A non-destructive test was developed to measure the static mechanical properties of the locomotor structure (bell) in the hydromedusan jellyfish, Polyorchis penicillatus (Eschscholtz, 1829). A nonlinear stress-strain relationship was found, and the mean static structural stiffness of the bell was 150 N m−2. Visualization procedures that showed the natural changes in the geometry of the deformation of the bell were used to calculate the static modulus of elasticity of the mesoglea, and gave a modulus of 400 N m−2. Dynamic measurements on isolated samples of mesoglea gave a mean storage modulus of 1000 N m−2. The resilience of the material was about 58%. These data were integrated to imply that the dynamic structural stiffness of the bell is at least 400 N m−2. Attempts to measure the dynamic structural stiffness directly indicate that the dynamic stiffness of the intact bell lies between 400 and 1000 N m−2. All, or most, of the potential energy stored in the mesoglea during contractions of the bell is stored as strain energy in the radial mesogleal fibres.
In the field: an interview with Harald Wolf
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In our new Conversation, Harald Wolf talks about his fieldwork experiences working with desert ants in Tunisia to understand their navigation.
Propose a new Workshop
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Our Workshops bring together leading experts and early-career researchers from a range of scientific backgrounds. Applications are now open to propose Workshops for 2024, one of which will be held in a Global South country.
Julian Dow steps down and John Terblanche joins the JEB team
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After 15 years with the journal, Julian Dow from University of Glasgow, UK, is stepping down as a Monitoring Editor. We wish Julian all the best for the future and welcome John Terblanche, Stellenbosch University, South Africa, who is joining the team. Julian talks about his long association with The Company of Biologists and the journal and John tells us about his life and career in this News article.
The capture of crude oil droplets by filter feeders at high and low Reynolds numbers
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Researchers from the University of Montreal, Canada, reveal how tiny filter feeding barnacles and Daphnia entrap and consume minute droplets of crude oil, introducing the pollutant at the bottom of the food chain.
Patterns and processes in amphibious fish
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In their Review, Keegan Lutek, Cassandra Donatelli and Emily Standen discuss the biomechanics and neural control of terrestrial locomotion in amphibious fish. They explore how locomotor mode depends on body shape, physical constraints and phylogeny.
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