Lerps

Lerps are protective, sugary, crust-like coverings formed by the nymphs of certain psyllid insects on the leaves of their host plants, most notably Eucalyptus. The insect larvae secrete a waxy, crystalline substance that hardens into a translucent mass known as a lerp. The nymph resides beneath or inside the lerp as it feeds on sap, and the cover helps shield it from desiccation and some predators while it matures. Lerps appear as small, rounded to elongated scales attached to leaves and branches, varying in color from white to pale amber.

Lerps are common in Australia and parts of the Pacific where lerp-producing psyllids occur on eucalyptus and other hosts. The lerp microhabitat supports a community of organisms; predators and scavengers, including certain birds and predatory insects, feed on the lerp scales and the nymphs within them. The presence of lerps can influence local leaf-health and may interact with plant defense responses, though the primary ecological role is tied to the psyllid life cycle.

In computing and mathematics, lerp stands for linear interpolation. A linear interpolation estimates intermediate values between two endpoints as a function of a parameter t between 0 and 1. Lerp is widely used in computer graphics, animation, shading, and data processing to blend values smoothly over time or space. While sharing a name, the biological lerp and the computational lerp describe distinct concepts in different fields.