Márcia de Fátima Ribeiro

Working-class royalty: bees beat the caste system

The struggle among social classes or castes is well known in humans. Here, we show that caste inequality similarly affects societies of ants, bees and wasps, where castes are morphologically distinct and workers have greatly reduced reproductive potential compared with queens. In social insects, an individual normally has no control over its own fate, whether queen or worker, as this is socially determined during rearing. Here, for the first time, we quantify a strategy for overcoming social control. In the stingless bee Schwarziana quadripunctata, some individuals reared in worker cells avoid a worker fate by developing into fully functional dwarf queens.

Bees for development: Brazilian survey reveals how to optimize stingless beekeeping.

Stingless bees are an important asset to assure plant biodiversity in many natural ecosystems, and fulfill the growing agricultural demand for pollination. However, across developing countries stingless beekeeping remains an essentially informal activity, technical knowledge is scarce, and management practices lack standardization. Here we profited from the large diversity of stingless beekeepers found in Brazil to assess the impact of particular management practices on productivity and economic revenues from the commercialization of stingless bee products. Our study represents the first large-scale effort aiming at optimizing stingless beekeeping for honey/colony production based on quantitative data. Survey data from 251 beekeepers scattered across 20 Brazilian States revealed the influence of specific management practices and other confounding factors over productivity and income indicators. Specifically, our results highlight the importance of teaching beekeepers how to inspect and feed their colonies, how to multiply them and keep track of genetic lineages, how to harvest and preserve the honey, how to use vinegar traps to control infestation by parasitic flies, and how to add value by labeling honey containers. Furthermore, beekeeping experience and the network of known beekeepers were found to be key factors influencing productivity and income. Our work provides clear guidelines to optimize stingless beekeeping and help transform the activity into a powerful tool for sustainable development.

Exceptional High Queen Production in the Brazilian Stingless Bee Plebeia remota

In Plebeia remota only a few gynes (young virgin queens) are usually reared per year. However, in two laboratory colonies an extraordinarily high number of gynes emerged within a short period of time. These gynes were significantly smaller than those produced in low numbers by other colonies. Morphometric characters and behaviour of the gynes were recorded. Possible reasons for the phenomenon of exceptional high gyne production are discussed.

Impacto da precipitação pluviométrica sobre a atividade de vôo de Plebeia remota (Holmberg, 1903) (Apidae, Meliponini)

Hilario, S.D., Ribeiro, M.F. & Imperatriz-Fonseca, V.L. Rain effect on flight activity of Plebeia remota (Holmberg, 1903) (Apidae, Meliponini). Biota Neotrop. Sep/Dez 2007 vol. 7, no. 3 http://www.biotaneotropica. org.br/v7n3/pt/abstract?article+bn02307032007. ISSN 1676-0603. Through an automated system, foragers’ flight activity of four colonies of Plebeia remota was registered simultaneously from December 1998 to December 1999. The large amount of data obtained has allowed a quantitative and seasonal analysis of the rain impact on the bees’ flight activity. The colonies came from two different localities: Cunha, Atlantic Rainforest in Sao Paulo State and Prudentopolis, Araucaria Forest in Parana State. Percent numbers related to the flight activity for the moment that preceded the rain in one hour, as well as during and after the precipitation are presented. In all colonies, it was observed that the flight activity of P. remota has predominantly decreased before and during the precipitation. After it stopped raining, there was a predominance of increases, what indicates a compensation of flight activity in relation to the rainy period. In general, the greatest decrease of flight activity before rain, occurred in the autumn and the greatest increase of flight activity after rain, occurred in the spring. Alterations in this activity were observed with the variation of intensity, frequency and duration of precipitation. The external activity was little modified when the precipitation was up to 1.0 mm. However, when the rain intensity increased, the bees reduced strongly their flight activity. When the rain occurred only once per day, the decreases in the flight activity were greater, when compared to intermittent rain. Rains that lasted more than one hour caused larger decreases in the flight activity than precipitations of short duration. Flight activity was quite different when we compared days with rain and days without rain, as well as, flight activity was differently influenced in rainy days in the summer and in the winter. However, this behavior (response of flight activity to rain) did not allow to discriminate both populations.

Efeito do vento sobre a atividade de vôo de Plebeia remota (Holmberg, 1903) (Apidae, Meliponini)

Atraves de um sistema automatizado, a atividade do voo de forrageiras de quatro colonias de Plebeia remota foi registrada, simultaneamente, de dezembro de 1998 a dezembro de 1999. A grande quantidade de dados obtidos permitiu uma analise quantitativa e sazonal do efeito da velocidade e direcao do vento sobre a atividade de voo. Nas quatro estacoes, a menor atividade de voo de Plebeia remota ocorreu quando nao houve vento ou quando a velocidade media do vento esteve abaixo de 0,5 m/s. Os picos de atividade de voo ocorreram em velocidades de vento maiores e variaram segundo as estacoes e as colonias. No verao, os picos de atividade de voo estiveram entre 3,5 e 5,5 m/s de velocidade, no outono, na classe 4,0-4,5 m/s, e na primavera entre 4,5 e 6,0 m/s. Entretanto, no inverno, houve clara restricao da atividade externa sob velocidades de vento superiores a 5,5 m/s. As forrageiras de P. remota orientaram preferencialmente seus voos para certas direcoes de vento. Exceto no verao, as direcoes predominantes de voo foram similares entre as quatro colonias. Estas direcoes tambem coincidiram com a posicao dos recursos florais mais utilizados pelas colonias. Quando as forrageiras tinham que sair da colonia com vento contra, se registrou menor atividade de voo.

Can climate shape flight activity patterns of Plebeia remota (Hymenoptera, Apidae)?

A atividade do voo de forrageiras de quatro colonias de Plebeia remota (Holmberg, 1903) foi simultaneamente registrada, de dezembro de 1998 a dezembro de 1999 por meio de um sistema automatizado constituido de fotocelulas e de um Controlador Logico Programavel (CLP). As colonias eram provenientes de duas regioes diferentes: Cunha, SP e Prudentopolis, PR, Brasil. A atividade de voo de P. remota foi influenciada por fatores climaticos diferentes em cada estacao. No verao, as intensidades de correlacoes entre a atividade de voo e os fatores climaticos foram menores do que em outras estacoes. Durante o outono e o inverno, a radiacao solar foi o fator que mais influenciou a atividade de voo, enquanto que na primavera, esta atividade foi influenciada principalmente pela temperatura. Exceto no verao, os mesmos fatores climaticos influenciaram igualmente a atividade voo todas as colonias. Nao foi possivel distinguir diferencas nas atividades de voo segundo as origens geograficas das colonias. Informacao sobre as diferencas sazonais na atividade de voo de P. remota serao uteis para a predicao de cenarios de distribuicao geografica perante as mudancas climaticas.

Bourgeois Behavior and Freeloading in the Colonial Orb Web Spider Parawixia bistriata (Araneae, Araneidae)

Spiders of the tropical American colonial orb weaver Parawixia bistriata form a communal bivouac in daytime. At sunset, they leave the bivouac and construct individual, defended webs within a large, communally built scaffolding of permanent, thick silk lines between trees and bushes. Once spiders started building a web, they repelled other spiders walking on nearby scaffolding with a “bounce” behavior. In nearly all cases (93%), this resulted in the intruder leaving without a fight, akin to the “bourgeois strategy,” in which residents win and intruders retreat without escalated contests. However, a few spiders (6.5%) did not build a web due to lack of available space. Webless spiders were less likely to leave when bounced (only 42% left) and instead attempted to “freeload,” awaiting the capture of prey items in nearby webs. Our simple model shows that webless spiders should change their strategy from bourgeois to freeloading satellite as potential web sites become increasingly occupied.

EVALUATION OF FLORAL CHARACTERISTICS OF MELON HYBRIDS (Cucumis melo L.) IN POLLINATOR ATTRACTIVENESS

Floral morphology and biology are important characteristics for plant-pollinator interactions and may influence the behavior of these agents. This study aimed to determine which floral attributes of different melon hybrids influence this interaction and, consequently, their attractiveness in simultaneous crops. The study was conducted in the region of Petrolina, State of Pernambuco (PE)/Juazeiro, State of Bahia (BA) and Mossoro, State of Rio Grande do Norte (RN), in areas with the following melon hybrids: Yellow type, Piel de Sapo, Cantaloupe and Galia. For studies on floral morphology and biology, hermaphrodites and male flowers of each hybrid were analyzed for their size and nectar chamber size, pollen and nectar production, anthesis time and flower lifespan. Floral visitors were observed simultaneously in hybrids of three types of melon, from 5:00 a.m. to 6:00 p.m., in the two study sites. Evaluations of the corolla diameter and flower height indicated that the hermaphrodite flowers were larger in size than male flowers in all types of melon investigated, in both study sites. As for nectar chamber, male flowers are larger in width, but smaller in height, compared to hermaphrodite flowers. Regarding the volume of nectar, differences were found between floral types for the hybrids evaluated, in the two study sites; the hermaphrodite flowers produced 2-7 times more nectar than male flowers in all studied hybrids. Observations of visits of Apis mellifera to areas with simultaneous flowering of the three types of melon demonstrated differences in the frequency of visits between hybrids, floral type and foraged resource. Flowers of the hybrids Piel de Sapo and Cantaloupe exhibited larger corolla diameter, larger dimensions of the nectar chamber and greater supply of resources for foraging, which could explain the higher number of visits of bees to their flowers in the sites studied.

Foraging of Honeybees (Apis mellifera) on Flowers of Yellow Melon (Cucumis melo): Duration of Visits

Studying the pollinators’ foraging behaviour is quite important for pollination. Time spent by the pollinator in floral handling is one of the aspects of this behaviour. Honeybees ( Apis mellifera ) are the main responsible for the pollination of melon ( Cucumis melo ), but there are few studies on their foraging, mainly in the region of Petrolina, state of Pernambuco, and Juazeiro, state of Bahia, in Brazil. This study aimed to compare bee visitation to hermaphrodite (HF) and male (MF) flowers in a crop area where different number of hives were used. For each floral type, 10 flowers were observed, in each experiment (0, 1, 2 or 3 hives). The duration of bee visits (n = 10) was registered in three times of the day: 8 a.m., 11 a.m., and 4 p.m. In general, HF received significantly longer visits than MF, in all experiments, except when using one hive. In fact, significant correlations were found between the duration of visits and number of hives for HF, but not for MF. This is probably related to the attractiveness of HF and to the availability of floral resources. The studies of duration of pollinator’ visits are relevant in agriculture and should be considered when evaluating the efficiency of pollination in melon.

Morphometric differences and fluctuating asymmetry in Melipona subnitida Ducke 1910 (Hymenoptera: Apidae) in different types of housing

A geometric morphometrics approach was applied to evaluate differences in forewing patterns of the Jandaira bee (Melipona subnitida Ducke). For this, we studied the presence of fluctuating asymmetry (FA) in forewing shape and size of colonies kept in either rational hive boxes or natural tree trunks. We detected significant FA for wing size as well as wing shape independent of the type of housing (rational box or tree trunks), indicating the overall presence of stress during the development of the studied specimens. FA was also significant (p < 0.01) between rational boxes, possibly related to the use of various models of rational boxes used for keeping stingless bees. In addition, a Principal Component Analysis indicated morphometric variation between bee colonies kept in either rational hive boxes or in tree trunks, that may be related to the different origins of the bees: tree trunk colonies were relocated natural colonies while rational box colonies originated from multiplying other colonies. We conclude that adequate measures should be taken to reduce the amount of stress during bee handling by using standard models of rational boxes that cause the least disruption.