Flowers of field pennycress (Thlaspi arvsense L.) and winter camelina (Camelina sativa (L.) Crantz.) produce abundant pollen and nectar in early spring and thereby may be valuable for pollinators. Insects observed in field plots of these flowers were classified into seven easily identifiable groups (bumblebee, honeybee, solitary bee, butterfly/moth, beetle, fly and other) and monitored for 2 years at three sites in the Upper Midwest region of the USA. Average seasonal observations across years and sites varied from 1.6 to 5.3 total insects/min for field pennycress and 1.4 to 4.5 insects/min for winter camelina. Lowest visitation rates occurred in central Iowa and highest rates in south-eastern Minnesota for both crops. Multiple regressions showed that visitation rates for specific insect groups were correlated poorly but significantly (p <.10) with select variables. For example, in field pennycress, visitation by combined bumblebees and honeybees (Apidae) increased with greater air temperature at sampling time and annual site precipitation, whereas fly (Diptera) visitation was related to sampling date and flower cover. Similarly, in winter camelina, solitary bees were linked to increasing air temperature at sampling time and annual site precipitation, whereas flies were correlated with wind speed and flower cover at sampling. Field pennycress and winter camelina are reliably attractive to beneficial pollinating insects across a wide geographic region, but visitation rates and proportional representation of various insect groups depended on a range of site and weather characteristics.
Bibliographical noteFunding Information:
The authors thank Alex Hard, Jim Eklund, Joe Boots, Chuck Hennen and Scott Larson for expert field assistance. The authors thank James Eckberg for helping with data collection and experimental design. Funding for this research was supported by a grant from USDA‐National Institute of Food and Agriculture‐Coordinated Agricultural Program (Award no. 2016‐69004‐24784). Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the US Department of Agriculture. The USDA is an equal opportunity employer and provider.
- Camelina sativa
- Thlaspi arvense
- early-season forage
Forcella, F., Patel, S., Lenssen, A. W., Hoerning, C. A., Wells, M. S., Gesch, R. W. & Berti, M. T., Data Repository for the University of Minnesota, 2020