The regulation of brood reduction in Booted Eagles Hieraaetus pennatus through habitat heterogeneity

Brood reduction, the death of one or more chicks through siblicide or starvation, can occur through density‐dependence in fecundity. Brood reduction may arise in territorial breeding systems either as a response to a high level of territorial interference in a situation of high density or as a result of habitat heterogeneity. To test the predictions of the two main hypotheses that attempt to explain how density‐dependent fecundity is generated, the Habitat Heterogeneity Hypothesis (HHH) and the Individual Adjustment Hypothesis (IAH), we analysed the relationship between density and fecundity in an expanding population of Booted Eagles in Doñana National Park, Spain, using an 18‐year data series. We also studied the occurrence and frequency of brood reduction in the same Booted Eagle population to appreciate further its effects and the factors that influence its occurrence and frequency. Our results support the HHH in the present situation of high density, as fecundity in the better territories (older and more frequently occupied) was higher than in low quality territories and was not affected by population density in high density periods. Nevertheless, the fecundity of high quality territories was affected (although not significantly) by population density in periods of low density, suggesting that the IAH was supported when only high quality territories were occupied. Older territories were used more frequently and chicks in these areas hatched earlier and suffered lower mortality than in new territories. We found a significant negative relationship between mean fecundity and its skewness, a finding that also supports HHH. During years of food shortage, less frequently occupied territories suffered higher rates of brood reduction. Brood reduction in this Booted Eagle population was a consequence of the heterogeneous structure of the habitat, with some territories having a higher probability of brood reduction than others. Parental nutritional condition did not affect brood reduction. The effect of brood reduction on nestling quality and population dynamics is also discussed.     

五种食用菌氨基酸含量的测定及营养评价

研究测定了五种食用菌中氨基酸的含量,并利用五种非生物学指标对蛋白质的营养价值进行评价。五种食用菌氨基酸种类齐全,必需氨基酸占氨基酸总量的百分比分别达到45.94%、37.62%、42.45%、41.54%、35.98%。茶树菇和姬松茸的限制性氨基酸为半胱氨酸和甲硫氨酸,鸡腿菇、香菇和黑木耳的限制性氨基酸是缬氨酸。不同的评价指标对蛋白质进行营养评价,评价结果会有所差异。     

人工冬虫夏草的氨基酸含量及其营养价值评价

目的为明确人工和野生冬虫夏草在氨基酸方面的差异,并为进一步开发利用人工冬虫夏草提供理论依据,对室内全人工培殖冬虫夏草和产自四川康定的野生冬虫夏草的氨基酸营养价值进行分析评价。方法用日立L-8800型全自动分析仪检测氨基酸含量并根据FAO/WHO的氨基酸评分标准模式和鸡蛋蛋白模式进行氨基酸营养价值评价。结果人工冬虫夏草氨基酸种类齐全,其全草氨基酸总量高于产自康定的野生冬虫夏草;其全草的鲜味氨基酸高于产自康定的野生冬虫夏草;其全草必需氨基酸总量低于产自康定的野生冬虫夏草。人工冬虫夏草必需氨基酸与氨基酸总量的比值高于WHO/FAO评分模式而低于鸡蛋蛋白模式。结论人工冬虫夏草氨基酸不仅种类组成合理,而且具有较高的营养价值。这一结果为人工冬虫夏草的进一步开发利用提供了理论基础。     

Enhanced production and partial characterization of an extracellular polysaccharide from newly isolated Azotobacter sp. SSB81

A strain was selected by its highest extracellular polysaccharide (EPS) production ability compare to other isolates from the same rhizospheric soil. The selected strain was identified by 16S rDNA sequencing and designated as SSB81. Phylogenetic analysis of the gene sequence showed its close relatedness with Azotobacter vinelandii and Azotobacter salinestris. Maximum EPS (2.52 g l⁻¹) was recovered when the basal medium was supplemented with glucose (2.0%), riboflavin (1 mg l⁻¹) and casamino acid (0.2%). The EPS showed a stable viscosity level at acidic pH (3.0–6.5) and the pyrolysis temperature was found to be at 116.73 °C with an enthalpy (ΔH) of 1330.72 Jg⁻¹. MALDI TOF mass spectrometric result suggests that polymer contained Hex₅Pent₃ as oligomeric building subunit. SEM studies revealed that the polymer had a porous structure with small pore size distribution indicating the compactness of the polymer. This novel EPS may find possible application as a polymer for environmental bioremediation and biotechnological processes.     

Lactobacillus reuteri CRL 1098 prevents side effects produced by a nutritional vitamin B12 deficiency

Aims:  To evaluate the efficiency of the vitamin B_12-producing Lactobacillus reuteri CRL1098 strain in preventing the symptoms caused by a nutritional cobalamin-deficient diet in pregnant female mice and their weaned offspring.
Methods and Results:  Pregnant female mice were divided into three groups: animals fed with a B₁₂-deficient diet (DD), animals fed with DD plus L. reuteri CRL1098 and animals fed with a B₁₂-sufficient diet. The animals received the different feedings from the end of gestation up to weaning. At the end of the trials, they and their corresponding offspring were bled to determine haematological, immunological and histological parameters. The administration of the pseudovitamin B₁₂-producing strain prevented the symptoms observed in female and weaned young animals fed with a nutritional B₁₂-deficient diet.
Conclusions:  Our data suggest that the pseudovitamin B₁₂ produced by L. reuteri CRL1098 is biologically active and effective in preventing the pathologies caused by the nutritional deficiency of B₁₂ both in pregnant mice and their offspring.
Significance and Impact of the Study:  The ability of L. reuteri CRL1098 to prevent a nutritional vitamin deficiency was demonstrated for the first time. The addition of a GRAS micro-organism to complement the B₁₂ content in deficient foods is an interesting biotechnological alternative.     

White-Tailed Deer Foraging Habitat in Intensively Established Loblolly Pine Plantations

ABSTRACT Stand establishment techniques involving multiple herbicide applications are commonly used on industrial pine (Pinus spp.) plantations, raising concern over potential effects on white-tailed deer (Odocoileus virginianus) forage production. We tested effects of stand establishment intensity on deer forage in 1–5-year-old loblolly pine (Pinus taeda) plantations (n = 4) in the East Gulf Coastal Plain of Mississippi using forage biomass and 4 measures of nutritional carrying capacity that reflected crude protein or digestible energy requirements for body maintenance and lactation. We also assessed whether forage biomass combined with a deer use rating effectively indexed nutritional carrying capacity. Treatments were combinations of mechanical site preparation, chemical site preparation (CSP), and herbaceous weed control (HWC). Total forage biomass and forage biomass of grasses and forbs were reduced by broadcast HWC. Forage biomass of vines was reduced both by CSP and by multiple broadcast HWC applications. Maintenance-level carrying capacity estimates were reduced by broadcast HWC; lactation-level estimates were higher in moderate-intensity treatments. We believe the inherently low fertility of this region makes high-quality forage production a more important management priority than increasing forage quantity. Chemical or chemical and mechanical site preparation combined with banded HWC provided the best option for providing both forage quality and quantity in open-canopied, intensively managed pine plantations. Biomass-based indices may be suitable for indexing protein-based maintenance-level carrying capacity in this region, but our results indicated they were not useful for indexing other carrying capacity estimates.     

A reliable body condition scoring technique for estimating condition in African buffalo

Evaluating animal body condition is a necessary component of many ecological studies. Although many methods for assessing animal body condition have been developed, relatively few can be used for estimating condition on live animals. Noninvasive body condition scoring techniques have been developed for assessing condition in livestock and more recently such techniques have been applied to wild ungulates. In this study, we examined the reliability of a body condition scoring technique for assessing condition in African buffalo (Syncerus caffer caffer). We compared a body condition score (BCS) based on visual assessment and manual palpation of an animal’s body to two standard metrics of condition widely used in mammals: kidney fat index (KFI) and haematocrit (HCT). Across all buffalo, BCS was significantly and positively correlated with both KFI and HCT. For HCT, this pattern was observed among adults, juveniles, males and females; and in the wet season but not in the dry season. For KFI, BCS was significantly and positively correlated with KFI among adults, juveniles and males, but not in females. Overall, our results suggest that the BCS technique can serve as a useful method for estimating body condition in buffalo.     

Dragonfly associations (Insecta: Odonata) in relation to habitat variables: a multivariate approach

In a dragonfly survey, carried out in a lowland wetland area in eastern Austria, a total of 19 resident species was recorded. Multivariate statistical procedures were used to analyse the relationship between dragonfly assemblage patterns and environmental variables. Besides widespread and euryoecious species with unspecific habitat requirements two dragonfly associations were identified: on the one hand species mainly occurring at temporary natural and near-natural ponds characterised by rush and reed vegetation, on the other hand species preferring permanent waters such as the artificial waterbodies in the investigation area characterised by floating macrophytes. Water persistence and the existence of floating macrophytes determined the formation of species assemblages.     

Developmental thresholds and day-degree requirements of Paratanytarsus grimmii and Corynoneura scutellata (Diptera: Chironomidae): two midges associated with potable water treatment

Abstract.  Studies on the development and mortality of Paratanytarsus grimmii (Schneider) and Corynoneura scutellata (Winnertz), which can infest potable water distribution networks, were carried out at eight constant temperatures between 10 °C and 27 °C. Using weighted linear regression, the developmental thresholds were calculated as 7.9 and 8.7 °C for P. grimmii and C. scutellata , respectively. Corynoneura scutellata had a day-degree requirement of 172.4 per generation and developed significantly faster ( P  < 0.001) than P. grimmii with a day-degree requirement of 294.1. Both species were identified as multivoltine with a maximum theoretical number of five generations per year for P. grimmii and seven for C. scutellata . These results are discussed in the context of the management of chironomid infestations within water-treatment works.     

Adaptation of the gypsy moth to an unsuitable host plant

The pattern of adaptation with regard to life history traits and traits thought to be important in feeding habits of caterpillars in two populations of the gypsy moth (Lymantria dispar L.; Lepidoptera: Lymantriidae) originating from the locust tree (Robinia pseudoacacia; Fabaceae) and oak (Quercus petrea; Fagaceae) forests were investigated in the laboratory. The Robinia population has experienced unsuitable locust tree leaves as an exclusive food resource for more than 40 years. Since Quercus species are the principal host plants of the gypsy moth, the specific objectives of this study have been to measure the extent of differentiation between ancestral and derived populations in several life history traits (egg-to-adult viability, duration of larval and pupal stages, and pupal weight) and nutritional indices – relative growth rate (RGR), relative consumption rate (RCR), assimilation efficiency (AD), gross growth efficiency (ECI), and net growth efficiency (ECD). Significant differences between the Quercus and Robinia populations were detected in pupal duration, RGR, RCR, and AD. The presence of a significant population × host interaction in traits such as preadult viability, duration of pupal stage, RGR, and ECI suggests that adaptation of the gypsy moth to the unsuitable host might be ongoing. Using a full-sib design, we screened for genetic variation in life history traits within both populations, and examined the genetic correlations of performance across oak and locust leaves within both populations. The genetic variances for analyzed life history traits were lower under conditions that are commonly encountered in nature. Our data show that positive cross-host genetic correlations preponderate within both populations.