Abstract
The walnut twig beetle, Pityophthorus juglandis Blackman (Coleoptera: Scolytidae), vectors the fungus Geosmithia morbida, which has been implicated in thousand cankers disease of walnut. Little is known about the flight behavior of the insect across seasons, or about the variability in its flight patterns with weekly fluctuations in weather. We sampled flying adults weekly over a 142-week period (from 29 August, 2011 to 2 June, 2014) with 12-unit black plastic multiple funnel traps baited with a male-produced aggregation pheromone in California, USA. Up to 5000 beetles were captured per trap per week, although catches in most weeks were less than 100 insects. Trap catches were regressed against terms for precipitation, solar radiation, vapor pressure, air temperature, relative humidity, wind speed, and trap catches in preceding weeks. The number of beetles captured in each of the preceding two weeks explained most variation in a current week’s catch. This strong temporal autocorrelation was present in regression models developed for males, females, and both sexes pooled. These models were improved by including two environmental variables. Captures of P. juglandis increased with mean weekly air temperature and decreased with increasing mean minimum relative humidity. The percentage of variation in male, female, or total trap catch explained by the temporal variables and the two environmental variables in these multiple regression models ranged from 72% to 76%. While the flight of this invasive insect will likely be affected by site-specific factors as it spreads to new areas, the strong temporal correlation present in this system may provide a useful starting point for developing flight models for newly invaded areas.
| Original language | English (US) |
|---|---|
| Article number | 156 |
| Journal | Insects |
| Volume | 11 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 2020 |
Bibliographical note
Funding Information:Funding: Funding for this work was provided by the USDA Forest Service, Pacific Southwest Research Station, and by grants from the USDA Forest Service, Washington Office Forest Health Protection and USDA APHIS CPHST administered by Mary Louise Flint through cooperative agreements #10-CA-11272172-055 and 10-JV-11272172-092 between the USDA FS PSW Station and the UC-Davis Department of Entomology.
Funding Information:
Acknowledgments: The authors thank Shakeeb Hamud and Lori Nelson (USDA Forest Service, Davis, CA), Daren Harris, Stacy Hishinuma, Jennifer King, Irene Lona, Kristina Tatiossian, and Lauren Walker (University of California, Davis, Department of Entomology and Nematology) for their assistance in data collection. Jennifer King, Irene Lona, and Lauren Walker managed the beetle catch data and assisted with collecting and preparing the data sets on the environmental variables. We also thank Jacques Régnière (Natural Resources Canada, Laurentian Forestry Center, Québec, Canada) for his comments on an earlier version of the manuscript. Funding for this work was provided by the USDA Forest Service, Pacific Southwest Research Station, and by grants from the USDA Forest Service, Washington Office Forest Health Protection and USDA APHIS CPHST administered by Mary Louise Flint through cooperative agreements #10-CA-11272172-055 and 10-JV-11272172-092 between the USDA FS PSW Station and the UC-Davis Department of Entomology. The authors are especially grateful to Bruce Moltzan for facilitating the funding from the USDA FS and to David Lance for facilitating the funding from USDA APHIS.
Funding Information:
for this work was provided by the USDA Forest Service, Pacific Southwest Research Station, and by grants from the USDA Forest Service, Washington Office Forest Health Protection and USDA APHIS CPHST administered by Mary Louise Flint through cooperative agreements #10-CA-11272172-055 and 10-JV-11272172-092 between the USDA FS PSW Station and the UC-Davis Department of Entomology. Acknowledgments: The authors thank Shakeeb Hamud and Lori Nelson (USDA Forest Service, Davis, CA), Daren Harris, Stacy Hishinuma, Jennifer King, Irene Lona, Kristina Tatiossian, and Lauren Walker (University of California, Davis, Department of Entomology and Nematology) for their assistance in data collection. Jennifer King, Irene Lona, and Lauren Walker managed the beetle catch data and assisted with collecting and preparing the data sets on the environmental variables. We also thank Jacques R?gni?re (Natural Resources Canada, Laurentian Forestry Center, Qu?bec, Canada) for his comments on an earlier version of the manuscript. Funding for this work was provided by the USDA Forest Service, Pacific Southwest Research Station, and by grants from the USDA Forest Service, Washington Office Forest Health Protection and USDA APHIS CPHST administered by Mary Louise Flint through cooperative agreements #10-CA-11272172-055 and 10-JV-11272172-092 between the USDA FS PSW Station and the UC-Davis Department of Entomology. The authors are especially grateful to Bruce Moltzan for facilitating the funding from the USDA FS and to David Lance for facilitating the funding from USDA APHIS.
Publisher Copyright:
© 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Keywords
- Climate
- Humidity
- Invasive species
- Juglans nigra
- Regression analysis
- Scolytidae
- Temperature
- Thousand cankers disease
- Walnut twig beetle
- Weather
