Black dwarf honey bee
Apis andreniformis, or the black dwarf honey bee, is a relatively rare species of honey bee whose native habitat is the tropical and subtropical regions of Southeast Asia.
A. andreniformis was the fifth honey bee species to be described of the seven known species of Apis. Until recently, however, the actual identity of the species was poorly understood. It was not recognized as its own species, but was instead considered to be a part of the species Apis florea. Recent studies have highlighted notable differences between the bees and have thus separated them into distinct species.
A. andreniformis can be distinguished from other Apis species by noting their dark black coloration, making them the darkest of their genus. Originally, it was thought that A. andreniformis was a part of the species A. florea, but recent studies have noted morphological differences that have separated the two. Some distinctions include: structural differences in the endophalli, a larger wing venation in A. andreniformis, and a longer basitarsal extension in A. florea. Additionally, there are slight color variations between the two species. In typical A. andreniformis, its first two abdominal segments are black and its scutellum is reddish brown, while in A. florea, the first two abdominal segments are reddish brown and their scutellum is black, though there is some variation that makes color unreliable. Another distinguishing factor is the presence of black hairs on the tibia of A. andreniformis, which are white in A. florea.
Other differentiating characteristics include cubital indexes and proboscis length. A. andreniformis has an index of 6.37, while A. florea has one of 2.86. The proboscis of A. andreniformis has a length of 2.80 mm, while that of A. florea is 3.27 mm.
Within the species, queens can typically be distinguished from workers and drones by their near entire black coloration.
A. andreniformis is found in southeast Asia, specifically southern China, India, Burma, Laos, Vietnam, Thailand, Malaysia, Indonesia, and the Philippines. They are commonly found in sympatric distribution with A. florea. Although they are sympatrically distributed, it is uncommon to have nests of different species in the same tree or bush. Each species tends to be found closer to nests of its own species rather than its sister species. A. andreniformis is considered a lowland species because they are most commonly found in elevations below 1,000 m, although they may migrate to higher elevations during rainy seasons. Similarly, they are found in tropical and subtropical regions, while cavity-dwelling honey bees can be found in colder climates.
Different types of honey bees may use different types of dances to communicate with their hive. Most cavity-dwelling species use vertical waggle dances, while open-air nesters do not perform a gravity oriented waggle dance and instead perform a horizontal dance. The shape of the nest creates a platform above the nest that can be used as a stage for communication. The dance is a straight run pointing directly to the source of pollen or nectar that the forager has visited. Since the dance of other Apis species is vertical, it is not actually directed towards the food source, as it is in A. andreniformis.
Queens of A. andreniformis commonly engage in polyandry, where the queen will mate with multiple drones, usually about 10-20 times in total. Due to the large amount of mating, queens must expel any excess semen. Excessive mating puts females at increased risk to predation since it must occur during flight and outside the nest in the open air. She is also at risk for sexually transmitted diseases and injury from unexpected inclement weather. Some Apis males put a "mating sign" in the sting chamber of the queen that she is unable to remove. This prevents her from avoiding unwanted copulation with other drones. In contrast, this sign is not found in A. andreniformis, suggesting that queens have control over the number of mates they copulate with. Although there is a lot of risk to the queen, benefits may arise from the increased genetic diversity within the colony. Genetic diversity can lead to increased resistance to disease and illnesses.
