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.

Mating Behavior of Horseshoe Crabs, Limulus Polyphemus

Behaviour ◽  
1990 ◽  
Vol 114 (1-4) ◽  
pp. 206-220 ◽  
Author(s):  
H. Jane Brockmann
Keyword(s):  
Sperm Competition ◽  
Mating Behavior ◽  
Female Choice ◽  
Breeding System ◽  
Reproductive System ◽  
Full Moon ◽  
Experimental Manipulation ◽  
Limulus Polyphemus ◽  
Horseshoe Crabs ◽  
Satellite Males

AbstractHorseshoe crabs have an explosive breeding system not unlike that of some frogs and toads. They synchronize nesting to only a few hours each day at the time of the spring new and full-moon high tides. Males search for females as they come to the breeding beaches, grasp them with specially modified claws and cling to them, sometimes for weeks. Females lay several clutches of eggs in the sand and the male fertilizes them externally, the only extant arthropod with such a reproductive system. Unattached males cluster around the nesting couple, pushing on and occasionally displacing attached males. An experimental manipulation demonstrated that satellite males are capable of fertilizing eggs which suggests that sperm competition is the primary explanation for the presence of unattached males on the beach. Like other explosively breeding species, male Limulus search for females, often grabbing inappropriate objects, and satellite males compete for access to females. There is little assortative mating and attached and unattached males do not differ in size. In extreme explosively breeding species like Limulus, selection favors those males that are best able to locate and remain attached to females, and there is little opportunity for female choice or male-male competition.

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 Concerns Related to the COVID-19 in Adult Norwegians during the First Outbreak in 2020: A Qualitative Approach

2021 ◽  
Vol 18 (8) ◽  
pp. 4312
Author(s):  
Laila Skogstad ◽  
Inger Schou-Bredal ◽  
Tore Bonsaksen ◽  
Trond Heir ◽  
Øivind Ekeberg ◽  
...  
Keyword(s):  
Qualitative Analysis ◽  
Educational Level ◽  
Qualitative Approach ◽  
Cross Sectional ◽  
Response Options ◽  
Serious Illness ◽  
Additional Information ◽  
Qualitative Thematic Analysis ◽  
Norwegian Population ◽  
Shed Light

Concerns related to the first outbreak of the COVID-19 pandemic in the Norwegian population are studied in a cross-sectional web-survey conducted between 8 April and 20 May 2020. The qualitative thematic analysis of the open-ended question “Do you have other concerns related to the pandemic?”, followed a six-step process. Concerns from 1491 informants were analyzed, 34% of women and 30% of men (p = 0.05) provided concerns. Respondents with higher educational level reported concerns more often (86% vs. 83%, p = 0.022). The qualitative analysis revealed five themes—society, health, social activities, personal economy and duration—and 13 sub-themes, mostly related to the themes “society” and “health” (724 and 704, respectively). Empathy for others was prominent, for society (nationally and globally), but also concerns related to infecting others and family members at risk for developing serious illness if infected. The responses to the open-ended question yielded additional information, beyond the information obtained from questions with pre-categorized response options, especially related to concerns about society and health. Themes arising from the qualitative analysis shed light on what are important concerns for people during the pandemic and this may serve as targeted measures for the authorities.

scholarly journals Interstellar and interplanetary solids in the laboratory

2015 ◽  
Vol 11 (A29B) ◽  
pp. 416-419 ◽  
Author(s):  
Emmanuel Dartois ◽  
Ivan Alata ◽  
Cécile Engrand ◽  
Rosario Brunetto ◽  
Jean Duprat ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Environmental Parameters ◽  
Interstellar Matter ◽  
Additional Information ◽  
Set Constraints ◽  
Physico Chemical ◽  
Space Environments ◽  
Chemical Conditions ◽  
Extraterrestrial Material ◽  
Shed Light

AbstractThe composition of interstellar matter is driven by environmental parameters and results from extreme interstellar medium physico-chemical conditions. Astrochemists must rely on remote observations to monitor and analyze the interstellar solids composition. They bring additional information from the study of analogues produced in the laboratory, placed in simulated space environments. Planetologists and cosmochemists access and spectroscopically examine collected extraterrestrial material in the laboratory. Diffuse interstellar medium and molecular clouds observations set constraints on the composition of organic solids that can then be compared with collected extraterrestrial materials analyses, to shed light on their possible links.

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.

scholarly journals Forensic NMR metabolomics: one more arrow in the quiver

Metabolomics ◽  
2020 ◽  
Vol 16 (11) ◽  
Author(s):  
Emanuela Locci ◽  
Giovanni Bazzano ◽  
Alberto Chighine ◽  
Francesco Locco ◽  
Ernesto Ferraro ◽  
...  
Keyword(s):  
Drugs Of Abuse ◽  
Recent Literature ◽  
Metabolic Profiles ◽  
Time Since Death ◽  
Post Mortem ◽  
Nmr Metabolomics ◽  
Additional Information ◽  
Shed Light ◽  
Metabolic Signatures

Abstract Introduction NMR metabolomics is increasingly used in forensics, due to the possibility of investigating both endogenous metabolic profiles and exogenous molecules that may help to describe metabolic patterns and their modifications associated to specific conditions of forensic interest. Objectives The aim of this work was to review the recent literature and depict the information provided by NMR metabolomics. Attention has been devoted to the identification of peculiar metabolic signatures and specific ante-mortem and post-mortem profiles or biomarkers related to different conditions of forensic concern, such as the identification of biological traces, the estimation of the time since death, and the exposure to drugs of abuse. Results and Conclusion The results of the described studies highlight how forensics can benefit from NMR metabolomics by gaining additional information that may help to shed light in several forensic issues that still deserve to be further elucidated.

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