Melipona bicolor

The entrance to a M. bicolor nest

As with all Melipona species, M. bicolor build well-protected nests inside pre-existing cavities. Their nests typically have a single entrance, which is long and narrow and penetrates deep into the nest. The nest cavity consists of two parts: a well-developed involucrum, surrounding a nest consisting of several layers of horizontally arranged combs, and outside the involucrum, which house a number of food pots. A significant amount of food can be stored in these pollen and honey pots. The pots can be large, getting as big as 4 cm in diameter. The pots sizes do vary with the state of the colony however.[6]

Inside the nest, the brood combs are constructed sequentially; these combs are removed as soon as the brood emerges from the cells. M. bicolor engage in a process called Provision and Oviposition Process, or POP. This process encapsulates nest construction, mass provisioning, egg laying, and cell closure.[6]

Distribution of M. bicolor

Common amongst eusocial bees, females make up the worker and queen populations. The workers are responsible for tasks including nest defense, brood care, colony maintenance, and provisioning. The queen influences the physiology and behavior of the workers, which are infertile females. The only role the males plays is in reproduction; his function is to mate with the queen and supply the necessary genetic complementation for reproduction.[8]

In Melipona bees, there exists a precise system of chemical communication in order to maintain the organization of the various activities constantly being performed by individuals. This chemical communication is based on the production of pheromones, which are substances with intra-specific action. Numerous exocrine glands across the bee body produce these pheromones.[8]

Melipona bicolor also communicates through sound, particularly between foraging parties.[9] As a member of the foraging party happens upon an area of high-quality food, it increases the length and frequency of emitted sounds in order to attract other members of the party towards the food source. The recruitment sounds also increase in duration as the distance to the food source increases.[9] Sound production offers a way for members of a foraging party to communicate, even when out of site of each other, while maximizing the group's ability to acquire food.

M. bicolor exhibits a rare case of mating amongst stingless bees. It is facultatively polygynous, meaning one or more physogastric queens can be found in the same colony.[7] These queens interact with each other within the colony. They may rest together in a common court, and exhibit an interesting behavior when active. During the patrolling phase, a queen attempts to touch the abdomen of another queen. The other queen turns her abdomen away, and what follows is the two queens circling one another, trying to touch the other's abdomen. This circling behavior typically ends with the queens standing side by side with their heads toward the cell. In a polygnous colony, the queens are almost always in motion.[6]

Virgin queens are also tolerated in M. bicolor. They have not only been observed walking around the nest, but also standing close to one of the egg-laying queens during POP. This suggests a more egalitarian dominance relationship amongst the species.[7]

There is an advantage to polygyny during situations where a colony must rapidly produce brood cells, such as during periods of food scarcity. Under these conditions, the queens are limited in their egg production and rely on the larval food from the brood cells. Polygyny allows for a greater production rate for the colony. It is speculated that alternating periods of significant flowering of food plants and food shortages are the ecological condition that favors polygyny.[6]

M. bicolor are mostly active outside of their nest in the morning, when humidity is high and light intensity and temperature are moderate. They forage for food in the first few hours of the morning, a trend similar to that of the species Melipona quadrifasciata. However, they tend to collect mud and resin mostly in twilight. Further, they typically exit the nest with debris during the first hours of the morning, and again at twilight. Temperature is the most important environmental factor concerning the external activity of Melipona bees. M. bicolor also exhibit greater flight activity when the relative humidity is high. This may because of their habitats of high humidity, and being accustomed to fog. The strength of the colony also affects the times when the workers are most active.[3]

In some cases, workers of many species of stingless bees, including M. bicolor are able to lay eggs and produce male offspring. M. bicolor worker bees can lay two morphologically distinct type of eggs: some have a patterned chorion, and others are unpatterned. If the worker lays an unpatterened egg, she typically leaves the cell, which gives the queen the ability to eat this egg. However, sometimes workers lay patterned eggs after the brood cell is filled with food, and quickly close the cell right after. The worker could lay these eggs either before the queen has oviposited, or soon after, which would result in two eggs in the same brood cell. If the queen doesn't eat the eggs, the worker typically succeeds in producing male offspring.[7]

The predators for M. bicolor include many of the same predators for other Meliponini species, such as birds, lizards, spiders, and mammals such as tayras and kinkajous.[10] Since they are a species of stingless bee, they do not have a great defense against predators.

M. bicolor is polylectic, meaning the species gathers pollen from many different species of flowering plants. However, they prefer pollen from Myrtaceae, Melastomataceae, and Solanaceae. While sex determination in Melipona is genetic, food plays a vital role as it can maximize the queens’ production. Excess pollen is harvested during the winter, which allows the colony to produce more larval food.[11]

M. bicolor produces a honey similar to most Melipona bees species, which is distinct from Apis honey, and is thus frequently reared by meliponine beekeepers. But this is not as common as with the species from the Amazon region, where M. bicolor bees are not found. That region has great potential for production of stingless bee honey; with the recent initiatives towards sustainable development of the Amazon rain forest, the production of honey is bound to increase.[12]

Since M. bicolor is a very tame species of stingless bee, they are great for beekeeping. Each colony can produce about 2 liters of a tasteful honey for season, or even more in warm regions.