Hosts or Prey
Western flower thrips and various other thrips
Identification
The obvious indication that this wasp is present is a change in the appearance of parasitized thrips. When the thrips matures to the last instar the wasp larva inside causes the thrips to become swollen and tubular. The oblong, yellow to orange body of the immature wasp becomes visible through the host covering. Unlike unparasitized thrips that mature into a winged adult, parasitized thrips are killed before they mature.
The adult, mature larva, and pupa of C. menes are about 1/32 inch (0.8 mm) long, varying by host size. The adult has a black to dark brown head and thorax and red eyes. The abdomen varies from black to dark or light brown or yellow.
The parasitoid egg, larva, and pupa occur hidden inside host thrips. The egg is oval to teardrop shaped and about 1/1,000 inch (0.02 mm) long. The larva is distinctly segmented, elongate, legless, and orange to yellow.
The wasp pupa is oblong and initially orange to yellow. It darkens as it ages and develops distinct appendages folded against its body. The pupating wasp causes the host skin to split open and the shriveled thrips covering can be observed beneath the immature wasp as it orients upright on its rear end and becomes an adult.
Life Cycle
Ceranisus menes develops through 4 life stages: egg, larva, pupa, and adult. Some populations of C. menes consist only of females that reproduce parthenogenetically. If thrips are available for host feeding by the wasp, adult female C. menes live about 3 weeks when temperatures average 77ºF. The adult female lays about 80 eggs during her lifetime. She prefers to oviposit in first and early-second instar thrips.
Parasitized early-instar thrips continue to develop, but become inactive when they age to the late second instar. When the thrips larva develops into a prepupa it becomes discolored and swollen and is killed by the C. menes larva inside. Within a few days the host skin splits and the pupal wasp rises out of the thrips cadaver that is a dried skin attached both to the plant surface and to the base of the wasp pupa. The wasp pupa orients itself almost perpendicular to the substrate with its rear downward where it remains for several days until it matures into an adult wasp.
Adult female C. menes kill additional thrips by feeding on the them. They puncture thrips with their ovipositor and consume the exuding body fluids. They commonly sting and feed on the same thrips multiple times until it dies. Host feeding increases the wasp's longevity and egg laying.
Development time from an egg to a reproductive adult is about 1 month. Ceranisus menes has several generations per year.
Habitat
Ceranisus menes occurs in coastal and inland valleys of California. It can be found in tree and field crops, gardens, landscapes, and wildlands wherever its host thrips occur. To improve its biological control
- Control ants because they attack natural enemies or various pests.
- Grow flowering insectary plants to provide nectar and pollen to feed 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
At least 5 Ceranisus species occur in California: Ceranisus americensis, C. loomansi, C. menes, C. planitianus, and C. russelli. All are parasitoids of thrips. Ceranisus menes parasitizes at least 34 species of thrips. Its economically important hosts include avocado thrips, citrus thrips, tobacco thrips, and several species of flower thrips.
More Information
- Biological Control of Thrips Pests: A Review on Thrips Parasitoids (PDF), Wageningen Agricultural University Papers
- The Biology of Ceranisus menes (Walker) (Hym., Eulophidae), a Parasitoid of the Bean Flower Thrips Megalurothrips sjostedti (Trybom) (Thys., Thripidae): a Comparison Between African and Asian Populations, Thesis, University of Ghana
- Parasitoids as Biological Control Agents of Thrips Pests (PDF), Thesis, Wageningen University, The Netherlands
- A Review of the Nearctic Species of the Thrips-Attacking Genus Ceranisus Walker (Hymenoptera: Eulophidae), Transactions of the American Entomological Society
- Universal Chalcidoidea Database, Natural History Museum of London
Scientific classification:
- Phylum: Arthropoda
- Class: Insecta
- Order: Hymenoptera
- Family: Eulophidae
