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Updated: Jul 12, 2026

Manipulation of Color Patterns in Jumping Spiders for Use in Behavioral Experiments
Published on: May 21, 2019
Effect of lizards on spider populations: manipulative reconstruction of a natural experiment
Abstract:
Which species affect one another, how intensely, and the mechanisms of those effects are crucial data for understanding how ecological communities work. Tropical islands without lizards, the major top predators, have about ten times as dense web spider populations as those with lizards; processes responsible for this effect were experimentally simulated by removing lizards from randomly selected mainland plots. Spider densities in removal plots averaged 2.5 times as high as controls. Spider survival, prey abundance, and prey consumption were all negatively affected by lizards. Contrary to most studies, predator removal caused an increase in the number of spider species.
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Testing a Claim about Mean: Known Population SD
Estimating a population mean requires the samples to be distributed normally. The data should be collected from the randomly selected samples having no sampling bias. The sample size needed to be higher than 30, and most importantly, the population standard deviation should be already known.
In most realistic situations, the population standard deviation is often unknown, but in rare circumstances, when it...
Naturalistic Observations

