Floral traits and environmental factors regulate insect visits to
flowering plants at night
Flower-visiting insects have co-evolved with flowering plants. While it
has been shown that floral traits and environmental factors influence
insect visitation during the day, it is still unclear how these factors
influence their visitation at night. We sampled a montane meadow located
near Jilin in northeastern China in July and August of 2019, for 4
nights each month, and two time periods each night. We sampled 94
flower-visiting insect species in total and documented floral traits and
ambient factors. We first allocated all the insects to three functional
groups (pollination, predation, and herbivory). Most nocturnal insects
exhibited predation behavior, and had the highest species turnover rate.
We then focused on environmental factors and found that ambient
temperature and relative humidity strongly influenced the diversity of
flower-visiting insects. In addition, variation partitioning analysis
suggested that ambient temperature had a stronger effect on the
flower-visiting insects during the early night hours, whereas relative
humidity had a stronger effect on them in the later night hours.
Finally, focusing on floral traits, most insects preferred flowers with
moderately sized corolla diameters (20 to 30 mm). Furthermore, display
size had a strong linear correlation with flower-visiting insect species
richness and frequency of presence. In sum, our findings suggest that
ambient temperature, relative humidity and floral display size strongly
regulate the behavior of nocturnal flower-visiting insects.