Osmoregulatory responses of glaucous-winged gulls (Larus glaucescens) to dehydration and hemorrhage

The effects of dehydration and hemorrhage on plasma ionic, osmotic, and antidiuretic hormone (arginine vasotocin) concentrations and of hemorrhage on salt gland secretion and glomerular filtration rate were evaluated in glaucous-winged gulls, Larus glaucescens. Dehydration for 24 h did not affect plasma ionic, osmotic or arginine vasotocin concentrations; 72 h dehydration significantly elevated plasma osmolality, plasma sodium and chloride concentrations, and plasma arginine vasotocin concentration, but did not affect plasma potassium concentration. Constant infusion of 0.8 mol·l^-1 NaCl increased plasma arginine vasotocin concentration and produced salt gland secretion in seven gulls; four secreted well, while three secreted less well. Removal of 20% blood volume during saline infusion immediately reduced (P<0.001) salt gland secretion rate in all gulls. After bleeding, good secretors maintained glomerular filtration rate and urine flow rate; the poorer secretors increased glomerular filtration rate and became diuretic. Blood replacement returned salt gland secretion rate to the prebleeding level (P<0.05) without affecting salt gland secretions sodium concentration in gulls which secreted well, but did not restimulate salt gland secretion in gulls which secreted poorly. Reinfusion of blood had no effect on glomerular filtration rate. Bleeding and blood replacement did not affect plasma arginine vasotocin concentration.Abbreviations AVT arginine vasotocin - ECF extracellular fluid - ECFV extracellular fluid volume - EDTA ethylenediaminetetra-acetate - EWL evaporative water loss - GFR glomerular filtration rate - Hct hematocrit - LB large blood sample - [Na⁺]_pl plasma sodium concentration - Osm_pl plasma osmolality - PEG polyethylene glycol - RH relative humidity - RIA radioimmunoassay - SB small blood sample - SGS salt gland secretion - T _a ambient temperature - TFA trifluoroacetic acid - UFR urine flow rate     

Reproductive parameters in relation to food supply in the whiskered tern ( Chlidonias hybrida )

It is generally accepted that breeding terns are sensitive to food supply and that their reproductive effort could be substantially affected by the availability and access to resources. In this study we examined reproductive parameters in the whiskered tern Chlidonias hybrida in relation to food supply during the courtship feeding period (food brought by males to females) over a 2-year period (2004–2005). We also studied whether the condition of the nestlings [body condition index (BCI)] was related to a proxy of the reproductive investment of the adults (the clutch size) during a season of food shortage. Behavioural observations showed a decrease in the intensity of male courtship feeding between years (2004 > 2005), and a strong shift in the relative abundance of the two prey groups (invertebrates/fish; invertebrate prey dropped from 88.0 to 49.3%) brought by males. This change in food delivery rates did not result in a delay in laying, but there was a significant difference in mean clutch size between years (2.71 ± 0.49 eggs in 2004 and 2.05 ± 0.78 eggs in 2005) without any within-year variation in relation to the laying dates. The egg size (volume and length) was related to the year (2004 < 2005), suggesting a trade-off in the quantity and the quality of eggs between the two seasons. We also found no evidence that the investment in a large clutch affected nestling BCI in the course of the food shortage season. Since many pairs (about 60%) interrupted breeding during the incubation stage, we assumed that parents that succeeded in rearing nestlings in these conditions were probably ‘high-quality’ individuals. Our results therefore showed that whiskered terns are sensitive to the varying food conditions they experienced throughout the courtship period. The diversity of prey types could be a key factor in the reproductive investment of this tern species.     

Egg Size and Formation of the Geographical Range in <Emphasis Type="Italic">Thysanoessa inermis</Emphasis> (Kroyer, 1846) (Crustacea: Euphausiacea) in the Norwegian and Barents Seas

Using materials on the euphausiacean Thysanoessa inermis collected in the Norwegian and Barents seas (from 60°N to 73°N) we studied the variability of size characteristics in the eggs (diameter of embryos and egg capsules and the width of the perivitelline space) and their correlations with water temperature and salinity. The size of embryos showed almost no variability irrespective of the location of the sampling site and the water temperature and salinity; the perivitelline space performs a protective function, and its width showed a tendency to decrease with increasing water temperature and salinity. The similarities in the size of embryos in T. inermis populations thousands of kilometers away from each other might be explained, first, by the relatively small age of the populations (the age of the population from the Barents Sea did not exceed 6000–7000 years) and second, by movement of the crustaceans with currents from the Norwegian Sea to the Barents Sea.     

Egg and clutch sizes of a goby Rhinogobius giurinus in the Aizu River, Kii Peninsula, Japan

Egg and clutch sizes, and gonad somatic index (GSI) at maturity of the amphidromous goby Rhinogobius giurinus were examined in the Aizu River, Wakayama Prefecture, Japan. The goby tended to have a larger clutch size, with smaller eggs, and matured at the lower GSI, compared with those in the three sympatric amphidromous species of R. brunneus complex. Higher water temperature and abundant food conditions may affect the optimal egg size in R. giurinus. Besides, higher larval survival rate during downstream migration may affect lower GSI at maturity in this goby that usually inhabits lower reaches of the river.     

The interactive effects of temperature,food level and maternal phenotype on offspring size in Daphnia magna

Invertebrate offspring are usually larger in colder environments. To test for possible effects of covariates (e.g. maternal phenotype and feeding conditions) on this pattern, we performed a laboratory experiment to look at the effect of temperature on newborn weight in the planktonic crustacean Daphnia magna. Three tempèratures (12°C, 16°C and 22°C) and two food levels (10,000 cells ml^–1 and 150,000 cells ml^–1) were used, and offspring were examined from the first five clutches of mothers that had been maintained under the constant experimental conditions for three generations. Preliminary analysis suggested that newborn weight was significantly affected by temperature although patterns in the data were not clear cut. In addition, the covariates mother weight and clutch size were positively and negatively correlated with newborn weight, respectively; and later clutches tended to contain heavier offspring. Therefore, in an effort to control for the effects of the covariates, repeated-measures analysis of covariance was performed using ratio values of newborn weight/mother weight (relative newborn weight) as the dependent variable, clutch size as the covariate and clutch number as the repeated measures term. Now, temperature as a main effect in an ANCOVA model did not significantly influence relative newborn weight. The repeatedmeasure term clutch number also became nonsignificant, indicating that when differences in mother weight due to age were accounted for there were no overall differences in relative newborn weight between clutches from a particular mother. Temperature effects on relative newborn weight were only significant as part of interaction terms with food concentration and with clutch number. Thus there were different weight responses to temperature within food levels, and between clutch numbers within food levels. Under the low-food conditions newborn were heaviest at 16°C, lightest at 12°C and intermediate at 22°C. Conversely, under the high-food condition newborn were lightest at 16°C, heaviest at 12°C and again intermediate at 22°C. However, newborn tended to be heavier under the low food condition, and food concentration was highly significant as a main effect. Mother growth rate showed no significant relationship with newborn weight. It is concluded that direct temperature effects on relative newborn weight are marginal and nonsignificant. Temperature effects through interactions with food concentration and clutch number are important determinants of newborn weight, but relatively speaking account for only a small proportion of observed variance in newborn weight (25%), compared with the direct effect of food concentration (67%).     

Socio-sexual factors of troop fission in wild Japanese monkeys (Macaca fuscata yakui) on Yakushima Island,Japan

The troop fissions which occurred in a wild population of Japanese monkeys (Macaca fuscata yakui) were observed from 1977 to 1979 on Yakushima Island. The fissions were initiated in the breeding season by non-troop males who established a consort relation with estrous females. In order to analyze the socio-sexual factors which accelerated the fissions, the male emigrations and immigrations before and after two successive fissions, and the copulation frequencies, competition among males and preferences of mating partners in both sexes in the 1977–78 breeding season after the first fission were examined. The results indicated that three factors (a large number of non-troop males, a shortage of troop males and the females' choice of mating partners) effectively influenced on the establishment of consort relationships between non-troop males and estrous females. It is suggested that these factors may exert different effects on the troop disorganization in relation to troop size. In small-sized troops, a large number of non-troop males and a shortage of troop males may lead to stronger competition between them, and the females' choice affected by prolonged intimate relations with the dominant TMs may reduce their priority of access to estrous females. This situation possibly stimulates fission or male emigration in small-sized troops under the natural conditions on Yakushima Island. In contrast, in large-sized troops under isolated conditions, a surplus rather than a shortage of troop males may contribute to troop disorganization, as most former studies have suggested. A higher socionomic sex ratio may decrease the mating activities of subordinate troop males and increase the competition among them. This situation possibly accelerates the fission of large-sized troops through prolonged interactions between females and subordinate or peripheral troop males. A lower ratio and the females' choice, however, raise the mating chances of subordinate troop males and may not promote the fission of large-sized troops under isolated conditions. This study was financed in part by a Grant-in-Aid for Special Project Research on Biological Aspects of Optimal Strategy and Social Structure from the Japan Ministry of Education, Science and Culture, and by the Cooperative Research Fund of the Primate Research Institute, Kyoto University.     

Identification of a putative egg-laying hormone in neural and ovarian tissues of the black tiger shrimp, Penaeus monodon, using immunocytochemistry

The existence of an egg-laying hormone (ELH) was identified for the first time in the black tiger shrimp, Penaeus monodon, by means of immunoenzyme and immunofluorescence techniques. This was achieved using a polyclonal antibody produced against expressed recombinant ELH of the female Australian blacklip abalone, Haliotis rubra. The shrimp ELH reactive material was found to be localised within female neurosecretory tissues and the secretory tissue of the antennal gland, but was not identified in the X-organ sinus gland within the eyestalk. It was also present in the ovary, where the amount of ELH present was observed to be greatest in the period prior to spawning. These findings implied that the induction of P. monodon spawning might be involved with humoral regulation relating to ELH expression.     

Monthly and diurnal variations in food choice byMacaca fuscata yakui during the major fruiting season at Yakushima Island, Japan

An ecological survey was conducted on two groups of wild Japanese macaques (Macaca fuscata yakui) inhabiting the warm-temperate, broad-leaved forest of Yakushima Island. The survey was designed to determine and explain monthly and diurnal variations in both duration of feeding and food choice, and to explain these variations from a nutritional perspective. Feeding activity increased during the hour before sunset, while leaf eating in particular tended to be observed later in the day throughout the study period. A diverse and unstable diet promoted monthly differences in fat and protein consumption. The mean lipid and calorific content of the food and the rate of protein intake were high in early autumn.Ficus fruits were not selected when unripeArdisia sieboldii fruits were available, but were an important food resource in a general context. Differences in nutritional intake at different times of the day were determined by the combination of species eaten although no single species was preferred at a particular time. Similarities with experimental results in laboratory animals suggest that a physiological, rather than a behavioural, response was regulating nutritional intake. A high consumption of proteins before rest might produce satiety in the macaques and give them the opportunity to digest and absorb complicated or toxic metabolites slowly during the night.     

Vertical distribution of wild Yakushima macaques (Macaca fuscata yakui) in the western area of Yakushima Island, Japan: Preliminary report

A census of wild Yakushima macaques (Macaca fuscata yakui) was carried out in a 23-km² area of the western coast of Yakushima Island, Japan. We analyzed the census data to investigate changes in monkey distribution associated with the vertical distribution of vegetation. In the lowland coastal zone of 0–300 m above sea level (a.s.l.), 4.8 troops and 62.4–99.8 monkeys are estimated to have existed per km². In the mountainside zones of 300–900 m a.s.l., the troop density decreased to 1.3–1.6 troops/km². Since there was no difference in size between the coastal and mountainside troops, population density should decrease with altitude to about 30–36 monkeys per km². On the other hand, 2.4 troops and about 36 monkeys were estimated to have inhabited per km² in the mountain summit zone of 900–1,323 m a.s.l. Nature Conservation College     

Body mass of female great tits (Parus major) at egg laying

Based on automated weighing of nest-boxes, we found that female great tits (Parus major) usually maintained their body mass during the egg-laying period. A drop in temperature (3°C or more) during laying was followed by a drop in body mass, and female body mass also depended slightly but significantly on mean temperature on the other days. Day to day change in body mass depended negatively on the actual body mass. Moreover, the repeatability of the morning body mass was high (r _I =0.90, n=24). Thus, female body mass seems to be regulated around a female specific, but temperature-dependent, level during laying. The lack of strong correlation between female average body mass and clutch size makes it improbable that body mass at laying plays a leading, proximate role in the control of clutch-size of great tits.     

Ypsilonidium bananisporum sp. nov. (Ceratobasidiales) from Iriomote Island, Japan

Ypsilonidium bananisporum sp. nov. belonging to Ceratobasidiales is described and illustrated. This fungus has all the characteristics of the genusYpsilonidium including reticulate-hypochnoid basidiomes, broad hyphae branching at right angles, broadly clavate basidia with two sterigmata, and basidiospores germinating by repetition. It differs from all hitherto known species in the genus by producing suballantoid to banana-shaped basidiospores, measuring 19.5–22×5.5–6 μm. Contribution No. 314 of the Tottori Mycological Institute.     

Interannual variations of reproductive parameters in a booted eagle (Hieraaetus pennatus) population: the influence of density and laying date

A population of booted eagles (Hieraaetus pennatus) consisting of 21–29 pairs was studied for 7 years (1998–2004) in a forested mountainous region of southeastern Spain. The average egg-laying time was 25 April (earliest 31 March, latest 26 May). Sixty-eight percent of territorial pairs produced eggs, and 81% of reproductive pairs successfully raised at least one offspring. Mean clutch size was 1.91 eggs, and 84% hatched. The survival rate of chicks was high, with only 17% dying. The major known cause of nestling mortality was predation, mainly by the Eurasian eagle owl (Bubo bubo). The mean number of flying offspring was 0.91 per territorial pair, 1.29 per reproductive pair and 1.65 per successful pair. All population breeding parameters analysed were density independent, but most showed a significantly negative relationship with mean laying date.     

Pleosporales in Japan (5): Pleomassaria, Asteromassaria, and Splanchnonema

Eight species in Pleomassariaceae are described and illustrated. They are Pleomassaria maxima, Pl. swidae, Pl. siparia “type A,” Prosthemium canba, Asteromassaria macroconidica, A. pulchra, Splanchnonema mori, and S. argus. Of these, Pl. swidae on twigs of Swida controversa, Pr. canba on Betula ermanii, and A. macroconidica on twigs of Prunus ×yedoensis and an unknown woody plant are new. Three species, Pl. siparia “type A,” A. pulchra, and S. argus, are reported from Japan for the first time. A new combination, S. mori (≡ Massaria mori), is proposed.     

Summer dietary compositions of sika deer on Yakushima Island,southern Japan

Summer food habits of Sika deer (Cervus nippon yakushimae) on Yakushima Island, southern Japan, were studied focusing in particular onPseudosasa owatarii, a dwarf bamboo native to the island. Fecal analyses showed that the food habit of the Sika deer on Yakushima island was plastic: the dietary composition was dominated by graminoids (ca. 90%), particularlyP. owatarii (50%–60%) in the bamboo grassland of theP. owatarii zone above the timber line, whereas leaves and non-leafy parts of woody plants were important in the crytomeria forest and evergreen broad-leaved forest below the timber line. The maximum culm age ofP. owatarii was 8.5 yr, but the majority of leaves (97.8%) were younger than 2.5 yr. Since the weight contribution of the leaves is great (27.7%) and the turnover rate is high, theP. owatarii grassland affords a good foraging place for the Sika deer on Yakushima Island.     

Egg-size variation in the bluethroat (Luscinia s. svecica): constraints and adaptation

We examined inter- and intra-clutch egg-size variation in the bluethroat (Luscinia s. svecica), an open-nesting passerine breeding in the sub-alpine region in southern Norway. By removing first clutches shortly after egg-laying, we induced laying of a repeat clutch. Females significantly reduced the number of eggs from the first to the second nesting attempt, but increased mean egg size. Females in good condition laid significantly larger eggs than those in poor condition. Consistent with predictions of the brood survival hypothesis, assuming an adaptive investment in last eggs to ensure survival of all eggs in the clutch, we found that the size of the last eggs in first clutches was generally larger than the mean egg size of the clutch, and that the relative size of the last egg increased with clutch size. However, a large last egg reflected a general increase in egg size throughout the laying sequence rather than a specific investment in the last egg only. Egg size was not significantly influenced by sex or paternity (within-pair versus extra-pair) of the embryo. In repeat clutches the last egg was not consistently larger than the mean for the clutch. We conclude that female bluethroats face resource limitations during egg formation early in the season, and that the patterns of increase in egg size with laying order for first clutches, and from first to repeat clutches, can largely be explained by proximate constraints on egg formation.     

Notes onLaboulbenia coneglanensis (Ascomycetes, Laboulbeniales) in Japan

Laboulbenia coneglanensis isolated from Japanese harpaline carabids is described and photographed. It is compared morphologically withL. flagellata from Japan and Europe, which is similar in appearance. The most important difference between the two species is in antheridial character and host range. Other characters such as coloration, perithecial shape, especially the shape of the perithecial apex, and size of ascospores are also useful for distinction.Laboulbenia ophoni var.dilatata described by Maire (1920) is regarded as a synonym ofL. coneglanensis.     

The problem of optimal clutch size in a tritrophic system: the oviposition strategy of the thistle gallfly Urophora cardui (Diptera,Tephritidae)

The problem of optimal clutch sizes is a central theme in life history theory. Optimal allocation of eggs is especially complicated for insects in tritrophic systems. In this study we analyze some of the processes determining clutch sizes of the thistle gallfly Urophora cardui, a monophagous tephritid fly associated with Cirsium arvense. U. cardui forms multilocular shoot galls, which vary broadly in their size and number of their gall cells. We investigate various fitness consequences of gall size. An analysis of the number of cells per gall (which is correlated with gall diameter and gall weight) showed that in U. cardui there is mutual facilitation rather than larval competition. Increasing numbers of larvae per gall led to a decreasing mortality and increasing larval weight. Larval weight in turn was positively correlated with the probability of survival to adulthood and with adult weight and fecundity. Thus, all fitness parameters measured favoured large galls. Clutch sizes in oviposition experiments were distinctly larger than the number of gall cells of field populations and in cage experiments, suggesting high mortality of eggs and/or early larval instars. There was a significant relationship between the internal structure (i.e., the size of the growing point) of the bud and clutch size, suggesting that U. cardui females are able to measure bud quality and adapt clutch sizes accordingly. Clutch size was positively correlated with the female's age at first oviposition and negatively with the number of previous ovipositions and previously laid eggs. Since the potential egg capacity per female is higher than the average number of larvae it is likely to produce during its short adult lifespan, U. cardui females tend to be time-limited rather than egglimited, which might favour large clutches once an appropriate oviposition site has been located. As the development of the gall and hence the fate of a clutch depends on a number of unpredictable factors, exclusive concentration of eggs in a few large clusters would involve risks which could be avoided by increasing the number of clutches. Therefore we interpret the high variation of clutch sizes in U. cardui as a mixed strategy of bet hedging and gambling.     

青海湖棕头鸥(Larus brunnicephalus)夏秋季活动区研究

2006年4～9月,采用无线电遥测技术对青海湖重要繁殖水鸟棕头鸥(Larus brunnicephalus)在不同繁殖阶段的活动性,以及与人和鸟的关系进行了研究.对6只棕头鸥个体的遥测结果表明,繁殖初期棕头鸥的活动区较大,进入繁殖中期,活动区明显变小;随后繁殖后期的活动区面积有所增加,到了迁徙前期,活动区面积已接近繁殖初期.不同阶段活动区核心面积(50%Fixed Kernel)与活动区变化趋势基本一致.繁殖初期、中期、后期和迁徙前期活动区面积分别为(15.48 km2±4.54 km2)、(1.61 km2±0.41 km2)、(3.53 km2±2.63 km2)和(11.61 km2±9.36 km2).棕头鸥在不同繁殖阶段的日活动区大小有显著差异.繁殖初期,棕头鸥经常活动于鸬鹚岛、蛋岛和布哈河口,它们都是棕头鸥较好的取食地,鸬鹚岛和蛋岛由于有许多游客投喂食物;在繁殖中期,棕头鸥进入孵化阶段,活动区较繁殖前期明显缩小.由于湟鱼返回布哈河口一带产卵繁殖,棕头鸥经常聚集在此地取食;在繁殖后期,棕头鸥需要寻找大量的食物进行育雏,因此活动范围再度扩大;进入迁徙前期,幼鸟已经长大并学会飞翔,其活动区进一步扩大,与繁殖初期较为接近.     

Ribosomal DNA variations in Erianthus, a wild sugarcane relative (Andropogoneae-Saccharinae)

Variation at the 18S+26S and 5S ribosomal DNA loci was assessed on 62 Erianthus Michx. clones, representing 11 species, and 15 clones from two Saccharum L. species used as a reference. Genus-specific markers for Erianthus Michx. sect. Ripidium Henrard (Old World species) were identified. Ribosomal DNA units in Erianthus sect. Ripidium exhibited an additional BamHI site compared to Saccharum, and 5S units showed length and restriction-site differences between Erianthus and Saccharum. These markers will be useful to follow introgression in Saccharum x Erianthus hybrids. Six ribosomal units (for 18+26S genes) were revealed in Erianthus sect. Ripidium, differing by restriction-site positions and/or length. These results provided new information on species relationships and evolution within the genus Erianthus. The Indonesian and Indian forms of E. arundinaceus (Retz.) Jeswiet gave different restriction patterns, which were similar to those of E. bengalense (Retz.) R. C. Bharadwaja and E. procerus (Roxb.) Raizade, respectively. The two 2n=20 species, E. ele-phantinus Hook.f. and E. ravennae (L.) P. Beauv., could also be differentiated at this locus. Two of the New World Erianthus species studied, E. rufipilus (Steud.) Griseb. and E. longisetosus Andersson, appeared more like Erianthus sect. Ripidium, whereas E. trinii Hack, and E. brevibardis Michx. showed patterns consistent with Miscanthus sinensis Andersson and S. spontaneum L., respectively. Finally, the comparison of rDNA restriction maps among Erianthus sect. Ripidium, Saccharum, sorghum and maize, led to unexpected conclusions concerning the relationships between the different genera and the position of Erianthus in the Saccharum complex.