Floral visitors often display preferences for certain nectar plants. These preferences may change seasonally with changing floral abundance. In this study, we examined nectar plant preferences and seasonal diet shifts of Hemaris, a genus of day-flying hawkmoth. In our study system, Hemaris feeds on the flowers of knapweed, a non-native plant, until swamp thistle, a native plant, blooms.
Hemaris thysbe nectaring at swamp thistle. Photo by E. Tartaglia