Effects of hatchling body colour and rearing density on body colouration in last-stadium nymphs of the desert locust, Schistocerca gregaria

Abstract.  The influences of hatchling character and rearing density on body colour at the last-nymphal stadium are investigated for the desert locust, Schistocerca gregaria . Hatchlings are divided into five groups based on the darkness of the body colour and reared either under isolated or crowded conditions. Two types of body colour variation at the last-nymphal stadium are separately analysed (i.e. the background colour and black patterns). Under isolated conditions, the background body colour is either greenish or brownish. Most individuals are greenish and the highest percentage of brownish insects is obtained from hatchlings with the darkest body colour. Under crowded conditions, the background colour is yellow or orange and the percentage of yellowish nymphs tends to decrease when they are darker at hatching. The intensity of black patterns differs depending on the body colour at hatching and subsequent rearing density. Most isolated-reared nymphs exhibit few or no black patterns but nymphs with some black patterns also appear, particularly among those that had been dark at hatching. Under crowded conditions, the black patterns become more intense when they are darker at hatching. Therefore, last-stadium nymphs with typical solitarious or gregarious body colouration appear when they have the phase-specific body colouration at hatching as well. The present results demonstrate that both body colour at hatching and rearing density during nymphal development influence body colouration at the last-nymphal stadium.     

Phosphorylation of myo-inositol in ripening grains of rice and wheat. Incorporationof phosphate-32P and myo-inositol-3H into myo-inositol phosphates

To elucidate the mechanism of the phosphorylation of myo-inositolin the process of phytate formation, feeding experiments oforthophosphate-³²P and myo-inositol-³H in the ripening grainsof rice and wheat were performed. It was found that ³²P and³H were incorporated into myo-inositol mono- and hexa-phosphates.The same results were obtained when a mixture of "cold" myo-inositolpolyphosphates was administered to the grains before feedingphosphate-³²P. Based on these results it is concluded that phosphorylationof free myo-myo-inositol in the formation of phytate does nottake place in a stepwise fashion but may proceed through anunknown myo-inositol derivative. (Received August 2, 1967; )     

Melanocytes Fail to Survive in Hair Bulbs of the Shiba Goat (Capra hircus) With the Dominant Black-Eyed White Phenotype

Dominant black-eyed white phenotypes are one of the most commonly observed traits in domestic animals. Their genetic control mechanisms, however, have not been elucidated. As the first step to approach the problem, we examined histologically the patterns of the distribution of pigment cells in Shiba goats (two each of day-73-postcoitum and day-112-postcoitum fetuses, and a 15-week-old kid) with the dominant black-eyed white phenotype. Melanocytes were present and fully pigmented in the choroid and the sclera of eyes, as well as in dorsal skin epidermis of the fetuses and of the kid. Melanocytes were also found in approximately 6% of the hair bulbs in the fetal dorsal skin, while the rest (94%) lacked them. Hair follicles of the kid did not harbor melanocytes except for some in the early anagen stage. The results suggest that the survival of melanocytes was inhibited specifically in the hair follicles of the Shiba goat with the dominant black-eyed white phenotype and that the ostensibly similar phenotypes in the Shiba goat and in the SI or W mutants of the mouse, where melanocytes die en route to the hair bulbs, are regulated by different mechanisms.     

Effects of ablation of the pars intercerebralis on ecdysteroid quantities and yolk protein expression in the blowfly Protophormia terraenovae

Quantities of ecdysteroid are compared in the haemolymph and ovaries of the blowfly Protophormia terraenovae Robineau‐Desvoidy (Diptera: Calliphoridae) under reproductive (LD 18 : 6 h at 25 °C) and diapause (LD 12 : 12 h at 20 °C) conditions. The effects of ablation of the pars intercerebralis or ovaries on ecdysteroid quantities and of ablation of the pars intercerebralis on yolk protein expression are examined. Under reproductive conditions, the levels of ecdysteroid in vitellogenic females are high, although the levels in previtellogenic females and females with mature ovaries are low. Under diapause conditions, there are low quantities of ecdysteroid in both the haemolymph and ovaries. Ecdysteroid titres in the haemolymph are not significantly affected by the removal of the ovaries, suggesting that tissues other than the ovaries are also involved in the production of ecdysteroids. Reproductive females in which the pars intercerebralis of the brain is experimentally ablated have ecdysteroid levels that are not significantly different from sham‐operated or intact females. However, yolk protein expression in the fat body is suppressed after removal of the pars intercerebralis. These results suggest that the suppression of ecdysteroid levels in the haemolymph and ovaries is associated with reproductive diapause, and that the pars intercerebralis could play a role in yolk protein synthesis without mediating ecdysteroid production.     

The diversity of hemi-epiphytic figs (Ficus ; Moraceae) in a Bornean lowland rain forest

The diversity and niche specificity of hemi-epiphytic figs in a lowland dipterocarp forest in Sarawak were investigated in 1998. Twenty-seven fig species (264 individuals, c. 120 ha) colonized a diversity of host taxa (35 families), but densities were very low and only 1.77% of trees> 30 cm d.b.h. were occupied. There were no significant associations with host taxa or host-bark roughness but among 11 common species (≥9 individuals) the distributions of all other parameters (host-d.b.h., height and position of colonization, crown illumination, soil-texture and slope-angle) were significantly different, and we identified five fig guilds. The guilds corresponded to canopy strata, and appeared to reflect the establishment microsite requirements of different species. A fundamental trade-off within the hemi-epiphytic habit was revealed: Species colonizing larger hosts were rarer, because of lower host densities and more specific microsite requirements, but had better light environments and attained a larger maximum size. The single strangler species appeared to escape many of these constraints, and an important source of mortality caused by host-toppling, indicating the advantages of this strategy. Thus, the hemi-epiphytic figs in this community have come to fill a remarkable diversity of niches, despite low levels of competition, through the exigencies of a complex environment.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 78 , 439–455     

GENERAL ACCOUNTS ON THE OÖCYTE GROWTH AND THE IDENTIFICATION OF VITELLOGENIN BY MEANS OF IMMUNOSPECIFICITY IN THE COCKROACH, BLATTELLA GERMANICA (L.)

The female Blattella germanica pushes out an oötheca 11 days after adult ecdysis and carries it for about 25 days until nymphs hatch out. The terminal oöcyte begins to accumulate yolk abruptly 4 or 5 days after adult ecdysis and grows fully on day 10 when its volume reaches 180 times as compared to that at adult ecdysis.
Vitellogenin, the vitellogenic female-specific protein, was identified by immunoelectrophoresis and Ouchterlony's test. Fluctuation of vitellogenin in the blood, ovary and embryo at various stages was analyzed. Vitellogenin appears in the female blood 3 or 4 days after adult ecdysis and disappears soon after terminal oöcytes have been released to an oötheca. In the ovary, it appears 4 or 5 days after adult ecdysis and disappears when terminal oöcytes leave the ovary. It remains in embryos until shortly before hatching, but is absent in newly hatched nymphs.     

Mass mortality of Japanese macaques in a western coastal forest of Yakushima

The mass mortality of wild Japanese macaques (Macaca fuscata Blyth) was observed in a warm temperate forest of Yakushima, southern Japan. Demographic changes of eight troops between August 1998 and August 1999 were studied and 56% of macaques disappeared from the five intensively studied troops. Mortality varied among troops: two troops became extinct, while another troop did not decrease in size. The rate of mortality of the other troops was between 33 and 80%. The variation in mortality among the troops was either the outcome of local concentrations of mortality or of intertroop competition. The rate of mortality decreased with increasing distance from the two extinct troops and with increasing troop size; these two factors could not be separated statistically. The direct cause of death was diagnosed as pneumonia for four out of five fresh carcasses. The fleshy fruit production in autumn 1998 was the lowest in 14years, and macaques had relied on leaves earlier than in usual years. It was exceptionally hot and dry in the summer of 1998. The exceptionally poor fruit production and hot summer of this year, with the resulting shortage of high-quality foods, was consistent with the scenario that mass mortality was due to the poor nutritional conditions. However, the possibility that epidemics caused the mass mortality cannot be ruled out. Our findings proved that primates in a seemingly stable habitat experience fluctuations in demographic parameters under natural conditions.     

抑前胸腺肽在家蚕体内的活性作用

家蚕Bombyx mori抑前胸腺肽是昆虫脑神经肽的一种,体外实验表明它能抑制处于活动时期的家蚕前胸腺合成蜕皮激素,因此抑前胸腺肽可能对昆虫的变态起着重要的作用。将抑前胸腺肽以不同的浓度分单一注射和加强注射导入家蚕体内,不同的时间间隔取样,利用蜕皮激素放射免疫分析方法,观察到了抑前胸腺肽在家蚕体内的活性作用以及引起家蚕体内血淋巴中蜕皮激素浓度的动态变化,首次证明了抑前胸腺肽在体内对家蚕前胸腺合成蜕皮激素有强烈的抑制作用。     

Factors influencing adult emergence from soil and the vertical distribution of burrowing scarab beetles Dasylepida ishigakiensis

The present study investigates the emergence of adult white grub beetles Dasylepida ishigakiensis Niijima et Kinoshita (Coleoptera: Scrabaeidae) from soil as well as their burrowing behaviours. ‘Standby behaviour’ (i.e. adults come to the soil surface where they expose their heads) is shown in the field and, along with emergence behaviour, is entrained by LD photocycles. These 24‐h rhythms persist after transfer to continuous light conditions for 2 days. By contrast, beetles transferred from LD photocycles to continuous dark conditions fail to show standby behaviour; thus, it appears to be manifested only in the presence of illumination. Under dark conditions, beetles emerge completely from the soil directly at the time when standby behaviour is otherwise expected to occur. Emerged adults then burrow back into the soil before dawn. Virgin and mated males, as well as virgin females, which are expected to emerge from the soil for mating on later evenings, burrow to a relatively shallow depth (<2 cm), whereas mated females burrow deeper (2–10 cm). Soil properties such as moisture, grain size, topography and temperature influence the burrowing behaviour and the depths that the beetles reach.