Budburst phenology and host use by Operophtera brumata (Linnaeus, 1758) (Lepidoptera: Geometridae) in three Mediterranean oak species

Abstract

Operophtera brumata L. performance varies among three Mediterranean oak species. Quercus canariensis Willd is more susceptible to infestation probably due to its (i) early leafing, (ii) high nutritional value for the larvae, and (iii) widespread abundance. Larvae of Operophtera brumata were observed for the first time in an outbreak in Tunisia affecting Quercus canariensis, Quercus afares Pomel, and Quercus suber L. Due to its polyphagous nature and the important ecological and economic damage it causes, it is most relevant to understand its interaction with North African oaks species. In this paper, budburst phenology of the three oak species, larval performance, and genetic patterns of O. brumata were studied in northwestern Tunisia. In the spring of 2010, 2011, and 2012, budburst phenology of host species and larval densities were monitored weekly. Larval performance of O. brumata on the three oak species was analyzed. DNA extraction, PCR, and DNA sequencing were performed. Budburst of Q. canariensis and Q. afares was earlier than Q. suber. Q. canariensis was the most infested host. Larvae which fed on Q. canariensis had faster development, lower mortality, and higher pupal weight than larvae fed on Q. afares and Q. suber. Molecular analyses showed that Tunisian haplotypes were not different from those in Spain, Italy, and Germany. Results indicated differences in larval performance. Q. canariensis was the most favorable host species. Its high density in the field and early leafing coinciding with larval hatching made this species particularly susceptible.