Sergio Dias Hilário

Foraging Activity in Plebeia remota, a Stingless Bees Species, Is Influenced by the Reproductive State of a Colony

Colonies of the Brazilian stingless bee Plebeia remota show a reproductive diapause in autumn and winter. Therefore, they present two distinct reproductive states, during which colony needs are putatively different. Consequently, foraging should be adapted to the different needs. We recorded the foraging activity of two colonies for 30 days in both phases. Indeed, it presented different patterns during the two phases. In the reproductive diapause, the resource predominantly collected by the foragers was nectar. The majority of the bees were nectar foragers, and the peak of collecting activity occurred around noon. Instead, in the reproductive phase, the predominantly collected resource was pollen, and the peak of activity occurred around 10:00 am. Although the majority of the foragers were not specialized in this phase, there were a larger number of pollen foragers compared to the phase of reproductive diapause. The temperature and relative humidity also influenced the foraging activity.

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.

A scientific note on the founding and the early growth of new nests of the stingless bee Plebeia remota

Department Biodiversidade e Ecologia, Pontifícia Universidade Católica do Rio Grande do Sul, Av. Ipiranga, 6681, 90619900, Porto Alegre, RS, Brazil Department Ecologia, IB, Universidade de São Paulo, R. do Matão Trav. 14, 321, 05508-090, São Paulo, São Paulo, Brazil Department Entomologia e Acarologia, ESALQ, Universidade de São Paulo, Av. Pádua Dias, 11, 13418-900, Piracicaba, São Paulo, Brazil Department Ciências Animais, Universidade Federal do Semi-Árido, Av. Francisco Mota, 572, 59625-900, Mossoró, Rio Grande do Norte, Brazil

Thermal evidence of the invasion of a stingless bee nest by a mammal

Melipona bicolor, an inhabitant of the Atlantic Rainforest, nidifies in hollows of live or dead trees. In order to study thermoregulation of a nest of this species, a temperature data logger was installed inside a hollow tree. After this, an intruder dug a hole, invaded the nest, and probably consumed its honey, pollen and bees, having remained there during three days. Thermal evidence and its behavior allowed the delimitation of a small number of suspects, which we analyzed here. The intruder was a small mammal, predominantly nocturnal, that takes shelter in burrows, probably the yellow armadillo (Euphractus sexcinctus). Other evidence, if collected immediately after invasion, could precisely indicate precisely the species.