Viscosity negatively affects the nutritional value of blue lupin seeds for broilers

This study examines the impact of Lupinus angustifolius variety (C) and inclusion level (L) in broiler diets on the nutritional value, viscosity of ileal digesta and activity of gut microbiota. The experiment was conducted on 154 female 21-day-old broilers, allocated to 11 groups (kept individually). A reference lupin-free diet and 10 test diets containing one of five lupin seeds; Kadryl, Regent, Dalbor, Bojar and Tango, mixed with the reference diet at a ratio of 25 : 75 or 32 : 68 dry matter (DM) (low or high level of inclusion) were prepared. Diets were fed for 6 days, excreta were collected over last 4 days. Apparent metabolizable energy corrected to zero N balance (AME_N) of diets and AME_N of lupin seeds were calculated. Birds were sacrificed, ileal and caecal digesta were pooled by segments from two birds, and the activity of bacterial enzymes was determined. The ileal digesta viscosity was measured immediately (ileal viscosity immediate (IVI)) or after 6 days storage at −18°C (ileal viscosity frozen). AME_N of test diets were lower than the reference diet. Lupin AME_N values ranged from 6.04 MJ/kg DM for Regent at high level to 9.25 MJ/kg DM for Bojar at low level. High inclusion level numerically decreased AME_N value in all cultivars, except for Kadryl, for which it increased (significant C×L interaction). The IVI value was 2.6 mPa·s in the reference group, but ranged from 6.3 to 21.7 mPa·s in lupin-fed birds. It increased significantly with level for Regent, Dalbor and Tango but not for the other two cultivars (significant C×L interaction). There was a negative correlation between IVI and: apparent total tract N retention, fat digestibility from test diets, AME_N of diets and lupins. Ileal viscosity immediate was positively correlated with the activity of ileal α- and β-glucosidase and negatively with ileal α-galactosidase and caecal α-glucosidase. Ileal viscosity frozen ranged from 3.2 to 5 mPa·s and it was not correlated with lupins AME_N. This suggests that the digesta viscosity caused by narrow-leafed lupin is detrimental to its nutritional value and interfere with the gut microbial activity. In addition, the lupins viscosity was measured by two in vitro methods: the water extract viscosity (WEV) method and after incubation in conditions imitating in vivo digestion (enzyme-treated extract viscosity (EEV)). In vivo viscosity was weakly reflected by in vitro measurements as there was no correlation between IVI and WEV or EEV. Overall, findings suggest that the different cultivars of narrow-leafed lupin may have different value for practical application in broiler diets.     

In vitro digestibility of fern and gymnosperm foliage: implications for sauropod feeding ecology and diet selection

Sauropod dinosaurs, the dominant herbivores throughout the Jurassic, challenge general rules of large vertebrate herbivory. With body weights surpassing those of any other megaherbivore, they relied almost exclusively on pre-angiosperm plants such as gymnosperms, ferns and fern allies as food sources, plant groups that are generally believed to be of very low nutritional quality. However, the nutritive value of these taxa is virtually unknown, despite their importance in the reconstruction of the ecology of Mesozoic herbivores. Using a feed evaluation test for extant herbivores, we show that the energy content of horsetails and of certain conifers and ferns is at a level comparable to extant browse. Based on our experimental results, plants such as Equisetum, Araucaria, Ginkgo and Angiopteris would have formed a major part of sauropod diets, while cycads, tree ferns and podocarp conifers would have been poor sources of energy. Energy-rich but slow-fermenting Araucaria, which was globally distributed in the Jurassic, was probably targeted by giant, high-browsing sauropods with their presumably very long ingesta retention times. Our data make possible a more realistic calculation of the daily food intake of an individual sauropod and improve our understanding of how large herbivorous dinosaurs could have flourished in pre-angiosperm ecosystems.     

Evolution of tooth crown shape in Mesozoic birds,and its adaptive significance with respect to diet

Both the evolution of tooth morphology and the relationship between dental features and diet in toothed birds have long been studied. Here we quantify variation in tooth crown shape in 28 key Mesozoic bird species, and examine differences in dental morphology among birds belonging to different taxonomic groupings and inferred to have had different diets. Using geometric morphometric methods (GMM) and phylogenetic comparative methods (PCM), we found few clear differences in tooth crown shape between different taxonomic and ecological categories, and our analysis provides little support for many dietary inferences drawn in previous studies. However, the Solnhofen Archaeopteryx, Jeholornis, Protopteryx, Pengornis, Longipteryx, Tianyuornis, Mengciusornis, Ichthyornis and Hesperornis all were found to possess relatively specialized tooth crown shapes, perhaps reflecting specialized diets such as insectivory, granivory, piscivory and consumption of soft-shelled arthropods. Similarity in tooth crown shape across many Mesozoic birds may indicate the lack of dietary specialization, and the association between tooth form and diet may have been weakened in any case by ‘functional replacement’ of the dentition by a horny beak and, in many cases, gastroliths.     

The composition and nutritional status of the diet of Oreochromis niloticus in Lake Chamo, Ethiopia

The stomach contents of Oreochromis niloticus from L. Chamo were microscopically examined and chemically analysed in order to study the relationship between food quality, growth and condition. More than 20 genera of phytoplankton plus Copepoda, Rotifera and nauplii were present in the stomach contents. The diatom, Melosira , was the most dominant alga in the diet, contributing about 30% of the organic matter. The composition of the food in terms of organic nutrients was dominated by carbohydrate (20.3% dry weight). Both protein and fat made low contributions to the diet; 10% and 5.8% dry weight, respectively. The overall performance of the fish in assimilating food was high: 43.3% for ash free dry weight, 61.2% for protein, 57.2% for lipid, 29% for carbohydrate and 55.7% for energy. The digestible protein-energy ratio was 15.7 mg kJ⁻¹, suggesting that the food was qualitatively good both for fast growth and for maintaining good condition. It was concluded that the small amount of good quality food ingested, the low fish population density in the lake and the high temperature of the water are the major factors responsible for making O. niloticus a fast-growing fish in Lake Chamo.     

The Effect of Sea Level Rise on Dabbling Duck Energetic Carrying Capacity

Waterfowl migrating and overwintering in the Atlantic Flyway depend on adequate availability of wetland plant communities to survive winter and fuel reproduction in the subsequent breeding season. Energetics models are the primary tool employed by conservation planners to estimate energetic carrying capacity based on energy supply and demand in different wetlands to assist with effective habitat conservation. Coastal impoundments have been used to provide a consistent, annual source of energy for migrating and wintering waterfowl. But few studies have attempted to comprehensively assess the relative value of managed coastal impoundments compared with unmanaged tidal salt marshes to wintering waterfowl in the Mid-Atlantic region with further consideration to the effect of sea level rise changing availability. We estimated biomass and energy of preferred foods for 5 dabbling duck species in 7 impoundments and 3 tidal salt marshes over winter by collecting soil core (n = 1,364), nekton (n = 426), and salt marsh snail (Melampus spp.; n = 87) samples in October, January, and April 2011–2013. Food-energy density was greater in freshwater impoundments for nearly all dabbling ducks (range = 183,344–562,089 kcal/ha), and typically greater in brackish impoundments (range = 169,665–357,160 kcal/ha) than most tidal salt marsh communities (range = 55,693–361,429 kcal/ha), whereas mudflat (range = 96,223–137,473 kcal/ha) and subtidal (range = 55,693–136,326 kcal/ha) communities typically contained the least energy. Extrapolating to the state level, we estimated 7.60 × 10⁹–1.14 × 10¹⁰ kcal available within a 16-km buffer from the Delaware Bayshore, depending on species. Combining estimates for daily energy expenditure and food energy, we estimated 2.86 × 10⁷–7.06 × 10⁷ duck energy days currently available to dabbling ducks over winter. We estimated that in the next century, dabbling duck carrying capacities are likely to decrease under all but the most conservative sea level rise scenarios because of the gradual replacement of land-cover types that provide high energy density (i.e., low marsh, high marsh communities) with those that provide low energy density (i.e., subtidal, mudflat communities). Coastal impoundments in Delaware, USA, will provide increasingly important habitat for wintering dabbling ducks in the coming decades provided they are properly maintained and retain their current energetic density because they will contain a growing proportion of the available duck energy days on the landscape. Our research will assist managers in meeting target population goals for dabbling ducks in Delaware and the Mid-Atlantic region by highlighting key differences in the function and value of various wetlands. © 2021 The Wildlife Society.     

Biology of the sauropod dinosaurs: the evolution of gigantism

The herbivorous sauropod dinosaurs of the Jurassic and Cretaceous periods were the largest terrestrial animals ever, surpassing the largest herbivorous mammals by an order of magnitude in body mass. Several evolutionary lineages among Sauropoda produced giants with body masses in excess of 50 metric tonnes by conservative estimates. With body mass increase driven by the selective advantages of large body size, animal lineages will increase in body size until they reach the limit determined by the interplay of bauplan, biology, and resource availability. There is no evidence, however, that resource availability and global physicochemical parameters were different enough in the Mesozoic to have led to sauropod gigantism. We review the biology of sauropod dinosaurs in detail and posit that sauropod gigantism was made possible by a specific combination of plesiomorphic characters (phylogenetic heritage) and evolutionary innovations at different levels which triggered a remarkable evolutionary cascade. Of these key innovations, the most important probably was the very long neck, the most conspicuous feature of the sauropod bauplan. Compared to other herbivores, the long neck allowed more efficient food uptake than in other large herbivores by covering a much larger feeding envelope and making food accessible that was out of the reach of other herbivores. Sauropods thus must have been able to take up more energy from their environment than other herbivores. The long neck, in turn, could only evolve because of the small head and the extensive pneumatization of the sauropod axial skeleton, lightening the neck. The small head was possible because food was ingested without mastication. Both mastication and a gastric mill would have limited food uptake rate. Scaling relationships between gastrointestinal tract size and basal metabolic rate (BMR) suggest that sauropods compensated for the lack of particle reduction with long retention times, even at high uptake rates. The extensive pneumatization of the axial skeleton resulted from the evolution of an avian‐style respiratory system, presumably at the base of Saurischia. An avian‐style respiratory system would also have lowered the cost of breathing, reduced specific gravity, and may have been important in removing excess body heat. Another crucial innovation inherited from basal dinosaurs was a high BMR. This is required for fueling the high growth rate necessary for a multi‐tonne animal to survive to reproductive maturity. The retention of the plesiomorphic oviparous mode of reproduction appears to have been critical as well, allowing much faster population recovery than in megaherbivore mammals. Sauropods produced numerous but small offspring each season while land mammals show a negative correlation of reproductive output to body size. This permitted lower population densities in sauropods than in megaherbivore mammals but larger individuals. Our work on sauropod dinosaurs thus informs us about evolutionary limits to body size in other groups of herbivorous terrestrial tetrapods. Ectothermic reptiles are strongly limited by their low BMR, remaining small. Mammals are limited by their extensive mastication and their vivipary, while ornithsichian dinosaurs were only limited by their extensive mastication, having greater average body sizes than mammals.     

中国中生代昆虫化石研究新进展

回顾了1990年以来中国中生代昆虫化石研究的新进展,简述了我国学者在古昆虫分类学、昆虫内部形态学、昆虫系统学、古生态学、昆虫生物地层学、昆虫区系的历史演变、生物古地理学、昆虫与植物的关系等8个方面取得的突出贡献,并给出了我国发现的世界最低层位昆虫科级类群表。     

Updating maintenance energy requirement for the current sheep flocks and the associated effect of nutritional and animal factors

There is evidence indicating that using the current UK energy feeding system to ration the present sheep flocks may underestimate their nutrient requirements. The objective of the present study was to address this issue by developing updated maintenance energy requirements for the current sheep flocks and evaluating if these requirements were influenced by a range of dietary and animal factors. Data (n = 131) used were collated from five experiments with sheep (5 to 18 months old and 29.0 to 69.8 kg BW) undertaken at the Agri-Food and Biosciences Institute of the UK from 2013 to 2017. The trials were designed to evaluate the effects of dietary type, genotype, physiological stage and sex on nutrient utilization and energetic efficiencies. Energy intake and output data were measured in individual calorimeter chambers. Energy balance (E_g) was calculated as the difference between gross energy intake and a sum of fecal energy, urine energy, methane energy and heat production. Data were analysed using the restricted maximum likelihood analysis to develop the linear relationship between E_g or heat production and metabolizable energy (ME) intake, with the effects of a range of dietary and animal factors removed. The net energy (NE_m) and ME (ME_m) requirements for maintenance derived from the linear relationship between E_g and ME intake were 0.358 and 0.486 MJ/kg BW^0.75, respectively, which are 40% to 53% higher than those recommended in energy feeding systems currently used to ration sheep in the USA and the UK. Further analysis of the current dataset revealed that concentrate supplement, sire type or physiological stage had no significant effect on the derived NE_m values. However, female lambs had a significantly higher NE_m (0.352 v. 0.306 or 0.288 MJ/kg BW^0.75) or ME_m (0.507 v. 0.441 or 0.415 MJ/kg BW^0.75) than those for male or castrated lambs. The present results indicate that using present energy feeding systems in the UK developed over 40 years ago to ration the current sheep flocks could underestimate maintenance energy requirements. There is an urgent need to update these systems to reflect the higher metabolic rates of the current sheep flocks.     

Some characteristics of the trichoptera distribution in the Mesozoic of Eurasia (Insecta: Trichoptera)

The stratigraphic distribution and peculiarities of burial of caddis cases from 293 Mesozoic localities in Eurasia are analyzed. An attempt is made to analyze and interpret the co-occurrence of trichopteran cases and adults in the major localities. The main stages in the evolution of the building behavior of trichopteran larvae in the Mesozoic have been elucidated.     

Rethinking the nature of fibrolamellar bone: an integrative biological revision of sauropod plexiform bone formation

We present novel findings on sauropod bone histology that cast doubt on general palaeohistological concepts concerning the true nature of woven bone in primary cortical bone and its role in the rapid growth and giant body sizes of sauropod dinosaurs. By preparing and investigating longitudinal thin sections of sauropod long bones, of which transverse thin sections were published previously, we found that the amount of woven bone in the primary complex has been largely overestimated. Using comparative cellular and light‐extinction characteristics in the two section planes, we revealed that the majority of the bony lamina consists of longitudinally organized primary bone, whereas woven bone is usually represented only by a layer a few cells thin in the laminae. Previous arguments on sauropod biology, which have been based on the overestimated amount, misinterpreted formation process and misjudged role of woven bone in the plexiform bone formation of sauropod dinosaurs, are thereby rejected. To explain the observed pattern in fossil bones, we review the most recent advances in bone biology concerning bone formation processes at the cellular and tissue levels. Differentiation between static and dynamic osteogenesis (SO and DO) and the revealed characteristics of SO‐ versus DO‐derived bone tissues shed light on several questions raised by our palaeohistological results and permit identification of these bone tissues in fossils with high confidence. By presenting the methods generally used for investigating fossil bones, we show that the major cause of overestimation of the amount of woven bone in previous palaeohistological studies is the almost exclusive usage of transverse sections. In these sections, cells and crystallites of the longitudinally organized primary bone are cut transversely, thus cells appear rounded and crystallites remain dark under crossed plane polarizers, thereby giving the false impression of woven bone. In order to avoid further confusion in palaeohistological studies, we introduce new osteohistological terms as well as revise widely used but incorrect terminology. To infer the role of woven bone in the bone formation of fast‐growing tetrapods, we review some aspects of the interrelationships between the vascularity of bone tissues, basal metabolic rate, body size and growth rate. By putting our findings into the context of osteogenesis, we provide a new model for the diametrical limb bone growth of sauropods and present new implications for the evolution of fast growth in vertebrates. Since biomechanical studies of bone tissues suggest that predominant collagen fibre orientation (CFO) is controlled by endogenous, functional and perhaps phylogenetic factors, the relationship between CFO and bone growth rate as defined by Amprino's rule, which has been the basis for the biological interpretation of several osteohistological features, must be revised. Our findings draw attention to the urgent need for revising widely accepted basic concepts of palaeohistological studies, and for a more integrative approach to bone formation, biomechanics and bone microstructural features of extant and extinct vertebrates to infer life history traits of long extinct, iconic animals like dinosaurs.     

Effect of winter flooding on mass and gross energy of bottomland hardwood acorns

Decomposition of red oak acorns (Quercus spp.; Section Erythrobalanus) could decrease forage biomass and gross energy (GE) available to wintering ducks from acorns. We estimated changes in mass and GE for 3 species of red oak acorns in flooded and non-flooded bottomland hardwood forests in Mississippi during winter 2009–2010. Mass loss of acorns was ≤8.1% and reduction in GE ≤0.03 kcal/g after exposure for 90 days. These small changes in mass and GE of red oak acorns would have minimal effect on carrying capacity of bottomland hardwood forests for ducks. © 2012 The Wildlife Society.     

The nutritional value of feeding on crops: Diets of vervet monkeys in a humanized landscape

Anthropogenic influences have dramatically altered the environments with which primates interact. In particular, the introduction of anthropogenic food sources to primate groups has implications for feeding behaviour, social behaviour, activity budgets, demography and life history. While the incorporation of anthropogenic foods can be beneficial to primates in a variety of nutritional ways including increased energetic return, they also carry risks associated with proximity to humans, such as risk of being hunted, disease risk and risk of conflict. Given such risks, we initiated a 3‐year study where we sought to understand the underlying nutritional motivations for anthropogenic food resource use by vervet monkeys (Cercopithecus aethiops) in the humanized matrix surrounding the Nabugabo Field Station in central Uganda. Feeding effort, defined as proportion of feeding scans spent on anthropogenic food, was not associated with ripe fruit availability nor with crop availability as determined by phenological monitoring. Likewise, there was no difference in the protein, fibre, or lipid composition of crop food items compared to wild food items. Individuals spent less time feeding overall in months over the 3 years with a higher proportion of time spent feeding on crop foods, suggesting a potential benefit in terms of accessibility (reduction in the proportion of activity budget devoted to feeding).     

How to rely on the unreliable: Examples from Mesozoic bryophytes of Transbaikalia

Three new fossil bryophytes are described from Jurassic and Lower Cretaceous deposits of the Transbaikalia region of Russia. The complex thalloid hepatic Khasurtythallus monosolenioides gen. et sp. nov. belongs to the Marchantiidae, but its combination of characters precludes unequivocal placement in any of the five orders of this subclass, representing most likely an extinct lineage. Paleaethallus squarrosus gen. et sp. nov. is a thalloid plant with scales similar to those of complex thalloid hepatics, although their arrangement and the overall plant structure has little in common with any extant hepatics. Dispersed moss capsules, three of which have attached calyptrae, are described as a form genus Kulindobryum gen. nov. Despite incomplete preservation, some rare characters indicate possible relationship to the genus Tayloria of the Splachnaceae, an extant family of mosses adapted to grow on animal dung, dead bodies and bones. Notably, Kulindobryum co‐occurs with bones of the small feathered dinosaurs Kulindadromeus, which also supports an affiliation of Kulindobryum with the Splachnaceae. The most common and best known Mesozoic moss for the region, the genus Bryokhutuliinia, is appraised for its systematic position and probable affinities with the Dicranales. A scoring approach is introduced for the comparative method of taxonomic placement of fossils with partial suites of morphological characters at the family or order level.     

大气CO2浓度升高对农产品品质影响的研究进展

大气中不断升高的CO₂浓度以及人类饮食的营养质量是目前我们面临的两个重大问题.目前,大气中CO₂浓度已达到380 μmol·mol^-1,预测到2050年大气CO₂浓度将达到550 μmol·mol^-1.农产品的品质不仅取决于遗传基因,而且受生长环境条件的影响.大量研究表明,农作物的生长发育和产量形成都对CO₂浓度升高做出了响应,而且这种变化对农产品的品质也产生了重要影响.本文对目前国内外模拟CO₂浓度升高对农产品品质影响研究中采用的常见方法进行了比较,并综述了近年来在CO₂浓度升高对水稻、小麦、大豆和其他一些蔬菜类农产品品质影响方面的研究进展.大量试验结果表明,CO₂浓度升高条件下,大宗作物籽粒中蛋白质含量下降,微量元素总体上有下降趋势,而蔬菜类农产品的品质有一定程度改善.最后,本文根据目前研究现状对一些问题进行了讨论并提出了今后的研究方向.     

Seasonal variation in nutritional characteristics of the diet of greater white-fronted geese

We studied diet and habitat use of greater white-fronted geese (Anser albifrons) from autumn through spring on their primary staging and wintering areas in the Pacific Flyway, 1979–1982. There have been few previous studies of resource use and forage quality of wintering greater white-fronted geese in North America, and as a consequence there has been little empirical support for management practices pertaining to habitat conservation of this broadly distributed species. Observations of >2,500 flocks of geese and collections of foraging birds revealed seasonal and geographic variation in resource use reflective of changes in habitat availability, selection, and fluctuating physiological demands. Autumn migrants from Alaska arrived first in the Klamath Basin of California and southern Oregon, where they fed on barley, oats, wheat, and potatoes. Geese migrated from the Klamath Basin into the Central Valley of California in late autumn where they exploited agricultural crops rich in soluble carbohydrates, with geese in the Sacramento Valley feeding almost exclusively on rice and birds on the Sacramento–San Joaquin Delta primarily utilizing corn. White-fronted geese began their northward migration in late winter, and by early spring most had returned to the Klamath Basin where 37% of flocks were found in fields of new growth cultivated and wild grasses. Cereal grains and potatoes ingested by geese were low in protein (7–14%) and high in soluble nutrients (17–47% neutral detergent fiber [NDF]), whereas grasses were low in available energy (47–49% NDF) but high in protein (26–42%). Greater white-fronted geese are generalist herbivores and can exploit a variety of carbohydrate-rich cultivated crops, likely making these geese less susceptible to winter food shortages than prior to the agriculturalization of the North American landscape. However, agricultural landscapes can be extremely dynamic and may be less predictable in the long-term than the historic environments to which geese are adapted. Thus far greater white-fronted geese have proved resilient to changes in land cover in the Pacific Flyway and by altering their migration regime have even been able to adapt to changes in the availability of suitable forage crops. © 2010 The Wildlife Society.     

菱斑巧瓢虫替代饲料的研究

瓢虫成虫饥饿24h后,通过室内对菱斑巧瓢虫Oenopia conglobata (Linnaeus)成虫饲喂24种人工饲料,研究菱斑巧瓢虫的取食行为;以桃蚜(MP)作对照,选择羊肝+蔗糖(SLS)、猪肝+蔗糖(PLS)、黄粉虫蛹+蔗糖(TMPS)3种饲料研究瓢虫产卵量;以白蛾周氏啮小蜂蛹(CCP)、SLS、PLS和MP对瓢虫成虫进行交叉饲喂试验,每周期7d,研究饥饿后恢复产卵时间和产卵量的差异;最后以CCP和MP饲喂瓢虫幼虫,观察其发育历期。结果表明:在羊肝、鸡心、菜蛾幼虫、鸡肝和黄粉虫蛹组中,无论是否添加蔗糖,瓢虫取食情况较好。瓢虫成虫饲喂SLS、TMPS、PLS及MP后,MP组的14d单雌产卵量为166.25粒、SLS组为18.15粒、PLS为9.65粒和TMPS组3.90粒,瓢虫恢复产卵的时间也有差异,MP组仅需要1d,而其它组需要3d至至5d。交叉饲喂试验发现,CCP组产卵量(40.67～46.87粒/雌)明显高于常用饲料-PLS组(4.53～7.13粒/雌),但与MP组(61.80～82.07粒/雌)仍有一定差距。利用CCP饲喂瓢虫幼虫,可以完成整个发育历期,但是存活率较低,1～4龄幼虫各龄期内存活率在63.64%～87.50%之间,并且发育历期(21.23d)明显长于饲喂MP组(15.71d)。     

大气CO2浓度升高对农产品品质影响的研究进展

大气中不断升高的CO2浓度以及人类饮食的营养质量是目前我们面临的两个重大问题.目前,大气中CO2浓度已达到380 μmol·mo1-1,预测到2050年大气CO2浓度将达到550 μmol·mol-1.农产品的品质不仅取决于遗传基因,而且受生长环境条件的影响.大量研究表明,农作物的生长发育和产量形成都对CO2浓度升高做出了响应,而且这种变化对农产品的品质也产生了重要影响.本文对目前国内外模拟CO2浓度升高对农产品品质影响研究中采用的常见方法进行了比较,并综述了近年来在CO2浓度升高对水稻、小麦、大豆和其他一些蔬菜类农产品品质影响方面的研究进展.大量试验结果表明,CO2浓度升高条件下,大宗作物籽粒中蛋白质含量下降,微量元素总体上有下降趋势,而蔬菜类农产品的品质有一定程度改善.最后,本文根据目前研究现状对一些问题进行了讨论并提出了今后的研究方向.     

九段沙湿地鸻形目鸟类迁徙季节环境容纳量

根据对九段沙湿地2005年春、秋季食物资源调查来计算迁徙期鸻形目鸟类的环境容纳量。结果表明,九段沙湿地春季食物总量为4541．20kgAFDW（去灰分干重）,秋季为2279．64kgAFDW,按鸻形目鸟类有效栖息生境计算,春季鸟类可利用食物资源量为3429．03kgAFDW,秋季为1700．92kgAFDW。通过鸟类体型类群分类（根据去脂净重、基础代谢率和体长）和能量消耗模型可以得出,九段沙湿地迁徙季节总食物量理论上可维持的鸻形目鸟类最大数量约为春季350万只,秋季175万只。按有效生境计算,春季约为260万只,秋季约为130万只。考虑到食物取入率的影响,九段沙湿地实际可容纳约13～26万只鸟类。根据地理信息分析可知,高潮位期有效栖息地的缺乏可能是限制鸟类数量达到估计上限的主要原因,建议在不危害保护区生态安全的前提下,开辟一些隐蔽性强的裸地和浅水塘,以提高鸻形目鸟类对九段沙湿地资源的利用率。     

橘小实蝇幼虫液体人工饲料中pH值对其生长发育的影响

本文主要研究了橘小实蝇液体人工幼虫饲料中不同酸度对橘小实蝇生长发育的影响。继代饲养3代的结果表明：饲料酸度对橘小实蝇化蛹率和后代卵孵化率没有影响;对橘小实蝇蛹重、成虫羽化率和产卵量有显著影响。橘小实蝇液体人工幼虫饲料的pH值调节至3.6时仍可以获得质量较高的橘小实蝇。