Virtual Copepod Page

Project Icon: 
Project Goals: 

To create visually convincing images of copepods to demonstrate individual behaviors in a research or educational setting.

Celeste Fowler
Scripps Institution
of
Oceanography
Dr. Jeannette Yen
School of Biology
Georgia Institute of
Technology
Dr. Jules Jaffe
Scripps Institution
of
Oceanography
 
 




All images, animations, models, and scripts are copyright 2000 Scripps Institution of Oceanography and may not be published or re-used without permission.



Please explore the interactive virtual copepod. Click on the rendering and drag to rotate.

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Abstract submitted to ASLO 2000

 

VCP: Introduction

Very Basic Copepod Introduction

(Skip this if you already know what a copepod is.)

Copepods are a type of crustacean, the class of animals that also includes shrimps, lobsters, and crabs. Copepods are one of the most abundant animals on the planet. Most are saltwater plankton, living their entire lives in the open ocean without ever touching the bottom or surface. Copepods also live on the sea bottom, in fresh water, as parasites on fish, in caves...

Euchaeta Biological Introduction

Copepods in the genus Euchaeta are planktonic and predatory. Congeners of Euchaeta (Kingdom Animalia, Phylum Crustacea, Class Copepoda, Order Calanoida, Superfamily Clausocalanoidea, Family Euchaetidae, Genus Euchaeta) live in seas from the Antarctic to the tropics, within the fjords of Norway and Puget Sound, and in deep lochs of Scotland. In their respective open-ocean planktonic communities, these copepods are often biomass dominants because of their high abundance, large size, and high lipid content (up to 70% their body weight). The image to the right was taken by Yen and Strickler and shows a typical Euchaeta. The long antennules are lined with sensitive setal receptors to detect fluid motion and odors. This photo of the live subarctic species, shows its natural coloration with blue oocytes within the oviducts and iridescence imparted by the thin caudal setae. The robust capture appendages, the paired maxillipeds, are shown extended away from anterior section of body.

 

Euchaeta are gigantic (for copepods), with the adult subtropical females growing to 2.4 millimeters in length and the polar species reaching up to 1 cm. Males are somewhat smaller. Their maxillipeds are used to capture and eat other copepods. These photos depict the structure of the capture appendages, the maxillipeds and maxillae. The left photo is a drawing from Wickstead(1959). The right is a scanning electron micrograph by J. Yen(1985).

 

Computer Visualization Introduction

We created and animated our model using 3D Studio Max from Discrete Logic. This high-end animation package is widely used by movie special effects artists.

To create our models and animations, we first looked at illustrations in the literature. Rose 1933 gave us a good starting point. To create the prosome, we scanned 2D images from Rose into the computer and traced them using Bezier curves to create the outline of the prosome as seen from the left-hand side. We then made an estimate of curves representing the outline of the prosome as seen from the rear. Using these two sets of curves, we were able to create a Bezier patch surface approximating the prosome. We then checked our results by rendering images from several viewpoints and comparing them against preserved specimens. We also showed the images to Annie Townsend, curator of the SIO Planktonic Invertebrates Collection. She was able to suggest many important improvements.

The other segments of the prosome and urosome were constructed in a similar fashion, as were the appendages. We found that NURBS surfaces generally gave better results with less effort than other techniques for modelling curved surfaces.

Setae provided a special animation challenge, as there are so many of them. After exploring several techniques we used loft surfaces created from circles and Bezier splines. The tip of each seta was attached to a controller, so that each seta could be individually positioned if necessary. We generally avoided this by attaching the tips of each set of setae to a master controller. To give a more natural appearance, the setae on the maxillae are translated and rotated using a random noise function.

To animate our model, we first determined the range of motion of the joints by examining preserved specimens. We then looked at video of live animals. Using key frame animation, we were able to approximate the motion of the living animals. Once the computer model had been animated, it could be examined from any angle and at any speed.

All images, animations, models, and scripts are copyright 2000 Scripps Institution of Oceanography and may not be published or re-used without permission.

VCP: Still Image Gallery

Bottom oblique view

Bottom oblique view

Close-up view

Close-up view

Comparison Top

Comparison Top

Head-on capture view

Head-on capture view

Left Comparison Image

Left Comparison Image

Left view

Left view

Still top oblique view

Still top oblique view

 
Top oblique view close up

Top oblique view close up

 

 

 

 


VCP: Animations & Movies

3D rendering of a copepod 1st antenna


3D Surface Rendition Images provided by Marie Bundy Animation created by Corey Accardo.

Tethered Capture


Here we see the carnivorous copepod, Euchaeta rimana (2.4 mm), restrained on a tether so that it remains within the field of view. A smaller copepod, Acartia (0.7 mm), makes contact with the predator but that does not trigger the attack response. When the prey escapes and sheds a wake toward the predator, then the predator reaches out with its maxillipeds and grabs the small copepod prey. The prey is then seen as a small morsel being shoved into the mandibles of the predatory copepod. (Videos done by J. Yen in collaboration with J.R. Strickler).

Tethered Escape Behavior

High-speed video (1000 fps) of the leg movements of Calanus pacificus. Note the sequence of coordinated movements of the 5 pairs of swimming legs. The name "swimming legs" is misleading as they are only used in the escape or lunge movements while the cephalic appendages are used in normal swimming.(Video recorded by S. Wilson)

Untethered Capture

This sequence shows how a freely swimming predatory copepod, Euchaeta rimana (2.4 mm, central image), lunges after another smaller copepod prey (Acartia, 0.7 mm, images to right of larger copepod). The Acartia was entrained in the feeding current of Euchaeta. When it detected the presence of the predator, it jumped away and shed a jet-like wake toward the predator. The predator sensed the strength and directionality of the prey's wake and lunged at it accurately to capture it in 3D space (capture occurred in upper right corner of frame; Doall et al. submitted). Lunge is much faster in relative speed than that of a running cheetah. (Videos done by J. Yen in collaboration with J.R. Strickler).

Untethered Escape Behavior

This sequence shows how a freely swimming predatory copepod, Euchaeta rimana (2.4 mm, central image), lunges after another smaller copepod prey (Acartia, 0.7 mm, images to right of larger copepod). The Acartia was entrained in the feeding current of Euchaeta. When it detected the presence of the predator, it jumped away and shed a jet-like wake toward the predator. The predator sensed the strength and directionality of the prey's wake and lunged at it accurately to capture it in 3D space (capture occurred in upper right corner of frame; Doall et al. submitted). Lunge is much faster in relative speed than that of a running cheetah. (Videos done by J. Yen in collaboration with J.R. Strickler).

Horizontal Spin

Computer-Generated Horizontal Spin Appendages in neutral position.

Fly-Around

Computer-Generated Fly-Around Appendages in neutral position.

Computer Visualization of Capture Behavior

Computer Visualization of Capture Behavior.

Computer Visualization of Capture Behavior

Computer Visualization of Capture Behavior

Computer Visualization of Capture of Prey

Computer Visualization of Capture of Prey

Computer Visualization of Capture of Prey 2

Computer Visualization of Capture of Prey 2

Computer Visualization of Escape Behavior

Computer Visualization of Escape Behavior: Note how the antennules oppose the motion of the tail, preventing the animal from moving backwards when the tail comes up.
Capture time sequence

Capture time sequence

This sequence of images shows the side view and head down view of the capture response of the subtropical carnivorous copepod, Euchaeta rimana (2.4 mm), as recorded using high-speed film (J. Yen, D.M. Fields, M.H. Doall in collaboration with J.S. Strickler). At 0 msec, the maxillepeds (mxp) are tucked in against the body (the arm-like appendage is the mxp in the upper frame and the straight appendages in the lower panel are the paired antennules extending to either side of the body). At 6 msec, the mxp begin to extend with its setae flared (upper panel) and the 'elbows' bowed out. The paired maxillae are also seen to participate in this capture response. At 8 msec, the mxp are fully extended with setae fully flared (upper panel), reaching out far from its body (lower panel). At 16 msec, the show is nearly over with the mxp withdrawing closer to the body (upper panel) and being tucked in among the other cephalic appendages (lower panel). (Slides prepared by R. Foster).
Capture time sequence 2

Capture time sequence 2

This sequence of images shows the side view and head down view of the capture response of the subtropical carnivorous copepod, Euchaeta rimana (2.4 mm), as recorded using high-speed film (J. Yen, D.M. Fields, M.H. Doall in collaboration with J.S. Strickler). At 0 msec, the maxillepeds (mxp) are tucked in against the body (the arm-like appendage is the mxp in the upper frame and the straight appendages in the lower panel are the paired antennules extending to either side of the body). At 6 msec, the mxp begin to extend with its setae flared (upper panel) and the 'elbows' bowed out. The paired maxillae are also seen to participate in this capture response. At 8 msec, the mxp are fully extended with setae fully flared (upper panel), reaching out far from its body (lower panel). At 16 msec, the show is nearly over with the mxp withdrawing closer to the body (upper panel) and being tucked in among the other cephalic appendages (lower panel). (Slides prepared by R. Foster).

 


VCP: Links



Copepods have a strong presence on the web. Here are some links:

 

All images, animations, models, and scripts are copyright 2000 Scripps Institution of Oceanography and may not be published or re-used without permission.

VCP: Acknowledgements & Bibliography

  Acknowledgements

We'd like to thank the following people for their help:

Bibliography

In addition to our examination of preserved specimens, we obtained anatomical data from several sources including:

Behavior data and other information for the project came from the following sources:

We used the following software packages:

 

All images, animations, models, and scripts are copyright 2000 Scripps Institution of Oceanography and may not be published or re-used without permission.