scholarly journals Predation on settling bivalve larvae by benthic suspension feeders: the role of hydrodynamics and larval behaviour

1993 ◽  
Vol 97 ◽  
pp. 183-192 ◽  
Author(s):  
C Andre ◽  
PR Jonsson ◽  
M Lindegarth
2018 ◽  
Vol 75 (2) ◽  
pp. 193-200 ◽  
Author(s):  
Bernhard Zens ◽  
Martin Glas ◽  
Michael Tritthart ◽  
Helmut Habersack ◽  
Hubert Keckeis

The dispersal of fish larvae in rivers might result from water movement but also from larval behaviour. Although potentially crucial for dispersion, knowledge of the role of behaviour is still fragmentary. This study intends to contribute to the question of how riverine fish larvae drift or move. All dispersal-relevant movement patterns of larvae of a characteristic rheophilic species were analyzed based on the parameters (i) swimming activity, (ii) direction of movement, and (iii) the orientation towards the current vector. Experiments were conducted in a novel flume mesocosm at three different flow scenarios covering the current velocity range of natural habitats. Mean current velocities in these scenarios were under, near, and over the “critical current velocity”, above which fish larvae are not able to constantly hold their position in the water column. Three consecutive larval stages were tested to account for possible ontogenetic shifts in movement behaviour, both during the day and at night. Our results strongly suggest that the assumption of mainly passively drifting larvae has to be refused; in total, 92.6% of all observed movement events were characterized by swimming activity and directed orientation, whereas only 7.4% could be assigned to passive drift. During downstream movement, a significant portion of movement events (57.1%) was attributed to larvae that orientated in an upstream direction and performed active swimming movements.


Open Biology ◽  
2017 ◽  
Vol 7 (8) ◽  
pp. 170136 ◽  
Author(s):  
Daniel Thiel ◽  
Philipp Bauknecht ◽  
Gáspár Jékely ◽  
Andreas Hejnol

Animal behaviour often comprises spatially separated sub-reactions and even ciliated larvae are able to coordinate sub-reactions of complex behaviours (metamorphosis, feeding). How these sub-reactions are coordinated is currently not well understood. Neuropeptides are potential candidates for triggering larval behaviour. However, although their immunoreactivity has been widely analysed, their function in trochozoan larvae has only been studied for a few cases. Here, we investigate the role of neuropeptides in the defence behaviour of brachiopod larvae. When mechanically disturbed, the planktonic larvae of Terebratalia transversa protrude their stiff chaetae and sink down slowly. We identified endogenous FLRFamide-type neuropeptides (AFLRFamide and DFLRFamide) in T. transversa larvae and show that the protrusion of the chaetae as well as the sinking reaction can both be induced by each of these peptides. This also correlates with the presence of FLRFamidergic neurons in the apical lobe and adjacent to the trunk musculature. We deorphanized the AFLRFamide/DFLRFamide receptor and detected its expression in the same tissues. Furthermore, the ability of native and modified FLRFamide-type peptides to activate this receptor was found to correspond with their ability to trigger behavioural responses. Our results show how FLRFamide-type neuropeptides can induce two coherent sub-reactions in a larva with a simple nervous system.


2014 ◽  
Vol 506 ◽  
pp. 15-30 ◽  
Author(s):  
N Weidberg ◽  
C Lobón ◽  
E López ◽  
L García Flórez ◽  
MdP Fernández Rueda ◽  
...  
Keyword(s):  

2008 ◽  
Vol 82 (2) ◽  
pp. 351-361 ◽  
Author(s):  
Ján Schlögl ◽  
Jozef Michalik ◽  
Kamil Zágorŝek ◽  
François Atrops

A Lower Tithonian cavity-dwelling community from pelagic carbonate platform deposits of the Czorsztyn Unit, Western Carpathians, represents a succession of mostly solitary coelobite organisms, dominated by scleractinian corals and small-sized serpulids during the initial recruitment stage, and by serpulids during the following recruitment stages. These bioconstructors were accompanied with other suspension feeders: thecideidine brachiopods, oysters, bryozoans, sponges, crinoids and sessile foraminifers. The boundary between the first and the second recruitment stage represents an interval of aggregate growth interruption, when a thin sheet of cyclostome bryozoans developed. Corals and serpulids Neovermilia and Vermiliopsis are primary bioconstructors; all other associated organisms profited from the free spaces between the serpulid tubes. The aggregates were already bioeroded, mineralized and encrusted during their growth. Serpulid larvae show a special recruitment pattern. Their tubes were observed attached on the inner surfaces of adult serpulid tubes only. Possible causes of such a larval behaviour involve several physical, biological or chemical factors. Except for the first recruitment stage, the rest of the succession seems to be physically controlled by the gradual infilling of cavities.


2005 ◽  
Vol 83 (1) ◽  
pp. 51-61 ◽  
Author(s):  
William R Bates

Protochordate reproduction and development are influenced by many kinds of environmental factors. For example, spawning, sexual and asexual reproduction, larval behaviour, and life-cycle transitions (metamorphosis) are key processes known to be affected by environmental factors. This review must be restricted primarily to only one group of protochordates, the ascidians or "sea squirts", because information on the reproductive ecology of hemichordates and cephalochordates is limited to only a few studies. Topics discussed in the present review include (i) environmental factors that regulate larval settlement, (ii) how pelagic embryos avoid damage to DNA caused by UV radiation, (iii) the effect of water temperature and food availability on sexual reproduction in colonial ascidians, (iv) environmental regulation of asexual budding, (v) environmental regulation of metamorphosis, and (vi) the possible role of the environment in the evolution of direct-developing ascidians. A novel role for HSP90 and nitric oxide signaling in the integration of environmental factors with cell signaling pathways in ascidians is discussed near the end of this review. Throughout this review, the multiple roles of environmental stress on ascidian reproduction and development are emphasized.


2019 ◽  
Vol 152 ◽  
pp. 104790 ◽  
Author(s):  
Gastón Alurralde ◽  
Verónica L. Fuentes ◽  
Tamara Maggioni ◽  
Juancho Movilla ◽  
Alejandro Olariaga ◽  
...  

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