scholarly journals Swimming capacity and pleopod beat rate as a function of sex, size and moult stage in Northern krill Meganyctiphanes norvegica

2003 ◽  
Vol 250 ◽  
pp. 205-213 ◽  
Author(s):  
MA Thomasson ◽  
ML Johnson ◽  
JO Strömberg ◽  
E Gaten
Keyword(s):  
Moult Stage ◽  
Beat Rate ◽  
Meganyctiphanes Norvegica ◽  
Swimming Capacity

scholarly journals On the Stability of a Stochastic Nonlinear Model of the Heart Beat Rate During a Treadmill Exercise

2020 ◽  
Vol 53 (2) ◽  
pp. 16457-16461
Author(s):  
Mohammad Mostafa Asheghan ◽  
Bahram Shafai ◽  
Joaquín Míguez
Keyword(s):  
Nonlinear Model ◽  
Treadmill Exercise ◽  
Heart Beat ◽  
Beat Rate ◽  
Heart Beat Rate ◽  
The Stability

Experimental Studies of Plankton Luminescence

1964 ◽  
Vol 44 (2) ◽  
pp. 435-484 ◽  
Author(s):  
A. C. Hardy ◽  
R. H. Kay
Keyword(s):  
Breeding Season ◽  
Laboratory Study ◽  
Experimental Studies ◽  
Observation Chamber ◽  
Inhibiting Effect ◽  
Main Work ◽  
Mechanical Disturbance ◽  
Meganyctiphanes Norvegica ◽  
Effect Of Light

Experimental studies of plankton luminosity have been made with specially designed photomultiplier equipment; this records (on a Servograph Recorder) the flashes given off either by a sample of plankton or by individual animals placed in a container in a dark observation chamber. The apparatus is described.Apart from preliminary laboratory records on the flashing of Beroë, Pleurobrachia and Pyrosoma, and record of the general luminosity in the sea at a depth of 62 m (made with an underwater version of the apparatus), the main work has been a laboratory study of the luminescence of dinoflagellates and of the euphausiacean Meganyctiphanes norvegica.The dinoflagellate experiments showed the inhibiting effect of light, both natural and artificial, on luminescence, and the stimulating effect of mechanical disturbance which may override the former inhibition. A rise in temperature increased luminosity and cooling reduced it. A difference in the pattern of the luminosity of plankton samples containing dinoflagellates was shown by the introduction of actively swimming animals of different kinds. The dinoflagellates in the samples were mainly Peridinium depressum, Ceratium horridum and C. tripos var. balticum.The Meganyctiphanes experiments showed a spontaneous flashing in seventeen out of twenty-seven tests and in one test the animals maintained such activity for the greater part of a 24 h period. In addition to their bright flashing, the photophores would at times keep up a dull glow for long periods (especially see the observations of F. Körte in the Appendix). Spontaneous flashing does not only occur in the breeding season as had been suggested by Mauchline (1960).

The Swimming Capacity of the Golden Hamster

1963 ◽  
Vol 44 (2) ◽  
pp. 265
Author(s):  
Charles G. Wilber
Keyword(s):  
Golden Hamster ◽  
Swimming Capacity

The Euphausiidæ in the Neighbourhood of Plymouth. II. Nyctiphanes Couchii and Meganyctiphanes noruegica.

1925 ◽  
Vol 13 (4) ◽  
pp. 810-847 ◽  
Author(s):  
Marie V. Lebour
Keyword(s):  
Life History ◽  
Remaining Life ◽  
Larval Stages ◽  
History Of ◽  
Meganyctiphanes Norvegica

The present paper is a continuation of last year's work on the Euphausiidæ in the neighbourhood of Plymouth (Lebour, 1924), in which the early larval stages were described of Nyctiphanes Couchii, Meganyctiphanes norvegica and, less fully, those of Thysanoessa inermis and T. neglecta. These two last-named forms are reserved for a detailed description in another paper, only Nyctiphanes and Meganyctiphanes being dealt with here. The first paper described these as far as the last Calyptopis stages, and it was shown that they were much alike although perfectly distinct, especially as regards colour. The nauplii and metanauplii were easily distinguishable. The whole of the remaining life-history of Nyctiphanes Couchii has now been elucidated and also that of Meganyctiphanes norvegica, with the exception of a few late larval stages. The absence of these, however, does not materially affect our knowledge of its life-history.

scholarly journals Guppies prefer to follow large (robot) leaders irrespective of own size

2018 ◽  
Author(s):  
David Bierbach ◽  
Hauke J. Mönck ◽  
Juliane Lukas ◽  
Marie Habedank ◽  
Pawel Romanczuk ◽  
...  
Keyword(s):  
Body Size ◽  
Risk Taking ◽  
Poecilia Reticulata ◽  
Direct Evidence ◽  
Behavioral Patterns ◽  
Behavioral Differences ◽  
Leaders And Followers ◽  
Biomimetic Robotic Fish ◽  
Risk Taking Behavior ◽  
Swimming Capacity

AbstractBody size is often assumed to determine how successful an individual can lead others with larger individuals being more likely to lead than smaller ones. However, direct evidence for such a relation is scarce. Furthermore, even if larger individuals are more likely to lead, body size correlates often with specific behavioral patterns (e.g., swimming capacity) and it is thus unclear whether larger individuals are more often followed than smaller ones because they are larger or because they behave in a certain way. To control for behavioral differences among differentially-sized leaders, we used biomimetic robotic fish – Robofish – of different sizes. Robofish is accepted as a conspecific by live guppies (Poecilia reticulata) and provides standardized behaviors irrespective of its size. We specifically asked whether larger leaders are preferentially followed when behavior is controlled for and whether the preferences of followers depend on their own body size or their risk taking behavior (‘boldness’). We found that live guppies followed larger Robofish leaders closer than smaller ones and this pattern was independent of the followers’ own body size as well as risk-taking behavior. This is the first study that shows a ‘bigger is better’ pattern in leadership in shoaling fish that is fully independent of behavioral differences between differentially-sized leaders and followers’ own size and personality.

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