Limits...
Natural populations of shipworm larvae are attracted to wood by waterborne chemical cues.

Toth GB, Larsson AI, Jonsson PR, Appelqvist C - PLoS ONE (2015)

Bottom Line: Natural populations of teredinid larvae were significantly more abundant close to wooden structures enclosed in plankton net compared to empty control nets, clearly showing that shipworm larvae can sense and respond to chemical cues associated with suitable settling substrate in the field.However, the flume experiments, using ecologically relevant flow velocities, showed that the boundary layer around experimental wooden panels was thin and that the mean flow velocity exceeded larval swimming velocity approximately 5 mm (≈ 25 larval body lengths) from the panel surface.Therefore, we conclude that the scope for remote detection of waterborne cues is limited and that the likely explanation for the higher abundance of shipworm larvae associated with the wooden panels in the field is a response to a cue during or after attachment on, or very near, the substrate.

View Article: PubMed Central - PubMed

Affiliation: University of Gothenburg, Department of Biological and Environmental Sciences-Tjärnö, Strömstad, Sweden.

ABSTRACT
The life cycle of many sessile marine invertebrates includes a dispersive planktonic larval stage whose ability to find a suitable habitat in which to settle and transform into benthic adults is crucial to maximize fitness. To facilitate this process, invertebrate larvae commonly respond to habitat-related chemical cues to guide the search for an appropriate environment. Furthermore, small-scale hydrodynamic conditions affect dispersal of chemical cues, as well as swimming behavior of invertebrate larvae and encounter with potential habitats. Shipworms within the family Teredinidae are dependent on terrestrially derived wood in order to complete their life cycle, but very little is known about the cues and processes that promote settlement. We investigated the potential for remote detection of settling substrate via waterborne chemical cues in teredinid larvae through a combination of empirical field and laboratory flume experiments. Natural populations of teredinid larvae were significantly more abundant close to wooden structures enclosed in plankton net compared to empty control nets, clearly showing that shipworm larvae can sense and respond to chemical cues associated with suitable settling substrate in the field. However, the flume experiments, using ecologically relevant flow velocities, showed that the boundary layer around experimental wooden panels was thin and that the mean flow velocity exceeded larval swimming velocity approximately 5 mm (≈ 25 larval body lengths) from the panel surface. Therefore, we conclude that the scope for remote detection of waterborne cues is limited and that the likely explanation for the higher abundance of shipworm larvae associated with the wooden panels in the field is a response to a cue during or after attachment on, or very near, the substrate. Waterborne cues probably guide the larva in its decision to remain attached and settle, or to detach and continue swimming and drifting until the next encounter with a solid substrate.

No MeSH data available.


Related in: MedlinePlus

Laboratory flume experiment.Flow velocity fields around wooden panels measured with particle image velocimetry (PIV). Green color represents masked out areas that could not be analyzed and these are somewhat larger than the wooden panel. Coloured areas represent flow velocities below 0.4 cm s-1 i.e. twice the competent shipworm larva swimming speed. In white areas the flow velocity exceeds 0.4 cm s-1.
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pone.0124950.g005: Laboratory flume experiment.Flow velocity fields around wooden panels measured with particle image velocimetry (PIV). Green color represents masked out areas that could not be analyzed and these are somewhat larger than the wooden panel. Coloured areas represent flow velocities below 0.4 cm s-1 i.e. twice the competent shipworm larva swimming speed. In white areas the flow velocity exceeds 0.4 cm s-1.

Mentions: The average PIV vector fields show that there are 2 areas where the water is re-circulated resulting in flow speeds much lower than the free stream velocity. A recirculating cell is formed close to the surface just behind the leading edge (upstream end) of the panel and at the downstream end a wake is formed. In these recirculating areas, dye is accumulated (Fig 4A). Furthermore, downstream of the recirculating cell behind the leading edge the flow speed is reduced in the area close to the panel surface. Fig 5 shows the magnitude of the resulting flow velocities around the panel at the three free stream speeds tested. Velocities below 0.4 cm s-1, representing twice the competent shipworm larva swimming speed, are shown in color code whereas areas with flow velocities above 0.4 cm s-1 are shown in white. In the areas with velocities below 0.4 cm s-1, it can be expected that larvae sensing attractive cue filaments also can elicit a behavior that increase the possibility to encounter and attach to the wooden panel. In areas with flow velocities above 0.4 cm s-1, larval behavior most likely cannot affect the encounter probability since the larvae are quickly transported away.


Natural populations of shipworm larvae are attracted to wood by waterborne chemical cues.

Toth GB, Larsson AI, Jonsson PR, Appelqvist C - PLoS ONE (2015)

Laboratory flume experiment.Flow velocity fields around wooden panels measured with particle image velocimetry (PIV). Green color represents masked out areas that could not be analyzed and these are somewhat larger than the wooden panel. Coloured areas represent flow velocities below 0.4 cm s-1 i.e. twice the competent shipworm larva swimming speed. In white areas the flow velocity exceeds 0.4 cm s-1.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4430175&req=5

pone.0124950.g005: Laboratory flume experiment.Flow velocity fields around wooden panels measured with particle image velocimetry (PIV). Green color represents masked out areas that could not be analyzed and these are somewhat larger than the wooden panel. Coloured areas represent flow velocities below 0.4 cm s-1 i.e. twice the competent shipworm larva swimming speed. In white areas the flow velocity exceeds 0.4 cm s-1.
Mentions: The average PIV vector fields show that there are 2 areas where the water is re-circulated resulting in flow speeds much lower than the free stream velocity. A recirculating cell is formed close to the surface just behind the leading edge (upstream end) of the panel and at the downstream end a wake is formed. In these recirculating areas, dye is accumulated (Fig 4A). Furthermore, downstream of the recirculating cell behind the leading edge the flow speed is reduced in the area close to the panel surface. Fig 5 shows the magnitude of the resulting flow velocities around the panel at the three free stream speeds tested. Velocities below 0.4 cm s-1, representing twice the competent shipworm larva swimming speed, are shown in color code whereas areas with flow velocities above 0.4 cm s-1 are shown in white. In the areas with velocities below 0.4 cm s-1, it can be expected that larvae sensing attractive cue filaments also can elicit a behavior that increase the possibility to encounter and attach to the wooden panel. In areas with flow velocities above 0.4 cm s-1, larval behavior most likely cannot affect the encounter probability since the larvae are quickly transported away.

Bottom Line: Natural populations of teredinid larvae were significantly more abundant close to wooden structures enclosed in plankton net compared to empty control nets, clearly showing that shipworm larvae can sense and respond to chemical cues associated with suitable settling substrate in the field.However, the flume experiments, using ecologically relevant flow velocities, showed that the boundary layer around experimental wooden panels was thin and that the mean flow velocity exceeded larval swimming velocity approximately 5 mm (≈ 25 larval body lengths) from the panel surface.Therefore, we conclude that the scope for remote detection of waterborne cues is limited and that the likely explanation for the higher abundance of shipworm larvae associated with the wooden panels in the field is a response to a cue during or after attachment on, or very near, the substrate.

View Article: PubMed Central - PubMed

Affiliation: University of Gothenburg, Department of Biological and Environmental Sciences-Tjärnö, Strömstad, Sweden.

ABSTRACT
The life cycle of many sessile marine invertebrates includes a dispersive planktonic larval stage whose ability to find a suitable habitat in which to settle and transform into benthic adults is crucial to maximize fitness. To facilitate this process, invertebrate larvae commonly respond to habitat-related chemical cues to guide the search for an appropriate environment. Furthermore, small-scale hydrodynamic conditions affect dispersal of chemical cues, as well as swimming behavior of invertebrate larvae and encounter with potential habitats. Shipworms within the family Teredinidae are dependent on terrestrially derived wood in order to complete their life cycle, but very little is known about the cues and processes that promote settlement. We investigated the potential for remote detection of settling substrate via waterborne chemical cues in teredinid larvae through a combination of empirical field and laboratory flume experiments. Natural populations of teredinid larvae were significantly more abundant close to wooden structures enclosed in plankton net compared to empty control nets, clearly showing that shipworm larvae can sense and respond to chemical cues associated with suitable settling substrate in the field. However, the flume experiments, using ecologically relevant flow velocities, showed that the boundary layer around experimental wooden panels was thin and that the mean flow velocity exceeded larval swimming velocity approximately 5 mm (≈ 25 larval body lengths) from the panel surface. Therefore, we conclude that the scope for remote detection of waterborne cues is limited and that the likely explanation for the higher abundance of shipworm larvae associated with the wooden panels in the field is a response to a cue during or after attachment on, or very near, the substrate. Waterborne cues probably guide the larva in its decision to remain attached and settle, or to detach and continue swimming and drifting until the next encounter with a solid substrate.

No MeSH data available.


Related in: MedlinePlus