Hosts or Prey
Scale insects, mostly soft scales
Identification
The most obvious evidence this tiny wasp or its relatives are present is the blackening of scale nymphs that are generally brown, green, orange, or yellow. Parasitized scales develop a crusty, somewhat puffy (mummified) covering. After the wasp completes its development and emerges as an adult it leaves a rounded hole in the scale that remains darkened.
The adult C. lycimnia is about 1/25 inch (1 mm) long. The head and body are black except that adult females have a bright lemon yellow scutellum (shield-shape structure on the back of the thorax). The adult male is one-half as large as the female and has a dark (not yellow) scutellum. The bulging eyes are dark brown. The antennae are brown and the legs are black and yellowish.
Eggs, larvae, and pupae occur hidden inside host scales. The pale eggs are elongate oval to teardrop shaped with rounded ends. The pale larvae are maggotlike with distinct segments. The oblong pupae are initially pale but as they age blacken and develop distinct appendages folded against the body.
Life Cycle
Coccophagus lycimnia develops through four life stages: egg, larva, pupa, and adult. Adult female wasps investigate a scale by repeatedly touching it with their antennae. This commonly causes the scale to excrete a honeydew droplet, which the wasp consumes. Consuming honeydew increases adult parasitoid longevity.
Female C. lycimnia prefer to oviposit in second instar hosts. Her fertilized eggs produce females and unfertilized eggs produce male wasps. As the immature wasp develops it kills the scale and emerges as an adult before the host matures to a reproductive adult.
Adult female C. lycimnia also feed on hosts. During host feeding the female wasp punctures scale bodies with her ovipositor and consumes the exuding body fluids. Host feeding increases parasitoid longevity and the number of eggs females can lay. Scales that are host fed upon are killed without being parasitized.
Male C. lycimnia are less common than females. Unlike females that are parasitoids of scales, male C. lycimnia are parasitoids of immature female C. lycimnia or other wasps that parasitize the same hosts, such as Metaphycus species. This type of male biology is called autoparasitism.
Overwintering is as a larva in second instar scales. In late winter or spring the parasitoid pupates and emerges as an adult wasp. The adult lives about 2 weeks when temperatures are warm if honeydew and host scales are available for nutrition.
Egg to reproductive adult development time is 3 to 4 weeks when temperatures are warm. Coccophagus lycimnia has multiple generations per year.
Habitat
Coccophagus lycimnia can occur anywhere plants are infested with its host scales. The scale hosts are generally woody species, such as fruit and nut crops, residential fruit and landscape trees, ornamental shrubs, and woody wildland plants.
Coccophagus lycimnia takes only a few seconds to lay an egg. Therefore when ants that protect scales and attack parasitoids are present C. lycimnia can still be an effective natural enemy. In comparison many Metaphycus species that commonly parasitize many of the same hosts take a relatively long time to lay an egg. Therefore Metaphycus parasitism can be relatively low when ants are present.
To increase parasitoid abundance and biological control
- Control ants that attack natural enemies of scales and various other pests.
- Grow flowering insectary plants to provide nectar to nourish adult parasitoids and predators.
- 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 tips see Protecting Natural Enemies and Pollinators and Relative Toxicities of Pesticides Used in Almonds to Natural Enemies and Honey Bees.
Species
At least 26 Coccophagus species occur in California. Coccophagus lycimnia parasitizes over 100 species of scale insects, mostly soft scales but also certain pit scales. Economically important hosts of C. lycimnia include black scale, brown soft scale, citricola scale, and European fruit lecanium.
More Information
- Aphelininae of North America (PDF), U.S. Department of Agriculture
- Bionomics of Aphelinidae , Annual Review of Entomology
- Longevity and Fecundity of Coccophagus lycimnia (Walker) (Hymenoptera: Aphelinidae), a Primary Parasitoid of Coccus hesperidum (Homoptera: Coccidae), Journal of Agricultural Science
- Universal Chalcidoidea Database, Natural History Museum of London
Scientific classification:
- Phylum: Arthropoda
- Class: Insecta
- Order: Hymenoptera
- Family: Aphelinidae
