The Microanatomy of the Eye of Amblyomma Americanum (Acari: Ixodidae) and Resultant Implications of its Structure1, 2

The transmission electron microscope was used to detail the microanatomy of the eye of the lone star tick, Amblyomma americauum (L.). The eye of the lone star tick consists of cuticular lens and 30–40 underlying photoreceptor neurons. The lens contains bundles of specialized lenticular pore canals that appear to function as light or wave guides. The photoreceptor neurons possess the microanatomical structures common to all rhabdomeric photoreceptors. The simplicity of the tick eye is believed to be a primitive condition and this eye is the first arhabdomate eye described for the phylum Arthropoda. The photoreceptor neurons of Amblyomma show affinities with the arhabdomate eyes of the flatworms and snails.