Pilifer

Definition

A hair-bearing sensory organ located on the head of hawkmoths (subtribe Choerocampina) that functions as an acoustic detector of high-frequency echolocation calls emitted by insectivorous bats. The pilifer is part of a specialized hearing system that enables these moths to perform evasive flight maneuvers and avoid predation. The structure consists of modified setae or hairs connected to sensory neurons that are tuned to the ultrasonic frequencies (typically 20–60 kHz) produced by foraging bats.

Etymology

From Latin pilus (hair) + -fer (bearing), referring to the hair-like structure of the organ.

Example

In the death's-head hawkmoth Acherontia atropos, the pilifer responds to bat echolocation frequencies, triggering erratic flight patterns that reduce capture success by aerial-hunting bats.

Synonyms

• labral pilifer

Related Terms

• tympanal organ
• tympanic membrane
• ultrasonic hearing
• acoustic startle response
• bat-moth coevolution
• choerocampine hawkmoths
• sensory setae

Usage Notes

The term specifically refers to the antennal/head-based hearing organ in choerocampine hawkmoths, not to be confused with the abdominal tympanal organs found in many other Lepidoptera such as geometrid and noctuid moths. Some authors use 'labral pilifer' to emphasize its position near the labrum. The structure is absent in non-choerocampine sphingids.