Food, Feeding Behavior and Feeding Ecology of Nemerteans

The feeding biology of nemerteans is reviewed, new informationis presented, and the role of nemerteans in natural communitiesis discussed and evaluated. Most nemerteans are carnivorous,the majority feeding on live, often specific, prey, while someare scavengers. Macrophagous feeding is found in the Palaeonemertea,Heteronemertea and some of the Hoplonemertea; the more specializedsuctorial feeding is limited to five of the hoplonemertean families,and suspension feeding (omnivorous diet) occurs only in thehighly specialized symbiotic monogeneric Bdellonemertea. Feeding adaptations seem to be related to the nature and employmentof the proboscis, the dilatability of the mouth, and the structureof the anterior part of the digestive tract. The transport ofdissolved organic materials from seawater has been demonstrated,but its role in nemertean nutrition is just being contemplated.Present meager information on predation has shown nemerteansto have actually and potentially large effects on prey populationsand thus on the communities in which they live. As the feedingbiology of only a relative handful of species has been studied,much basic comparative research is needed before we can corroborateor refute our present ideas concerning the ecological rolesof nemerteans.     

寻找黑脸琵鹭觅食地

黑脸琵鹭的觅食地在哪里?民以食为天,鸟为食而亡。弄清黑脸琵鹭的食物来源,对保护它们至关重要。     

Molecular Detection of Marine Invertebrate Larvae

The ecological patterns of many invertebrate larvae remain an ongoing mystery, in large part owing to the difficult task of detecting them in the water column. The development of nucleic-acid–based technology has the potential to resolve this issue by direct identification and monitoring of embryonic and larval forms in situ. We report herein on the successful development and application of nucleic-acid–based sandwich hybridization assays that detect barnacles using rRNA-targeted probes with both group-(order Thoracica) and species-(Balanus glandula) specificity. Primary results include the determination of target 18S rRNA sequences and the construction of “capture” probes for detection of larvae using hybridization techniques. In addition, we modified existing protocols for whole cell hybridization of invertebrate larvae as confirmation of the sandwich hybridization results. We used both hybridization techniques successfully in the laboratory on a plankton time series collected over 3 months, as well as a week-long in situ deployment of the technique in Monterey Bay, CA. The adaptability of this technology promises to be further applicable to various organisms and could be used to enhance our understanding of larval presence in the world's oceans.     

Food Transfer and Development of Feeding Behavior and Food-Associated Vocalizations in Cotton-Top Tamarins

Food transfer between adults and infants is common in many marmoset and tamarin monkeys, and is often accompanied by vocalizations. We hypothesized that vocalizations by adults in a food transfer context creates an opportunity for infants to learn not only what foods are appropriate but what vocalizations are appropriate in feeding contexts. We studied the development of feeding behavior and food-associated vocalizations in 10 infant cotton-top tamarins through the first 20 wks of life. Infants obtained solid food through transfers from older group members, primarily the adult male, beginning at weeks 5–6. Both adults and infants vocalized during food transfers with adults, producing rapid sequences of the call types adults normally give when feeding. Infants were usually successful in obtaining food primarily when the adult was vocalizing. The sooner infants were active participants in food transfers, the sooner they began to feed independently. In the early weeks, infants produced a large number of vocal types during food transfers, but with increasing age there was a steady increase in the number of adult-form food calls and a reduction in other, non-food-associated calls. Infants that fed independently at an early age produced fewer non-food-associated calls by the last month of observation. Infants called at higher rates to their most preferred food. Food transfers accompanied by vocalizations may provide an opportunity for infants to learn about appropriate foods as well as the vocalizations that accompany feeding in adults, and may represent a form of 'coaching' or information donation by adults.     

Changes in Baboon Feeding Behavior: Maturity-dependent Fruit and Seed Size Selection within a Food Plant Species

Despite considerable inter- and intraindividual variation in fruit and seed size in many plant species, researchers have given little attention to the relevance of the traits for primate fruit choice within a food plant species and its implications for tree regeneration. We studied feeding behavior and selectivity of olive baboons (Papio anubis) in the African locust bean (Parkia biglobosa, Mimosaceae), via direct observations of habituated groups and indirect evidence from leftovers of pods after feeding events. Olive baboons acted as both seed predators and dispersers for Parkia biglobosa. They fed on and destroyed unripe seeds, and swallowed intact ripe seeds when consuming mature fruit pulp. Predation rate was high, and only 10% of the seeds were dispersed. Predation and dispersal of seeds is linked to seed number and size. Digestible unripe seeds accounted for 10% of the unripe fruit mass, while indigestible ripe seeds made up 28% of the mature fruit mass. With these constraints, olive baboons increased food gain per fruit by selecting unripe pods containing a high number of large and heavy seeds. Consequently, only pods with fewer and smaller seeds remained for maturation. Thereafter, baboons fed on mature pods containing the smallest seeds, and exploited pods with more seeds to a greater extent than those with fewer seeds. Thus, fruits with small seeds and an intermediate seed number contributed the most to dispersal by baboons.     

Invertebrate Models of Kallmann Syndrome: Molecular Pathogenesis and New Disease Genes

Kallmann Syndrome is a heritable disorder characterized by congenital anosmia, hypogonadotropic hypogonadism and, less frequently, by other symptoms. The X-linked form of this syndrome is caused by mutations affecting the KAL1 gene that codes for the extracellular protein anosmin-1. Investigation of KAL1 function in mice has been hampered by the fact that the murine ortholog has not been identified. Thus studies performed in other animal models have contributed significantly to an understanding of the function of KAL1. In this review, the main results obtained using the two invertebrate models, the nematode worm Caenorhabditis elegans and the fruit fly Drosophila melanogaster, are illustrated and the contribution provided by them to the elucidation of the molecular pathogenesis of Kallmann Syndrome is discussed in detail. Structure-function dissection studies performed in these two animal models have shown how the different domains of anosmin-1 carry out specific functions, also suggesting a novel intramolecular regulation mechanism among the different domains of the protein. The model that emerges is one in which anosmin-1 plays different roles in different tissues, interacting with different components of the extracellular matrix. We also describe how the genetic approach in C. elegans has allowed the discovery of the genes involved in KAL1-heparan sulfate proteoglycans interactions and the identification of HS6ST1 as a new disease gene.     

Food and Feeding Ecology of Puffins

This study shows that although annual fluctuations occur in the main prey types of Skomer Puffins, food availability does not appear to limit breeding success. Most birds found food close to the colony, showing peaks of activity early in the day and again in late afternoon; and two out of four experimental pairs were able to rear 'twins', though the growth-rates of these were less than for single chicks. Some interesting observations are given on the feeding of the chick and on kleptoparasitism of adults by Jackdaws and gulls.     

Serotonin and Leech Feeding Behavior: Obligatory Neuromodulation

Leeches have distinct advantages for investigating the behavioralfunctions of monoamines. Serotonin (5-hydroxytryptamine, 5-HT)is synthesized by a population of identifiable neurons and storedat unusually high intracellular concentrations. Identified serotonergicneurons evoke biting, salivation and pharyngeal pumping, andneuronal 5-HT is required for these physiological componentsof leech feeding behavior. Those stimuli which initiate andterminate ingestion by intact leeches, excite and inhibit the5-HT neurons respectively. Hence, leech 5-HT neurons are activein contexts in which the animal feeds. In leeches representingdifferent orders of Hirudinea, homologous 5-HT neurons appearto have similar roles in feeding. Serotonin not only affectssalivation, biting and pharyngeal peristalsis in these annelids,but also in nematodes, arthropods and molluscs. These comparativedata suggest that serotonin may function generally in the modulationof feeding.     

饲养条件下织金瘰螈摄食行为的观察

采用室内饲养观察与食物投喂实验相结合的方法,于2011年9月²012年4月研究了织金瘰螈Paramesotriton zhijinensis摄食行为和食物选择。结果表明:织金瘰螈特别喜食的食物包括扁卷螺、萝卜螺、蝌蚪、水丝蚓;较为喜食的食物包括椎实螺、环毛蚓、彩石鲋、蝇蛆、小无齿蚌、河虾、褐栉鰕虎鱼;偶食的食物包括环棱螺、黄粉虫、蜻蜓稚虫、螺类卵带、水生昆虫及幼虫。织金瘰螈发现食物目标靠视觉,判断食物性质靠嗅觉。摄食方式为吞食性摄食。摄食策略主要采取伏击法,并结合搜索法。摄食过程包括:发现食物,靠近并迅速张口咬住食物,食物挣扎时,紧咬不动,食物不动时,借助甩头将食物逐步吞进口腔,进入口腔的食物,通过闭嘴、抬头、头颈后仰、撑起前肢协助进入食道和胃。影响摄食的主要生态因子包括光照、水温和食物密度。     

Growth of a Molecular Base for Feeding: The Mind Body Dualism

It is often difficult to identify the ‘who, when, and where’ of advances in medicine and surgery because it's a rare advance indeed (such as the use of digitalis by William Withering) that can be clearly related to the astuteness of one person at one time and place.     

水螅摄食中的特殊行为

取经中性红活染后的杆吻虫喂水螅,仔细观察了水螅的摄食行为.结果表明,水螅垂唇端部能够相互识别出同类;水螅的垂唇与胃区能协力把杆吻虫吞入胃腔,触手经常随食物进入胃腔;吞食时经常出现头部内翻或外翻;个体间及其成体与芽体间常出现争夺食物的现象,当垂唇端部互不相触时,体型较大的个体常常把较小个体或芽体连同食物一起吞食;垂唇内胚层腺细胞对食物有消化作用,对同类无伤害;水螅的神经系统已有初步的整合功能.     

Feeding Behavior and Survival of Glucose-Averse Blattella germanica (Orthoptera: Blattoidea: Blattellidae) Provided Glucose as a Sole Food Source

Glucose-averse (Glu/Glu) male German cockroaches, Blattella germanica, rejected brief exposures to glucose solutions despite food deprivation so extreme as to cause high mortality. In the 24-h period following 5 days of food deprivation, both Glu/Glu and wild-type (+/+) were given a continuous source of 1 M glucose solution. Although Glu/Glu visited the solution as frequently as +/+, feeding bouts were significantly shorter. These truncated feeding bouts were sufficient to extend Glu/Glu longevity to ca. 80 days, regardless of glucose concentration. When provided continuously, the glucose was completely rejected by Glu/Glu for the first 3 days. However, by day 9, glucose intake levels were similar to those of wild-type cockroaches. The initial feeding lag probably accounted for the lower long-term survival of the Glu/Glu vs the +/+ strain. Under the stress of food deprivation, glucose-averse B. germanica modify their feeding behavior toward glucose like many phytophagous insects provided non-host plants in no-choice situations.     

Temperature, Food Availability, and the Development of Marine Invertebrate Larvae

SYNOPSIS. Marine invertebrates develop in waters that extendfrom the poles to the equator, experiencing the full range ofenvironmental temperature and food conditions. How selectionhas modified their development under the influence of thesetwo factors has been a matter of debate. In this paper we arguethat the primary influence on developmental rate is temperature,while other factors such as food availability are much lessimportant. From existing literature we demonstrate that (1)developmental rates of both lecithotrophic and planktotrophicasteroids decrease in a similar way from the tropics to thepoles, as they do also in other groups of invertebrates (echinoids,molluscs, crustaceans), and (2) rates of development at anyone temperature cluster around the function describing the effectof temperature, without any relationship to egg size, suggestingthat developmental rates are near the maximum for a given temperatureregardless of other variables such as nutrition. We also investigatedthe response of development to temperature in four species ofplanktotrophic asteroids, one tropical, one temperate, two polar.There was limited temperature compensation among these fourspecies, but little or no apparent ability to compensate forthe retarding effects of reduced temperature within species.Arrhenius analysis of the data suggests that Q₁₀ values forthe upper region of each species' tolerance range are approximately2, indicating that enzyme-based reactions have evolved to beclosely integrated with uncatalyzed, temperature-dependent,physicalchemical processes. Values of Q₁₀ at lower regions ofthe tolerance range, on the other hand, range between 9.5 and14.7, indicative of abrupt temperature-dependent shifts in reactionequilibria, or in the organization of macromolecules and membranes.We conclude that temperature itself, rather than egg size, food,or other variables, best explains observed latitudinal differencesin developmental rates in marine invertebrates.     

Relative Importance of Bacteria and Fungi in a Tropical Headwater Stream: Leaf Decomposition and Invertebrate Feeding Preference

Bacteria and fungi provide critical links between leaf detritus and higher trophic levels in forested headwater food webs, but these links in tropical streams are not well understood. We compared the roles of bacteria and fungi in the leaf decomposition process and determining feeding preference for two species of freshwater shrimp found in the Luquillo Experimental Forest, Puerto Rico, using experimental microcosms. We first tested the effects of four treatments on decomposition rates for leaves from two common riparian species, Cecropia scheberiana (Moraceae) and Dacryodes excelsa (Burseraceae), in laboratory microcosms. Treatments were designed to alter the microbial community by minimizing the presence of bacteria or fungi. The fastest decay rate was the control treatment for D. excelsa where both bacteria and fungi were present (k = −0.0073 day⁻¹) compared to the next fastest rate of k = −0.0063 day⁻¹ for the bacterial-conditioned D. excelsa leaves. The fastest decay rate for C. scheberiana was also the control treatment (k = −0.0035 day⁻¹), while the next fastest rate was for fungal-conditioned leaves (k = −0.0029 day⁻¹). The nonadditive effect for leaf decomposition rates observed in the control treatments where both fungi and bacteria were present indicate that bacteria and fungi perform different functions in processing leaf litter. Additionally, leaf types differed in microbial colonization patterns. We next tested feeding preference for leaf type and microbe treatment in microcosms using two species of freshwater shrimp: Xiphocaris elongata, a shredder, and Atya lanipes, a scraper/filterer. To estimate feeding preferences of individual shrimp, we measured change in leaf surface area and the amount of particles generated during 5-day trials in 16 different two-choice combinations. X. elongata preferred D. excelsa over C. scheberiana, and leaves with microbial conditioning over leaves without conditioning. There was no clear preference for fungal-conditioned leaves over bacterial-conditioned leaves. This lack of preference for which microbes were responsible for the conditioning demonstrates the importance of both bacterial and fungal resources in these tropical stream food web studies.     

Winter Food and Feeding requirements of the Starling

The Starling is an increasing and highly successful species. This study suggests that in large part this is due to its ability to utilise grain and household waste products, which enables it to survive in severe winter weather when natural foods are unobtainable.     

Looking for Progenitors: A Molecular Approach to Finding the Origins of An Invasive Weed

One of the major problems in determining the origin of invasive species is that often their arrival is unnoticed. Only when population levels increase is their presence noticed but by this time determining the point of arrival is confounded by the extensive spread of the species. Here we use molecular markers (ISSRs) to determine the origin of an invasive weed in the Kalahari region, a species for which several origins could be possible. We show that molecular markers can be useful tools in determining the origin of invasive species