Hosts or Prey
Scale insects mainly but also other plant-sucking insects formerly called Homoptera
Identification
The adult lady beetle (ladybug or ladybird beetle) is about 1/6 inch (4 mm) long. It is round when viewed from above and dome shaped (convex) when viewed from the side. It is generally shiny burgundy colored to dark brown but can be nearly black. Each wing cover has 2 or 3 reddish orange spots that are the source of the specific epithet; the Latin word bipustulatus means 2-blistered. On some individuals the spots merge into a transverse line.
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The eggs are oblong, yellowish, and about 1/25 inch (1 mm) long. The mature larva is spiny and about 1/5 inch (5 mm) long. It is mostly dark brown with black and pale or yellowish markings.
The oblong pupa is about 1/6 inch (4 mm) long. It occurs within the spiny skin of the last instar glued to plant parts. As it ages the pupal case splits open to reveal the pupa and distinct appendages develop folded against the body.
Life Cycle
Lady beetles develop through 4 life stages: egg, larva, pupa, and adult. The adult female lays about 30 to 60 eggs singly near scales on which the emerging larvae feed. After hatching the larvae develop through 4 increasingly larger instars. Pupae occur on the bark or leaves, mostly on scale-infested plants.
Adults and larvae prey mainly on armored scales and soft scales. Adults consume about 4 scales per day during their life span of about 3 months. A larva consumes about 100 scales during its development. Actual consumption varies mainly by the size of the hosts.
The predator is most abundant during the late spring to fall. It can be difficult to find during winter when it becomes inactive.
Egg to reproductive adult development time is about 6 weeks when temperatures are warm. Chilocorus bipustulatus has about 6 generations per year.
Habitat
After earlier unsuccessful attempts to establish C. bipustulatus in the United States it was imported by University of California entomologists from Israel in 1951. It was reared and released in the northern San Joaquin Valley of California for control of olive scale. The beetle established from this introduction and now occurs in at least the Central Valley and Central Coast of California.
To improve biological control
- Control ants because they attack lady beetles and other natural enemies.
- 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., periodically hose off small plants).
- Avoid the application of broad-spectrum, persistent insecticides for all pests because they are toxic to natural enemies.
See Protecting Natural Enemies and Pollinators for more information.
Species
At least 191 species of lady beetles occur in California. These include at least 5 Chilocorus species: C. bipustulatus, C. cacti, C. fraternus, C. kuwanae, and the twicestabbed lady beetle (C. orbus). All are predators mostly of scale insects. Chilocorus bipustulatus is sometimes called the heather lady beetle.
More Information
- The California Beetle Database, Santa Barbara Museum of Natural History
- The Coccinellidae (Coleoptera) of America North of Mexico, Journal of the New York Entomological Society
- Chilocorus bipustulatus (L.), The Hebrew University of Jerusalem
- Establishment of the Coccinellid, Chilocorus bipustulatus Linnaeus, in California Olive Groves, UC Berkeley, The Pan-Pacific Entomologist
- Species Chilocorus bipustulatus - Heather Lady Beetle, BugGuide, Iowa State University
Scientific classification:
- Phylum: Arthropoda
- Class: Insecta
- Order: Coleoptera
- Family: Coccinellidae
