摘要:

Protantheashows a previously undescribed behaviour pattern, in which an expanded anemone rapidly loses muscular tone, collapses, and hangs limply. Recovery is slow (30–60 minutes). In captivity collapse occurs every 5–27 hours (mean 13.5 hours). It involves a considerable loss of volume and possibly aids removal of waste materials from the coelenteron. Collapse is associated with high levels of endodermal slow system (SS2) activity and a reduction in spontaneous nerve net activity. These events probably cause inhibition and reduction of spontaneous contractions and hence loss of muscle tone. Excess magnesium, however, also eliminates contractions but does not cause collapse, so the normal behaviour must also include mouth opening and subsequent loss of coelenteric fluid.

ISSN:0091-181X    

DOI:10.1080/10236248509387051

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Squids (Lolliguncula) learn readily to come to feed when a horizontal rectangle is shown, but to avoid a vertical rectangle. They retain the discrimination over a period of 9 days without showing of the figures. A squid can also learn to discriminate between white and black spheres. A white horizontal rectangle is distinguished from a white sphere.

ISSN:0091-181X    

DOI:10.1080/10236248509387052

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Swimming behaviors of bonnethead sharks (Sphyrna tiburo) were observed in response to chemical stimulation. Large volume (10 ml) samples were introduced into the path of swimming sharks. In still water, tight turning and circling were observed while samples introduced in the presence of a water current elicited a swimming pattern of connected loops moving downcurrent. A headmount attached to the shark allowed small volume (0.5 ml) samples to be directed into the olfactory capsules. Stimulation in still water produced the turning and circling behaviors as observed for the large volume samples and stimulation in moving waters produced the same connected loops pattern. Other experiments confirmed that the small volume samples quickly dilute below threshold and therefore the behaviors observed in response to the 0.5 ml samples are swimming patterns released by the chemical signal but are presumed to be modulated by factors other than chemical cues. Additionally, it was demonstrated that bonnethead sharks can detect and respond to concentration differences between the left and right olfactory capsules. This means that these sharks are capable of tropotactic orientation in a chemical gradient.

ISSN:0091-181X    

DOI:10.1080/10236248509387053

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Lateral ciliary activity was studied on gill preparations of the musselMytilus edulis.Electrical stimulation of the branchial nerve accelerated ciliary beating. The cilioex‐citatory effect of electrical stimulation of the branchial nerve on the lateral ciliated cell decreased after intramuscular injection of 6‐OH‐DOPA. Scanning electron microscopic observations of the branchial nerve and visceral ganglion show degeneration of neuronal structures. Therefore, it appears likely that the lateral ciliated cell is dependent on the branchial nerve and visceral ganglion for its neuronal regulation.

ISSN:0091-181X    

DOI:10.1080/10236248509387054

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Four individualOctopus dofleiniwere followed over a fifteen day period in their underwater habitat by sonic tracking. Octopuses had small home ranges (250 m2maximum) which were stable over the two weeks of observation. These ranges overlapped those of other octopuses extensively, and animals did not keep a constant distance from one another, which suggests they were solitary and non‐social. Activity was slightly higher at night, and was not correlated with changes in other environmental variables. TheO. dofleinimade frequent short hunting trips (mode 0.5 hours), tending to have more and longer excursions at night. Octopuses are predators who appear to have flexible activity and, in the short term, restricted home range areas.

ISSN:0091-181X    

DOI:10.1080/10236248509387055

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

1.Research into the visual shape discrimination abilities of compound‐eyed animals has almost exclusively been limited to insects, the crustaceans having been virtually ignored. The two groups have many dissimilarities, having primarily adapted in different habitats to different lifestyles. Differences may exist in visual systems and visually mediated behavior.2.Fiddler crabs(Uca pugilator), without training, differentially approached dissimilar silhouettes presented simultaneously, demonstrating visual discrimination between stationary, geometric shapes of equal‐area. The strength of response was ordered hierarchically: vertical rectangle, horizontal rectangle, triangle, square, circle.3.Basic geometric shapes were used to facilitate replication and comparison with research findings from other species.

ISSN:0091-181X    

DOI:10.1080/10236248509387056

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Lytechinus variegatusdoes not locate food items at a distance. Agar blocks containing 5% dry weightThalassia testudinumorGracilaria verrucosawere perceived only at 3–8 cm distance. Individuals exposed to 1% extracts ofG. verrucosachanged neither their rate nor direction of movement, suggesting a lack of ortho‐ or klinokine‐tic resposes. Individuals exposed to extracts ofT. testudinummoved less rapidly but did not exhibit search behavior. Unlike many carnivorous marine invertebrates,L. variegatusrelies more upon random encounters than upon directed movement as a search strategy. This indicates an important difference between carnivore and herbivore feeding strategies. The frequency of feeding has no effect upon the feeding rate of large (114.5 ± 21.6 g wet weight; mean ±1 standard deviation)Lytechinus variegatus.Equivalent amounts of agarose blocks containing 5% dry weightThalassia testudinumwere consumed per feeding bout whether the echinoids were fed at daily, 3‐day, or 6‐day intervals. Small (37.7 ± 16.5 g wet weight)L. variegatusconsumed less food when fed at intervals, an effect of starvation. This suggests thatL. variegatushave a constant rate of ingestion, independent of hunger or of satiation, within the constraints of their well‐being. However, rates of movement in the laboratory were higher for individuals fedad libitumthan for starved individuals. This suggests that energy expenditure for movement is reduced when food is scarce and that movement is increased to exploit the available resources when food is abundant.

ISSN:0091-181X    

DOI:10.1080/10236248509387057

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0091-181X    

DOI:10.1080/10236248509387050

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor