The spectral transmission of non-salticid spider corneas

Abstract

Although many salticid spiders have been shown to have corneas that transmit ultraviolet (UV) light, whether the corneas of non-salticid spiders transmit UV has not been previously investigated. In this study, we determined the spectral corneal transmission properties of 38 species belonging to 13 non-salticid families. We used these data to estimate the T 50 transmission cut-off value, the wavelength corresponding to 50% maximal transmission for each species. The corneas of almost all species from the families Deinopidae, Lycosidae, Oxyopidae, Pisauridae, Sparassidae and Thomisidae, all of which have been reported to rely to a substantial extent on vision, transmitted short wavelength light below 400 nm, ranging from 306 to 381 nm. However, species from the families Atypidae and Ctenizidae are not known to rely substantially on vision, and the corneas of these species tended to absorb light of wavelengths below 380 nm, which may not allow UV sensitivity in these spiders. Liphistiidae, the family widely regarded as most basal among spiders, is of particular interest. The species in this family are not known to make substantial use of vision, and yet we found that liphistiid corneas transmitted UV light with a low T 50 value (359 nm). T 50 values of non-salticid spider corneas also varied with light habitat. Species living in dim environments tended to have UV-opaque corneas, but species inhabiting open areas had UV-transmitting corneas. However, there was no evidence of corneal transmission properties being related to whether a species is diurnal or nocturnal.

Visual preference of flower‐visiting crab spiders (Ebrechtella tricuspidata) for host flowers

“…possess four morphologically distinct types of photoreceptor cells in their principal eyes (Blest & O'Carroll ). As a diurnal spider, the corneas of E. tricuspidata have been found to have the highest T 50 transmission cut‐off value (wavelength corresponding to 50% maximal transmission) among non‐salticid spiders (Hu et al ., ). Therefore, we surmise that E. tricuspidata probably has excellent visual abilities.…”

The spider cuticle: a remarkable material toolbox for functional diversity

“…( g ) 3D representation of corneal nanostructures in the eyes of a spider. Reproduced with permission from [73]. (Online version in colour.)…”

“…In jumping spiders, the two so-called primary eyes are dedicated to high resolution imaging, whereas the so-called secondary eyes are mainly motion detectors together providing large horizontal fields of view close to 360° [70,71,111]. The highly transparent cornea and lenses of the primary eyes of jumping spiders allow almost 100% light transmission in the spiders' visual range, which extends from UV (around 300 nm) in some species, up to around 700 nm [72,73]. The cornea and the lens of spider eyes are made of lamellated cuticle (figure 6).…”

“…The highly transparent cornea and lenses of the primary eyes of jumping spiders allow almost 100% light transmission in the spiders' visual range, which extends from UV (around 300 nm) in some species, up to around 700 nm [ 70 , 71 ]. The cornea and the lens of spider eyes are made of lamellated cuticle ( figure 6 ).…”