Bionomics ofNeodiprionspecies on white fir in northeastern California

Abstract

Two sawfly species that feed on white fir were studied in Modoc County, California: Neodiprion near de/eo,,; Ross and N. abietis complex. Neod;prio" near deleonl comprised 91 percent of the field NeoJ;prio" populations and spun opaque brown cocoons in the litter or soil. Neodiprio« abietis accounted for 9 percent of the field population and spun translucent cocoons that appear green and are attached to foliage. Full-grown larvae, pupae, and adults of the two strains were morophologically distinct, though eggs and young larvae were not. Differences in morphology, phenology, physiology, and behavior are described for the two species. Mortality factors are identified, primarily for N. near deleoni. Parasitoids emerged from eggs and cocoons; many parasitoids that emerge from cocoons attack larvae. Larval predation was observed only rarely, except for predation by theridiid spiders. Sampled cocoons showed: 16 to 21 percent parasitized, 21 to 22 percent attacked by predators, 24 to 37 percent unknown mortality, and 25 to 34 percent sawfly emerged. Encapsulated ichneumonid eggs were found in 10 to 41 percent of emerging sawflies.

Comparison of Methods for Species-Tree Inference in the Sawfly Genus Neodiprion (Hymenoptera: Diprionidae)

“…57 taxonomy for the lecontei group (e.g., Ross, 1961;Becker, 1965;Becker et al, 1966, Becker andBenjamin, 1967;Knerer, 1984;Smith, 1988;Knerer and Wilkinson, 1990). By comparison, the sertifer group remains inadequately studied (although some progress has been made, e.g., Sheehan and Dahlsten, 1985;Smith and Wagner, 1986), and species boundaries and overall diversity are poorly understood. Because the species-tree methods used in this study require a priori species designations, the analyses described here focus on the lecontei group.…”

Mitonuclear Discordance Is Caused by Rampant Mitochondrial Introgression in Neodiprion (Hymenoptera: Diprionidae) Sawflies

“…A substantial amount of work on the lecontei group has helped untangle some of the more perplexing species complexes (e.g., Ross 1961; Becker et al 1966; Becker and Benjamin 1967; Knerer 1984; Knerer and Wilkinson 1990), and species in this group can now be identified with some confidence. Progress has also been made in the sertifer group (e.g., Sheehan and Dahlsten 1985; Smith and Wagner 1986), but this group is still poorly known in comparison to the lecontei group. Because our study requires confidence in a priori taxonomic designations, we focus on the much more intensively studied lecontei group.…”

Aetiology of melanized inclusions in the body cavity ofNeodiprion sertifer(Geoffroy) (Hym., Diprionidae) adults

“…This would be consistent with the bacterial hypothesis only if inclusions may be induced after the eonymphal moult, which has not been shown. The association between encapsulated parasitoids in the haemolymph and inclusions (S heehan and D ahlsten , 1985) is unlikely to have a direct connection with the gut environment, but NPV transmitted by parasitoids (R aimo et al., 1977; O lofsson , 1989) may provide a possible link.…”

“…Increased frequencies of inclusions were reported to be correlated with exposure to suboptimal temperatures during the larval stage in N. sertifer (S ullivan and W allace , 1968a) and G. hercyniae (F ogal and K wain , 1972) and with the occurrence of an eonymphal diapause in G. hercyniae (S ullivan and W allace , 1968a). S heehan and D ahlsten (1985) reported inclusions in adults of a Neodiprion species containing encapsulated parasitoid eggs.…”