Two different and sublethal isolates of Nosemalymantriae (Microsporidia) reduce the reproductive success of their host, Lymantria dispar

Abstract

We examined the effects of two microsporidian isolates of Nosema lymantriae (Germany isolate; Schweinfurt isolate) on the reproductive success of Lymantria dispar L. All possible mating combinations were tested. Both isolates affected the fecundity of infected females and the hatch of neonates. The infection of female L. dispar with either isolate resulted in a higher proportion of non-viable eggs; the survival of neonates during egg stage was not affected. When L. dispar larvae were infected with N. lymantriae [Germany] the number of eggs per egg mass decreased between 24 and 61%. When both adults were infected, the hatch rate decreased to 26%. While the infection of the male or the female host with the Germany isolate affected the number of eggs per egg mass and the hatch of progeny, we did not find a significant effect when male hosts were infected with the Schweinfurt isolate; only infection of the female L. dispar resulted in a reduction of the number of eggs per egg mass between 26 and 37%.

Keywords:

• Lymantria dispar
• microsporidia
• Nosema lymantriae
• fecundity
• sublethal effects

Acknowledgements

This research was supported by the Federal Ministry of Education, Science, Research and Technology (BMBF Germany). We thank Drs Gernot Hoch and Leellen Solter for comments for an earlier draft of this manuscript. The authors wish to thank USDA/APHIS for providing gypsy moth egg masses.