摘要:

Monthly analysis of plasma and urine was carried out in a natural population of the ground squirrelSpermophilus beecheyi.Ionic and osmotic concentration of the urine varied greatly with season, reflecting changes in water availability, diet, and perhaps adrenal gland activity. Plasma concentrations remained constant over the twelve month period.In laboratory tests, urine and plasma were analyzed in animals trapped in both summer and winter, and in two laboratory stocks; one maintained on saline solutions the other on minimal water for maintenance of weight.The comparison between field and laboratory suggested that minimal water and saline treatments of this type were more stressful than field conditions, even in this period of very low rainfall. Minimal water rations in the laboratory produced renal hypertrophy and changes in plasma osmotic concentrations, both conditions not found in summer field populations. Controlad libitumgroups suggested a possible seasonal difference in urine sodium levels which should be considered in laboratory water balance testing.Although the commonly used indications of water economy in rodents may be valid for laboratory comparisons, these results indicate the difficulties in field interpretation.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb03124.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Maccabeus tentaculatusPor, 1973 from the infralittoral bottoms of Cyprus is described. A detailed description of this new type of priapulid is given. The animals are characterized by a tubiculous life, a peculiar tentacular crown and a “trap‐feeding” nutrition of small prey animals. A whole series of morphological peculiarities of the external and internal morphology corresponds to the mode of life and feeding of the animals. All the specimens found are females. The larva is a typical priapulid larva. All the stages to the adult have been

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb03125.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Cape Debundsha receives 10 m (400 inches) of rain per year, and the water of the small crater lake on the cape has one of the lowest conductivities in Africa (11–13 µmho/cm/20 C). The lake has a maximum depth of 13·5 m. At the time of our visit in April 1972 the lake was stratified with a depletion of oxygen in the hypolimnion. The phytoplankton was dominated byBotryococcus, and the zooplankton was dominated by the ostracodOncocypris debundshae.Both these organisms are closely associated with the surface film. Other zooplankters includedThermocyclops hyalitws, and in deeper water during the daytime the larvae ofChaoborus ceratopogones.The fauna of the lake includes 12 species of testacean rhizopods, six species of rotifers, two oligochaetes, one snail, seven crustaceans, 15 insects and three acarines. Of the last group two species were new to science and one had been found only once previously. The ectoproct polyzoan,Lophopodella carteri, is recorded for the first time from West Africa, and the second time from Africa. The general impression of the fauna is one of sparseness, with an unusually high proportion of larval Odon

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb03126.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Experiments have been performed to measure the cooling rates of air space and equatorial regions of the incubated egg. The air space has a low specific heat so that it cools faster than the rest of the egg when an incubating bird leaves the nest. This rapid cooling of the air space reduces the water loss that would occur when a bird leaves the nest by 50% when compared with the water loss from an equivalent area of the rest of the shell. The overall influence of the air space is probably to reduce water losses during incubation by 10–15

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb03127.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Observations were made over a two year period on the nesting and hunting behaviour of a population ofPhilanthus crabroniformisSmith. Data are presented on the time and speed of provisioning, the capture of prey and the species taken, the design and location of nests, the approach to the nest with prey, and aggressive interactions between females.P. gibbosusFabr., also nested in the same area and took much the same prey. Unlike other sympatric pairsof Philanthuswhich have been studied, the two species in question were not totally segregated by separate nesting seasons nor by mutually exclusive habitat preferences. One aspect of the behaviour of the twoPhilanthuswhich was highly distinctive was the manner in which prey‐laden females approached their nests. Selection for divergence in approach patterns may have been exerted by miltogrammine flies, a major parasite of many digger wasp

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb03128.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

This cephalic sense organ ofMermis nigrescensis unusual in that it is innervated by a dendrite which ends in two dendritic processes. These dendritic processes contain numerous neurotubules. There is a basal plate at the base of the dendritic process, and this is associated with a well‐developed system of striated fibres which extend into the cytoplasm of the dendrit

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb03129.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb03131.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb03132.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb03133.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1974.tb03134.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY