Apis mellifera scutellata

A single East African lowland bee sting is no more venomous than a single European bee sting, though East African lowland honey bees respond more quickly when disturbed than do European honey bees. They send out three to four times as many workers in response to a threat. They will also pursue an intruder for a greater distance from the hive. Although people have died as a result of 100–300 stings, it has been estimated that the average lethal dose for an adult is 500–1,100 bee stings. In terms of industrial honey production, in its natural habitat and the neo-tropics, the African bee produces far more honey than its European counterparts. It is unclear if this is due to a superior nectar gathering ability, lack of adaptability in the European honey bees for tropical environment, or both. Producing more swarms and absconding (abandoning its nest) are also examples of adaptive traits for tropical environment. In times of prolonged dearth they would migrate to a better food source area, a strategy applied also by Apis dorsata, rather than waiting for a better season (European and Oriental bees). The lack of significant energy needs for thermoregulation of the brood nest in the tropics corresponds to a very rapid build-up of even the smallest african colonies, the higher in numbers and smaller in size swarming strategy makes perfect sense. ==Appearance==

The appearance of the East African lowland honey bee is very similar to the European bee. However, the East African lowland honey bee is slightly smaller. Its upper body is covered in fuzz, and its abdomen is striped with black. ==Habitat==

The native habitat of Apis mellifera scutellata includes the southern and eastern regions of Africa. The species was first imported across the Atlantic Ocean to Brazil before it spread to Central America, South America, and southern areas of the United States. The Africanized honey bee thrives in tropical areas and is not well adapted for cold areas that receive heavy rainfall. ==Foraging economics and bee habits==

Nectar content and harvesting Honey bees are challenged to balance energy consumption and replenishment in their pursuit of nectar. High thoracic temperatures required for foraging flight pose a thermoregulatory imbalance that honey bees attempt to alleviate by targeting particular viscosities and temperatures of nectar resources. In lower environmental temperatures where energy loss is more pronounced, it has been shown through Apis mellifera scutellata that honey bees seek warmer, less-concentrated and less-viscous nectar, an energetically favorable behavior. The relative advantage is so great that it is still more energetically favorable for a honey bee to collect warm nectar, even at low sugar concentrations (10%). Honey bees are energetically rewarded by harvesting nectar that is warmer than ambient temperatures because they make up for energy loss during foraging and obtain more nectar more easily. The bumblebee’s ability to differentiate flower warmth by color and target warmer flowers is one noted precedent for nectar temperature selection in honey bees. Significance of foraging It has been noted that A. mellifera scutellata have higher rates of colony growth, reproduction, and swarming than European honey bees (A. mellifera ligustica and A. mellifera mellifera), a fitness advantage that allowed them to become an invasive species. A study by Fewell and Bertram was conducted to understand the source of these differences. The differences in fitness strategy were thought to be accounted for by the fact that African worker bees have a greater preference for pollen over nectar, which is a direct food resource for the emerging brood. Behavioral differences The main difference found between African and European honey bees were a few behavioral traits in the worker bees that were all related to the workers’ food preference. at specific quantitative trait loci. African bees are "precocious foragers"; A. m. scutellata bees begin foraging for pollen significantly earlier than their European counterparts A. m. ligustica, and this is thought to be related to the fact that African colonies have a younger, skewed age distribution by comparison. However, this is not a direct cause for the different subsistence strategies between the two subspecies. African bees are more vulnerable to less predictable times of scarcity or attack and it is therefore to their advantage to produce as many young as possible, increasing the likelihood that some or even many will survive. Such circumstances would have favored the worker bees who preferred harvesting nectar in European colonies and pollen in African colonies, providing an explanation for how a divergence in worker behavior and age distribution evolved in A. m. scutellata and A. m. ligustica. Fewell and Bertram’s study is significant in that it provides a plausible method through which the fitness characteristics of the subspecies could have evolved from a small number of behavioral differences in worker bees. ==Parasitization==

The Apis mellifera capensis (the Cape honey bee) has monopolized social parasitism of Apis mellifera scutellata hosts in the southern region of South Africa. Specifically, A. mellifera capensis workers produce crucial pheromones, achieve reproductive status, and overthrow an A. m. scutellata queen. Social parasitism in the social insects can involve various forms of exploitation that disrupt the normal division of labor in the colony. The recent development of technology to study the genetic makeup of colonies has revealed that the offspring contribution of reproducing worker parasites merits closer attention. In 1990, 400 A. m. capensis colonies were moved into the vicinity of the A. m. scutellata subspecies. Ten years later, a single clonal…worker lineage was found to be devastating A. m. scutellata colonies in northern South Africa. The monopoly of this single lineage shows that they were able to subvert queen regulation of reproduction and worker recognition mechanisms. Dietemann et al. was able to prove that A. m. capensis worker parasites were able to produce mandibular pheromones that mimic that of A. m. scutellata queens while in their presence. The resulting breakdown of the division of labor leads to desertion or death of the parasitized colony. Method and results Although many pheromones contribute to reproduction, pheromones made in the mandibular gland of queens have been closely linked to reproduction, and they are produced by workers that reproduce. The pheromones prevent others from attacking them, induce workers to recognize them as queen, and give them access to higher quality foods. They also stop other workers from turning reproductive. A. m. capensis worker parasites create female clones and usurp the A. m. scutellata queen. The worker parasites and their increasing number of clones become the sole reproductive individuals in the colony. The destruction of the division of labor leads to reduced resources that eventually force the colony to leave or perish. Evolution of pheromone production The single lineage of parasitizing A. m. capensis may have gained evolutionary advantage because, compared to other related species, it is not susceptible to the host queen’s pheromonal reproductive suppression of workers. The non-invasive varieties of A. m. capensis produce less mandibular secretions than the invasive strain. In addition, they produce secretions that are not as similar to that of A. m. scutellata queens as that of the invasive strain. The single lineage was selected for its greater resistance to and greater ability to mimic and overwhelm the pheromonal regulation by host queens. Especially in the case of closely related species and subspecies, the biology and organization of potential host species are similar to that of potential parasitizing species, making them easier to infiltrate. On the other hand, potential parasites face the challenge of being discovered by the host queen, usually the sole reproductive individual in the colony. The existence of A. m. capensis worker parasites is an example of an alternative evolutionary strategy that allows them to increase their "direct fitness in foreign colonies rather than inclusive fitness in their natal nests." The invasive lineage of A. m. capensis succeeded either because of an inability to recognize the host A. m. scutellata queen signal correctly or a resistance to the signal. Ultimately this is an interesting example of a preexisting weakness towards social parasitism by A. m. capensis in A. m. scutellata. ==Evolution==

The underlying hypothesis for the aggressive behavior of East African lowland honey bees is based on the idea that this race of bees evolved in an arid environment, where the bees' food was scarce. Under this situation, selection favored more aggressive colonies, which protected their food source and hive from predators and robbed bees from other colonies. This behavior allowed more aggressive colonies to survive where the less aggressive colonies eventually were selected against by natural selection. ==See also==