Floral antagonists counteract pollinator‐mediated selection on attractiveness traits in the hummingbird‐pollinatedCollaea cipoensis(Fabaceae)

Abstract

Pollinator‐mediated selection toward larger and abundant flowers is common in naturally pollen‐limited populations. However, floral antagonists may counteract this effect, maintaining smaller‐ and few‐flowered individuals within populations. We quantified pollinator and antagonist visit rates and determined a multiplicative female fitness component from attacked and non‐attacked flowers of the Brazilian hummingbird‐pollinated shrub Collaea cipoensis to determine the selective effects of pollinators and floral antagonists on flower size and number. We predicted that floral antagonists reduce the female fitness component and thus exert negative selective pressures on flower size and number, counteracting the positive effects of pollinators. Pollinators, mainly hummingbirds, comprised 4% of total floral visitation, whereas antagonist ants and bees accounted for 90% of visitation. Nectar‐robbers involved about 99% of floral antagonist visit rates, whereas florivores comprised the remaining 1%. Larger and abundant flowers increased both pollinator and antagonist visit rates and the female fitness component significantly decreased in flowers attacked by nectar‐robbers and florivores in comparison to non‐attacked flowers. We detected that pollinators favored larger‐ and many‐flowered individuals, whereas floral antagonists exerted negative selection on flower size and number. This study confirms that floral antagonists reduce female plant fitness and this pattern directly exerts negative selective pressures on flower size and number, counteracting pollinator‐mediated selection on floral attractiveness traits.

Temporal changes in the most effective pollinator of a bromeliad pollinated by bees and hummingbirds

“…Self-incompatibility in this species seems to work as a barrier to autogamous pollination, since small bees access the anthers, make long visits to the flower, and manipulate the pollen. In fact, pollinators usually do not operate independently of herbivores (florivores in this case), which may generate a tradeoff between the fitness functions by each kind of organism (Ashman, 2002;Gómez & Zamora, 2006;Gélvez-Zúñiga et al, 2018).…”

Peer Review #1 of "Temporal changes in the most effective pollinator of a bromeliad pollinated by bees and hummingbirds (v0.1)"

“…Selfincompatibility in this species seems to work as a barrier to autogamous pollination, since small bees access the anthers, make long visits to the flower, and manipulate the pollen. In fact, pollinators usually do not operate independently of herbivores (florivores in this case), which may generate a trade-off between the fitness functions by each kind of organism (Ashman, 2002;Gómez & Zamorra, 2006;Gélvez-Zúñiga et al, 2018). Manuscript to be reviewed Our results allow us to conclude that hummingbirds and large bees were the main and the secondary pollinators of E. lindenii, respectively.…”

More is not always better: responses of the endemic plant Vellozia nanuzae to additional nutrients

“…These results indicate that nutritional enrichment of nutritionally poor environments can result in toxic conditions for native species, and thus trigger adverse effects at the ecosystem level (Fernandes & Price 1991). Although other species of the campo rupestre ecosystem had an opposite response with higher growth rates with nutritional enrichment (Calliandra fasciculata, Negreiros et al 2009;Collaea cipoensis, Negreiros et al 2009;Baccharis dracunculifolia, Negreiros et al 2014), these species are widespread (C. fasciculata: Barneby 1998), autochorous (C. cipoensis: Gélvez-Zúñiga et al 2018), or pioneer (B. dracunculifolia: Müller et al 2007 species. Clearly, the number of species studied so far does not allow us yet to propose a general trend for the response of campo rupestre species.…”