Lodgepole pine seedset increase by mesh bagging is due to Leptoglossus occidentalis (Hemiptera: Coreidae) exclusion.
Keywords:
Heteroptera, Hemiptera, Coreidae, foraging behaviour, crop loss, internal cone temperature, relative humidity,Abstract
Lodgepole pine (Pinus contorta Dougl. ex. Loud. var latifolia) seed orchards in British Columbia, Canada, suffer from low seedset problems. Seedset can be improved by installing mesh bags over the 2nd-year cones. One mechanism of improved seedset has been shown to be exclusion of the seed-feeding Western Conifer Seedbug, Leptoglossus occidentalis, but the possibility of microclimate alteration leading to improved seedset has not been carefully explored. We measured the internal cone temperatures of cones both inside and outside mesh bags, as well as the relative humidity around cones both inside and outside bags. We also installed time-lapse cameras that, every 5 minutes, photographed unbagged cones situated near bagged cones, and examined the photographs for feeding by L. occidentalis. Internal temperatures of cones inside bags were warmer, accumulated more heat units, and had higher peak temperatures than cones outside bags. Humidity was slightly higher inside bags in late-season, particularly during rainy days. The evidence did not support the hypothesis that microclimate change is the cause of improved seedset inside bags. On the other hand, the cameras showed extensive feeding by L. occidentalis on unbagged cones, and showed a strong correlation between the amount of time a cone was fed upon and the subsequent seedset. Therefore the increase in seedset due to the mesh bags is not related to microclimate change, but is caused by exclusion of L. occidentalis.
References
Bates, S.L., J.H. Borden, A.R. Kermode and R.G. Bennett. 2000. Impact of Leptoglossus occidentalis (Hemiptera: Coreidae) on Douglas-fir seed production. Journal of Economic Entomology 95:1444-1451.
Bates, S.L., W.B. Strong and J.H. Borden. 2002a. Abortion and seed set in lodgepole and western white pine conelets following feeding by Leptoglossus occidentalis (Heteroptera: Coreidae). Environmental Entomology 31:1023-1029.
Bates, S.L., C.G. Lait, J.H. Borden and A.R. Kermode. 2002b. Measuring the impact of Leptoglossus occidentalis (Heteroptera: Coreidae) on seed production in lodgepole pine using an antibody-based assay. Journal of Economic Entomology 95:770-777.
Forest Genetics Council of British Columbia. 2013a. Annual Report, 2012/13. Victoria, Canada.
Forest Genetics Council of British Columbia. 2013b. Business Plan, 2013/14. , Victoria, Canada.
Forest Genetics Council of British Columbia. 2014. Information About Conifer Seed Orchards.
URL: http://www.fgcouncil.bc.ca/sel-c-coni.html
Hedlin, A.F., H.O. Yates, D.C. Tovar, B.H. Ebel, T.W. Koerber and E.P. Merkel. 1980. Cone and seed insects of North American conifers. Environment Canada, Canadian Forestry Service, Ottawa, Canada.
Koerber, T.W. 1963. Leptoglossus occidentalis (Hemiptera: Coreidae), a newly discovered pest of coniferous seed. Annals of the Entomological Society of America 56:229-234.
Kolotelo, D., E. Van Steenis, M. Peterson, R. Bennett, D. Trotter and J. Dennis. 2001. Seed Handling Guidebook. British Columbia Tree Improvement Branch, BC Ministry of Forests, Victoria, BC Canada.
Kuznetsova, A., P.B. Brockhoff and R.H.B. Christensen. 2014. lmerTest: Tests for random and fixed effects for linear mixed effect models (lmer objects of lme4 package). R package version 2.0-6. , URL http://CRAN.R-project.org/package=lmerTest.
Meidinger, D. and J. Pojar. 1991. Ecosystems of British Columbia. BC Ministry of Forests, Victoria, BC, Canada.
Owens, J.N. 2006. The reproductive biology of lodgepole pine. Extension Note 07, Forest Genetics Council of British Columbia, Victoria, Canada.
R Core Team. 2013. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL http://www.R-project.org/.
Richardson, T.A. 2013. Immigration and dispersal patterns, cues mediating host selection and calibration of field surveys with estimates of population abundance of Leptoglossus occidentalis in a seed orchard. M.Sc Thesis, University of Northern British Columbia, Prince George, BC, Canada.
Strong, W.B., R.G. Bennett and G. Hales. 1998. Leptoglossus and low seedset in Lodgepole Pine seed orchards. Seed and Seedling Extension Topics, BC Ministry of Forests, 11: 11-13.
Strong, W.B., S.L. Bates and M.U. Stoehr. 2001. Feeding by Leptoglossus occidentalis (Hemiptera: Coreidae) reduces seed set in lodgepole pine (Pinaceae). The Canadian Entomologist 133:857-865.
Strong, W.B. 2006. Seasonal changes in seed reduction in lodgepole pine cones caused by feeding of Leptoglossus occidentalis (Hemiptera: Coreidae). The Canadian Entomologist 138:888-896.
von Aderkas, P. 2014. Study of seed shortfall in lodgepole pine as well as cone induction in lodgepole pine and Douglas-fir (2014/15). File 1070-20/CS15FHQ061, Forest Genetics Council of BC, Biotechnology Advisory Committee, Victoria, BC Canada.
Webber, J. 2014. Interior Lodgepole Pine Orchard Seed Set: Summary of Field Trials, 2000 to 2012. OTIP Project 0722 Report, BC Ministry of Forests, Tree Improvement Branch, Victoria, BC Canada.
Zahradnik, T.D. 2012. Exploitation of electromagnetic radiation as a foraging cue by conophagous insects. Ph.D. Thesis, Simon Fraser University, Burnaby, British Columbia Canada.
Downloads
Published
Issue
Section
License
Authors who publish with the Journal of the Entomological Society of British Columbia agree to the following terms:
-Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
-Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
-Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
