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Premise: Pollinators with flower constancy and long nectar‐feeding organs should favor less or no sexual dimorphism in the individual flowers of dioecious plants. This hypothesis is deduced because such pollinators can discriminate between intersexual flower size differences, and morphological differences between male and female flowers often diminish pollen transfer. Methods: We compared floral traits and pollinator behavior between male and female flowers in the hawkmoth‐pollinated species, Trichosanthes cucumeroides. In field studies, we removed petal fringes on both sexes and observed pollinators to assess the role of elaborate petal fringes in pollinator attraction and pollination success for each flower sex. Results: Female flowers had a similar front flower size and fringe extension as male flowers, supporting our hypothesis. In contrast, females allocated fewer resources to floral biomass. Additionally, they had smaller and narrower petal lobes, lower fringe density, shorter tubes with inferior nectar rewards, and lower display size than males, which is inconsistent with the hypothesis. Nocturnal hawkmoths prefer flowers with long fringe extensions. Fringe removal significantly decreased hawkmoth visitations to both female and male flowers but reduced success only in females. A literature survey indicated that female flowers of specialist‐pollinated species are similar in size or larger than the males and thus tend to attract more pollinators compared with female flowers of generalist‐pollinated species. Conclusions: Female flowers have evolved fringe extensions that are similar to those of male flowers, likely increasing pollinator attraction even slightly, and had less biomass in other floral parts and produced less nectar compared with male flowers. Our findings imply that female‐biased resource limitation and flower‐size sensitivity of pollinators together exert sex‐specific selection of floral traits in T. cucumeroides. [ABSTRACT FROM AUTHOR]

In this study, we observed diverse ambush predators on the flowers of nine plant species and detected some of these predators eating flower-visiting moths at night. Praying mantises were the most abundant group of ambush predators found on flowers; they frequently ate flower-visiting moths as well as diurnal flower visitors. Attacks by ambush predators on diurnal pollinators affect subsequent flower-visiting behavior. [Extracted from the article]

However, the flower visitors differed greatly between day and night; diurnal flower visitors were mainly bees (54.7%), hoverflies (9.0%), and butterflies (34.5%), whereas nocturnal flower visitors were exclusively moths (99.7%; Appendix S1: Table S6). If settling moths can recognize ambush predators on flowers, they should avoid the flowers with predators more frequently than those without predators. Although nocturnal insects such as moths are important pollinators of many flowering plants (Hahn and Brühl 2016), the impact of ambush predators on nocturnal pollinators remains unclear. Keywords: mantis; mantisfly; Mantodea; Neuroptera; pollinators; predation; Scutigeromorpha; settling moths EN mantis mantisfly Mantodea Neuroptera pollinators predation Scutigeromorpha settling moths 1 4 4 11/02/21 20211101 NES 211101 Ambush predators such as spiders affect the flower-visiting behavior of diurnal pollinators such as bees (Dukas 2001, Dukas and Morse 2003), potentially causing diurnal pollinators to avoid flowers where ambush predators wait (Dukas 2001). [Extracted from the article]

Generalized pollination systems may be favored in early spring flowering plants, as during this period pollinator activity is unpredictable. Many previous studies have concentrated on the importance of diurnal visitors in pollination, and consequently, information on the contribution of nocturnal visitors to pollination in early spring is limited. This study was conducted to evaluate the relative importance of diurnal and nocturnal pollinators in the early spring flowering dioecious shrub Stachyurus praecox (Stachyuraceae), in two temperate forests in central Japan. Visitors to the female and male flowers were observed during day and night, and their relative contributions to seed set were compared. The pollinator observations revealed that the diurnal and nocturnal insects visited both male and female flowers, and that the main flower visitors were diurnal small bees and flies as well as nocturnal settling moths. The diurnal and nocturnal flower visitors also acted as pollinators, as the pollen grains of S. praecox were attached to the insects collected from the female flowers. Pollination experiments demonstrated that the contributions of diurnal pollinators to the seed set were higher than those of the nocturnal pollinators. The results of this study indicate that S. praecox has a generalized pollination system, comprising both diurnal insects and nocturnal settling moths. Although the roles of diurnal insects are more important in the pollination of S. praecox, nocturnal settling moths may have a complementary role in early spring. [ABSTRACT FROM AUTHOR]