Pamphilius

Taxonomy

Family: Pamphiliidae
Family common name: web-spinning and leaf-rolling sawflies
Subfamily: Pamphiliinae
Tribe: Pamphiliini
Genus: Pamphilius Latreille, 1803
Subgenera: none

Background

The Pamphiliidae are called the web-spinning and leaf-rolling sawflies because of their shelter-building behavior as larvae.

The speciose genus Pamphilus is a leaf-roller of a variety of hosts. Larvae create rolled tubes of leaf matter and silk to live inside of for protection. The leaf rolls are fairly distinctive, and some species can be recognized by their tube morphology (Middlekauff 1964).

Diversity

There are 122 described species worldwide, all restricted to the Northern Hemisphere. Eighteen species occur in North America, including one introduced (Taeger et al. 2010).

A key to North American species of Pamphilius is included in Middlekauff 1964.

Diagnostic characteristics

May be confused with

Pamphiliidae are recognized by a somewhat large quadrate head, elongate filform antennae, and tarsal claws often with inner teeth. Pamphilius can be distinguished from Onycholyda by the absence of hooked setae in the malar space, and from other genera by the presence of fore wing vein Sc1 and the tarsal claw shape (Goulet 1992).

Exotic pest species of concern

One sawfly introduced to North America from central Asia, P. persicum, is recorded as a defoliating pest of Prunus persica (peach) trees in orchards in the early twentieth century (Walden 1907, Shinohara 1985b). Recently, however, no significant outbreaks resulting in high levels of damage have been reported.

Host associations

Larvae in North America feed on foliage of deciduous tree and shrub species of several families. Rosaceae hosts include species from: Amelanchier (serviceberry), Rubus (blackberry), Prunus (cherry, plum, peach), Malus (apple), and Rosa (rose). Hosts from other angiosperm families include species from: Siricidae sawflies; on tergite 10 in females, sternite 9 in males ">Cornus (dogwood), Corylus (hazel), Populus (cottonwood), Quercus (oak), Salix (willow), Betula (birch), Fagus (beech), and Viburnum (Middlekauff 1964).

Life history

Females oviposit eggs, singly or in groups of up to 12, on the underside of leaves alongside a vein. Eggs are slightly cylindrical and white. After hatching, the larva begins to roll the leaf into a tube-shaped nest. The leaf-tube shape varies across species and may be cone-shaped, corkscrew-shaped or comprising several leaves clumped together. In all cases, silk is used to cinch the leaf in the preferred position and hold the tube together. The larvae generally do not use thoracic legs for locomotion and instead use strands of silk to pull their body along a surface, or inch along like a worm. Mature larvae fall to the ground and burrow into the soil at a depth of 2–6 inches where they press surrounding soil into a cell and overwinter. Pupation and emergence occur in the spring (Middlekauff 1964, Shinohara and Byun 1993).

Adults fly on sunny days during the spring and summer. Some adults may feed on pollen and have been observed visiting flowers of strawberry. Pamphilius is generally univoltine, although there are records of an occasional two-year life cycle (Middlekauff 1964).

Distribution

World: The genus is widespread and common from central Europe and Scandinavia, east to Siberia, and also occurs in Asia (Van Achterberg and Van Aartsen 1986).

North America: Pamphilius are known from forested regions, generally the United States Northwest, Northeast, and Southeast, and throughout southern Canada, as far north as Alaska (Middlekauff 1964, Lindquist and Harnden 1970).

Map data from: GBIF.org (26 June 2019) GBIF Occurrence Download Pamphilius

Details about data used for maps can be found here.

Pamphilius pacificus female lateral habitus; photo by J. Orr, WSDA

Pamphilius pacificus female lateral habitus; photo by J. Orr, WSDA

Pamphilius pacificus female dorsal habitus; photo by J. Orr, WSDA

Pamphilius pacificus female dorsal habitus; photo by J. Orr, WSDA

Pamphilius pacificus female face; photo by J. Orr, WSDA

Pamphilius pacificus female face; photo by J. Orr, WSDA

Pamphilius pacificus male lateral habitus; photo by J. Orr, WSDA

Pamphilius pacificus male lateral habitus; photo by J. Orr, WSDA

Pamphilius pacificus male dorsal habitus; photo by J. Orr, WSDA

Pamphilius pacificus male dorsal habitus; photo by J. Orr, WSDA

Pamphilius sp. male face; photo by J. Orr, WSDA

Pamphilius sp. male face; photo by J. Orr, WSDA

Pamphilius sp. fore wing; photo by J. Orr, WSDA

Pamphilius sp. fore wing; photo by J. Orr, WSDA

Pamphiliidae post-ocellar lateral furrows; photo by J. Orr, WSDA

Pamphiliidae post-ocellar lateral furrows; photo by J. Orr, WSDA