Importance of diet in the growth, survivorship and reproduction of the no-tillage pest Armadillidium vulgare (Crustacea: Isopoda)

Abstract

The studies of Armadillidium vulgare as pest are virtually null worldwide.However under no-tillage systems this species has found an adequate environment for its development and it has become an important pest in some crops in Argentina.It has been shown that the composition of vegetables affects the isopods biology.Our hypothesis was that soybean leaf litter has high nutritive value which allows A. vulgare to grow faster, survive longer, and have higher fecundity favoring the population increase and turning it into a crop pest.Growth and survivorship of juveniles and adults, egg incubation period, offspring number per female and offspring mean body weight were determined in individuals fed with leaf litter of soybean, sunfl ower, wheat and pasture.The growth rate coeffi cient, k, in juveniles was higher for soybean, intermediate for pasture and lower for sunfl ower.Adult growth was faster under the soybean diet.Survivorship under soybean and pasture was longer than under sunfl ower and wheat in both juveniles and adults.The reproductive parameters were similar in all diets, food did not generate any change in the reproductive aspects of A. vulgare.Results of the present study represent a source of information about the A. vulgare biology under different diets of agricultural origin to establish the basis for Integrated Management of this species as pest.Under soybean litter provision A. vulgare found the best conditions for faster growth, longer survival and relatively higher fecundity.In fi elds with soybean as preceding crop or in systems with high frequency of soybean in the crop rotation a more abundant population of A. vulgare would be found as well as with larger individuals which could cause more damage to the following crop in the rotation.