Geographic variation for colour in the sandburrowing beetle Chaerodes trachyscelides White (Goleoptera: Tenebrionidae) on New Zealand beaches analysed using CIELAB L * values

Chaerodes trachyscelides White is a highly specialized, flightless burrowing beetle confined to the narrow strip of sand at and just above high water level on sandy marine beaches in New Zealand. Although the ventral surface of the beetle is always pale, the dorsal surface varies from pale to almost black. Large samples of this beetle were taken, together with the sand, from 11 beaches on New Zealand's three main islands. The colour of the dorsal surface of each individual beetle and that of the sand samples was measured using reflectance spectroscopy and expressed as CIE L*,a*,b* (CIELAB) values. The L* values, which are objective, quantitative measures of the degree of lightness of the beetles, were subjected to statistical and frequency analysis. Although the species was very variable in colour and the variation appeared to be continuous, a highly significant correlation was obtained between the mean of the L* values for the samples on each beach and that of the sand, the correlation coefficient being 0.961. This close association between the lightness of the beetles and that of the sand suggests the variable melanism functions as cryptic colouration. On most beaches, the distribution oflightness among the beetles sampled conformed to a normal curve. For beetles from sites where the sand was relatively uniform, such as the black Taranaki beaches, the L* frequency distribution curves were narrow and the coefficient of variation of mean beetle colour was relatively small indicating low colour variability. In contrast, the greatest within-site variability occurred on the two Stewart Island beaches sampled, where in each case there was less uniformity in the colour of the sand. At one of these sites, Maori Beach, darker sand present below the high water level is often deposited on the zone occupied by the beetles after storms. On Lonneker's Beach, the distribution of L* values among the beetles sampled was actually bimodal. On this small beach, there was an area of intensely black sand in the zone occupied by the beetles, but most of the rest was covered with light golden sand. These results are interpreted as evidence that the variability of colour of Chaerodes beetles has the effect of populations being able to match the colour of the sand of their home beaches, presumably as a consequence of the differential survival of individuals.     

The sympatric breeding of Common and Scottish Crossbills Loxia curvirostra and L. scotica and the evolution of crossbills

Within the strongly polytypic Red Crossbill L. curvirostra there are many reports of two or more 'subspecies' nesting sympatrically, without interbreeding. This 13-year study examines one such case, in Scotland, where an endemic form is resident and another was thought to occur after irruptions from its main range in continental Europe. Both forms were present in the study area every year; sympatric breeding was proved in 9 years and probably occurred in the other four. There was no suggestion of interbreeding and the Scottish form should be treated as a separate species, L. scotica , the Scottish Crossbill. This is the only endemic species of bird in Britain and one of very few European endemics. The evolution of crossbills in Europe is discussed in the light of recent palynological evidence and the taxonomic status of the Parrot Crossbill L. pytyopsittacus is re-examined.     

Re-mating between and within breeding seasons in the Greater Flamingo Phoenicopterus ruber roseus

Data on re-mating between and within breeding seasons were collected between 1983 and 1994 as part of a long-term study of the Greater Flamingo Phoenicopterus ruber roseus in the Camargue, southern France. Flamingos have bred in the Rhône delta for centuries and since 1972 have done so annually on an artificial island in the Etang du Fangassier. A sample of chicks has been ringed each year since 1977; many of these birds were later observed back at the breeding site and were used in this study. The mate-switching rate between consecutive breeding seasons was 98.3%. This result is contrary to what has been reported from captive flocks where extensive mate fidelity occurred between consecutive breeding seasons. Mate-switching also was observed in the Camargue within breeding seasons, following breeding failure, and seems to be linked to male breeding strategy in response to the need to synchronize hatching and the limited energy supply of breeding females. The absence of a long-term pair bond in Greater Flamingos contrasts with current views on the evolution of mate fidelity in relation to longevity in birds.     

Effects of CCC on the Formation and Abortion of Flowers in the First Inflorescence of Tomato (Lycopersicon esculentum Mill.)

Treatment of tomato plants with (2-chloroethyl)trimethylammoniumchloride (CCC) reduced their growth in height and d. wt andincreased the number of flowers formed in the first inflorescence.In plants grown at a high temperature with low light, applicationof CCC reduced the incidence of flower abortion in the firstinflorescence. Effects of -cyclopropyl--(4-methoxyphenyl)--(pyrimidin-5-yl)methanol(ancymidol) were similar to those of CCC while a third growthretardant, N-dimethylaminosuccinamic acid (B-9), was effectivein reducing growth in height but was without apparent effecton flower number or flower abortion. An interaction occurred between CCC and GA₃ such that effectsof CCC on growth and flowering were reduced when GA was alsoapplied. Yields of diffusible gibberellin-like substances fromthe shoot tips were markedly reduced by treating plants withCCC but were apparently not affected by treating plants withB-9. It is suggested that effects of CCC on flowering in tomatoare mediated, in part at least, through changes in levels ofendogenous gibberellins.     

Ultrastructure of Endosperm Protein Bodies in Developing Rice Grains Differing in Protein Content

Ultrastructural aspects of the development of protein bodies(aleurone grains) in endosperm of grains of two rices differingin protein content are described. Formation of rough endoplasmicreticulum complexes prior to protein deposition was observedonly in the higher protein grain. From 8 days after floweringthree types of protein body were observed, one of which wasrestricted to the peripheral endosperm (sub-aleurone) layers.The higher protein grain had a greater number of protein bodiesand rough endoplasmic reticulum in the endosperm cells thanthe lower protein grain. Increase in total protein with maturitywas the result of increased number of protein bodies ratherthan increase in size; the protein bodies were concentratedin the peripheral endosperm layers.     

Incubation in Mice Provides a Signal for the Differentiation of Trypanosoma cruzi Epimastigotes to Trypomastigotes1

The differentiation of Trypanosoma cruzi epimastigotes into trypomastigotes was studied in diffusion chambers sub-cutaneously implanted in mice. Using epimastigotes of the Tulahuén strain, transformation was first evident at 16 h after implantation and reached its maximum (92% trypomastigotes) by 24 h. Shortly before their differentiation into trypomastigotes, epimastigotes were found to develop resistance to lysis by the alternative pathway of complement. Furthermore, implantation of stationary-phase (as opposed to log-phase) parasites resulted in the accumulation of large numbers of complement-resistant epimastigotes in the chambers. These observations suggest that epimastigotes pass through a complement-resistant transitional stage before differentiating into trypomastigotes and that transformation may require cell division. In a further series of experiments, epimastigotes recovered 7 h after implantation in mice were found to differentiate into trypomastigotes when cultured in vitro for an additional 17 h at 37°C. This observation indicates that the events which trigger the morphologic transformation of epimastigotes into trypomastigotes can be dissociated operationally from the differentiation process itself.     

Growth Cycle-Dependent Overproduction and Accumulation of Protoporphyrin IX in Tetrahymena: Effect of Heavy Metals1

Cells of the ciliate Tetrahymena pyriformis GL overproduce and accumulate massive quantities of the heme intermediate, protoporphyrin IX. Protoporphyrin is localized intracellularly in discrete membranous compartments. The amount of porphyrin stored in the cell changes dramatically as cells progress through the growth cycle. Porphyrin overproduction is stimulated by δ-aminolevulinic acid, but only during the mid-stationary phase. Overproduction of protoporphyrin IX apparently results from an increase, late in the growth cycle, of activities subsequent to δ-aminolevulinic acid synthetase. Feedback inhibition in the pathway by accumulated protoporphyrin IX does not occur. The presence of Co²⁺ completely inhibits accumulation of protoporphyrin IX in a manner reversed by δ-aminolevulinic acid. Sn⁴⁺ stimulates protoporphyrin IX accumulation in the culture.