Worm Feeding Research Articles

Feeding Behavior of Dipolydora commensalis (Polychaeta: Spionidae): Particle Capture, Transport, and Selection

Feeding Behavior of Dipolydora commensalis (Polychaeta: Spionidae): Particle Capture, Transport, and Selection

Studies on the origin and distribution of palytoxin in a Caribbean coral reef

In coral reefs of the Caribbean Sea (Colombia) palytoxin (PTX) has been detected in zoanthid species of the genera Palythoa and Zoanthus by assaying the delayed haemolysis in human erythrocytes produced by aqueous extracts, which is inhibited by ouabain pretreatment, and by HPLC. The toxin content of the polyps and colonies is highly variable and is not correlated with their reproductive cycle or with the amount of symbiotic algae. Sequestration of PTX has been observed in crustaceans ( Platypodiella sp.) living in close association with Palythoa colonies and in polychaete worms ( Hermodice carunculata) feeding on the zoanthids. Resistance of marine animals to the toxin may enable it to enter food chains.

Foliar Insecticide Evaluation for Control of Corn Earworm on Sweet Corn, 1994

Abstract ‘Silver Queen’ sweet corn was planted on 24 May at the North Alabama Horticulture Substation in Cullman, Alabama. Treatment plots were 6 rows, each 10 meters long, replicated four times in a randomized complete block design. The four middle rows of each plot were sprayed with insecticides beginning at “tassel push", when the tassels were first observed growing up from the whorl, and on a 3-4 day schedule throughout the silking period until harvest. Sprays were applied on 19, 22, 26, 29 July, and on 1 and 4 Aug. Spray application was made by a self-propelled high-clearance sprayer with one hollow cone nozzle over the row and 1—6 nozzles on drop extension tubes on either side of the row (additional nozzles ere added as corn height increased). Spray volume remained constant on all spray dates at 80 gal/acre. Treatment effectiveness was determined at harvest (8 Aug) by examination of 25 randomly-picked ears per plot (100 ears per treatment) for CEW feeding damage to the ear tips. Worm feeding damage not associated with the ear tip was classified as “side damage” (assumed to be caused by other lepidopterous species). Ears were considered unmarketable if CEW damage to the ear extended 38 mm (1.5 inches) beyond the tip of the ear, or if “side damage” was present.

The winter feeding ecology of Avocets Recurvirostra avosetta on intertidal areas. I. Feeding strategies

The behaviour of Avocets Recurvirostra avosetta feeding on emerged intertidal areas in a major wintering area, the Tagus estuary (Portugal), was studied during 2 years.Avocets used four different feeding strategies. By far the most common was the Normal Feeding Strategy, in which the median sweeping rate was 28 sweeps per min and the percentage of swallowing movements (ingestions) was very high (median = 90%). No prey were visible in the bill while birds were using this strategy. Another less common feeding strategy was the Worm Feeding Strategy, in which the sweeping rate was higher (median = 46 sweeps/min) and the percentage of swallowing movements was much lower (median = 6%). While using the Worm Feeding Strategy, Avocets preyed on ragworms Nereis diversicolor. The Mixed Feeding Strategy and Scrobicularia plana Siphons Feeding Strategy were rarely observed.In a detailed study on the use of the mudflats by Avocets, it was found that the density of birds on the upper shore was much higher than on the lower shore. There were differences in feeding behaviour between these two areas, although the same feeding strategy was used. On the lower shore, where there was a lower biomass of prey available, sweeping rates were higher and aggressive behaviour did not occur. On the upper shore, sweeping rates were lower and aggressive behaviour was frequent, with some birds defending territories. Nevertheless, estimated food intake rates were 1.5 times higher on the upper shore.

Interaction of parasitism and nutrition and their effects on production and clinical parameters in goats

Weaned wether goats ( n = 144) approximately 6 months of age were placed in a 2 × 3 factorial design experiment for 5 months to test the main effects and interaction of two levels of nutrition (growth+maintenance, NUT1; twice growth+maintenance, NUT2) and three levels of Haemonchus contortus burden (0, 500 and 2000 larvae administered every 2 weeks: W0, W500 and W2000, respectively) on weight, feed intake, level of infection and packed cell volume (PCV). The rationale for the experimental design was based on the lack of information concerning the interaction between nutritional status and worm burden. Results indicated significant effects of worm burden levels on PCV, faecal egg contents (eggs per gram of feces (EPG)), actual worm numbers, feed intake and efficiency of feed utilization. Nutrition×worm burden interactions were also significant for PCV and EPG. However, the differences detected for PCV and actual worm numbers did not translate into large or consistent differences in body weight. Goats on NUT2, after an initial period, showed little difference in body weight, irrespective of worm burden. Within the NUT1 level, W0 kids weighed more than W500 or W2000 kids throughout the study. Although not statistically significant, this constitutes a trend towards an interaction between nutrition and worm burden. In both nutrition levels, there were no body weight differences between W500 and W2000 until the last 14 days. Feed intake was depressed in the first 3 months of the experiment for infected animals, but was subsequently followed by a compensatory reaction. Lower establishment rates, based on actual worm counts, were observed for the higher infection level, but in both infection levels establishment rates tended to decrease with time. Nutrition was found to be more important to counteract the consequences of a parasitic infection than to counteract the establishment of that same infection.

Effect of Haemonchus contortus infection on the clearance of antipyrine, sulfobromophthalein, chloramphenicol, and sulfathiazole in lambs

SUMMARY A study was made to determine the effect of Haemonchus contortus parasitic infection in lambs on the clearance of several IV administered drugs. Clearance of sulfobromophthalein or sulfathiazole from the plasma of lambs was unaffected by infection with H contortus. Clearance of antipyrine was enhanced by the infection, and thiabendazole treatment did not alter this effect. Clearance of chloramphenicol (cap), administered as the succinate ester (caps), was not changed by the infection, but it was increased after treatment with thiabendazole. Changes in the mean body residence time and initial plasma concentration of caps and cap after treatment with thiabendazole indicate that hydrolysis of caps to cap was reduced. High concentrations of caps apparently enhanced its own elimination directly rather than via the expected sequence involving hydrolysis, glucuronidation, and excretion of cap-glucuronide. Enhanced clearance of antipyrine following infection of lambs with H contortus can be explained in at least 2 ways. First, it is possible that the lambs did not have mature amounts of hepatic drug metabolizing enzyme activity as reported by other investigators, which may be explained by breed differences or animal husbandry practices. Second, infection of lambs by H contortus may have triggered an inductive response in hepatic cytochrome P- 450-mediated activities, which might result via a generalized enhancement in hepatic protein synthesis associated with the physiologic response to replace plasma proteins and other blood components lost through gastrointestinal hemorrhage caused by the active feeding of adult worms. Other phase-II reactions such as acetylation, glucuronidation, and glutathione-S-transferase apparently were not affected.

Impact of Fall Army worm (Lepidoptera: Noctuidae) Feeding on the Quality and Yield of Coastal Bermuda grass

The impact of fall army worm (FAR), Spodoptera frugiperda (J. E. Smith) feeding on the quality and yield of bermuda grass, Condone dactylic (L.) Pres., cv. Coastal, was determined. Yield losses of Coastal were 0.5 to 1.1 metric ton/ha when artificially infested with population densities of 1.1 to 9.9 larvae per 0.1 m2. Feeding by FAR also resulted in lower yields of digestible dry matter (245 kg/ha) and crude protein (72 kg/ha) in Coastal. An economic injury level of 8 FAR larvae per 0.1 m2 for Coastal was calculated based on a hay price of $54 per metric ton and cost of control of $6.74 per ha. From these data, an economic threshold of four fourth and fifth in stars per 0.1 m2 was determined for Coastal.

AnIn VitroAnalysis of Egg Mortality inCancer anthonyi: The Role of Symbionts and Temperature

Several symbionts occur on crab eggs. These symbionts, and the effect of temperature, have been implicated as causal mechanisms of egg mortality in Cancermagister. The contribution of three symbionts (a fungus, Lagenidium callinectes; bacteria, i.e., Leucothrix sp.; and a nemertean worm, Carcinonemertes epialti) to egg mortality on Cancer anthonyi were investigated in vitro using a multifactorial experimental design at four different temperatures. The nemertean worm was found to contribute most to egg mortality on the individual crab and at the crab population level because its prevalence was high (>95%) and it had a relatively constant feeding rate. Lagenidium callinectes caused from 20-75% egg mortality on individual crabs but its prevalence was nil. A Lagenidium-like fungus had a low prevalence (2.6%) and was not associated with egg mortality. While bacteria were omnipresent, they were found to cause negligible crab egg mortality. Few significant interactions were observed between the symbionts. Temperature had a significant effect on worm feeding rates, worm oviposition, and fungal attack rates. At low temperatures (4 and 10°C), symbionts killed fewer eggs than at higher temperatures (15 and 20°C). Extreme temperatures (4 and 20°C) caused variable degrees of egg mortality, yet some eggs survived at these temperatures. Temperature also had a profound effect on egg development. At 20°C, eggs developed almost twice as fast as those at 10°C. Development appeared to stop at 4°C.

A cell that dies during wild-type C. elegans development can function as a neuron in a ced-3 mutant.

Mutations in the C. elegans gene ced-3 prevent almost all programmed cell deaths, so that in a ced-3 mutant there are many extra cells. We show that the pharyngeal neuron M4 is essential for feeding in wild-type worms, but in a ced-3 mutant, one of the extra cells, probably MSpaaaaap (the sister of M4), can sometimes take over M4's function. The function of MSpaaaaap, unlike that of M4, is variable and subnormal. One possible explanation is that its fate, being hidden by death and not subject to selection, has drifted randomly during evolution. We suggest that such cells may play roles in the evolution of cell lineage analogous to those played by pseudogenes in the evolution of genomes.

The Role of Schistosoma mansoni Males in Feeding and Development of Female Worms

Female Schistosoma mansoni from unisexual infections have scant pharyngeal musculature, thin intestinal cecal walls, pale and scanty intestinal contents, and lack acidic thiol proteinase digestive enzyme as determined by indirect immunofluorescence using a monoclonal antibody. Their intake of host erythrocytes, measured by 51Cr labeling, is about one-fourth that of paired adult females, and they appear to be starved. In contrast, paired adult females have heavier pharyngeal musculature and intestinal cecal walls and abundant digestive enzyme in the anterior third of their intestinal tract. Females in worm pairs surgically transplanted into uninfected mice continued to feed, but separated females were carried into the liver and deteriorated. Adult female S. mansoni, newly separated from their male partners and incubated in vitro with labeled erythrocytes, ingested marginally fewer cells than did still-paired females, indicating their ability to continue feeding almost normally at least for a period after separation. Paired and ex-paired adult females declined similarly in feeding rate with increased time in vitro. In Schistosomatium douthitti, females grow and mature without males, the pharyngeal musculature and cecal walls are well developed, the gut is full of ingested blood, and the acidic thiol proteinase is present in both unisexual and paired female worms. There are different stimulatory pathways for growth and for reproductive maturation in S. mansoni, although both processes require physical contact with the male. We believe that the growth-stimulating function results from the muscular action of the clasping male, which helps the immature female to pump blood into her intestine, thereby overcoming a state of relative starvation.

Reflective Mulches Influence Plant Survival, Production, and Insect Control in Fall Tomatoes

Abstract Aluminum mulches lowered soil temperatures and reduced heat stress for young tomato transplants, increasing their survival and height. Yields were improved in all mulch treatments. Greatest yields of large and extra-large fruits were obtained from plants grown on aluminum alone, on aluminum in combination with black plastic, and on black plastic alone. Aphids were repelled by the aluminum mulches, while fruit injury increased due to tomato pinworm and tomato fruit worm feeding in these plots.

An energy budget for an omnivorous cyprinid: Rutilus rutilus (L.)

Two to three year old roach (9–15 g body weight) were fed ad libitum with grass or with meal worms. After three weeks, both groups of fish showed a positive energy budget. However, with a grass diet, production was low (only 7% of that of meal worm feeding fish) with an increased of lipids, whereas the protein content of the body decreased. Non-crude fiber organic matter of grass was utilized to 47.6%, that of meal worms to 82.4%.

Hookworm disease: host-pathogen biology.

The hallmark of hookworm infection, a common helminthic disease, is iron deficiency anemia. The development of anemia is dependent on the intensity of infection, the species of hookworm, and the ability of the host to resist infection and to maintain adequate stores of iron. When conditions are appropriate, the incidence of anemia caused by hookworm is high and has a significant economic impact since it results in a reduction of worker productivity. Loss of blood is caused by direct ingestion of red cells and by tissue trauma produced by worm attachment and feeding. This focal trauma may involve multiple villi and is characterized by local hemorrhage, tissue cytolysis, and neutrophilic response. Although focal intestinal lesions are apparent, their significance is questionable since diffuse mucosal changes are absent in intestinal biopsies of patients with heavy hookworm infection. Short-range control measures protecting against hookworm infection have not succeeded. Development of a vaccine against hookworm infection in humans is problematic since functional protective immunity in humans has not yet been demonstrated and no suitable animal model of hookworm infection in humans is available. At present, the most effective method of intervention appears to be supplementation of food staples with iron.

Carcinonemertes errans and the Fouling and Mortality of Eggs of the Dungeness Crab, Cancer magister

Laboratory experiments analyzing the correlation between epibiotic fouling and mortality of the eggs of the Dungeness crab, Cancer magister Dana, reveal that both can result from predation on crab eggs by the nemertean Carcinonemertes errans Wickham. Fouling appears to be stimulated by the release of yolk material into the egg clutch through worm feeding and defecation. Significant correlations exist between worm density and both fouling and mortality in field samples. The ranking of the correlations between these three parameters suggest that nemertean activity is the causative agent and that fouling is only incidentally correlated to egg mortality through its correlation to worm density. Key words: Carcinonemertes errans, Cancer magister, crab-egg fouling, crab-egg mortality

Variation of Pickle worm Feeding and Oviposition on Muskmelon and Cucumbers1

Abstract Feeding of pickle worm Diaphania nitidalis (Stoll), on muskmelon (Cucumis melo L.) differed, but more definitive laboratory testing under controlled condition is needed to determine if usable resistance mechanisms are involved. Few differences were detected in larval feeding on muskmelon seedlings with various characteristics. However, adult pickleworms laid fewer eggs on glabrous muskmelon and cucumber (Cucumis sativus L.) plants than on pubescent ones.

Effect of Anthelmintic Treatment on Feedlot Performance of Growing and Finishing Heifers

Thirty-six heifer calves and 24 yearling heifers with natural infections of parasitic nematodes were fed to evaluate the effect of levamisole and morantel tartrate on fecal worm egg counts, growth rate, feed efficiency and apparent digestibility of diets. Treatment with either anthelmintic reduced (P< .01) the fecal worm egg counts (EPG) at 7 days after treatment while counts similar to pretreatment values were still present in nonmedicated heifers. The addition of 5% stabilized animal fat to growing diets had no (P> .05) influence on EPG values. Fecal EPG counts for both nonmedicated and medicated heifers were similar at the end of the finishing trials. Growth rate, feed efficiency and apparent digestibility of diets were not different (P> .05) due to anthelmintic treatment. However, heifers receiving either of the medication treatments gained about 4% faster than nonmedicated heifers which resulted in a trend toward improved feed utilization values.

Factors' governing ingestion by the earthworm Lumbricus terrestris (L.), with special reference to apple leaves

SUMMARYCaptive worms fed little on fresh apple leaves, but did so readily after the leaves had been leached in water. This was due to their being soft and easy to fragment and not to loss of unpalatable substances during the leaching process. A simple apparatus to measure leaf texture is described. Worm feeding rates were similar for leaves of similar texture but of different phenolic content. Filter paper was accepted as food. The addition of leaf leachates to filter paper disks increased feeding rates, so did added bacterial cells. The part played by leaf micro‐organisms in the nutrition of worms and their effect on leaf texture is discussed. Unsoftened leaf material was readily eaten provided it was small enough to be swallowed whole. Leaves from various aromatic plants were eaten by starved worms, but rejected by well‐fed ones. Starved worms given aromatic leaf material together with apple leaf preferred the latter. Various unusual materials were eaten, but polyester foam was accepted only when coated with bacterial cells. Responses to chemical as well as to tactile stimuli seem to be involved.

On the trace-fossil Chondrites

Summary The problematical fossil Chondrites , well known from the Flysch of the Alps, Carpathians and Apennines, and from the Lias of Germany, is shown to be common in various Palaeozoic formations of the British Isles and also in the English Lias. The varying forms taken by the fossil are described and explained and shown to be primarily the result of different modes of preservation and not of taxonomic significance. A consideration of the different modes of preservation, as well as of the morphology of the fossil, permits its interpretation as a trace-fossil resulting from the driving of a system of branching tunnels in the sea-bed sediment. A new reconstruction of the fossil has been made. It is tentatively explained as the product of a sipunculoid worm feeding on sediment by means of its extensible proboscis. Various implications of the mode of occurrence of the fossil in particular circumstances are considered.