Relation between egg production and food consumption in species of the genus Pardosa (Lycosidae, Araneae) under experimental conditions of food-abundance and food-shortage

Abstract

1. The amount of food intake during the egg ripening period and the conversion of this food into eggs (biomass and number of eggs) in four Pardosa species is described. The amount of food taken in is dependent on the size of the spider species. Basically the process of conversion of food into egg-biomass is the same for all four species. Thus the size of the spider species mainly determines the number of eggs in the egg-sac. There are however minor differences in "efficiency" of the process and in dryweight of the eggs between the species. These differences which are discussed complicated the general process of food conversion into number of eggs. 2. When food shortages are supplied during the egg ripening period two reactions can be observed: a) All species tend to keep the dry weight of the eggs at a constant level. b) Some species produce the same number of eggs under conditions of small food shortages as under conditions of maximum food supply, using reserve material from the body of the female. In this case the female either shows no increase in body weight or a decrease while others immediately adapt the number of eggs to the quantity of food given. Under conditions of strong food shortages, however, both groups of species show the same reaction.