How does the shield of a spider mite look? - briefly
The spider mite’s shield is a hard, dome‑shaped covering formed by fused dorsal plates, usually translucent to pale yellow and slightly convex. It protects the body and gives the mite a smooth, glossy appearance.
How does the shield of a spider mite look? - in detail
The dorsal shield covering the adult spider mite is a rigid, plate‑like structure that overlays the entire opisthosoma. It measures approximately 300–400 µm in length and 200–250 µm in width, varying slightly among species. The cuticle is heavily sclerotized, giving it a glossy, amber‑to‑brown hue that often darkens with age.
Key morphological elements include:
- Shape: oval to slightly elongate, with a gently convex dorsal surface.
- Margin: a distinct, raised edge encircles the shield, forming a shallow rim that protects the underlying tissues.
- Surface texture: fine reticulate pattern formed by intersecting ridges; visible under 100× magnification.
- Setae: several stiff, hair‑like setae emerge from the posterior half, each anchored in a small socket and ranging from 15 to 30 µm in length.
- Pores and glands: numerous circular pores (3–5 µm) distributed uniformly; some associated with secretory glands that release waxy substances.
- Coloration: overall brownish‑orange, with occasional lighter patches near the anterior margin; pigmentation intensifies toward the posterior edge.
Internally, the shield rests on a thin layer of hemolymph that provides hydraulic support, allowing limited flexion during locomotion. The combination of a hardened exoskeletal plate, peripheral setae, and embedded pores creates a protective yet functional covering essential for the mite’s survival on plant surfaces.