Author : Jeffrey W. Boone
Publisher :
ISBN 13 : 9780494211748
Total Pages : 72 pages
Book Rating : 4.2/5 (117 download)
Book Synopsis Parasitism of Pikonema Alaskensis, a Dispersing Herbivore on Black Spruce (Picea Mariana) in Central Newfoundland by : Jeffrey W. Boone
Download or read book Parasitism of Pikonema Alaskensis, a Dispersing Herbivore on Black Spruce (Picea Mariana) in Central Newfoundland written by Jeffrey W. Boone and published by . This book was released on 2006 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: The yellowheaded spruce sawfly, Pikonema alaskensis Rohwer (Hymenoptera: Tenthredinidae), is a destructive defoliator of young spruce trees. Early-instar larvae feed predominantly in the lower crown, while late-instar larvae disperse upwards to complete feeding and development in the upper crown. The role of larval parasitism with respect to this dispersal behaviour was investigated. Both early and late-instar larvae had reduced parasitism in the upper crown as opposed to the lower crown, indicating that this region was enemy-free space. Despite parasitism costs in the lower crown, early-instar larvae had better overall survival in this crown level due to better quality resources. The role of parasitism and resources changed as larvae aged and dispersed within the tree crown, therefore, stressing the need to examine both bottom-up (i.e. resources) and topdown (i.e. natural enemies) factors when exploring their influence on the behaviour of insect herbivores.