摘要:

Glucose solutions (160 mg/kg and 320 mg/kg body weight) were injected into the haemolymphatic sinuses ofAplysia depilansthrough an implanted cannula, and the effects on feeding behaviour were noted. The feeding parameter examined was the ingestion velocity of a standard weed ribbon(Ulva):it was evaluated from the time taken to ingest each of ten successive centimetres of the ribbon.

ISSN:0091-181X    

DOI:10.1080/10236248809378668

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The primitive marine pulmonateAmphibola crenataexhibits isosmotic intracellular regulation over the range of 25%‐150% sea water with the exception of 75%‐85% sea water where the cells swell isotonically by entry of water and inorganic solutes. Under hypo‐osmotic conditions, potassium is lost throughout the experimental salinity range, chloride is lost belowca50% seawater at the same rate as potassium, but the lowering of the sodium concentration is attributable solely to the increased hydration of the cells. Under hyperosmotic conditions, all three ions are accumulated, sodium and chloride to a greater extent than potassium. In all salinities, potassium is at a higher concentration, and sodium and chloride at lower concentrations, than in the extracellular fluids. Sodium is associated with chloride in the cells, and potassium with organic anions. There is a negative correlation between sodium and potassium concentrations. The distribution of potassium and chloride between the inside and outside of the cells does not accord with a Donnan equilibrium. It is concluded that the mechanisms of hypo‐osmotic cell volume regulation inAmphibolainitially involve reductions in intracellular potassium and amino acids, with chloride largely replacing amino acids as the osmotic effector in very low external salinities. Hyperosmotic regulation involves an increase in all three ions, particularly sodium.

ISSN:0091-181X    

DOI:10.1080/10236248809378669

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Feeding strategies are different when adultIllex illecebrosusprey on large (trout) and small fish (mummichogs). Attacks on trout are characterized by (1) rotation as the squid changes from tail‐first to head‐first swimming; (2) an approach phase involving rapid acceleration towards the prey; (3) a tracking phase where the squid slowly follows the trout; (4) the capture phase. No tracking phase is present in attacks on mummichogs.

ISSN:0091-181X    

DOI:10.1080/10236248809378670

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

InNephrops norvegicusdamage to the compound eye following exposure to excess light is not restricted to the photoreceptor layer, but is followed by morphological changes to the dioptric apparatus. Retinula cell damage results in the disruption of the cone cell processes leading to distal retraction of the crystalline tracts. The shape of the cones is also affected and there is a redistribution of the distal pigments. Within two months of exposure the reflective properties of subcorneal elements are changed and damage may be seen in the intact eye. A method based on external observations of the intact eye has been developed for quantitatively estimating the damage to the dioptric layer. The figures obtained were compared with estimates of retinula cell damage in the same eyes calculated using measurements from serially sectioned material. The estimation of ommatidial damage without recourse to sectioning should be of immediate practical benefit.

ISSN:0091-181X    

DOI:10.1080/10236248809378671

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Oyster drills,Urosalpinx cinerea(Say),U. c. follyensisB. Baker andEupleura caudata etteraeB. Baker, were divided into unfed groups and groups fed oysters or barnacles. Drills were tested in assays for their ability to detect prey odors of barnaclesBalanus balanoides, musselsMytilus edulis, oystersCrassostrea virginica, and clams,Mercenaria mercenaria. Two‐choice tests determined if drills were equally attracted to specific prey and to water without added prey. Four‐choice tests determined the response of drills to odors of three prey species and control sea water presented simultaneously. Behavior of individual drills was recorded in 80 tests. In two‐choice tests, at least one group of each of the two subspecies ofU. cinerearesponded significantly to all prey species. In both 2‐ and 4‐choice tests, strongest responses were to barnacles.U. cinerearesponded about equally to mussels and oysters;U. c. follyensisreacted more strongly to oysters than to mussels. Diet had little effect on choices. UnfedU. cinereaandU. c. follyensiswere more active than those fed either oysters or barnacles. In two‐choice tests, unfedE. caudata etteraeresponded to barnacles, oysters, and mussels. In four‐choice testsE. caudata etteraeresponded to barnacles. Examination of responses of individuals showed that in all cases responses to barnacles were significantly higher than predicted and responses to oysters and mussels were lower than predicted. Ingestive conditioning plays at most a minor role in the attraction of adult oyster drills to prey.

ISSN:0091-181X    

DOI:10.1080/10236248809378672

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The tide‐associated persistent activity rhythms of the ocypod crabs,Uca pugnaxandU. pugilatorwere observed in constant conditions, some for as long as three months. In some animals the twice/day peaks of activity were found to scan the day at significantly different rates from one another. Individual peaks in some animals split into two fragments. And at times, one peak would fade and then return, or vanish completely. These examples of the independence between tide‐related activity peaks have become the basis for a hypothesis that each peak is controlled by its own clock(s). The basic period of these clocks is “circalunidian”, with periods varying up to about 4–8% on either side of 24.8 hours.

ISSN:0091-181X    

DOI:10.1080/10236248809378673

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0091-181X    

DOI:10.1080/10236248809378667

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor