Scaptotrigona postica

Distribution

"S. postica" is found in the southern, central-western and northern regions of Brazil as the dense tropical rain forests provide ideal nesting locations. These bees maintain an average nest temperature of 32˚C, which is a few degrees above the average temperature of the Brazilian rain forests. With the addition of an insulating layer, the nest temperature can be easily maintained in this environment. "S. postica" have also been found in Peru but are significantly more common in Brazil.

Behavior

"S. postica" communicate to recognize nest-mates, identify the caste of any individual bee, locate food, and signal danger.The specific scents that attract drones to virgin queens prior to reproduction are 2-alcohols and 2-ketones. The 2-alcohols attract the males from long distances to the virgin queen, while 2-ketones induce copulatory attempts when the male is closer to the queen. These compounds have been found in the queens’ mandibular glands but are absent in those of the worker female "S. postica"

Reproduction

The specific scents that attract drones to virgin queens prior to reproduction are 2-alcohols and 2-ketones. The 2-alcohols attract the males from long distances to the virgin queen, while 2-ketones induce copulatory attempts when the male is closer to the queen. These compounds have been found in the queens’ mandibular glands but are absent in those of the worker female "S. postica"Queen bees are the colony reproductive heads. While there is only one queen per colony, workers produce males without mating. However, these hemizygous individuals will always be male. So, eggs can be laid by the unfertilized females or the fertilized females.

Food

In a study carried out in São Paulo, the main plant used by "S. postica" for both pollen and nectar was "Eucalyptus", a popular introduced tree in the area. Pollen grains containing protein from "Eucalyptus" could be found in the midguts of all members of the "S. postica" colony. These pollen grains are digested fully between 6 and 28 hours. The protein requirements for "S. postica" differ based on the role and age of the individual. Worker and queen bees have similar protein requirements. Larvae ingest a significantly higher amount of pollen, as the protein is essential during development. Drones require a high-protein, pollen diet in order to function properly. However, older drones have more responsibilities outside of the nest, thus they prefer nectar and honey to pollen. Their change in diet from a pollen-base to a nectar/honey-base is most likely an adaptation to their new roles, which require more flight activity and increased energy expenditure.

Predators

A main predator of "S. postica" is the sphecid wasp "Trachypus boharti". This wasp is also found in Brazil and exclusively preys on the males of "S. postica". The wasps hover near the entrance of the nest in groups averaging to 11 wasps in a group. These wasps capture up to 50 "S. postica" drones per day close to the entrance of the nest. It captures the individual and preserves it using a secretion from the wasp's post-pharyngeal glands. Fortunately for "S. postica", these predation attempts are generally unsuccessful as "T. boharti" only captures a male drone 7% of the time. Most of these failed attempts are due to conflict with other wasps. Furthermore, if a wasp captures a different individual of the colony, it immediately releases the individual with no harm done. While the "T. boharti" only predate the drones of "S. postica", they do not seek specifically those individuals, rather they are attracted to all "S. postica" and select their prey after capture.

The defense for "S. postica" nest is to have on average 8 workers guarding the front of the nest at all times. Sometimes the guards are sitting nearby and, at others, they fly back and forth across the entrance. These bees are part of the tribe Meliponini, which do not have stingers. However, S. postica guard bees have been observed to bite nest intruders as they alert the other colony members through pheromone signaling. These alarm pheromones contain 2-heptonal and other ketones as active substances. "S. postica" workers also will display a specific leg posture when other members of the nest or other organisms attempt to take cerumen from the cubiculae.