Porous or non-porous? The challenge of studying unusual placoid sensilla of Megaphragma wasps (Hymenoptera, Trichogrammatidae) with electron microscopy

Extreme miniaturization implies a high degree of optimization, rendering the retention non-functional organs almost impossible. Two unique non-porous placoid sensilla on antennae females Megaphragma were described in literature. Placoid Hymenoptera have an olfactory function and always bear pores; apparent absence pores therefore raises questions whether such are functional their surface sculpture had been sufficiently well examined. We examined detail external microsculpture internal ultrastructure using Focused Ion Beam Scanning Electron Microscopy with various types sputtering show that these actually porous cuticle innervated by 11 or 12 neurons branched cilia, which is typical sensilla. Comparison methods electron microscopy allows us to conclude for accurate determination morphofunctional sensilla, especially miniature insects, it necessary study both morphology carefully selected scanning methods.