Relationship of floral morphology and development with the pattern of bee visitation in a species with pollen-flowers, Chamaecrista desvauxii (Fabaceae)

PREMISE Flowering plants with poricidal anthers are commonly visited by buzzing bees, which vibrate flowers to extract pollen. However, not all flower visitors are in fact pollinators, and features such as body size and duration of flower visits are important factors in determining pollination effectiveness. We tested whether bee‐to‐flower size relationships predict the pollination effectiveness of flower visitors of a buzz‐pollinated species (Chamaecrista ramosa, Fabaceae). METHODS We sorted 13 bee taxa into three groups: smaller than, equivalent to (“fit‐size”), and larger than flower herkogamy (spatial separation between anthers and stigma). We expected the latter two groups to touch the stigmas, which would be an indicator of pollination effectiveness, more frequently than the first group. To test this hypothesis, we assessed contact with stigmas, foraging behavior, and duration of visits for the three size groups of bees. RESULTS Our data reveal that small bees scarcely touched the stigmas, while large and fit‐size bees were the most efficient pollinators, achieving high stigma‐touching rates, conducting much shorter flower visits, and visiting flowers and conspecific plants at high rates during foraging bouts. CONCLUSIONS The results did not show size‐matching among bees and flowers, as expected, but rather a minimum size threshold of efficient pollinators. The finding of such a threshold is a nonarbitrary approach to predicting pollination effectiveness of visitors to herkogamous flowers with poricidal anthers.

Section: Discussionmentioning

confidence: 99%

Minimum size threshold of visiting bees of a buzz‐pollinated plant species: consequences for pollination efficiency

Neto

Vieira

Schlindwein

2021

“…Pollen‐pollinated lineages of Melastomataceae, such as Microlicia and Cambessedessia , are particularly diverse and endemic to the campo rupestre (Bochorny et al, 2019; Versiane, 2019). In addition, many plant species from several families that display variable degrees of specialization to pollen bees have recently been described in this habitat (Mesquita‐Neto et al, 2018; Nogueira et al, 2018; Konzmann et al, 2020). Some of these lineages also show an increased diversification in the campos rupestres , particularly Chamaecrista and Microlicia (Vasconcelos et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

Evolutionary lability in floral ontogeny affects pollination biology in Trimezieae

Lovo

Alcantara

Vasconcelos

et al. 2021

There is little direct evidence linking floral development and pollination biology in plants. We characterize both aspects in plain and ornamented flowers of Trimezieae (Iridaceae) to investigate how changes in floral ontogeny may affect their interactions with pollinators through time. METHODS:We examined floral ontogeny in 11 species and documented pollination biology in five species displaying a wide range of floral morphologies. We coded and reconstructed ancestral states of flower types over the tribal phylogeny to estimate the frequency of transition between different floral types.RESULTS: All Trimezieae flowers are similar in early floral development, but ornamented flowers have additional ontogenetic steps compared with plain flowers, indicating heterochrony. Ornamented flowers have a hinge pollination mechanism (newly described here) and attract more pollinator guilds, while plain flowers offer less variety of resources for a shorter time. Although the ornamented condition is plesiomorphic in this clade, shifts to plain flowers have occurred frequently and abruptly during the past 5 million years, with some subsequent reversals.CONCLUSIONS: Heterochrony has resulted in labile morphological changes during flower evolution in Trimezieae. Counterintuitively, species with plain flowers, which are endemic to the campo rupestre, are derived within the tribe and show a higher specialization than the ornamented species, with the former being visited by pollen-collecting bees only.

“…latistipula (Rando et al, 2020), is an endemic shrub widely distributed from the northern to the southern regions of Brazil (Irwin and Barneby, 1982). The flower diameter is around 2 cm with five sepals and five petals with one larger and more curved called the cucullus (Nogueira et al, 2018; Delgado, 2019). The flower has an heterantherous androecium with three larger and seven short fertile stamens with poricidal anthers (Gottsberger and Silberbauer‐Gottsberger, 1988; Nogueira et al, 2018) and a unicarpelar gynoecium enveloping the ovules.…”

Section: Methodsmentioning

confidence: 99%

“…The flower diameter is around 2 cm with five sepals and five petals with one larger and more curved called the cucullus (Nogueira et al, 2018; Delgado, 2019). The flower has an heterantherous androecium with three larger and seven short fertile stamens with poricidal anthers (Gottsberger and Silberbauer‐Gottsberger, 1988; Nogueira et al, 2018) and a unicarpelar gynoecium enveloping the ovules. Chamaecrista latistipula is self‐compatible and produces flowers nearly all year, with a flowering peak typically between January and March (Valadão‐Mendes, 2018).…”

Section: Methodsmentioning

confidence: 99%

The role of intraspecific variation in bumblebee body size and behavior on buzz pollination of a tropical legume species

Barbosa,

Delgado de Lima,

Mota

et al. 2023

Self Cite

PremiseThe outcomes of generalized mutualisms rely on partner trait variation. In pollination mutualisms, although less explored, intraspecific variation in pollinator traits can be pivotal for successful pollination. We investigated the role of intraspecific body size and behavioral trait variations of bumblebee Bombus morio on the pollination of a buzz‐pollinated legume species, Chamaecrista latistipula.MethodsTo explore the impact of body size and behavior of B. morio on the pollination of C. latistipula, we observed visits to virgin flowers and quantified the pollen removal and deposition (pollination performance) and fruit and seed production (reproductive fitness). By analyzing video and sound recordings, we measured B. morio body size and behavior on each flower, including bee vibration descriptors.ResultsWe observed intraspecific behavioral differences among B. morio bumblebees associated with different body sizes. Larger bumblebees had half the handling time and vibrational pulses, less angular displacement within flowers, and larger relative peak amplitudes during vibrations than smaller bumblebees did. Regardless of their large variation in size and behavior, bumblebees were equally effective in removing pollen and pollinating flowers. The high female reproductive fitness was independent of bumblebee body size and behavior, likely due to the interaction between both. On the other hand, larger bumblebees visited flowers for shorter periods, probably promoting higher male reproductive fitness.ConclusionsThis study is the first to highlight the large intraspecific variation of bumblebee body size and behavior in buzz‐pollinated flowers in the field. Together, body size and behavior effects unexpectedly cancel each other, generating a high buzz pollination efficiency.