Hosts or Prey
Eggs of leafhoppers that infest grapevines and certain other plants
Identification
Mymaridae are commonly called fairyflies because of their tiny size. The most obvious evidence of their presence is that the generally pale eggs of leafhoppers commonly change color (e.g., turn reddish) when an Anagrus larva or pupa is present inside. When the adult Anagrus emerges it leaves a round hole in the host egg and tiny dark fecal pellets (meconium) can be visible inside. When a leafhopper emerges the hole is commonly ragged and the egg shell is empty.
Adult Anagrus are about 1/50 inch (0.5 mm) long and blackish, brown, orange, yellow, or a mix of these varying by gender and species. The wings are relatively long and fringed with fine hairs that allow adults to float long distances with the wind.
The eggs, larvae, and pupae occur hidden in leafhopper eggs, which are embedded in plant parts. Anagrus eggs are less than 1/100 inch (0.25 mm) long. They are ovoid with a distinct stalk. Once the egg hatches and the larva feeds and grows, it causes the normally pale leafhopper egg to become distinctly colored.
The first instar (larva) Anagrus is elongate with about six apparent segments. The head of the maggotlike instars (larvae) has distinct mouthparts.
The pupa is oblong and tapered toward the rear. As it ages it develops distinct appendages that are folded against the body. After completing pupation the emerging adult chews a round hole in the leafhopper egg and surface of the plant in which the host is embedded.
Life Cycle
Anagrus develop through 4 life stages: egg, larva, pupa, and adult. The adult female searches for leafhopper eggs in which to deposit her eggs. If more than 1 Anagrus egg was laid in the same host egg, commonly the larvae will fight and only 1 survives to maturity. The adult female parasitizes about 20 to 40 eggs during her lifespan of about 1 week. After hatching from an egg, the larva develops through about 3 increasingly larger instars.
Some Anagrus species are parthenogenetic, they are all females and reproduce without mating. Other Anagrus species have males and females.
Overwintering in cold locations is as an adult in organic litter or other protected places. In most of California where winters are mild, overwintering is as immature stages within eggs of leafhoppers. Anagrus species have several generations per year.
Habitat
Anagrus species and spiders are the most important natural enemies of Erythroneura and Erasmoneura species leafhoppers that infest California vineyards. Anagrus hosts include variegated leafhopper, Virginia creeper leafhopper, and western grape leafhopper.
Anagrus parasitoids can be more abundant in vineyards that are adjacent to riparian areas and unmanaged vegetation. Where freezing temperatures are uncommon, Anagrus overwinters as mature larvae inside eggs of leafhoppers on these alternative hosts while grapevines and other deciduous hosts are leafless.
To improve biological control
- Control ants because they attack natural enemies of various pests.
- Grow flowering insectary plants to provide nectar to nourish adult natural enemies.
- Reduce dustiness that disrupts the activities of natural enemies (e.g., irrigate overhead or periodically hose off small plants).
- Avoid the application of broad-spectrum, persistent insecticides for all pests because they are toxic to natural enemies.
For more information see Protecting Natural Enemies and Pollinators and the table of relative toxicities of insecticides and miticides to natural enemies and honey bees for specific crops.
Species
Various Anagrus species have been introduced around the world to provide biological pest control. At least 14 Anagrus species occur in California: Anagrus armatus, A. atomus, A. avalae, A. columbi, A. daanei, A. delicatus, A. epos, A. erythroneurae, A. flaveolus, A. nigriventris, A. puella, A. sophiae, A. subfuscus, and A. tretiakovae. Each parasitizes multiple species of leafhoppers. For example A. epos parasitizes at least 21 species of leafhoppers.
More Information
- Anagrus Fairyflies (Hymenoptera: Mymaridae), Encyclopedia of Entomology
- Catalog of Hymenoptera in America North of Mexico. Vol. 1: Symphyta and Apocrita (Parasitica), U.S. Department of Agriculture
- Introduced Parasitoids and Predators of Arthropod Pests and Weeds: A World Review, U.S. Department of Agriculture
- Key Parasitoid of VCLH: Anagrus daanei, Virginia Creeper Leafhopper (VCLH) Areawide Project, UC Agriculture and Natural Resources
- Native Grass Ground Covers Provide Multiple Ecosystem Services in Californian Vineyards, Journal of Applied Ecology
- Morphological and Molecular Differentiation of the Anagrus epos Species Complex (Hymenoptera: Mymaridae), Egg Parasitoids of Leafhoppers (Hemiptera: Cicadellidae) in North America (PDF), Zootaxa
- Taxonomy of the Genus Anagrus Haliday (Hymenoptera: Mymaridae) of the World: an Annotated Key to the Described Species, Discussion of the Remaining Problems, and a Checklist (PDF), Acta Zoológica Lilloana
- Universal Chalcidoidea Database, Natural History Museum of London
Scientific classification:
- Phylum: Arthropoda
- Class: Insecta
- Order: Hymenoptera
- Family: Mymaridae
