scholarly journals Chemical encoding of risk perception and predator detection among estuarine invertebrates

2018 ◽  
Vol 115 (4) ◽  
pp. 662-667 ◽  
Author(s):  
Remington X. Poulin ◽  
Serge Lavoie ◽  
Katherine Siegel ◽  
David A. Gaul ◽  
Marc J. Weissburg ◽  
...  

An effective strategy for prey to survive in habitats rich in predators is to avoid being noticed. Thus, prey are under selection pressure to recognize predators and adjust their behavior, which can impact numerous community-wide interactions. Many animals in murky and turbulent aquatic environments rely on waterborne chemical cues. Previous research showed that the mud crab, Panopeus herbstii, recognizes the predatory blue crab, Callinectus sapidus, via a cue in blue crab urine. This cue is strongest if blue crabs recently preyed upon mud crabs. Subsequently, mud crabs suppress their foraging activity, reducing predation by blue crabs. Using NMR spectroscopy- and mass spectrometry-based metabolomics, chemical variation in urine from blue crabs fed different diets was related to prey behavior. We identified the urinary metabolites trigonelline and homarine as components of the cue that mud crabs use to detect blue crabs, with concentrations of each metabolite dependent on the blue crab’s diet. At concentrations found naturally in blue crab urine, trigonelline and homarine, alone as well as in a mixture, alerted mud crabs to the presence of blue crabs, leading to decreased foraging by mud crabs. Risk perception by waterborne cues has been widely observed by ecologists, but the molecular nature of these cues has not been previously identified. Metabolomics provides an opportunity to study waterborne cues where other approaches have historically failed, advancing our understanding of the chemical nature of a wide range of ecological interactions.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elise Payzan-LeNestour ◽  
Lionnel Pradier ◽  
James Doran ◽  
Gideon Nave ◽  
Bernard Balleine

AbstractResearch in the field of multisensory perception shows that what we hear can influence what we see in a wide range of perceptual tasks. It is however unknown whether this extends to the visual perception of risk, despite the importance of the question in many applied domains where properly assessing risk is crucial, starting with financial trading. To fill this knowledge gap, we ran interviews with professional traders and conducted three laboratory studies using judgments of financial asset risk as a testbed. We provide evidence that the presence of ambient sound impacts risk perception, possibly due to the combination of facilitatory and synesthetic effects of general relevance to the perception of risk in many species as well as humans. We discuss the implications of our findings for various applied domains (e.g., financial, medical, and military decision-making), and raise new questions for future research.


Epidemiological studies on the leishmaniases are disclosing a multiplicity of Leishmania species infecting a wide range of wild mammalian hosts, from marsupials to monkeys. In the primitive, silvatic habitat these parasites are transmitted by an equally wide variety of phlebotomine sandfly species (Diptera: Psychodidae: Phlebotominae). Transmission is not haphazard, however, and available evidence points to the existence of environmental barriers that normally limit the different Leishmania species to specific sandfly vectors, transmitting to certain mammalian species, within distinct ecotopes. In this situation, humans may become infected by a variety of leishmanial parasites when intruding into the different enzootics, if the sandfly vectors are anthropophilic. Many are not, however, and their parasites rarely, if ever, make contact with the human host. Natural or man-made ecological changes may result in modification of the epidemiological pattern of leishmaniasis, leading to either a reduction or an increase in the human disease.


2021 ◽  
Vol 288 (1944) ◽  
pp. 20202716
Author(s):  
Steve Kett ◽  
Ayush Pathak ◽  
Stefano Turillazzi ◽  
Duccio Cavalieri ◽  
Massimiliano Marvasi

Arthropods can produce a wide range of antifungal compounds, including specialist proteins, cuticular products, venoms and haemolymphs. In spite of this, many arthropod taxa, particularly eusocial insects, make use of additional antifungal compounds derived from their mutualistic association with microbes. Because multiple taxa have evolved such mutualisms, it must be assumed that, under certain ecological circumstances, natural selection has favoured them over those relying upon endogenous antifungal compound production. Further, such associations have been shown to persist versus specific pathogenic fungal antagonists for more than 50 million years, suggesting that compounds employed have retained efficacy in spite of the pathogens' capacity to develop resistance. We provide a brief overview of antifungal compounds in the arthropods’ armoury, proposing a conceptual model to suggest why their use remains so successful. Fundamental concepts embedded within such a model may suggest strategies by which to reduce the rise of antifungal resistance within the clinical milieu.


Author(s):  
P.F. Stevens

Linnaeus was educated in Sweden, and became a doctor of medicine in Harderwijk, Holland, in 1735. He visited other European countries then, but he never left Sweden after his return in 1738. After practising as a physician in Stockholm, he moved to Uppsala University as professor of medicine and botany in 1741. He articulated four different but complementary ways of understanding nature – through two kinds of classification, and through what can be called developmental and functional/ecological interactions. Linnaeus is best known for his classificatory work, for which he received material from all over the world. His classificatory precepts are elaborated in the Philosophia botanica of 1751, an enlarged version of the 365 aphorisms of his Fundamenta botanica of 1735; the other aspects of his work are diffused through his writings. His artificial classification system, initially very popular, was replaced by the ’natural’ system, more slowly in botany than in zoology, and more slowly in England than in some other countries. Current biological nomenclature is based on his Species plantarum, edition 1 (for plants), and Systema naturae, edition 10 (for animals). His codification of botanical terms remains influential. Almost 200 dissertations, most written by Linnaeus, were defended by his students. In these and other less well-known works, including the unpublished Nemesis divina (Stories of Divine Retribution), he covered a wide range of subjects. Quinarian thinking is noticeable in Linnaeus’ work – there are five ranks in systems, five years’ growth in flowers – and in some of the occult works that he knew. He also shows a strong combinatorial bent and a tendency to draw close analogies between the parts of animals and plants.


2008 ◽  
Vol 276 (1656) ◽  
pp. 437-445 ◽  
Author(s):  
Graham R Martin ◽  
Theunis Piersma

Visual fields were determined in two species of shorebirds (Charadriiformes) whose foraging is guided primarily by different sources of information: red knots ( Calidris canutus , tactile foragers) and European golden plovers ( Pluvialis apricaria , visual foragers). The visual fields of both species showed features that are found in a wide range of birds whose foraging involves precision pecking or lunging at food items. Surprisingly, red knots did not show comprehensive panoramic vision as found in some other tactile feeders; they have a binocular field surrounding the bill and a substantial blind area behind the head. We argue that this is because knots switch to more visually guided foraging on their breeding grounds. However, this visual field topography leaves them vulnerable to predation, especially when using tactile foraging in non-breeding locations where predation by falcons is an important selection factor. Golden plovers use visually guided foraging throughout the year, and so it is not surprising that they have precision-pecking frontal visual fields. However, they often feed at night and this is associated with relatively large eyes. These are anchored in the skull by a wing of bone extending from the dorsal perimeter of each orbit; a skeletal structure previously unreported in birds and which we have named ‘supraorbital aliform bone’, Os supraorbitale aliforme . The larger eyes and their associated supraorbital wings result in a wide blind area above the head, which may leave these plovers particularly vulnerable to predation. Thus, in these two shorebirds, we see clear examples of the trade-off between the two key functions of visual fields: (i) the detection of predators remote from the animal and (ii) the control of accurate behaviours, such as the procurement of food items, at close quarters.


1976 ◽  
Vol 39 (4) ◽  
pp. 258-262 ◽  
Author(s):  
R. W. DICKERSON ◽  
M. R. BERRY

Blue crabs are cooked in steam retorts or boiling water baths to assist in removing the meat from the shell. As a first step in determining if spores of Clostridium botulinum would survive the process, internal crab temperatures were measured during cooking in commercial plants. Tests were done in six states. Crabs were instrumented with thermocouples, and heating curves were recorded during normal commercial processing. The lowest terminal heating temperature achieved in an instrumented crab during steam retorting was 208 F; however, this temperature remained above 180 F for 4 min. In the boiling water bath, the terminal heating temperature was slightly lower (205 F) but the time above 180 F was longer (11 min).


2018 ◽  
Author(s):  
Kelsie L. Kelly ◽  
Caz M. Taylor

Blue crabs, Callinectes sapidus Rathbun, 1896, are ubiquitous along the Atlantic and Gulf coasts of the United States. These organisms play an integral role in the ecosystems of the Gulf of Mexico (GOM), where not only are they a keystone species, but are also socioeconomically important. The survival of embryonated eggs is necessary to ensure adequate recruitment into the next generation. Because the 2010 Deepwater Horizon oil spill (DWH) occurred during the peak of the blue crab spawning season, the incident likely impacted blue crab embryos. In order to assess the effect of oil on embryonic growth and development, we collected embryonated eggs from seven different female blue crabs from the GOM throughout the spawning season and exposed them to an oil concentration of 500 ppb (the approximate concentration of oil at the surface water near the site of the Deepwater Horizon oil rig). Exposure to oil at this concentration caused a significantly larger proportion of prezoeae versus zoeae to hatch from embryonated eggs in experiments lasting longer than 4 days. Exposure to oil did not significantly affect overall survival or development rate. The prezoeal stage is a little-studied stage of blue crab development. Though it may or may not be a normal stage of development, this stage has been found to occur in suboptimal conditions and has lower survival than zoeal stages. The larger proportion of prezoeae following prolonged exposure to oil thus indicates that crude oil at concentrations likely to be experienced by crabs after the DWH spill negatively impacted the development of blue crab embryos. In addition to providing insight into the effects of the Deepwater Horizon oil spill, this study sheds light on embryonic development in blue crabs, a critical, but poorly investigated phase of this important species’ life cycle.


Diversity ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 491
Author(s):  
Paul J. Rudershausen ◽  
Jeffery H. Merrell ◽  
Jeffrey A. Buckel

Tidal creeks along the southeastern U.S. and Gulf of Mexico coastlines provide nursery habitats for commercially and ecologically important nekton, including juvenile blue crabs Callinectes sapidus, a valuable and heavily landed seafood species. Instream and watershed urbanization may influence the habitat value that tidal creeks provide to blue crabs. We investigated natural and anthropogenic factors influencing juvenile blue crab occupancy dynamics in eight first-order tidal creeks in coastal North Carolina (USA). An auto-logistic hierarchical multi-season (dynamic) occupancy model with separate ecological and observation sub-models was fitted to juvenile blue crab presence/absence data collected over replicate sampling visits in multiple seasons at three fixed trapping sites in each creek. Colonization and survival are the processes operating on occupancy that are estimated with this formulation of the model. Covariates considered in the ecological sub-model included watershed imperviousness, the percent of salt marsh in each creek’s high tide area, percent salt marsh edge, site-level water depth, and site-level salinity. Temperature, salinity, and dissolved oxygen were covariates considered in the observation sub-model. In the ecological sub-model, watershed imperviousness was a meaningful negative covariate and site-level salinity was a positive covariate of survival probability. Imperviousness and salinity were each marginally meaningful on colonization probability. Water temperature was a positive covariate of detection probability in the observation sub-model. Mean estimated detection probability across all sites and seasons of the study was 0.186. The results suggest that development in tidal creek watersheds will impact occupancy dynamics of juvenile blue crabs. This places an emphasis on minimizing losses of natural land cover classes in tidal creek watersheds to reduce the negative impacts to populations of this important species. Future research should explore the relationship between imperviousness and salinity fluctuations in tidal creeks to better understand how changing land cover influences water chemistry and ultimately the demographics of juvenile blue crabs.


Author(s):  
Marie Chave ◽  
Valérie Angeon ◽  
Raphaël Paut ◽  
Robin Collombet ◽  
Marc Tchamitchian

Abstract Facing the challenge of the ecological transition of agriculture, biodiversity opens new avenues to enhance ecological interactions and reduce chemical input dependency. Designing biodiversity-based agrosystems requires an agroecological approach that combines key principles: exploring a wide range of concepts and solutions, adopting systemic reasoning, implementing a site-specific approach, developing an action-oriented process, and maintaining a continuous improvement dynamic. This type of approach has never been developed to harness mycorrhizal fungi, which are key components of soil biodiversity, because their beneficial action on crops depends on complex and underexploited ecological interactions. At present, mycorrhizae are mainly used through industrial inoculants that fit within the productionist paradigm. To shift toward agroecological approaches, we implemented a methodological framework conceived to better address the design of mycorrhiza-friendly cropping systems by sharing knowledge with farmers in four different study areas (Provence, French Guiana, Guadeloupe, and Martinique). This framework includes participative workshops, a board game, and prospective exercises to collect farmers’ proposals and the factors that prevent from implementing mycorrhiza-friendly cropping systems. We showed that 90% of the farmers proposed alternatives to industrial inoculants, 50% of them adopted systemic reasoning by combining these alternative proposals. Most farmers understood that they were all potential “mycorrhizae producers”. We showed, for the first time through on-farm experiments that valorization of indigenous mycorrhizal fungi strains using a donor plant is an effective practice to increase root colonization before planting (up to a frequency of 95% and an intensity of 32%). Considering the increasing supply of mycorrhizal inoculants and despite the uncertainty of related knowledge, we codesigned innovative practices. Learning communities (technical advisors, high school teachers, etc.) assumed responsibility for continuous improvement in knowledge and practices. Finally, beyond the issue of mycorrhizae, we showed that an agroecological approach could bring stakeholders one step further into the design of biodiversity-based agrosystems.


Check List ◽  
2016 ◽  
Vol 12 (6) ◽  
pp. 2006 ◽  
Author(s):  
Chiara Manfrin ◽  
Giovanni Comisso ◽  
Andrea Dall’Asta ◽  
Nicola Bettoso ◽  
J. Sook Chung

Since August 2015, an increasing number of Blue Crabs, Callinectes sapidus Rathbun, 1896, have been reported in the Marano and Grado Lagoon, Gulf of Trieste, in the northern Adriatic Sea. This species is not a new introduction and in fact the first record of C. sapidus in Italy and the entire Adriatic Sea dates back to 1949 in the Grado Lagoon. Interestingly, no other records of C. sapidus have been reported since the first record. Here, we note the re-appearance of C. sapidus in the Gulf of Trieste.


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