Neurotoma

Taxonomy

Family: Pamphiliidae
Family common name: web-spinning and leaf-rolling sawflies
Subfamily: Pamphiliinae
Tribe: Neurotomini
Genus: Neurotoma Konow, 1897
Subgenera: none

Background

The Pamphiliidae are called the web-spinning and leaf-rolling sawflies because of larval shelter-building behavior (Goulet 1992).

Neurotoma are web-spinners that spin silk while they feed. Adults are medium-sized, usually patterned, and often colorful. They feed on cherry, plum, peach, almond, and hawthorn trees in North America (Middlekauff 1958).

Diversity

There are 22 described species worldwide restricted to the Northern Hemisphere. Five species occur in North America, including the introduced N. edwardi (Taeger et al. 2010).

A key to North American species of Neurotoma is included in Middlekauff 1958.

Diagnostic characteristics

May be confused with

Pamphiliidae are recognized by a somewhat quadrate head and tarsal claws with inner teeth. Neurotoma can be distinguished from Pamphilius and Onycholyda by the lack of fore wing vein Sc1 and the lateral ocellar furrow, and from other genera in the family by the obviously bifid claw, in contrast to a small inner tooth (Goulet 1992).

Exotic pest species of concern

One Japanese species, N. harai, is unique in that it feeds on Quercus sp. (oak) trees rather than Rosaceae. It is not generally considered a pest in its native range (Shinohara et al. 2018).

Host associations

Larvae feed on plants of the family Rosaceae, including Prunus serotina (black cherry), P. pennsylvanica (pin cherry), P. americana (American plum), P. domestica (European plum), P. nigra (Canada plum), P. besseyi (sand cherry), P. cerasus (sour cherry), P. tenella (dwarf Russian almond), P. davidiana (Chinese wild peach), Crataegus succulenta (fleshy hawthorn) and C. brainerdi (Brainerd’s hawthorn) (Middlekauff 1958).

Life history

Females insert eggs singly or in groups on the underside of leaves alongside a vein. Eggs are long and white/gray. After hatching, larvae spin webs of silk, frass, and leaf matter in which they feed, safe from predators. Some species feed gregariously, others singly in small individual webs on flower buds or leaves. Mature larvae fall to the ground and burrow into the soil where they overwinter. Pupation and emergence occur in the spring. Neurotoma is generally univoltine (Middlekauff 1958).

Neurotoma inconspicua is commonly called the plum web-spinning sawfly and was recorded as a pest in the early twentieth century. Gregarious larvae feed in groups of as many as 46 at a time, sometimes seriously damaging Prunus (cherry, plum) crops in the Midwest (Severin 1920).

Distribution

World: Neurotoma is known from Europe, including east through Russia and in East Asia, including Japan, Korea, China, and as far south as Thailand (Middlekauff 1988, Taeger et al. 2010, Shinohara et al. 2018).

North America: In North America, Neurotoma is found in the Northeast and Midwest United States and eastern Canada, as far west as eastern British Columbia in the north, and as far south as Virginia in the east (Middlekauff 1958, Middlekauff 1988).

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

Details about data used for maps can be found here.

Neurotoma fasciata female lateral habitus; photo by J. Orr, WSDA

Neurotoma fasciata female lateral habitus; photo by J. Orr, WSDA

Neurotoma fasciata female dorsal habitus; photo by J. Orr, WSDA

Neurotoma fasciata female dorsal habitus; photo by J. Orr, WSDA

Neurotoma fasciata female face; photo by J. Orr, WSDA

Neurotoma fasciata female face; photo by J. Orr, WSDA

Neurotoma fasciata male lateral habitus; photo by J. Orr, WSDA

Neurotoma fasciata male lateral habitus; photo by J. Orr, WSDA

Neurotoma fasciata male dorsal habitus; photo by J. Orr, WSDA

Neurotoma fasciata male dorsal habitus; photo by J. Orr, WSDA

Neurotoma fasciata male face; photo by J. Orr, WSDA

Neurotoma fasciata male face; photo by J. Orr, WSDA

Neurotoma saltuum wings; photo by J. Orr, WSDA

Neurotoma saltuum wings; photo by J. Orr, WSDA

Neurotoma saltuum  antenna; photo by J. Orr, WSDA

Neurotoma saltuum antenna; photo by J. Orr, WSDA

Neurotoma saltuum tarsal claw; photo by J. Orr, WSDA

Neurotoma saltuum tarsal claw; photo by J. Orr, WSDA