Occurrence and performance of the aspen blotch miner, Phyllonorycter salicifoliella, on three host-tree species

Abstract

Larvae of the aspen blotch miner, Phyllonorycter salicifoliella Chambers (Lepidoptera: Gracillariidae), feed within leaves of three host-tree species in north-central Minnesota, USA. Far more individuals occur on Populus tremuloides than on P. balsamifera or P. grandidentata. We tested whether this pattern of host use reflected variable performance among alternative hosts by examining survivorship, sources of mortality, pupal mass, feeding efficiency, and development time of miners on each tree species. We also determined foliar water, nitrogen, condensed tannin, and phenolic glycoside content of host trees to test if host-tree chemical attributes were responsible for differences in performance. There was no significant difference in egg-to-adult survival among miners on different hosts, although dominant sources of mortality did vary. Miners on P. grandidentata suffered less parasitism and more predation than those on the other hosts, even though most parasitoid species attacked miners on all hosts. The other performance parameters varied among host species, but not in a consistent pattern. Pupal mass was greatest on P. tremuloides and P. balsamifera, the hosts with comparatively high foliar nitrogen and low phenolic glycoside concentrations. However, feeding efficiency was greatest and development time shortest for miners on P. grandidentata. Thus, pupal mass was the only index of performance maximized on P. tremuloides, the most commonly used host. Infrequent occurrence of Phyllonorycter salicifoliella on P. grandidentata results in part from phenological differences between this and the other host species. Low oviposition rates on P. balsamifera are correlated with low abundance of this host at the study site and a phenolic glycoside profile different from that of the other host species.

Preference and performance linkage of a leaf‐mining moth on different Salicaceae species

“…Egg densities on Populus sieboldii and S. hultenii were much higher than those on S. sachalinensis and S. miyabeana despite good survival on S. miyabeana and no survival on S. hultenii. Poor correlation between egg density and larval performance in the field agrees with the results of several studies of other leaf miners (Valladares and Lawton 1991;Auerbach and Alberts 1992;Koricheva and Haukioja 1994). One hypothesis to explain the poor correlation is that expected larval performance was considerably reduced by density-dependent mortality factors; this occurs because larvae on more-favored plants tend to reach high density and are more likely to suffer from density-dependent mortality.…”

“…In contrast to laboratory conditions, oviposition behavior may be affected by several environmental factors in the field. In this context, some studies have suggested that oviposition behavior was affected by difference in plant phenology (Auerbach and Alberts 1992), relative abundance of preferred host plants (Rausher 1980), or distribution of nonhost plants (Tahvanainen and Root 1972;Kareiva 1983;Visser 1986). For example, the butterfly Euphydryas chalcedona lays eggs on a less-preferred but easily accessible plant when a more-preferred plant is rare (Williams 1983;Williams et al 1983).…”

“…Ovipositing females should be favored by natural selection so as to lay eggs on plant species or parts on which offspring fitness is maximized (Thompson 1988). This advantage should be particularly true for insects immobile during the larval period, such as leaf miners, in which adult oviposition mainly determines larval feeding sites (Valladares and Lawton 1991;Auerbach and Alberts 1992;Stein and Price 1995). Therefore, we expect a positive correlation between preference and performance.…”

Effects of plant hybridization on herbivore-parasitoid interactions

“…We combined all eulophid parasitism, since species could not be reliably distinguished as larvae or from pupal cases at the time of dissection. There was evidence of host feeding predation (larval predation), indicated by a collapsed and empty skin of the sap-feeding-stage larva attached to the lower mine surface (Jervis and Kidd 1986;Auerbach and Alberts 1992). Host feeding predation on Phyllonorycter is usually attributed to eulophids (Van Dreische and Taub 1983; Barrett and Jorgensen 1986).…”

“…During dissection of Phyllonorycter mines, causes of mortality are usually easy to determine (Pottinger and LeRoux 1971;Auerbach and Alberts 1992;Fritz and Kaufman 1993). At the time collections were made (August), most surviving Phyllonorycter had pupated and emerged.…”