Philopatry in the alpine grasshopper, <i>Podisma pedestris:</i> a novel experimental and analytical method

Mason, Philip; Nichols, Richard A.; Hewitt, Godfrey M.

doi:10.1111/j.1365-2311.1995.tb00439.x

Cited by 19 publications

(31 citation statements)

References 28 publications

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“…The collation of movements was similar to that used by Mason et al (1995), as was the basic design of the statistical analysis. The study area was converted into a grid of 1 m 2 squares, and the centre of the square in which each capture had occurred was taken to be the point of capture.…”

Section: Discussionmentioning

confidence: 99%

“…Other similar estimates of grasshopper lifetime dispersal have used a grasshopper lifetime of 20 days, based on estimates from previous mark-recapture experiments (Virdee & Hewitt, 1990;Mason et al, 1995). Here, the estimated daily mortality rate was used to make a crude estimate of average grasshopper lifetime.…”

Section: Lifetime Dispersalmentioning

confidence: 99%

“…Two aspects of dispersal that may influence predictions about these patterns are nonrandom movement and occasional long-distance dispersal (see, for example, Conradt et al, 2000). In this study, a statistical approach developed by Mason et al (1995) was extended and used to estimate one type of non-random movement, philopatry, and also the propensity of individuals to make long-distance movements. This method was applied to estimating lifetime dispersal within a grasshopper hybrid zone, and to examine the potential effects of the results on the interpretation of hybrid zone structure.…”

Section: Introductionmentioning

confidence: 99%

“…Mason et al (1995) inferred philopatry in a flightless grasshopper by showing that dispersal over longer periods was less than that predicted by extrapolation from movements over short time periods, assuming that movement followed a random walk. Deviations from the assumption of movement via a random walk may have a significant effect on the efficacy of direct estimates of lifetime dispersal.…”

Section: Introductionmentioning

confidence: 99%

“…It allows a statistical comparison between these hypotheses and a simple random walk model. The analysis is an extension of the method first used by Mason et al (1995) and similarly accounts for spatial and temporal biases in recapture probabilities.…”

Section: Introductionmentioning

confidence: 99%

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Measuring dispersal and detecting departures from a random walk model in a grasshopper hybrid zone

Bailey

Lineham

Thomas

et al. 2003

Ecological Entomology

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Abstract. 1. The grasshopper species Chorthippus brunneus and C. jacobsi form a complex mosaic hybrid zone in northern Spain. Two mark-release-recapture studies were carried out near the centre of the zone in order to make direct estimates of lifetime dispersal. 2. A model framework based on a simple random walk in homogeneous habitat was extended to include the estimation of philopatry and flying propensity. Each model was compared with the real data, correcting for spatial and temporal biases in the data sets.3. All four data sets (males and females at each site) deviated significantly from a random walk. Three of the data sets showed strong philopatry and three had a long dispersal tail, indicating a low propensity to move further than predicted by the random walk model. 4. Neighbourhood size estimates were 76 and 227 for the two sites. These estimates may underestimate effective population size, which could be increased by the long tail to the dispersal function. The random walk model overestimates lifetime dispersal and hence the minimum spatial scale of adaptation.5. Best estimates of lifetime dispersal distance of 7-33 m per generation were considerably lower than a previous indirect estimate of 1344 m per generation. This discrepancy could be influenced by prezygotic isolation, an inherent by-product of mosaic hybrid zone structure.

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Section: Discussionmentioning

confidence: 99%

Section: Lifetime Dispersalmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Measuring dispersal and detecting departures from a random walk model in a grasshopper hybrid zone

Bailey

Lineham

Thomas

et al. 2003

Ecological Entomology

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Estimating Animal Abundance

Borchers¹,

Buckland²,

Zucchini³

2002

Statistics for Biology and Health

246

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Evaluation of movement parameters in insects - bias and robustness with regard to resight numbers

Samietz

Berger

1997

Oecologia

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Because of the low number of observation points per animal attainable in insect movement studies, linear parameters are frequently used to quantify the data. These linear parameters are evaluated, as well as several home range estimators, by means of an empirical study of the bush cricket Phaneroptera falcata (Insecta: Ensifera) and a Monte Carlo simulation model. The examination of differences between complete and artificially reduced data sets, as well as between the "real" (i.e. simulated) data set and the data recorded by a simulated observer, allows us to quantify robustness and bias of the evaluated parameters. We show that nearly all tested methods are strongly influenced by the resight number of the investigated individuals. Hence, those parameters should be used cautiously in studies with few resights, i.e. in insect studies as well as studies on vertebrates. Results of earlier studies should be reconsidered and some comparisons between different studies are questionable. Estimates of home range using a 95% ellipse with fewer than five locations are extremely unreliable (overestimation). The minimum convex polygon leads to a clear underestimation. The robustness of both parameters is low. Among the home range parameters the kernel method is most robust, but it leads to an overestimating bias. The harmonic mean method is the only home range parameter whose results are comparable to the area actually used. However, this method requires a minimum number of 11 observation points per individual. Evaluating the linear parameters, the mean daily movement and the total recorded movement are inappropriate for statistical analyses, because of their high sensitivity to the resight number. Maximum activity radius and dispersal range are much more robust. They are not as sensitive to sample size and deviate little from the "real" values of the parameters. However, this bias is statistically significant. The mean activity radius of an individual is the most useful linear parameter. This measure is very robust down to a sample size of four individual locations and compares well with the real parameter values.

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Philopatry in the alpine grasshopper, Podisma pedestris: a novel experimental and analytical method

Cited by 19 publications

References 28 publications

Measuring dispersal and detecting departures from a random walk model in a grasshopper hybrid zone

Measuring dispersal and detecting departures from a random walk model in a grasshopper hybrid zone

Estimating Animal Abundance

Evaluation of movement parameters in insects - bias and robustness with regard to resight numbers

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