Colonization of disturbed trees by the southern pine bark beetle guild (Coleoptera: Scolytidae)
- Texas A M Univ., College Station (United States)
The southern pine bark beetle guild [Dendroctonus frontalis Zimmermann, D. terebrans (Olivier), Ips calligraphus (Germar), I. grandicollis (Eichhoff), and I. avulsus (Eichhoff)] uses disturbed hosts as habitat for establishment of within-tree populations. The process of colonization of disturbed hosts was examined. Using a procedure designed to emulate effects of a lightning strike, pines were severely disturbed. Response was characterized by measuring beetle populations that (1) arrived at the trees and (2) successfully attacked the trees. Establishment of within-tree populations was characterized by measuring length of egg gallery excavated by attacking adults. The time delay between arrival and attack for D. frontalis and I. calligraphus was also calculated. Attack densities of both species became asymptotic as arrival increased. The percentage of arriving beetles that attacked ranged from 9 to 41 for D. frontalis and from 8 to 59 for I. calligraphus. Numbers of beetles that arrived at the tree but did not attack ranged from 2.7 to 50.2 beetles per dm[sup 2] for D. frontalis and from 0.2 to 10.0 beetles per dm[sup 2] for I. calligraphus. Most D. frontalis and I. calligraphus attacked on the day they arrived. The delay between arrival and attack was longer for I. calligraphus than the D. frontalis. Egg gallery excavated by D. frontalis increased throughout the study. Eventually, the Ips species were excluded from the lower half of the hole. The low attack densities observed in this study illustrate the significance of disturbed trees in providing refuges for enzootic levels of bark beetles. The aggregation behavior of beetle populations colonizing disturbed hosts supported the contention that these trees serve as foci for initiation of infestations. Furthermore, in disturbed pines, small numbers of beetles were capable of overcoming host defense systems.
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6807348
- Journal Information:
- Environmental Entomology; (United States), Vol. 22:1; ISSN 0046-225X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
60 APPLIED LIFE SCIENCES
BEETLES
BEHAVIOR
HABITAT
POPULATIONS
REPRODUCTION
PINES
DISEASES
HOST
ANIMALS
ARTHROPODS
COLEOPTERA
CONIFERS
INSECTS
INVERTEBRATES
PINOPHYTA
PLANTS
TREES
090700* - Biomass Fuels- Resources- (1990-)
540210 - Environment
Terrestrial- Basic Studies- (1990-)
553000 - Agriculture & Food Technology