Phylloxeridae

Classification

Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Hemiptera
Suborder: Sternorrhyncha
Superfamily: Phylloxeroidea
Family: Phylloxeridae

Pronunciation

How to pronounce Phylloxeridae: //ˌfɪloʊˈzɛrɪˌdiː//

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

Images

Phylloxera pilosula by the Smithsonian. Used under a CC0 license.

Vacuna californica by the Smithsonian. Used under a CC0 license.

Phylloxera salicola by the Smithsonian. Used under a CC0 license.

Phylloxera deplanata by the Smithsonian. Used under a CC0 license.

Phylloxera perforans by the Smithsonian. Used under a CC0 license.

Summary

Phylloxeridae is a family of small, plant-parasitic hemipterans known as phylloxerans. They have complex life cycles, induce galls on host plants, and can be significant agricultural pests, particularly to grapevines.

Physical Characteristics

Phylloxerids are very small to minute insects with high polymorphism making identification difficult. They have a three-segmented antenna in all forms. Their wings are held flat over the body at rest, with stalked Cu1 and Cu2 veins at the base. Adult females may have one or two additional sensorium on the flagellum. Wingless ovipositing females and males have vestigial mouthparts. Immature nymphs resemble adults but lack secondary sensorium, and sexuales exhibit a non-feeding pupiform larva.

Identification Tips

Phylloxerans can be distinguished from adelgids by their vulva instead of a sclerotized ovipositor and the absence of wax glands. They are differentiated from aphids by having 3 forewing veins compared to 4-6 in aphids.

Habitat

Phylloxerans are parasitic on woody plants and herbaceous plants, residing within galls on host plants and crevices of barks.

Distribution

Phylloxeridae have a worldwide distribution, originating from moderate climates with greater diversity in temperate regions, adapting to tropical conditions secondarily.

Diet

Phylloxerans are plant-parasitic, feeding on leaves and roots of deciduous trees and perennial fruit crops.

Life Cycle

The life cycle of phylloxerans involves cyclical parthenogenesis and host alternation, starting with a female fundatrix hatching from an overwintering egg, stimulating gall formation on primary hosts, and migrating to secondary hosts in spring for further generations before returning in autumn.

Reproduction

Some species are holocyclic (producing both asexual and sexual generations), while others are anholocyclic (producing only asexual generations).

Ecosystem Role

Phylloxerids play a role in the ecosystems as parasites of plants, which can indirectly affect plant health and biodiversity.

Economic Impact

Phylloxerids can transmit diseases to plants, with Daktulosphaira vitifoliae, the grape phylloxera, being historically significant as it devastated European grapevines in the late 19th century. This led to the grafting of European vines onto American rootstocks.

Evolution

Phylloxeridae is part of the order Hemiptera, with a debated phylogenetic relationship to Adelgidae and Aphididae. Recent studies suggest independent evolution from these relatives.

Similar Taxa

Misconceptions

Due to morphological similarities, phylloxerans are often confused with aphids and adelgids, despite being distinct in several taxonomic and biological traits.