I.—The Determination and Significance of the Egg Density
Published online by Cambridge University Press: 10 July 2009
The quantitative study of Tyroglyphid populations involves their separation from the food material, for which existing methods are not entirely satisfactory A new method is described which depends on chemical treatment to remove the bulk of the flour. It is made quantitative and independent of moisture-content variation by application of the lycopodium-spore method of Wallis. A techniqul for determining the numbers of hatched and unhatched eggs per unit weight of flour is described. It provides information on the rate of increase or decreas in the number of eggs (natality rate per unit time) and hence on the ability the species to survive in a particular environment. The egg distribution in an undisturbed culture of Tyroglyphus farinae (Deg.) is found to be uneven. The technique is applied to the study of a population of Thyreophagus entomophagus (Lab.) under controlled conditions of temperature and humidity and the results discussed.