Citation: Research shows copepods use pheromones to find mates (2014, January 28) retrieved 18 August 2019 from https://phys.org/news/2014-01-copepods-pheromones.html (Phys.org) —Copepods are tiny crustaceans, only millimeters long. Distributed sparsely in sea and fresh water, hundreds of body lengths may separate them. Oceanographer Laurent Seuront and biological physicist H. Eugene Stanley wanted to know how these small creatures find mates, as it would be unlikely for them to bump into each other accidently. In a study published in the Proceedings of the National Academy of Sciences, they determined that copepods change their movement patterns in response to pheromones produced by the opposite sex. One cubic meter of water may contain only a few copepods. As distances between individuals are very great, they cannot wait for chance encounters and must actively pursue potential mates in order for their species to survive. Because the strategy for locating mates must work over long distances, relative to the animals’ size, hydromechanical signals would not be effective, as such signals decay quickly. Therefore, it is likely that copepods use pheromones to find each other. Biologists already know that female copepods leave chemical trails, which males follow. However, previous experiments examining male trail-following behavior studied copepods in still water, in a laboratory environment. Copepods often live in turbulent environments, at the ocean’s surface and in estuaries, and Seuront and Stanley wanted to see how turbulence would affect the crustaceans’ responses to chemical signals.The researchers studied two copepod species found in the northern hemisphere: Temora longicornis, which lives in coastal waters, and Eurytemora affinis, which lives in estuaries. They placed male and females of both species in coastal or estuarial water that simulated their natural environments. Before placing the subjects in the water, Seuront and Stanley conditioned the water by placing various concentrations of copepods of the opposite sex in it and allowing them to remain there for 24 hours.Seuront and Stanley found that conditioning the water affected how the subjects moved. As the concentration of opposite sex copepods used to condition the water increased, movements became less random. Eventually, when the density was high enough, subjects began displaying movements associated with intense search strategies that depend on focusing on cues. These movements suggested that the copepods were reacting to pheromones released in the water during conditioning.Females and non-virgin males of both species displayed this change in movement pattern. However, virgin T. longicornis and E. affinis males did not show any response to female-conditioned water. This suggests that females have an innate response to male pheromones, while the male response to female pheromones is learned. The researchers think that as males gain mating experience, they learn how the pheromone field created by females can help them locate mates. Explore further Open wide: Zebrafish fool fast food Journal information: Proceedings of the National Academy of Sciences Copepod. Credit: Uwe Kils/Wikipedia This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. © 2014 Phys.org More information: Anomalous diffusion and multifractality enhance mating encounters in the ocean, Laurent Seuront, PNAS, DOI: 10.1073/pnas.1322363111AbstractFor millimeter-scale aquatic crustaceans such as copepods, ensuring reproductive success is a challenge as potential mates are often separated by hundreds of body lengths in a 3D environment. At the evolutionary scale, this led to the development of remote sensing abilities and behavioral strategies to locate, to track, and to capture a mate. Chemoreception plays a crucial role in increasing mate encounter rates through pheromone clouds and pheromone trails that can be followed over many body lengths. Empirical evidence of trail following behavior is, however, limited to laboratory experiments conducted in still water. An important open question concerns what happens in the turbulent waters of the surface ocean. We propose that copepods experience, and hence react to, a bulk-phase water pheromone concentration. Here we investigate the mating behavior of two key copepod species, Temora longicornis and Eurytemora affinis, to assess the role of background pheromone concentration and the relative roles played by males and females in mating encounters. We find that both males and females react to background pheromone concentration and exhibit both innate and acquired components in their mating strategies. The emerging swimming behaviors have stochastic properties that depend on pheromone concentration, sex, and species, are related to the level of reproductive experience of the individual tested, and significantly diverge from both the Lévy and Brownian models identified in predators searching for low- and high-density prey. Our results are consistent with an adaptation to increase mate encounter rates and hence to optimize reproductive fitness and success.
Kolkata: The fate of the iconic Priya Cinema Hall in South Kolkata, where a fire had broken out recently, continues to hang in the balance with the owner saying on Monday that he is unsure if the building would be used as a single-screen theatre, or for some other business activity. Arijit Dutta, the owner of Priya Entertainments, said he was flooded with requests to reopen the theatre. “All my family members and friends want me to re-open the 60-year-old theatre as public sentiment is involved with Priya Cinema. The single-screen theatre has witnessed special screenings of many cult Bengali films in the past few decades. I am yet to take a call on the matter,” he said. Also Read – Rain batters Kolkata, cripples normal lifeThe fire had started on the first-floor office of the hall around 10.15 pm on August 4, leading to panic among the late-night show viewers. They were, however, safely evacuated. After inspection, authorities of the Fire department claimed to have found shortcomings in the safety measures at the cinema hall. In a notice, the department asked the owners to install water sprinklers and smoke detectors within the auditorium for getting a “no-objection” certificate. Dutta said he was ready to abide by the directions of the Fire department, but insisted that the suggested norms were not common features in single screens across the country. “To my knowledge, no single screen theatre in the country has the equipment suggested by the officials. However, we are ready to go by the directions, considering public safety aspects,” he said.
3 min read Free Webinar | Sept 5: Tips and Tools for Making Progress Toward Important Goals Register Now » February 27, 2015 American mathematician John Allen Paulos once said: “Uncertainty is the only certainty there is, and knowing how to live with insecurity is the only security.”He’s right, and it’s very important to remember in light of the Federal Communications Commission today adopting net neutrality rules by a 3-2 vote.Many of those who disagree with the decision, such as Mark Cuban, based their opposition in the notion that FCC oversight of the Internet (including wireless) creates uncertainty that will imperil future innovation. Not only for Internet service providers like Comcast and Verizon, but also for the next generation of content provider that must rely on ISP infrastructure to deliver their wares.“If you’re like me and you think the best is yet to come, you don’t want the FCC involved because of all the uncertainty,” Cuban said today on CNBC. He added that because FCC commissioners are political appointees, we have no way of knowing who future commissioners will be or how they will wield their new powers.The only trouble is that uncertainty is not the exclusive province of things under government oversight. We had it before the vote, and would have had it no matter how many commissioners said ‘aye.’Absent net neutrality, do we know if ISPs would have created so-called “fast lanes” for content providers who are willing to pay a toll? Or simply slow down service of those who don’t? Do we know whether or not there will be a macro-economic event that slows down venture capital investment in new tech startups, or makes it harder for existing ones to go public? Do we know if some massive new data-hog will emerge, or if the ultimate Netflix killer is a company that somehow compresses the bits into something more manageable for existing pipes?Remember, we don’t even know that the broadband repair guy will show up between 1pm to 4pm, even though we are explicitly told that he will. Uncertainty all over the place.To be sure, it is possible that Cuban’s Internet doomsday will come to pass. I think it highly unlikely, but would never rule it out entirely. Likewise, it’s possible that net neutrality will result in greater innovation. After all, the law of unintended consequences swings both ways. And, in either case, future FCC appointees could make changes (just as future FCC appointees could have passed their own version of net neutrality rules, had today’s vote failed).All we really can do is make judgments based on the best information that is currently available. And reasonable people can disagree on it. But not if your opinion is based primarily on the specter of uncertainty, as if there is any legitimate alternative. Attend this free webinar and learn how you can maximize efficiency while getting the most critical things done right. This story originally appeared on Fortune Magazine