Long-term study of behaviors of two cohabiting sea urchin species, <i>Mesocentrotus nudus</i> and <i>Strongylocentrotus intermedius</i>, under conditions of high food quantity and predation risk in situ

Жадан, П. М.; Vaschenko, Marina A.

doi:10.7717/peerj.8087

Cited by 10 publications

(9 citation statements)

References 70 publications

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“…In this experiment, sea urchins did not form significant aggregations under the condition of evenly distributed food. This is different from the results of food-induced sea urchin aggregation reported in the field 2 , 13 , 30 . This difference indicates that the aggregation of sea urchins highly depends on condition of the food sources.…”

Section: Discussioncontrasting

confidence: 99%

Interaction among sea urchins in response to food cues

Sun

Zhao

et al. 2021

Sci Rep

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Interaction among sea urchins remains largely uninvestigated, although the aggregation of sea urchins is common. In the present study, 1, 15 and 30 sea urchins Strongylocentrotus intermedius (11.06 ± 0.99 mm in test diameter) were placed in a 1 m2 circular tank, respectively. Movement behaviors were recorded for 12 min to investigate potential interactions among sea urchins. After the 12-min control period, we added food cues into the tank and recorded the changes in sea urchins’ behaviors. For the first time, we here quantified the interactions among sea urchins in laboratory and found that the interactions varied with food cues and with different densities. The sea urchins dispersed in random directions after being released. There was no significant difference in the movement speed and the displacement of sea urchins among the three density groups (1, 15 and 30 ind/m2). The interaction occurred when sea urchins randomly contacted with the conspecifics and slowed down the movement speed. The speed of sea urchins after physical contacts decreased by an average of 40% in the density of 15 ind/m2 and 17% in the density of 30 ind/m2. This interaction resulted in significantly higher randomness in the movement direction and lower movement linearity in 15 and 30 ind/m2 than in 1 ind/m2. After the introduction of food cues, the movement speed, displacement and dispersal distance of sea urchin groups decreased significantly in all the three densities. The dispersal distance and expansion speed of sea urchins were significantly lower in 30 ind/m2 than those in 15 ind/m2. The present study indicates that the interaction among sea urchins limits the movement of individual sea urchin and provides valuable information into how large groups of sea urchins are stable in places where food is plentiful.

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Section: Discussioncontrasting

confidence: 99%

Interaction among sea urchins in response to food cues

Sun

Zhao

et al. 2021

Sci Rep

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“…The field studies were conducted in two bays in the northwestern Sea of Japan, Kievka Bay (42.830 N,133.691 E) and Alekseev Bay (42.981 N,131.730 E). Six separate sets of observations were performed from 2014-2019, two in Kievka Bay (August-September of 2014and 2015 and four in Alekseev Bay (May-June of 2016, July-September of 2017, June-September of 2018 and 2019). The objects of our studies were two sea urchin species, S. intermedius and M. nudus, which are common inhabitants of coastal communities in the study areas.…”

Section: Study Areas Sea Urchins and Video Recordingsmentioning

confidence: 99%

“…To attract sea urchins to the cameras' fields of view, flat mesh containers filled with the kelp Saccharina japonica (Laminariales, Phaeophyta), which is known to stimulate foraging activity in M. nudus and S. intermedius (Zhadan & Vaschenko, 2019), were used. Each container (hereafter the feeder) was composed of 2 steel frames with mesh stretched across them, 1.1 × 0.75 m in size, and contained 30-40 kg of kelp.…”

Section: Study Areas Sea Urchins and Video Recordingsmentioning

confidence: 99%

“…org/items/detail.cfm?ID=7365) we traced the spawning males and females with an interval of 1 min. The distance between two successive positions of the sea urchin (1 min apart) was defined as the step length (Lauzon-Guay, Scheibling & Barbeau, 2006;Zhadan & Vaschenko, 2019). The cell size (2 × 2 cm) of the feeder mesh was used as a scale.…”

Section: Video Recording and Statistical Analysesmentioning

confidence: 99%

“…Both experimental and field studies show that sea urchins use chemosensation to avoid predators as well as to find food (Campbell et al, 2001;Mann et al, 1984;Spyksma, Taylor & Shears, 2017;Zhadan & Vaschenko, 2019). Genomic analysis suggests that an elaborate chemosensory system involving several hundred putative chemoreceptor genes, in particular those encoding olfactory receptors, operates in sea urchins (Burke et al, 2006;Raible et al, 2006).…”

Section: Sea Urchin Males and Females Become Closer During Mass Spawningmentioning

confidence: 99%

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Quantitative study of the behavior of two broadcast spawners, the sea urchinsStrongylocentrotus intermediusandMesocentrotus nudus, during mass spawning events in situ

Жадан

Vaschenko

Permyakov

2021

PeerJ

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Background The spatial distribution of spawners and temporal parameters of spawning in motile invertebrates with external fertilization might influence reproductive success. However, to date, data on the prespawning and spawning behaviors of broadcast spawners in the field have been scarce and mostly qualitative. The present study was intended to clarify the behavioral adaptations of two sea urchin species, Strongylocentrotus intermedius and Mesocentrotus nudus, using quantitative analysis of their behavior during mass spawning events under natural conditions. Methods We analyzed in situ video recordings of sea urchin behavior obtained during six spawning seasons (2014–2019). The total number of specimens of each sea urchin species and the numbers of spawning males and females were counted. Quantitative parameters of sea urchin spawning (numbers of gamete batches, release duration of one gamete batch, time intervals between gamete batches and total duration of spawning) and movement (step length of spawners and nonspawners before and during spawning and changes in distances between males/nonspawners and females) were determined. Results For each species, 12 mass spawning events were recorded in which 10 or more individuals participated. The temporal dynamics of the numbers of males and females participating in mass spawning were well synchronized in both species; however, males began to spawn earlier and ended their spawning later than females. In both species, the most significant intersex difference was the longer spawning duration in males due to the longer pause between gamete batches. The total duration of gamete release did not differ significantly between sexes. The average duration of sperm release during mass spawning events was longer than solitary male spawning. Males and females showed significant increases in the locomotion rate 35 min before the start of spawning and continued to actively move during spawning. An increase in movement rate before spawning in males and females was induced by environmental factor(s). Nonspawners of both species showed increased locomotion activity but in the presence of spawning neighbors and less prominently than spawners. On a vertical surface, both echinoids moved strictly upward. On flat surfaces, males, females and nonspawners of both echinoids became closer during spawning. Discussion We showed that two sea urchin species with planktotrophic larvae display similar behavioral adaptations aimed at enhancing reproductive success. The high sensitivity of sea urchins, primarily males, to some environmental factors, most likely phytoplankton, may be considered a large-scale adaptation promoting the development of mass spawning events. The longer spawning duration in males and increased movement activity before and during spawning in both sexes may be considered small-scale adaptations promoting approach of males and females and enhancing the chances of egg fertilization.

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Who are We, and Who (or What) Do We Want to Become? An Evolutionary Perspective on Biotransformative Technologies

Lyons‐Weiler¹

2021

Biol Theory

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Human evolution sits at several important thresholds. In organic evolution, interplay between exogenous environmental and genetic factors rendered new phenotypes at rates limited by genetic variation. The interplay took place on adaptive fitness landscapes determined by correspondence of genetic and environmental relationships. Human evolution involved important emergences that altered the adaptive landscape: language, writing, organized societies, science, and the internet. These endogenous factors ushered in transformative periods leading to more rapidly evolving emergences. I explore the impact of development of emerging biotransformative technologies capable of being applied to effect self-genetic modification and artificial intelligence-augmented cognition on the evolutionary landscape of phenotypes important to cognitive plasticity. Interaction effects will yield unanticipated emergences resulting in hyperrealm adaptive landscapes with more rapid evolutionary processes that feed back upon more fundamental levels while vastly outpacing organic evolution. Emerging technologies exist that are likely to impact the evolution of cognitive plasticity in humans in ways and at rates that will lead to societal upheaval. I show that the theoretical contribution of organic evolution in future human evolution is expected to become comparatively insignificant relative to that made by endogenous environmental factors such as external cognition aids and manipulation of the human genome. The results support the conclusion of a strong recommendation of a moratorium on the adoption of any technology capable of completely altering the course of human evolution.

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Long-term study of behaviors of two cohabiting sea urchin species, Mesocentrotus nudus and Strongylocentrotus intermedius, under conditions of high food quantity and predation risk in situ

Cited by 10 publications

References 70 publications

Interaction among sea urchins in response to food cues

Interaction among sea urchins in response to food cues

Quantitative study of the behavior of two broadcast spawners, the sea urchinsStrongylocentrotus intermediusandMesocentrotus nudus, during mass spawning events in situ

Who are We, and Who (or What) Do We Want to Become? An Evolutionary Perspective on Biotransformative Technologies

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