Role of silk webbing in the biology ofHemicheyletia wellsina(Acari: Cheyletidae)

Hemicheyletia wellsina is a predator of several families of arthropod plant pests. Hemicheyletia wellsina females produce silk webbing that covers their egg clutches, but the function of the webbing is unknown. Experiments indicate the webbing can protect the eggs from predation, resulting in approximately a 71% increase in egg hatch compared to when silk was removed in the presence of the phytoseiid predator Metaseiulus occidentalis. Within 2–3 days after larvae hatch, they appear to no longer need protection, as 18 of 20 H. wellsina larvae captured and fed on the much larger adult M. occidentalis females. The silk also may regulate the relative humidity around the eggs.