovipara production. on autumn foliage influenced by leaf color: many offspring produced on orange-yellow foliage, few on red foliage.

Ecological Role

phytophagous insect on maples. Serves as for including Aphidius areolatus. High summer mortality of aestivating dimorphs attributed primarily to unidentified . As , potential pest of native and ornamental Acer ; size limited by phenological synchrony with host budburst.

Human Relevance

pest of ornamental maple trees in botanic gardens and urban plantings. Spread facilitated by international trade in Acer palmatum, A. japonicum, and other ornamental maples. dependent on synchronization between and tree ; poor synchrony results in small populations. Monitoring and management relevant to horticultural and arboreal industries.

Similar Taxa

More Details

Phenological Synchronization

success heavily dependent on synchrony between and tree budburst. Large between- and between-year variation in budburst timing can cause population failures, as observed in 1985.

Aestivation Mortality

Mean of 185 dimorphs per 40 cm branch recorded in May 1984; >99.9% mortality by autumn across three consecutive years (1982–1984). Mortality not density-dependent; slightly lower on key-fruits than leaves.

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Sources and further reading