Do floral resources in Eucalyptus plantations affect fitness parameters of the parasitoid Palmistichus elaeisis (Hymenoptera: Eulophidae)?

Abstract

Adult parasitoids depend on sugar-rich foods such as nectar and honeydew to meet their energy requirements. The availability of nectar, honeydew or fruit sap affects the longevity, fecundity and dispersal of parasitoids and consequently their potential as biocontrol agents. The aim of this study was to evaluate the development and reproduction of an important parasitoid of Brazilian ecosystems, Palmistichus elaeisis (Delvare and LaSalle 1993) (Hymenoptera: Eulophidae), fed with nectar from Eucalyptus flowers and flowering herbs. Males and females of this parasitoid were individualized in glass tubes, and their survival and longevity were evaluated in the following treatments: flowers of Bidens pilosa L. 1753, Emilia fosbergii Nicolson 1975, Galinsoga parviflora Cav. 1796, Sonchus oleraceus L. 1753, Taraxacum officinale F.H. Wigg. 1780 (Asteraceae) and Eucalyptus sp. (Myrtaceae), a honey droplet or no food. In the second trial, six P. elaeisis females were placed into plastic pots containing one Tenebrio molitor L. 1758 (Coleoptera: Tenebrionidae) host pupa under the same treatments. Parasitism and emergence, the duration of the egg–adult period, the number of adults per pupa, the sex ratio, the width of the head capsule and the body length of P. elaeisis were evaluated. Food sources of honey or flowering herbs increased the survival, longevity, period of parasitism, percentage of parasitized pupae and number of progeny of P. elaeisis. Longevity and reproduction were seriously compromised in the absence of sugar feeding.