SURVIVAL AND DEVELOPMENT OF IPS PARACONFUSUSLANIER (COLEOPTERA: SCOLYTIDAE) REARED AXENICALLY AND WITH TREE-PATHOGENIC FUNGI VECTORED BY COHABITING DENDROCTONUSSPECIES

AbstractSurvival and development of Ips paraconfususLanier larvae reared individually in intact Pinus ponderosaLaws. phloem without associated fungi and dietary supplements was demonstrated. Survival was reduced.in intact ponderosa pine phloem previously occupied by other larvae or by bluestaining fungi [i.e. Ophiostoma ips(Rumb.) vectored by I. paraconfusus, O. minus(Hedge.) H. & P. Syd. vectored by Dendroctonus brevicomisLeConte, O. clavigerum(Robins.-Jeff. & Davids.) vectored by D. ponderosaeHopkins, and Leptographium terebrantisBarras & Perry vectored by D. valensLeConte] compared with those reared without fungi or symbiotic yeasts. The highest proportion of larvae initiating tunnels and surviving to adult was observed for untreated eggs, and the lowest proportion occurred in the L. terebrantistreatment. Size was reduced and developmental rate was slower for larvae reared without fungi compared with larvae reared with associated fungi.Tunnels excavated by first- and second-instar larvae reared without associated fungi were longer than those excavated by larvae reared with associated fungi. The most frequent larval turnabouts occurred with larvae reared axenically and reared with Ipsyeast and O. ips. The fewest occurred with larvae reared with Ipsegg niche plugs and from untreated eggs. Females reared free of any fungi or with Penicilliumor Aspergillusdid not oviposit in surface-sterilized ponderosa pine logs. Naturally eclosed females from ponderosa pine logs in which they developed, laid eggs in these sterilized logs. Potential for a new association among bark beetles and fungi is discussed.