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the numbers of pairs of pro-legs; sawfly larvae have 6 or more pairs while caterpillars have a maximum of 5 pairs. the number of stemmata (simple eyes); the sawfly larvae have only two, [7] while caterpillars usually have twelve (six each side of the head). the presence of crochets on the prolegs; these are absent in the sawflies.
Some annelids and bivalves also have apposition eyes. They are also possessed by Limulus, the horseshoe crab, and there are suggestions that other chelicerates developed their simple eyes by reduction from a compound starting point. [1] Some caterpillars appear to have evolved compound eyes from simple eyes in the opposite fashion. [citation ...
[13]: 644 Caterpillars of many taxa that have sequestered toxic chemicals from host plants or have sharp urticating hair or spines, display aposematic colouration and markings. [66] Caterpillars undergo ecdysis and have a number of larval instars, usually five but varying between species. The new cuticle is soft and allows the increase in size ...
Spiders do not have compound eyes, but instead have several pairs of simple eyes with each pair adapted for a specific task or tasks. The principal and secondary eyes in spiders are arranged in four, or occasionally fewer, pairs. Only the principal eyes have moveable retinas. The secondary eyes have a reflector at the back of the eyes.
Caterpillars have short antennae and several simple eyes. The mouthparts are adapted for chewing with powerful mandibles and a pair of maxillae, each with a segmented palp. Adjoining these is the labium-hypopharynx which houses a tubular spinneret which is able to extrude silk. [ 16 ]
Despite appearances, butterflies and moths have different types of compound eyes. Though not universal, moths very commonly have superposition eyes, while butterflies equally commonly favour apposition eyes. This is due to the superposition eye's adaptations for low light environments suiting the nocturnal moths, and the apposition eye's ...
The eyes can be categorised by their location and are divided into the anterior median eyes (AME), anterior lateral eyes (ALE), posterior median eyes (PME), and posterior lateral eyes (PLE). The exact arrangement of the eyes varies significantly by family, and to a lesser degree genus, so is often used as a diagnostic feature to identify or ...
So-called under-focused lens eyes, found in gastropods and polychaete worms, have eyes that are intermediate between lens-less cup eyes and real camera eyes. Also box jellyfish have eyes with a spherical lens, cornea and retina, but the vision is blurry. [14] [15] Heterogeneous eyes have evolved at least nine times: four or more times in ...