The effects of florivory on floral attractiveness and fruit production in Daustinia montana (Convolvulaceae)

Abstract

• Florivory affects floral attractiveness in Daustinia montana . • Pollinator visits decrease when corolla damage increases in Daustinia montana . • Fruit production under natural conditions was greater among intact flowers. Floral attractiveness is a strong determinant of pollination success, although the same attributes that attract pollinators can also attract florivores. Consumption of the corolla and/or reproductive structures can reduce pollinator visitation frequencies and depress fruit and/or seed set. We hypothesized that florivory would negatively affect the visitation frequencies of floral visitors and natural fruit set in Daustinia montana , a herbaceous species endemic to Brazil. We collected inflorescences of D. montana and recorded the numbers of floral structures with signs of florivory, as well as the locations of that damage, to quantify natural florivory. Artificial damage experiments were carried out with the corollas and stamens to experimentally determine the influence of florivory on the frequency of floral visits. We also randomly marked intact flowers and those naturally damaged by florivory and measured fruit set. More intact floral buds were observed under natural conditions than buds damaged by florivory. We observed that all of the analyzed structures (stamens/pistil and corolla) are generally attacked simultaneously, as opposed to only one specific structure. Intact flowers (controls) demonstrated greater rates of pollinator visitation than experimentally damaged flowers. The visitation frequencies of nectar thieves were not different between intact flowers and artificially damaged flowers. Fruit set under natural conditions was greater for intact flowers than for those that had experienced natural florivory. Our data indicated that floral damage had negative effects on floral attractiveness to pollinators. The greater natural production of fruits from intact flowers is indicative of the degree to which florivory can impact plant reproduction.