Abstract
In most organisms, specific structures are responsible for detecting light patterns and vision. Several species of sea urchins appear to have a diffuse photoreceptor system that enables them to detect light and in some cases objects. The presence of extraocular vision was investigated on a sea urchin common in northern Oman, Diadema setosum. Urchins from 8- to 10-m deep coral communities were used in controlled experiments that quantified the orientation response of the urchins to various visual cues: size, contrast and colour of circular targets simulating urchins’ outlines. Urchins responded to black discs down to 11° initial visual angle but not to smaller discs. The minimum grey-scale value triggering a response was between 50 and 37% black. Urchins responded to red targets but not to green or blue ones. An average angular distance between spines of 5.3° suggested a visual acuity of about 10.6°. D. setosum thus showed extraocular vision allowing them to detect objects of different sizes, contrasts and to some extent colour, supporting the hypothesis that the whole sea urchin’s body acts as a single large compound eye.
| Original language | English |
|---|---|
| Pages (from-to) | 31-40 |
| Number of pages | 10 |
| Journal | Marine and Freshwater Behaviour and Physiology |
| Volume | 50 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Jan 2 2017 |
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Keywords
- behaviour
- Diadema setosum
- Echinoidea
- Extraocular vision
- sea urchin
ASJC Scopus subject areas
- Oceanography
- Physiology
- Aquatic Science
Cite this
Extraocular vision in the sea urchin Diadema setosum. / Al-Wahaibi, Mohamed K.; Claereboudt, Michel R.
In: Marine and Freshwater Behaviour and Physiology, Vol. 50, No. 1, 02.01.2017, p. 31-40.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Extraocular vision in the sea urchin Diadema setosum
AU - Al-Wahaibi, Mohamed K.
AU - Claereboudt, Michel R.
PY - 2017/1/2
Y1 - 2017/1/2
N2 - In most organisms, specific structures are responsible for detecting light patterns and vision. Several species of sea urchins appear to have a diffuse photoreceptor system that enables them to detect light and in some cases objects. The presence of extraocular vision was investigated on a sea urchin common in northern Oman, Diadema setosum. Urchins from 8- to 10-m deep coral communities were used in controlled experiments that quantified the orientation response of the urchins to various visual cues: size, contrast and colour of circular targets simulating urchins’ outlines. Urchins responded to black discs down to 11° initial visual angle but not to smaller discs. The minimum grey-scale value triggering a response was between 50 and 37% black. Urchins responded to red targets but not to green or blue ones. An average angular distance between spines of 5.3° suggested a visual acuity of about 10.6°. D. setosum thus showed extraocular vision allowing them to detect objects of different sizes, contrasts and to some extent colour, supporting the hypothesis that the whole sea urchin’s body acts as a single large compound eye.
AB - In most organisms, specific structures are responsible for detecting light patterns and vision. Several species of sea urchins appear to have a diffuse photoreceptor system that enables them to detect light and in some cases objects. The presence of extraocular vision was investigated on a sea urchin common in northern Oman, Diadema setosum. Urchins from 8- to 10-m deep coral communities were used in controlled experiments that quantified the orientation response of the urchins to various visual cues: size, contrast and colour of circular targets simulating urchins’ outlines. Urchins responded to black discs down to 11° initial visual angle but not to smaller discs. The minimum grey-scale value triggering a response was between 50 and 37% black. Urchins responded to red targets but not to green or blue ones. An average angular distance between spines of 5.3° suggested a visual acuity of about 10.6°. D. setosum thus showed extraocular vision allowing them to detect objects of different sizes, contrasts and to some extent colour, supporting the hypothesis that the whole sea urchin’s body acts as a single large compound eye.
KW - behaviour
KW - Diadema setosum
KW - Echinoidea
KW - Extraocular vision
KW - sea urchin
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U2 - 10.1080/10236244.2016.1265206
DO - 10.1080/10236244.2016.1265206
M3 - Article
VL - 50
SP - 31
EP - 40
JO - Marine and Freshwater Behaviour and Physiology
JF - Marine and Freshwater Behaviour and Physiology
SN - 1023-6244
IS - 1
ER -