scholarly journals Investigating mechanisms of polarized light sensitivity in the small white butterfly Pieris rapae

2019 ◽  
Author(s):  
Adam J. Blake ◽  
Gina S. Hahn ◽  
Hayley Grey ◽  
Shelby Kwok ◽  
Deby McIntosh ◽  
...  
Keyword(s):  
Visual System ◽  
Linear Polarization ◽  
Host Plants ◽  
Pieris Rapae ◽  
Polarized Light ◽  
Behavioral Responses ◽  
Color Difference ◽  
Light Sensitivity ◽  
Polarization Sensitivity ◽  
Compound Eyes

AbstractThere is an ever increasing number of arthropod taxa shown to have polarization sensitivity throughout their compound eyes. However, the mechanisms underlying arthropod perception of polarized reflections from objects such as plants are not well understood. The small white butterfly, Pieris rapae, has been demonstrated to exploit foliar polarized reflections, specifically the degree of linear polarization (DoLP), to recognize host plants. The well-described visual system of P. rapae includes several photoreceptor types (red, green, blue) that are sensitive to polarized light. Yet, the mechanism underlying the behavioral responses of P. rapae to stimuli with different DoLPs remains unknown. To investigate potential mechanisms, we designed several two-choice behavioral bioassays, displaying plant images on paired LCD monitors which allowed for independent control of polarization, color and intensity. We found that shifts in image intensity had a similar effect on P. rapae preferences for stimuli dissimilar in DoLP and dissimilar in color, suggesting DoLP differences are perceived as color. When a DoLP choice was offered between plant images manipulated in a manner to minimizing the response of blue, red, or blue and red photoreceptors, P. rapae shifted its preference for DoLP, suggesting a role for red, green and blue polarization-sensitive photoreceptors. Modeling of P. rapae photoreceptor responses to test stimuli suggests that differential DoLP is not perceived solely as a color difference. Our combined results suggest that P. rapae females process and interpret polarization reflections in a way different from that described for other polarization-sensitive taxa.

scholarly journals Polarization of foliar reflectance: novel host plant cue for insect herbivores

2019 ◽  
Vol 286 (1915) ◽  
pp. 20192198 ◽  
Author(s):  
Adam J. Blake ◽  
Matthew C. Go ◽  
Gina S. Hahn ◽  
Hayley Grey ◽  
Samuel Couture ◽  
...  
Keyword(s):  
Host Plant ◽  
Linear Polarization ◽  
Host Plants ◽  
Pieris Rapae ◽  
Polarization Sensitivity ◽  
Insect Herbivores ◽  
Colour Intensity ◽  
Foraging Decisions ◽  
Novel Host ◽  
Plant Image

Insect herbivores exploit plant cues to discern host and non-host plants. Studies of visual plant cues have focused on colour despite the inherent polarization sensitivity of insect photoreceptors and the information carried by polarization of foliar reflectance, most notably the degree of linear polarization ( DoLP ; 0–100%). The DoLP of foliar reflection was hypothesized to be a host plant cue for insects but was never experimentally tested. Here, we show that cabbage white butterflies, Pieris rapae (Pieridae), exploit the DoLP of foliar reflections to discriminate among plants. In experiments with paired digital plant images, P. rapae females preferred images of the host plant cabbage with a low DoLP (31%) characteristic of cabbage foliage over images of a non-host potato plant with a higher DoLP (50%). By reversing the DoLP of these images, we were able to shift the butterflies' preference for the cabbage host plant image to the potato non-host plant image, indicating that the DoLP had a greater effect on foraging decisions than the differential colour, intensity, or shape of the two plant images. Although previously not recognized, the DoLP of foliar reflection is an essential plant cue that may commonly be exploited by foraging insect herbivores.

Polarization analysis in the crayfish visual system

2001 ◽  
Vol 204 (14) ◽  
pp. 2383-2390 ◽  
Author(s):  
Raymon M. Glantz
Keyword(s):  
Visual System ◽  
Motor Neurons ◽  
Polarized Light ◽  
Cell Types ◽  
Afferent Input ◽  
Polarization Sensitivity ◽  
Polarization Analysis ◽  
Low Contrast ◽  
Motion Responses ◽  
Light Flashes

SUMMARY It is proposed that polarization sensitivity at the most peripheral stages of the crayfish visual system (lamina ganglionaris and medulla externa) is used to enhance contrast and thus may contribute to motion detection in low contrast environments. The four classes of visual interneurons that exhibit polarization sensitivity (lamina monopolar cells, tangential cells, sustaining fibers and dimming fibers) are not sensitive exclusively to polarized light but also respond to unpolarized contrast stimuli. Furthermore, many of these cells and the sustaining fibers in particular exhibit a greater differential e-vector responsiveness to a changing e-vector than to e-vector variations among steady-state stimuli. While all four cell types respond modestly to light flashes at an e-vector of 90° to the preferred orientation, the dynamic response to a changing e-vector is small or absent at this orientation. Because the sustaining fibers exhibit polarization sensitivity, and they provide afferent input to a subset of optomotor neurons, the latter were also tested for polarization sensitivity. The optomotor neurons involved in compensatory reflexes for body pitch were differentially sensitive to the e-vector angle of a flash of light, with maximum responses for e-vectors near the vertical. The motor neurons also exhibited a maximum response near the vertical e-vector to a continuously rotating polarizer. Two scenarios are described in which the sensitivity to a changing e-vector can produce motion responses in the absence of intensity contrast.

Two-Channel Polarization Analyzer in the Sustaining Fiber-Dimming Fiber Ensemble of Crayfish Visual System

1998 ◽  
Vol 80 (5) ◽  
pp. 2571-2583 ◽  
Author(s):  
Raymon M. Glantz ◽  
Andy McIsaac
Keyword(s):  
Visual System ◽  
Polarized Light ◽  
Polarization Sensitivity ◽  
Visual Responses ◽  
Polarization Analyzer ◽  
Peripheral Neurons ◽  
Steady State Responses ◽  
Vector Orientation ◽  
Channel Polarization ◽  
State Responses

Glantz, Raymon M. and Andy McIsaac. Two-channel polarization analyzer in the sustaining fiber-dimming fiber ensemble of crayfish visual system. J. Neurophysiol. 80: 2571–2583, 1998. Polarization sensitivity (PS) was examined in two classes of neurons, sustaining fibers and dimming fibers, in the medulla externa (second optic neuropile) of the crayfish, Pacifasticus leniusculus. Visual responses were recorded intracellularly and extracellularly. The influence of e-vector orientation (θ) was probed in steady-state responses, with brief flashes and with a rotating polarizer. The results indicate that the entire sustaining fiber population appears to be maximally sensitive to vertically polarized light. Although the evidence is less complete for dimming fibers, they appear to be maximally inhibited by vertically polarized light and excited by horizontally polarized light. Thus the sustaining fibers and dimming fibers form a two-channel polarization analyzer that captures the main features of the polarization system established in photoreceptors and lamina monopolar cells. The available evidence suggests that this two-channel system has the same characteristics across most or all of the retinula. Lateral inhibition in sustaining fibers is differentially sensitive to θ. Inhibition is substantial at θ = 90° (horizontal) and essentially absent at θ = 0°. The details of the sustaining fiber polarization response closely follow features established in more peripheral neurons, including the magnitude of PS, enhanced responsiveness to a changing e-vector, and modest directionality to a changing e-vector in∼40% of the cells.

scholarly journals Polarized light sensitivity in Pieris rapae is dependent on both color and intensity

2020 ◽  
Vol 223 (13) ◽  
pp. jeb220350 ◽  
Author(s):  
Adam J. Blake ◽  
Gina S. Hahn ◽  
Hayley Grey ◽  
Shelby A. Kwok ◽  
Deby McIntosh ◽  
...  
Keyword(s):  
Pieris Rapae ◽  
Polarized Light ◽  
Light Sensitivity

Fly photoreceptors - II. Spectral and polarized light sensitivity in the drone fly Eristalis

1975 ◽  
Vol 190 (1099) ◽  
pp. 225-237 ◽  
Keyword(s):  
Colour Vision ◽  
Polarized Light ◽  
Cell Types ◽  
Light Sensitivity ◽  
Visual Pigments ◽  
Spectral Peak ◽  
Polarization Sensitivity ◽  
Double Peaks

Eristalis tenax , the honeybee mimic, has photoreceptors mainly with double peaks as in typical flies, but the peaks are near 350 and 450 nm. Other cell types with peaks at 350 or 450 or 520 nm were encountered but not commonly. Measurements of the polarization sensitivity lead to the conclusion, as in Calliphora , that where there are two visual pigments they are separated in proximal and distal parts of the rhabdomere, with a twist between the two parts. Therefore there must also be two corresponding metarhodopsins. Receptors with a single spectral peak do not show this effect. Self-absorption can be excluded as an influence on spectral or polarization sensitivity. In its colour vision the drone fly is more like a typical fly than a bee but it has less green sensitive receptors and more blue sensitive ones than calliphora .

scholarly journals Spatial orientation of social caterpillars is influenced by polarized light

2021 ◽  
Vol 17 (2) ◽  
Author(s):  
Mizuki Uemura ◽  
Andrej Meglič ◽  
Myron P. Zalucki ◽  
Andrea Battisti ◽  
Gregor Belušič
Keyword(s):  
Visual System ◽  
Spatial Orientation ◽  
Polarized Light ◽  
Thaumetopoea Pityocampa ◽  
Polarization Sensitivity ◽  
Polarization Vision ◽  
Anatomical Analysis ◽  
Skylight Polarization ◽  
Rugged Surface ◽  
Anatomical Evidence

Processionary caterpillars of Thaumetopoea pityocampa (in Europe) and Ochrogaster lunifer (in Australia) (Lepidoptera: Notodontidae) form single files of larvae crawling head-to-tail when moving to feeding and pupation sites. We investigated if the processions are guided by polarization vision. The heading orientation of processions could be manipulated with linear polarizing filters held above the leading caterpillar. Exposure to changes in the angle of polarization around the caterpillars resulted in corresponding changes in heading angles. Anatomical analysis indicated specializations for polarization vision of stemma I in both species. Stemma I has a rhabdom with orthogonal and aligned microvilli, and an opaque and rugged surface, which are optimizations for skylight polarization vision, similar to the dorsal rim of adult insects. Stemmata II-VI have a smooth and shiny surface and lobed rhabdoms with non-orthogonal and non-aligned microvilli; they are thus optimized for general vision with minimal polarization sensitivity. Behavioural and anatomical evidence reveal that polarized light cues are important for larval orientation and can be robustly detected with a simple visual system.

scholarly journals Approach trajectory and solar position affect host plant attractiveness to the small white butterfly

2020 ◽  
Author(s):  
Adam J. Blake ◽  
Samuel Couture ◽  
Matthew C. Go ◽  
Gerhard Gries
Keyword(s):  
Host Plant ◽  
Plant Species ◽  
Host Plants ◽  
Pieris Rapae ◽  
Polarized Light ◽  
Plant Canopies ◽  
Reflected Light ◽  
Whole Plant ◽  
Plant Foraging ◽  
Solar Position

AbstractWhile it is well documented that insects exploit polarized sky light for navigation, their use of reflected polarized light for object detection has been less well studied. Recently, we have shown that the small white butterfly, Pieris rapae, distinguishes between host and non-host plants based on the degree of linear polarization (DoLP) of light reflected from their leaves. To determine how polarized light cues affect host plant foraging by female P. rapae across their entire visual range including the ultraviolet (300-650 nm), we applied photo polarimetry demonstrating large differences in the DoLP of leaf-reflected light among plant species generally and between host and non-host plants specifically. As polarized light cues are directionally dependent, we also tested, and modelled, the effect of approach trajectory on the polarization of plant-reflected light and the resulting attractiveness to P. rapae. Using photo polarimetry measurements of plants under a range of light source and observer positions, we reveal several distinct effects when polarized reflections are examined on a whole-plant basis rather than at the scale of pixels or of entire plant canopies. Most notably from our modeling, certain approach trajectories are optimal for foraging butterflies, or insects generally, to discriminate between plant species on the basis of the DoLP of leaf-reflected light.

The compound eyes of mantis shrimps (Crustacea, Hoplocarida, Stomatopoda). I. Compound eye structure: the detection of polarized light

1991 ◽  
Vol 334 (1269) ◽  
pp. 33-56 ◽  
Keyword(s):  
Compound Eye ◽  
Polarized Light ◽  
Structural Features ◽  
Polarization Sensitivity ◽  
Compound Eyes ◽  
Visual Tasks ◽  
Retinular Cells ◽  
High Degree ◽  
Structural Adaptations ◽  
Parallel Sampling

Stomatopod crustaceans possess compound eyes divided into three distinct regions: two peripheral retinae - the dorsal and ventral hemispheres — and the mid-band. Throughout the eye, in particular in the midband, there are many structural adaptations that potentially enable different portions of the eye to perform different visual tasks. A high degree of optical overlap between these eye regions allows the parallel sampling of various parameters of light from one direction in space. In consecutive papers, we present structural evidence that stomatopods have the receptors necessary for colour and polarization vision. The first paper describes the retinal structures that suggest the existence of polarization sensitivity in stomatopods. mid-band rows five and six, together with the hemispheres, are probably involved in this visual process. By using two strategies, rhabdomal modification and varying the orientation of similar ommatidial units in the three eye regions, stomatopods have the capacity to analyse polarized light in a very detailed manner. All the species included in this study live in shallow, tropical waters where polarized light signals are abundant. It therefore seems likely that their eyes have evolved to take advantage of such environmental cues. Structural evidence also suggests that all retinular cells in rows one to four of the mid-band, and the distal most retinular cells (R8) over most of the retina, are not sensitive to polarized light. These mid-band rows are instead adapted for colour detection. This function of the stomatopod retina and structural features concerned with colour sensitivity are described in paper II ( Phil. Trans. R. Soc. Lond. B 334, 57—84 (1991)).

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