Diaspididae

Common Name

Armored Scale Insects

Overview

Diaspididae, known as armored scale insects, are a family of true bugs within the order Hemiptera. These insects are minute sap-feeders that parasitize a variety of plants. Their name "armored scale" is derived from the protective covering they produce over their bodies.

Taxonomy

Key Characteristics

  • Size: Generally very small, typically less than 2 mm in length.
  • Shape: Flat and circular or oval.
  • Color: Varies widely, from white to brown to black.
  • Protective Covering: Known as a "test," it is made of wax and secreted by the insect.
  • Legs: Present only in the nymphal stages; adult females are usually legless.

Life Cycle

  • Egg: Laid beneath the protective covering.
  • Nymph: Also called "crawlers," these mobile stages disperse to new feeding sites.
  • Adult: Females remain sessile (stationary) under their protective scale, while males may have wings and can fly short distances to find mates.

Behavior and Ecology

  • Feeding: Primarily sap-feeders on a wide range of plants including crops, ornamentals, and trees.
  • Dispersal: Limited mobility; first instar nymphs are the primary dispersal stage.
  • Habitat: Common in temperate to tropical regions; often found on twigs, stems, and leaves.
  • Symbiosis: Some species are tended by ants, which protect them in exchange for honeydew.

Notable Species

  • Aspidiotus destructor: Coconut scale, a major pest of coconut palms.
  • Aonidiella aurantii: California red scale, a significant pest of citrus.
  • Chrysomphalus aonidum: Circular scale, harmful to various ornamental plants.

Conservation

  • Control Measures: Biological control with natural predators, chemical insecticides, and integrated pest management (IPM) approaches are commonly used.
  • Beneficial Role: Some species have potential as biological control agents against invasive plant species.

Significance to Humans

  • Agricultural Impact: Major pests of agricultural crops, causing economic losses.
  • Ornamentals: Damaging to ornamental plants, reducing aesthetic and market value.
  • Control Strategies: Effective management requires an understanding of their life cycle and ecology.

Fun Facts

  • Ancient History: Fossils of armored scale insects date back to the Cretaceous period.
  • Reproductive Rate: Some species can produce several generations per year under favorable conditions.
  • Protective Shield: The waxy covering can protect them from certain insecticides, making control difficult.
  • Diverse Range: Over 2,400 species have been described worldwide.