Background selection by the peppered moth (Biston betularia Linn.): individual differences

The hypothesis that dimorphically coloured, cryptic moths select appropriate rest sites by comparing their body scales to substrate reflectance was tested using typical and melanic morphs of the peppered moth, Biston betularia (L.). Experiments designed to block the individual's inspection of its inherited colour phenotype do not support Kettlewell's contrast/conflict (self-inspection) hypothesis. Instead, tracking of marked moths over successive days revealed individual differences in rest-site selection which were not related to treatments, experience (imprinting), nor closely to a moth's inherited colour pattern. Differences between family broods indicate that some genetic bias in background selection exists. The production of artificially selected lines with consistent but opposing preferences will allow us to investigate the co-evolution of pattern and behaviour.     

Relationships between egg size, chick size at hatching, and chick survival in the Whimbrel Numenius phaeopus

The relationships between egg size, chick size at hatching and chick survival in Whimbrels Numenius phaeopus were studied over a three-year period in the Shetland Isles. Three measurements of chick size at hatching were all positively correlated with egg volume, though the relationship was strongest with hatchling body-weight. In two of the three years the proportion of chicks from a brood which survived to fledging increased significantly with the mean hatching weight of chicks in the brood. Within broods, a significant effect of hatching weight on survival was detectable only up to 7 days after hatching. Between years the egg volumes and hatchling weights of individual female Whimbrels showed relatively little variability, indicating that these attributes could be controlled to a large extent by inheritance.     

A Diurnal Settling Rhythm in Platymonas subcordiformis Hazen*

SYNOPSIS. In cultures of Platymonas subcordiformis Hazen, grown in appropriate light-dark cycles, as many as 75% of the cells adhered to the surface of the glass culture vessel toward the end of the light period of each day. Cell division occurred primarily while the cells were attached. Subsequently, motile daughter cells were released into the growth medium by the rupture of the mother cell theca. The settling behavior appears to be an integral part of the life cycle being synchronized to the same extent as cell division.     

Ecological and morphological variation of Canary Island blue tits, Parus caeruleus (Aves: Paridae)

Canary Island blue tits have differentiated within the last million years. Compared with mainland populations they have short wings, large beaks and tarsi, and tend to be less variable in these parameters. Within the archipelago the eastern populations have the shortest wings and tarsi but the widest and deepest beaks. The eastern populations may have been derived from central island ones, following extinction of the original eastern populations during a warm period in the last Ice Age. New measurements have been used to test contrasting predictions of hypotheses that explain inter-island morphological variation in terms of either climatic or ecological influences. Neither hypothesis is sufficient to explain the variation. A model which combines mem is proposed as follows. Mild winter temperatures have selected for small body size and wing length, especially on the hot, dry, eastern islands. On the other pine-forested, islands, selection has favoured relatively long tarsi and long, slender, beaks for efficient foraging among pine foliage. The absence of die pine-dwelling coal tit from the islands has facilitated mis evolutionary shift. It is shown that blue tits in pines forage more in the needles and cones on the Canary Islands than they do on die North African mainland.     

Phosphate Compounds in Vertebrate Red Blood Cells

This review brings together and discusses the significance ofexisting information about water-soluble (small molecule) organicphosphate constituents of red blood cells in different vertebratespecies, with emphasis on 2,3 diphosphoglycerate (DPG), inositolpentaphosphate (IP₅) ATP and guanosine triphosphate (GTP), compoundswhich may play an important role in respiratory physiology bymodifying the affinity of hemoglobin for oxygen. Results onthe distribution and concentration of these compounds in redcells of vertebrate animals can be summarized as follows 1)DPG High in mammals (except cats and ruminants) Absent in crocodilianssquamata and fishes. High briefly in the bird embryo absentin adult. High briefly in turtle embryo low in juvenile lowto absent in adult 2 IP₅. High in birds. Absent in mammals,crocodilians squamata and fishes (with the exception of Arapaimagigas). Low in turtles 3 ATP Intermediate in mammals. High inbirds and turtles. Very high in squamata Intermediate to veryhigh in fishes. Low in crocodilians 4) GTP Very low in mammalsbirds, reptiles and amphibians (except for small pool in Ranatadpole). Low to very high in fishes.     

Tissue 3Vicia Faba

The establishment of a callus culture of Vicia faba root tissuegrowing on a modified Bonner and Devirian medium supplementedwith 10^-6 M 2,4-dichlorophenoxyacetic acid and 5.0 g/l yeastextract is reported. Experiments have been carried out to determinethe optimum growth conditions of the callus on semisolid mediaand an investigation made of the potential of this materialas an initial source of friable tissue yielding cell suspensionson dissociation in liquid medium. The development of two morphologicallydistinct types of callus tissue was observed on semi-solid mediumand chemical analysis has demonstrated a correlation betweenthe friability and cell-wall composition of these tissues.     

MICROBIOLOGICAL ASPECTS OF A VACUUM CONTACT-PLATE DEHYDRATION PROCESS

SUMMARY: A process for dehydrating fish under vacuum and in contact with heated plates is described. Although the conditions, in respect of time and temperature, appeared suitable for microbial development, a reduction in the number of bacteria usually occurred. A survey of the data accumulated over twenty months, including a series of experimental production periods, showed that the bacterial population estimated at 22° was reduced in the process as a whole to about 1% of its initial value and that estimated at 37° to about 10%. Species of the genus Micrococcus tended to predominate on the finished product. Contrary to earlier expectations, there should be no serious microbiological hazards if high standards of personal and factory hygiene are maintained.