Visual Performance of Horseshoe Crabs: Role of Underwater Lighting

Passaglia, Christopher L.; McSweeney, Margaret; Stewart, Kristine M.; Kim, E; Mole, E J; Powers, Maureen K.; Barlow, Robert B.

doi:10.1086/bblv193n2p205

Cited by 8 publications

(6 citation statements)

References 3 publications

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“…Such wave-induced flicker is a prominent feature of the shallow waters where Limulus mate and persists over a range of lighting conditions (37), which is consistent with the animal's ability to find mates day and night (10)(11)(12)(13). Behavioral studies in mating areas show that strobic light increases the probability that male Limulus turn toward and approach the low-contrast gray object (38). Model computations show that the strobic light reflects off low-contrast objects, enhancing their neural images as the objects move across the animal's visual field (Fig.…”

Section: Fig 3 Temporal Integration Of Optic-nerve Responses By Neumentioning

confidence: 69%

Deciphering a neural code for vision

Passaglia

Dodge

Herzog

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

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Deciphering the information that eyes, ears, and other sensory organs transmit to the brain is important for understanding the neural basis of behavior. Recordings from single sensory nerve cells have yielded useful insights, but single neurons generally do not mediate behavior; networks of neurons do. Monitoring the activity of all cells in a neural network of a behaving animal, however, is not yet possible. Taking an alternative approach, we used a realistic cell-based model to compute the ensemble of neural activity generated by one sensory organ, the lateral eye of the horseshoe crab, Limulus polyphemus. We studied how the neural network of this eye encodes natural scenes by presenting to the model movies recorded with a video camera mounted above the eye of an animal that was exploring its underwater habitat. Model predictions were confirmed by simultaneously recording responses from single optic nerve fibers of the same animal. We report here that the eye transmits to the brain robust ''neural images'' of objects having the size, contrast, and motion of potential mates. The neural code for such objects is not found in ambiguous messages of individual optic nerve fibers but rather in patterns of coherent activity that extend over small ensembles of nerve fibers and are bound together by stimulus motion. Integrative properties of neurons in the first synaptic layer of the brain appear well suited to detecting the patterns of coherent activity. Neural coding by this relatively simple eye helps explain how horseshoe crabs find mates and may lead to a better understanding of how more complex sensory organs process information.

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Section: Fig 3 Temporal Integration Of Optic-nerve Responses By Neumentioning

confidence: 69%

Deciphering a neural code for vision

Passaglia

Dodge

Herzog

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

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“…They did not find complete blindness for the fouled or darkened eyes, but a reduced ability to detect light with increased flash intensity and rapid flashing (Wasserman and Cheng 1996). Because light intensity and a strobic effect appear to play an important role in mate location (Herzog et al 1996;Passaglia et al 1997;Krutky et al 2000), it is possible that the inability of the crabs to respond to high intensity, strobic light may reduce their ability to distinguish low-contrast females in the subtidal zone, reducing the chances for successful mate recognition. Wasserman and Cheng (1996) hypothesized that darkening of the lateral eyes may have the same effect as a cataract on a human eye, leaving the crab with functional vision, but a somewhat diminished ability to discriminate its surroundings in order to locate a mate.…”

Section: Discussionmentioning

confidence: 98%

“…Thus, each male received a condition score of 0 through 5 for each eye; since we found that there were no significant differences between the scores for the right and left eyes, a single combined score of 0-10 for both eyes is presented. The condition of the median eyes was not included in this study, because only the lateral eyes are used when locating mates (Barlow et al 1982;Passaglia et al 1997). A similar scoring system (0-5 for each eye, combined to 0-10 for each crab) was used to assess the coverage of the lateral eyes by all species of epibionts.…”

Section: Frequency Of Eye Damage Among Attached and Unattached Malesmentioning

confidence: 99%

“…It has been shown that underwater lighting also plays an important role in enabling male horseshoe crabs to detect objects that vary in contrast against a background of sand. Strobic light enhances the visibility of low-contrast objects on sandy bottoms that would otherwise be difficult for the horseshoe crab to see (Herzog et al 1996;Passaglia et al 1997;Krutky et al 2000).…”

Section: Introductionmentioning

confidence: 99%

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Eye and clasper damage influence male mating tactics in the horseshoe crab, Limulus polyphemus

Duffy

Penn

Botton

et al. 2005

J Ethol

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In the horseshoe crab mating system, mated pairs are frequently accompanied by unattached satellite males as they spawn on intertidal beaches. Previous studies have shown that males locate females visually using their lateral (compound) eyes, and that attached (mated) males generally have less heavily worn or damaged carapaces than unattached males. The purpose of this study was to investigate the influences of lateral eye condition and clasper abnormalities on male mating tactics. Sexually mature males had two kinds of eye damage: deterioration caused by disease, and overgrowth by sessile invertebrates, such as bryozoans, mussels, and tube-building polychaetes. The lateral eyes of attached males had significantly less decay than unattached males. On the other hand, coverage of the lateral eyes by encrusting invertebrates was more extensive among attached than unattached males. Although overgrowth did not appear to impair a male's ability to pair with a female as severely as eye decay, it is conceivable that amplexus may have occurred before epibiont coverage was sufficient to obscure vision. Male crabs that were experimentally "blindfolded" by painting their lateral eyes with black nail polish were less likely to reattach to a female than controls. Appendage injuries were more frequent among unattached males than among attached males; in particular, 6.4% of unattached males but 0.0% of attached males had damaged claspers (the modified first legs required for amplexus). Unattached males in the population were "older," as judged by the degree of carapace wear, than attached males. Severe visual impairment and/or clasper damage may explain the reduced pairing success of older male horseshoe crabs, and underlie their choice of the alternative satellite male mating tactics.

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“…We developed and characterized an array of sensors configured similarly to an apposition compound eye and tested them on an autonomous robotic vehicle. The robot exhibits the ability to follow a specified target and avoid pre-defined obstacles using a simple control algorithm much like an insect searching for a mate or food and avoiding predators [2,3].…”

Section: Introductionmentioning

confidence: 99%

A bio-inspired apposition compound eye machine vision sensor system

et al. 2009

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The Wyoming Information, Signal Processing, and Robotics Laboratory is developing a wide variety of bio-inspired vision sensors. We are interested in exploring the vision system of various insects and adapting some of their features toward the development of specialized vision sensors. We do not attempt to supplant traditional digital imaging techniques but rather develop sensor systems tailor made for the application at hand. We envision that many applications may require a hybrid approach using conventional digital imaging techniques enhanced with bio-inspired analogue sensors. In this specific project, we investigated the apposition compound eye and its characteristics commonly found in diurnal insects and certain species of arthropods. We developed and characterized an array of apposition compound eye-type sensors and tested them on an autonomous robotic vehicle. The robot exhibits the ability to follow a pre-defined target and avoid specified obstacles using a simple control algorithm.

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Visual Performance of Horseshoe Crabs: Role of Underwater Lighting

Cited by 8 publications

References 3 publications

Deciphering a neural code for vision

Deciphering a neural code for vision

Eye and clasper damage influence male mating tactics in the horseshoe crab, Limulus polyphemus

A bio-inspired apposition compound eye machine vision sensor system

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