Colony strength and queen replacement in Melipona marginata (Apidae: Meliponini).

Physogastric queens of Melipona marginata were removed from their colonies in order to verify the acceptance of a new queen by workers. Colony strength was evaluated according to queen oviposition rate and comb diameters. Replacement was observed seven times. Its occurrence and speed related positively to colony strength, independently of queen's age. In weak colonies, queen replacement was observed only once, following colony population increase that occurred after introduction of combs from another colony. Worker oviposition after queen removal was observed three times: in a strong colony with virgin queens and males, and in two of the weak colonies. In the first two or three days of new queen oviposition, during which most of the eggs were eaten by the queen, worker oviposition preceded almost all provisioning and oviposition processes (POPs). After this period, worker oviposition decreased until it reached around 25% of the POPs. Daily oviposition rate of young queens decreased or was even interrupted by hatching of their first brood.

Colony strength and queen replacement in Melipona marginata (Apidae: Meliponini)

Rainhas fisogástricas de Melipona marginata foram removidas de suas colônias para verificar a aceitação de uma nova rainha pelas operárias. O estado da colônia foi avaliado de acordo com a taxa de oviposição da rainha e o diâmetro dos favos. Em sete dos casos, foi observada a substituição das rainhas, cuja ocorrência e velocidade estiveram relacionadas positivamente ao estado da colônia, independente da idade da rainha. Em colônias fracas, a substituição da rainha foi observada uma única vez, depois que a população da colônia aumentou, após a introdução de favos de cria de outra colônia. Após a remoção da rainha, a oviposição de operárias foi observada três vezes: em uma colônia forte, com rainhas virgens e machos, e em duas das colônias fracas. Nos primeiros dois ou três dias após o início da oviposição pela nova rainha, em quase todos os processos de aprovisionamento e postura (POPs), suas posturas eram precedidas pela oviposição de operárias (sendo a maior parte dos ovos comidos pela rainha), que diminuiu a partir daí até sua observação em cerca de 25% de todos os POPs. A taxa diária de oviposição de rainhas jovens decresceu ou foi interrompida com a eclosão de suas primeiras crias.

Responses to climatic factors by foragers of Plebeia pugnax Moure (in litt.) (Apidae, Meliponinae)

Flight activity of Plebeia pugnax Moure (in litt.) was studied in six colonies coming from Cunha, SP, from July to October 1994. Twice a week, from 8:00 a.m. to 6:00 p.m., for 5 minutes every half-hour, all the bees entering and leaving the hives were counted. Six hundred counts were made and the materials that foragers carried were recorded. Data were analysed in relation to temperature, relative humidity, light intensity and day time. Foragers' flight activity was relatively constant in a wide range of temperature, from 22 C to 34 C. The minimum temperature for the beginning of flight activity was 14 C. Effective flight activity (when foragers of all colonies were leaving the hives) occurred at 15 C. These bees also flew within a wide range of relative humidity, from 30 percent to 100 percent, decreasing slowly after 50 percent. Flight activity increased as light intensity rose and it has also increased as the hours passed by, reaching a peak around midday and decreasing gradually afterwards. Pollen was collected all day long, while resin collection was relatively constant and debris transportation was slightly higher after 10:00 h. From all known Plebeia species, this one flew on the lowest temperature ever registered for this genus