Three new species of Tetrapedia Klug, 1810 (Hymenoptera: Apidae) and a key to the species recorded in Brazil.

Three new species of Tetrapedia Klug, 1810 (Apidae) from Central Brazil are described and illustrated: Tetrapedia marina sp. nov., Tetrapedia tereza sp. nov., and Tetrapedia bruno sp. nov. Additionally, a key to the 22 species of Tetrapedia known from Brazil is provided. The lectotype of T. clypeata Friese is designated to establish the species name.

Contrasting patterns of foraging behavior in neotropical stingless bees using pollen and honey metabarcoding.

Stingless bees are major flower visitors in the tropics, but their foraging preferences and behavior are still poorly understood. Studying stingless bee interactions with angiosperms is methodologically challenging due to the high tropical plant diversity and inaccessibility of upper canopy flowers in forested habitats. Pollen DNA metabarcoding offers an opportunity of assessing floral visitation efficiently and was applied here to understand stingless bee floral resources spectra and foraging behavior. We analyzed pollen and honey from nests of three distantly related stingless bee species, with different body size and social behavior: Melipona rufiventris, Scaptotrigona postica and Tetragonisca angustula. Simultaneously, we evaluate the local floristic components through seventeen rapid botanical surveys conducted at different distances from the nests. We discovered a broad set of explored floral sources, with 46.3 plant species per bee species in honey samples and 53.67 in pollen samples. Plant families Myrtaceae, Asteraceae, Euphorbiaceae, Melastomataceae and Malpighiaceae dominated the records, indicating stingless bee preferences for abundant resources that flowers of these families provide in the region. Results also reinforce the preference of stingless bees for forest trees, even if only available at long distances. Our high-resolution results encourage future bee-plant studies using pollen and honey metabarcoding in hyper-diverse tropical environments.

Evolutionary lability in floral ontogeny affects pollination biology in Trimezieae.

PREMISE: 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.

Biogeography and early diversification of Tapinotaspidini oil-bees support presence of Paleocene savannas in South America.

Worldwide distributed tropical savannas were established only in the Miocene, with climatic cooling and rise of C4 grasses. However, there is evidence for an earlier presence of savanna-like vegetation in southern parts of South America. Here we investigated the biogeographic history of a clade of solitary bees which have endemic groups in areas covered by savannas and other types of open vegetation as well as forested areas. We hypothesized that these bees originated in savanna-like biomes and that shifts to forested areas and floral host shifts increased species diversification along their evolutionary history. We reconstructed a comprehensive phylogeny for Tapinotaspidini bees based majorly on original DNA sequences. We then used macroevolutionary tools to estimate ancestral range area and reconstructed ancestral habitat (open versus forested) and host plant association to analyze the effects of shifts in vegetation type and flower hosts on their diversification. Tapinotaspidini bees originated in the Paleocene and in a savanna-type, Cerrado-like, which is reinforced by reconstruction of open vegetation as the most probable ancestral area, thus bringing additional evidence to a much earlier origin of this vegetation type in South America. Shifts to forested areas occurred at least three times in a period of 30 Ma and were responsible for slight increases in diversification rates. Malpighiaceae is the ancestral floral host; host broadening occurred only in the Miocene and at least in three occasions. Host shifts, i.e. from Malpighiaceae to other oil families, occurred in the Eocene and Miocene. Both host broadening and host shifts did not significantly alter diversification rates, however exploitation of other oil sources were important in occupying new habitats. The link between biomes and host plant shifts and changes in diversification rate brings us additional insights into the evolution of bees and associated flora in South America.

Notes on oil sources for the bee genus Caenonomada(Hymenoptera, Apidae, Tapinotaspidini) / Notas sobre fontes de óleos florais do gênero Caenonomada (Hymenoptera, Apidae, Tapinotaspidini)

It is reported for the first time oil collecting by bees of the genus Caenonomada on flowers of Plantaginaceae. Females of Caenonomada unicalcarata were observed collecting oil on flowers of Angelonia cornigera, and males and females of Caenonomada bruneri and C. aff. unicalcarata were observed on flowers of Angelonia and Monopera (Plantaginaceae). The record of Caenonomada on Plantaginaceae suggests the use of trichomatic oil glands as a primitive condition in the tribe Tapinotaspidini.

Pela primeira vez é reportado a coleta de óleo por Caenonomada em Plantaginaceae. Fêmeas de Caenonomada unicalcarata foram observadas coletando óleo em flores de Angelonia cornigera, e fêmeas e machos de Caenonomada bruneri e Caenonomada aff. unicalcarata em flores de Angelonia e Monopera (Plantaginaceae). O registro de Caenonomada em Plantaginaceae sugere uma condição mais primitiva para o uso de glândulas tricomáticas de óleo na tribo Tapinotaspidini.