Inherent movement patterns of larval nematodes, with a stochastic model to simulate movement of infective hookworm larvae

Croll, Neil A.; Blair, A.J.

doi:10.1017/s003118200004628x

Cited by 16 publications

(7 citation statements)

References 13 publications

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“…2 B). Similar dispersal behavior has been observed in other species, including other nematodes (Berg and Brown, 1972;Croll and Blair, 1973;Croll, 1975b;Dethier, 1976). The tracks of individual worms and their population behavior suggest that dispersion in C. elegans may involve a random walk.…”

Section: Dispersal Behaviorsupporting

confidence: 81%

The Fundamental Role of Pirouettes inCaenorhabditis elegansChemotaxis

1999

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To investigate the behavioral mechanism of chemotaxis in Caenorhabditis elegans, we recorded the instantaneous position, speed, and turning rate of single worms as a function of time during chemotaxis in gradients of the attractants ammonium chloride or biotin. Analysis of turning rate showed that each worm track could be divided into periods of smooth swimming (runs) and periods of frequent turning (pirouettes). The initiation of pirouettes was correlated with the rate of change of concentration (dC/dt) but not with absolute concentration. Pirouettes were most likely to occur when a worm was heading down the gradient (dC/dt < 0) and least likely to occur when a worm was heading up the gradient (dC/dt > 0). Further analysis revealed that the average direction of movement after a pirouette was up the gradient. These observations suggest that chemotaxis is produced by a series of pirouettes that reorient the animal to the gradient. We tested this idea by imposing the correlation between pirouettes and dC/dt on a stochastic point model of worm motion. The model exhibited chemotaxis behavior in a radial gradient and also in a novel planar gradient. Thus, the pirouette model of C. elegans chemotaxis is sufficient and general.

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Section: Dispersal Behaviorsupporting

confidence: 81%

The Fundamental Role of Pirouettes inCaenorhabditis elegansChemotaxis

1999

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“…Theory suggests that migration should be density dependent, although the direction (positive or negative density dependence) may vary (Travis & French, 2000). The limited information available for nematodes supports density independence (Croll & Blair, 1973), but that experiment covered only a 20-fold range in density. A third assumption is that the random and directed components of movement are additive.…”

Section: Discussionmentioning

confidence: 96%

A model for nematode locomotion in soil

Hunt¹,

Wall²,

DeCrappeo³

et al. 2001

Nematology

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Locomotion of nematodes in soil is important for both practical and theoretical reasons. We constructed a model for rate of locomotion. The rst model component is a simple simulation of nematode movement among nite cells by both random and directed behaviours. Optimisation procedures were used to t the simulation output to data from published experiments on movement along columns of soil or washed sand, and thus to estimate the values of the model's movement coef cients. The coef cients then provided an objective means to compare rates of locomotion among studies done under different experimental conditions. The second component of the model is an equation to predict the movement coef cients as a function of controlling factors that have been addressed experimentally: soil texture, bulk density, water potential, temperature, trophic group of nematode, presence of an attractant or physical gradient and the duration of the experiment. Parameters of the equation were estimated by optimisation to achieve a good t to the estimated movement coef cients. Bulk density, which has been reported in a minority of published studies, is predicted to have an important effect on rate of locomotion, at least in ne-textured soils. Soil sieving, which appears to be a universal practice in laboratory studies of nematode movement, is predicted to negatively affect locomotion. Slower movement in ner textured soils would be expected to increase isolation among local populations, and thus to promote species richness. Future additions to the model that might improve its utility include representing heterogeneity within populations in rate of movement, development of gradients of chemical attractants, trade-offs between random and directed components of movement, species differences in optimal temperature and water potential, and interactions among factors controlling locomotion.

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“…The movement of infective larvae within mosquitoes may be entirely non-directional. However, although the pattern of behaviour shown by a population of nematode larvae is non-directed, many features of the tracks of individual larvae are idiosyncratic and measurable, occurring with a predictable frequency (Croll, 1971(Croll, , 1972Croll & Blair, 1973).…”

Section: Discussionmentioning

confidence: 99%

The migration of infective larvae of Brugia pahangi within the mosquito, Aedes aegypti

Lindsay

1986

Parasitology

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The course of the migration of infective larvae of Brugia pahangi within the mosquito, Aedes aegypti, is described. The presence of blood or eggs in the abdomens of mosquitoes at a time when the infective larvae are beginning their migration out of the thorax leads to a significant increase in the proportion of larvae accumulating in the abdomen. The evidence supports the hypothesis that infective larvae may accumulate in the labium as a direct consequence of the insect's internal anatomy i.e. infective larvae on moving into a confined space tend to remain there. In addition, the rate at which infective larvae migrate into the labium is shown to be density dependent.

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Inherent movement patterns of larval nematodes, with a stochastic model to simulate movement of infective hookworm larvae

Cited by 16 publications

References 13 publications

The Fundamental Role of Pirouettes inCaenorhabditis elegansChemotaxis

The Fundamental Role of Pirouettes inCaenorhabditis elegansChemotaxis

A model for nematode locomotion in soil

The migration of infective larvae of Brugia pahangi within the mosquito, Aedes aegypti

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