Abstract
The western conifer seed bug (WCSB, Leptoglossus occidentalis) is a pest of many pine species and is invasive worldwide. WCSB directly and indirectly deteriorates pine nut production by sucking seeds from cones. Currently, researchers think that WCSBs search for food by a combination of cues from visible light, infrared radiation, and chemicals such as monoterpenes. Some research revealed that WCSBs prefer larger cones, and it was thought that WCSBs suck seeds from and obtain more heat on larger cones. However, in early spring, we observed that most WCSBs gathered on male cones rather than on female cones and young cones. We hypothesized that male pine cones were warmer than female cones and needles, and WCSBs sucking male cones may receive more heat. To test these hypotheses, we measured spectral reflectance with a hyperspectral sensor and temperature of pine organs with tiny thermocouples, and the data were analyzed by a heat budget model. Our results revealed that male cones were significantly warmer and more reflective than female cones and needles, which may attract WCSBs. These results supported our hypothesis that WCSBs on male cones were warmer than those on other organs. This study will help further understanding of WCSBs and the adaptive value of pine cone colors.
Funder
Japan Society for the Promotion of Science
Publisher
Public Library of Science (PLoS)
Reference40 articles.
1. Heidemann O. New species of Leptoglossus from North America. Proc Entomol Soc Washingt. 1910.
2. Impact assessment of Leptoglossus occidentalis in Pinus pinea: Integrating population density and seed loss;AO Farinha;For Ecol Manage,2021
3. Potential factors behind the decline of Pinus pinea nut production in Mediterranean Pine Forests;Y El Khoury;Forests,2021
4. Effect of Leptoglossus occidentalis (Heteroptera: Coreidae) on seed development of douglas-fir at different times during the growing season in Western Oregon;TD Schowalter;J Econ Entomol,1990
5. Effect of cone feeding by Leptoglossus occidentalis on ponderosa pine seed development;SL Krugman;For Sci,1969