摘要:

Continuous recordings of the locomotor activity of the intertidal grapsid crabHelice crassain constant laboratory conditions were obtained from two individuals for periods in excess of three months. The records show that the strength of the tide‐related rhythm varies with time. On occasion the crabs are arrhythmic or only weakly rhythmic but clear rhythms are often spontaneously re‐established. Even after 3–6 months in the laboratory, clear rhythmicity is seen at times. Rhythms with periods varying from 6.5 h to 28 h were recorded. The relationship between the period of the overt rhythm and that of the underlying oscillatory system is considered.

ISSN:0091-181X    

DOI:10.1080/10236248809378682

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Various types of releases (in the sea, on wet sand, in a test bowl on a dry substrate and in the water) have confirmed thatIdotea balticarely primarily on sun compass in order to orient in an ecologically efficient direction and, contemporaneously, also on local cues. As idoteids either passively or actively change habitats throughout the year they should be able to adapt their orientation to new locations.

ISSN:0091-181X    

DOI:10.1080/10236248809378683

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The effect of temperature on the rate of oxygen consumption and heart rate has been investigated in the Red Sea, semi‐terrestrial crab,Ocypode saratan. The Q10values for both oxygen consumption and heart rate were often <2 and were relatively constant over a wide range of temperature. This suggests thatO. saratanis well adapted for life in a high temperature environment. It was noted, however, that behavioural mechanisms were important in reducing the degree of temperature stress that could be experienced in the field. The rates of oxygen consumption of immersed crabs were significantly lower than those of crabs maintained in air at the same temperature.

ISSN:0091-181X    

DOI:10.1080/10236248809378684

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Both physiological and environmental constraints can be important selective factors on behaviors. The results of the present study showed that fecundity is significantly reduced if copulation is delayed for as short a time as 6 ± 6h in the amphipod crustaceanGammarus palustris(Bousfield, 1969). This led to the prediction that selection would favor behaviors which minimize the likelihood of delays. In amphipods of this genus, amplexus occurs before the female molts and copulation occurs within minutes afterwards. The results of field observations support the prediction; it is estimated that 99% of the females are in amplexus when they molt. However, while the physiological constraints that were demonstrated show the advantages of pairing before copulation, it is speculated that amplexus as the specific pairing behavior evolved in response to the selective pressures of the free‐roaming habits ofG. palustris.

ISSN:0091-181X    

DOI:10.1080/10236248809378685

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Zoeae ofParalithodes camtschaticawere positively phototactic to white light intensities above 1 × 1013q cm−2s−1. Negative phototaxis occurred at low (1 × 1012q cm−2s−1), but not high intensities (2.2 × 1016q cm−2s−1). Phototactic response was directly related to light intensity. Zoeae also responded to red, green and blue light. Zoeae were negatively geotactic, but geotaxis was dominated by phototaxis. Horizontal swimming speed of stage 1 zoeae <4 d old was 2.4 ± 0.1 (SE) cms−1and decreased to 1.7 ± 0.1 cm s−1in older zoeae (P<0.01). Horizontal swimming speed of stage 2 zoeae was not significantly different from ≥4 d old stage 1 zoeae. Vertical swimming speed, 1.6 ± 0.1 cm s−1, and sinking rate, 0.7 ± 0.1 cm s−1, did not change with ontogeny. King crab zoeae were positively rheotactic and maintained position in horizontal currents less than 1.4 cm s−1. Starvation reduced swimming and sinking rates and phototactic response.

ISSN:0091-181X    

DOI:10.1080/10236248809378686

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Oxygen consumption and ammonia excretion rates were investigated in youngOctopus maya(hatching to 139 days old; 0.11–81.23 g wet body weight, BW; 22.5–23.9°C), young squids ofLoligo forbesi(hatching to 45 days old; 9.4–115.3 mg BW; 12.3–13.1°C) and young squids ofLolliguncula brevis(2.00–39.98 g BW; 23.8–24.7°C). Except at hatching, oxygen consumption and ammonia excretion rates on an individual basis(M)of these three cephalopods increased linearly with increasing body weight(BW)expressed asM = aBWb. Values ofbfor oxygen consumption were 0.900, 0.910 and 0.848 and for ammonia excretion were 0.744, 0.809 and 0.751 forO. maya, L. forbesiandL. brevis, respectively. Among the three species the valueavaried widely, whilebwas similar for both oxygen consumption and ammonia excretion rates. Based upon these data, metabolism for hatchlings ofO. mayaandL. forbesiwas estimated to be relatively lower than that of older juveniles. The O/N ratios for hatchlings ofO. mayaandL. forbesiwere relatively high and indicate an apparent dependence upon lipids in the immediate post‐hatching period, followed by standard protein energy utilization thereafter.

ISSN:0091-181X    

DOI:10.1080/10236248809378687

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0091-181X    

DOI:10.1080/10236248809378681

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor