scholarly journals Orientation of larval and juvenile horseshoe crabs Limulus polyphemus to visual cues: Effects of chemical odors

2010 ◽  
Vol 56 (5) ◽  
pp. 618-633 ◽  
Author(s):  
Julie M. Medina ◽  
Richard A. Tankersley
Keyword(s):  
Visual Cues ◽  
Chemical Cues ◽  
Aquatic Vegetation ◽  
Early Life History ◽  
Limulus Polyphemus ◽  
Visual Orientation ◽  
Offshore Water ◽  
Syringodium Filiforme ◽  
Horseshoe Crabs ◽  
Visual Targets

Abstract Adult horseshoe crabs Limulus polyphemus have long served as models for the study of vision in marine arthropods. Yet, little is known about the ability of early life history stages to detect and respond to visual cues. We examined the visually directed movements of larvae and first stage juveniles to horizons containing dark visual targets of different sizes. The study tested the hypotheses that (1) larval and juvenile crabs can detect and respond to visual targets and (2) the direction of orientation varies with the presence of chemical cues associated with settlement habitats. Orientation of larval and juvenile crabs to rectangles subtending angles from 30–330° was tested in a circular arena containing water that either lacked estuarine chemical cues (offshore water) or contained odors from aquatic vegetation or known predators. In the absence of chemical odors, larvae oriented toward and juveniles moved away from dark horizons subtending angles > 60°. When placed in water containing chemical odors from potential nursery habitats, including the seagrasses Halodule wrightii and Syringodium filiforme, crabs reversed their direction of orientation relative to their responses in offshore water. Odors from two known predators, the mummichug Fundulus grandis and blue crab Callinectes sapidus, had no affect on the orientation of larvae. Yet, juveniles responded to both odors by moving toward the visual target. Results support the hypothesis that the visual orientation of larval and juvenile horseshoe crabs changes upon exposure to habitat and predator cues and that the direction of the response undergoes an ontogenetic shift following metamorphosis.

scholarly journals Male horseshoe crabs Limulus polyphemus use multiple sensory cues to locate mates

2010 ◽  
Vol 56 (5) ◽  
pp. 485-498 ◽  
Author(s):  
Katharine M. Saunders ◽  
H. Jane Brockmann ◽  
Winsor H. Watson ◽  
Steven H. Jury
Keyword(s):  
Chemical Cues ◽  
Limulus Polyphemus ◽  
Sensory Cues ◽  
Additional Information ◽  
Cue Use ◽  
Horseshoe Crabs ◽  
Multisensory Cues ◽  
Attraction And Retention ◽  
Satellite Males ◽  
Shed Light

Abstract The use of multisensory cues to locate mates can increase an organism's success by acting as a back-up plan when one system fails, by providing additional information to the receiver, and by increasing their ability to detect mates using senses that have different ranges in a variable aquatic environment. In this contribution we review the sensory cues that male horseshoe crabs Limulus polyphemus are known to use when locating mates and then provide new data that shed light on this subject. During the breeding season, females migrate into shore during high tides to spawn. Males attach to females as they approach the beach or are attracted to pairs already spawning. Vision is well established as an important cue in attracting males. Although chemoreception is well known in other marine arthropods, and horseshoe crabs have the anatomy available, there are few studies on chemical cues in this species. Experiments are presented here that provide evidence for chemical cue use. We show that the attraction, and retention, of attached and satellite males to actively spawning females and mating pairs involves multimodal cues.

Male salamanders remember individuals based on chemical or visual cues

Behaviour ◽  
2009 ◽  
Vol 146 (11) ◽  
pp. 1485-1498 ◽  
Author(s):  
Nancy Kohn ◽  
Robert Jaeger
Keyword(s):  
Filter Paper ◽  
Forest Floor ◽  
Visual Cues ◽  
Chemical Cues ◽  
Plethodon Cinereus ◽  
Multiple Cues

AbstractThe use of multiple cues can enhance the detection, recognition, discrimination, and memorability of individuals by receivers. We conducted two experiments, using only males, to test whether territorial red-backed salamanders, Plethodon cinereus, could use only chemical or only visual cues to remember familiar conspecifics. In both experiments, focal males spent significantly more time threatening unfamiliar than familiar male intruders. They also chemoinvestigated the filter paper containing chemical cues of unfamiliar intruders more often than that of familiar intruders. These results suggest that red-backed salamanders can use both chemical and visual cues to recognize familiar individuals, allowing them to distinguish between less threatening neighbours and more threatening intruders in the heterogeneous forest floor habitat, where visual cues alone would not always be available.

Covert orienting of attention in macaques. II. Contributions of parietal cortex

1995 ◽  
Vol 74 (2) ◽  
pp. 698-712 ◽  
Author(s):  
D. L. Robinson ◽  
E. M. Bowman ◽  
C. Kertzman
Keyword(s):  
Reaction Time ◽  
Receptive Field ◽  
Parietal Cortex ◽  
Visual Cues ◽  
Reaction Time Task ◽  
Visual Response ◽  
Attention Task ◽  
Time Task ◽  
Visual Spatial ◽  
Visual Targets

1. To understand some of the contributions of parietal cortex to the dynamics of visual spatial attention, we recorded from cortical cells of monkeys performing attentional tasks. We studied 484 neurons in the intraparietal sulcus and adjacent gyral tissue of two monkeys. We measured phasic responses to peripheral visual stimuli while the monkeys attended toward or away from the stimuli or when attention was not controlled. Neurons were tested while the monkeys gazed at a spot of light (simple fixation task), actively attended to a foveal target (foveal attention task), performed a reaction time task (cued reaction time task), made saccadic eye movements to visual targets (saccade task), or responded to a repetitious peripheral target (probability task). 2. In a previous paper we demonstrated that monkeys, like humans, responded more quickly to visual targets when the targets followed briefly flashed visual cues (validly cued targets) (Bowman et al. 1993). It has been hypothesized that the cue attracts attention to its locus and results in faster reaction times (Posner 1980). In the present physiological studies, visual cues consistently excited these neurons when they were flashed in the receptive field. Such activity might signal a shift of attention. Visual targets that fell within the receptive field and that immediately followed the cue evoked relatively weak responses. This response was due to a relative refractory period. 3. Next we tested attentional processes in these tasks that were independent of the visual response to the cue. We placed the cue outside of the receptive field and the target within the receptive field. We found that 23% of these cells had a significant decrease in their firing rate to validly cued targets in their receptive fields under these conditions. Strong responses were evoked by the same target when the cue was flashed in the opposite hemifield (invalidly cued targets). Thus this group of neurons responded best when attention was directed toward the opposite hemifield. 4. For another group of parietal cells (13%) there was an enhanced response to targets in the visual receptive field when the cue was in the same hemifield. For the remaining 64% of the cells there was no significant modulation in this task. 5. The cued reaction time task involved exogenous control of attention; the sensory cue gave spatial and temporal direction to attention. We used several other tasks to test for endogenous control of attention.(ABSTRACT TRUNCATED AT 400 WORDS)

Response to Visual, Chemical, and Tactile Stimuli

2020 ◽  
pp. 333-360
Author(s):  
Jonathan H. Cohen ◽  
Charles E. Epifanio
Keyword(s):  
Chemical Cues ◽  
Vertical Plane ◽  
Early Life History ◽  
Water Soluble ◽  
Future Research ◽  
Free Swimming ◽  
Egg Hatching ◽  
Tactile Stimuli ◽  
Settlement And Metamorphosis ◽  
Tactile Cues

Early life history in marine benthic crustaceans often includes externally brooded eggs that hatch into free-swimming planktonic larvae. These larvae are relatively strong swimmers, and movement in the vertical plane provides a number of advantages, including modulation of horizontal transport and assurance of favorable predator–prey interactions. Swimming behavior in larval crustaceans is regulated by predictable external cues in the water column, primarily light, gravity, and hydrostatic pressure. Light-regulated behavior depends upon the optical physics of seawater and the physiology of light-detecting sensory structures in the larvae, which overall vary little with ontogeny. Swimming in response to light contributes to ecologically significant behaviors in planktonic crustacean larvae, including shadow responses, depth regulation, and diel vertical migration. Moreover, the photoresponses themselves, and in turn the evoked behaviors, change with the needs of larvae as development progresses. Regarding other sensory modalities, crustacean embryos and larvae respond to chemical cues using bimodal sensilla (chemosensory and mechanosensory) as contact receptors, and aesthetascs for detection of water-soluble cues. Processes and behaviors are stimulated by larval detection of chemical cues throughout ontogeny, including egg-hatching, avoidance of predators during free-swimming stages, and, ultimately, settlement and metamorphosis in juvenile habitats. The latter process can also involve tactile cues. The sensory-mediated behaviors described here for crustacean larvae have parallels in numerous arthropod and nonarthropod taxa. Emerging directions for future research on sensory aspects of behavior in crustacean larvae include multimodal sensory integration and behavioral responses to changing environmental stressors.

New insights into the evolution of lateral compound eyes in Palaeozoic horseshoe crabs

2019 ◽  
Vol 187 (4) ◽  
pp. 1061-1077 ◽  
Author(s):  
Russell D C Bicknell ◽  
Lisa Amati ◽  
Javier Ortega-Hernández
Keyword(s):  
Convincing Evidence ◽  
Limulus Polyphemus ◽  
Phylogenetic Position ◽  
Compound Eyes ◽  
Crown Group ◽  
Widespread Occurrence ◽  
Eye Evolution ◽  
Stem Group ◽  
Lateral Eye ◽  
Horseshoe Crabs

Abstract Vision allows animals to interact with their environment. Aquatic chelicerates dominate the early record of lateral compound eyes among non-biomineralizing crown-group euarthropods. Although the conservative morphology of lateral eyes in Xiphosura is potentially plesiomorphic for Euarthropoda, synziphosurine eye organization has received little attention despite their early diverging phylogenetic position. Here, we re-evaluate the fossil evidence for lateral compound eyes in the synziphosurines Bunodes sp., Cyamocephalus loganensis, Legrandella lombardii, Limuloides limuloides, Pseudoniscus clarkei, Pseudoniscus falcatus and Pseudoniscus roosevelti. We compare these data with lateral eyes in the euchelicerates Houia yueya, Kasibelinurus amicorum and Lunataspis aurora. We find no convincing evidence for lateral eyes in most studied taxa, and Pseudoniscus roosevelti and Legrandella lombardii are the only synziphosurines with this feature. Our findings support two scenarios for euchelicerate lateral eye evolution. The elongate-crescentic lateral eyes of Legrandella lombardii might represent the ancestral organization, as suggested by the phylogenetic position of this taxon in stem-group Euchelicerata. Alternatively, the widespread occurrence of kidney-shaped lateral eyes in stem-group Xiphosura and stem-group Arachnida could represent the plesiomorphic condition; Legrandella lombardii eyes would therefore be derived. Both evolutionary scenarios support the interpretation that kidney-shaped lateral eyes are ancestral for crown-group Euchelicerata and morphologically conserved in extant Limulus polyphemus.

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