Abstract:
Egg activation is a cellular transition of an arrested mature oocyte into a developing embryo through a coordinated series of events. Previous studies in Hymenoptera have indicated that mechanical pressure can induce egg activation. In this study, we developed the first egg activation protocol for the haplodiploid insect pest, Sirex noctilio (Hymenoptera: Siricidae), from two climatically different regions in South Africa to demonstrate the broad applicability of the method. In addition, activated eggs were exposed to three treatments involving water, pine sawdust, and the fungal symbiont of S. noctilio, Amylostereum areolatum (Russulales: Amylostereaceae), to determine if the symbiotic fungus is a requirement for egg development in an artificial laboratory environment, as the symbiotic fungus has been hypothesised to be necessary for egg and early larval development in a natural environment. A rearing protocol was developed for the first instar larvae using a modified Anoplophora glabripennis (Coleoptera: Cerambycidae) artificial diet. A significant difference between the mean survival rates of activated eggs from the two different regions was observed. Amylostereum areolatum was shown to be unnecessary for egg survival and adversely affected egg eclosion in an artificial laboratory environment. The maximum larval survival duration on the artificial diet was 92 days. The egg activation and rearing protocol developed in this study enables opportunities for research on the physiology, ecology, symbioses, and genetics of S. noctilio, which can be exploited for new genetic pest management strategies.
Description:
DATA AVAILABILITY STATEMENT :
The data presented in this study are available in Figshare at https://doi.org/10.6084/m9.figshare.24473938.v1, accessed on 2 November 2023.
SUPPLEMENTARY MATERIAL : TABLE S1: Pinus sp. log batch information; FIGURE S1: Treatments applied after egg activation of ten Sirex noctilio female wasps from Mpumalanga and Western Cape, respectively; TABLE S2: Ingredients for Sirex noctilio artificial diet with manufacturers; FIGURE S2: Rearing of Sirex noctilio larvae emerging from activated eggs.