Reisla Oliveira

Searching for a Manageable Pollinator for Acerola Orchards: The Solitary Oil-Collecting Bee Centris analis (Hymenoptera: Apidae: Centridini)

ABSTRACT Acerola (Malpighia emarginata DC; Malpighiaceae) is an important fruit crop in Brazil. Among its pollinators, Centris (Heterocentris) analis (F.) stands out due to its abundance at flowers and prompt acceptance of trap-nests. For the first time, we propose the commercial use of Centris bees as orchard pollinators. To develop protocols for rearing and management of these bees, we analyzed trap-nest acceptance, brood-cell construction, and larval diet in Acerola orchards. Although Centris species, in general, use numerous pollen host plants, females of C. analis showed remarkable flower fidelity to Acerola for pollen supply when nesting in the orchard. Such fidelity was previously expected only for floral oil collection. The ease of acceptance of trap-nests by females of C. analis, their prolonged yearly activity period, multivoltine life history, and high pollinator efficiency characterize C. analis as an excellent potentially manageable pollinator in Acerola orchards.

Do consecutive flower visits within a crown diminish fruit set in mass-flowering Hancornia speciosa (Apocynaceae)?

Hancornia speciosa is a self-incompatible, mass-flowering, sphingophilous fruit crop (mangaba) of northeast and central Brazil. The flowers have a precise pollination apparatus, which optimizes pollen transfer between flower and pollinator. While the pollination mechanism avoids self-pollination, mass-flowering promotes geitonogamy. During a flower visit, almost half of the exogenous pollen grains adhering to the proboscis are deposited on the stigma surface. A pollination experiment with a nylon thread simulating six consecutive flower visits within a crown revealed that only the first two flowers visited (positions 1 and 2) are highly likely to set fruit. Super-production of flowers, and consequently obligate low fruit set, seem to be part of the reproductive strategy of the obligate outcrossing plant, Hancornia speciosa.

Two common species dominate the species-rich Euglossine bee fauna of an Atlantic Rainforest remnant in Pernambuco, Brazil

Nowadays, the northern part of the Atlantic Rainforest of Brazil is largely destroyed and forest remnants rarely exceed 100 ha. In a 118 ha forest fragment within a state nature reserve of Pernambuco (Reserva Ecológica Gurjaú), we surveyed the orchid bee fauna (Apidae, Euglossini) using eight different scent baits to attract males. Once a month during one year, the bees were actively collected with entomological nets, from November 2002 to October 2003 by two collectors. We collected 2,908 orchid bee males belonging to 23 species, one of the highest richness values of the Northern Atlantic Rainforest. Bees of only two species, Euglossa carolina (50%) and Eulaema nigrita (25%), which occurred throughout the year, accounted for three quarter of the collected individuals. Both species are typical for open or disturbed areas. Rainforest remnants like those of Gurjaú within the predominant sugar cane monocultures in the coastal plains of the northern Atlantic Rainforest play an important role in orchid bee conservation and maintenance of biodiversity.

Plasticity in Male Territoriality of a Solitary Bee Under Different Environmental Conditions

The use of alternative male mating tactics has evolved in most insect orders. The maintenance of these tactics is often associated with discrepancy in morphological attributes of males, especially size (Brockmann 2008). In addition, variations in environmental conditions, such as heterogeneity of habitat and abiotic features (Łukasik et al. 2006; Larison 2007), and demographic conditions, such as population density (Borgia 1980; Radwan 1993; Tomkins and Brown 2004), influence the frequencies of different tactics and their average fitness benefits. Among solitary bees, the simultaneous occurrence of variation in male body size and plasticity in mate searching behaviour is relatively well documented. Larger males adopt tactics that involve struggles for direct access to receptive females in nests or for the guard of attractive floral resources, while the smaller males alternatively search for mates through nonaggressive tactics (e.g. Alcock 1996, 1997; Oliveira and Schlindwein 2010; Oliveira et al. 2012). How environmental or social conditions influence behavioural plasticity, however, has been poorly examined. J Insect Behav (2013) 26:690–694 DOI 10.1007/s10905-013-9385-5

Floral colour change in Byrsonima variabilis (Malpighiaceae) as a visual cue for pollen but not oil foraging by oil-collecting bees

Pollinators search for multiple flora resources throughout their life cycle. Most studies, however, only assess how bees discriminate floral cues in the context of nectar foraging. In the present study, we sought to elucidate whether oil-collecting bees discriminate flowers of Byrsonima variabilis (Malpighiaceae) with petals of different colours when foraging for pollen or oil. As the colour of the standard petal changes during anthesis, we characterised the spectral reflectance patterns of flowers throughout anthesis and modelled chromatic perceptual space to determine how these colour patterns are perceived by bees. Through the quantification of flower pollen in the different phases, we found that the colour of the standard petal is an honest cue of the presence of pollen. Centridine bees preferentially visited flowers with a yellow (bee’s green) colour when searching for pollen, but indiscriminately visited flowers with different petal colours when searching for floral oil. We suggest that standard petals, in the species studied and others of the genus, like nectar guides, act as pollen guides, which oil-collecting females use to detect pollen-rich flowers. Moreover, they use different floral clues during foraging for different resources in the same host plant.

Nocturnal Bee Pollinators Are Attracted to Guarana Flowers by Their Scents

Floral scent is an important component of the trait repertoire of flowering plants, which is used to attract and manipulate pollinators. Despite advances during the last decades about the chemicals released by flowers, there is still a large gap in our understanding of chemical communication between flowering plants and their pollinators. We analyzed floral scents of guarana (Paullinia cupana, Sapindaceae), an economically important plant of the Amazon, using chemical analytical approaches, and determined the attractiveness of the scent to its nocturnal bee pollinators using behavioral assays in the field. Pollen loads of attracted bees were also analyzed. Inflorescences of guarana emit strong scents, both during day and at night, with some semi-quantitative differences between day- and night-time scents. Synthetic scent mixtures containing some of the identified floral scent components, including the most abundant ones, i.e., linalool and (E)-β-ocimene, successfully attracted the nocturnal Megalopta bee pollinators. Pollen analyses revealed that many of the attracted bees had pollen grains from previous visits to guarana flowers on their bodies. Overall, our data show that guarana flowers attract nocturnal bee visitors by their strong scents and suggest that the chemical communication between this plant and its pollinators is a key component in crop production of this economically important plant species.

Perch Usage by Hummingbirds in a Fragment of Atlantic Forest in Brazil

ABSTRACT We investigated if there are aspects of perches that are more attractive for hummingbirds, such as perch height, diameter, and distance from a food patch. The study was conducted in a fragment of Atlantic Forest of the Itacolomi State Park, in Minas Gerais, Brazil, with artificial feeders simulating a rich food patch. Characteristics of perches used by the recorded hummingbirds, such as height, diameter and distance from the food patch, were measured. From the six hummingbird species recorded visiting the artificial feeders, two preferentially used perches with certain characteristics: Thalurania glaucopis used more perches at a height of 0.51–1.0 m (intermediary high), and Leucochloris albicollis used more perches located 1.1–2.0 m distance from the food patch. T. glaucopis was territorial and defended the food patch; L. albicollis was subordinate and did not defend the food patch. The other species seemed to use perches randomly. Our results suggest that hummingbirds used perches according to t...