[6] Additionally, it has escaped captivity after being introduced as a greenhouse pollinator in countries where it is not native, so this bee is now considered an invasive species in many of these places, including Japan, Chile, Argentina, and Tasmania.

This fate is determined for larvae that receive more food, have longer instar stages, and higher levels of juvenile hormone biosynthesis.

[12] This first phase can last a variable amount of time in B. terrestris, after which a switch point is reached, and the queen begins to lay some unfertilized eggs, which develop into males.

The colony persists until fall in temperate zones and then workers begin to lay unfertilized eggs that if they mature will become males.

Mating with multiple males might provide benefits of genetic variability among the brood, but it does not happen in this or any but the most highly derived social bees.

[14] This is due to haplodiploidy in Hymenopteran social insects in which males (drones) are haploid and females (workers and queens) are diploid.

Workers born early in the first brood are more likely to become egg layers due to their increased size and age, which allows more time for ovarian development.

Lastly, due to intense competition for the opportunity to reproduce, older workers often harass the queen by attacking her and buzzing loudly.

This suggests that the presence of a queen is enough to prevent workers from laying eggs, which helps her maintain genetic control over her colony's brood.

[16][19] Workers have low levels of JH and ovarian development during the early stages of the colony cycle and also after the competition point.

In B. terrestris, successful foragers will return to the nest and run around frantically and without a measurable pattern, unlike the ritualized dance of the honeybee.

Although the mechanism by which this recruitment strategy functions is unclear, it is hypothesized that running around likely spreads a pheromone that encourages other bees to exit and forage by indicating the location and odor of food nearby.

Conversely, in colonies with ample food reserves bees will be less responsive to these pheromones likely to save time and energy from unnecessary foraging.

However, the return often takes several days, indicating B. terrestris might be utilizing familiar foliage and natural landmarks to find the nest.

If males also contribute to pollination, this might increase previously predicted pollen flow ranges based on worker flight behavior.

[26] In addition to identifying specific colors for foraging purposes, it has also been shown that young worker bees have to learn complex motor skills in order to efficiently collect nectar and pollen from flowers.

[27] Even within a species, different populations have varying levels of innate blue preference and exhibit intraspecific variation in learning rate during association tasks.

[29] While bees are highly adept at discrimination tasks, they are still limited by the magnitude of difference needed in hue to properly carry out these tests.

B. terrestris individuals have a faster learning curve for visiting unfamiliar, yet rewarding flowers, when they can see a conspecific foraging on the same species.

[34] A study by Manlik et al. (2017) showed that N. bombi infection prevalence varies widely over time, and is associated with mitochondrial DNA genotypes in B.

This suggests that foragers have compromised immune systems due to increased energetic expenses and might be predisposed to fly parasites.

[36] While B. terrestris is a singly mating species, a polyandrous system would potentially be beneficial because it would be possible to attain greater genetic variability for resistance against disease.

This virus is thought to have spread to B. terrestris, and in 2004, as many as 10% of queen bees bred commercially in Europe were found dead with deformed wings.

[40] For example, B. terrestris has a large niche overlap with local Japanese bee species in terms of flower resources and nest sites.

Lack of available food due to these unpredictable circumstances can often negatively affect colony growth, reproduction, and resistance to parasites.

[37] In their 2014 study published in Functional Ecology researchers using Radio-Frequency Identification (RFID) tagging technology on the bees, found that a sublethal exposure to either a neonicotinoid (imidacloprid) and/or a pyrethroid (?-cyhalothrin) over a four-week period caused an impairment of the bumblebee's ability to forage.

[46] Research published in 2015 showed that bees prefer solutions containing neonicotinoids, even though the consumption of these pesticides caused them to eat less food overall.

[47] Since 1987, B. terrestris has been bred commercially for use as a pollinator in European greenhouse crops, particularly tomatoes—a task which was previously carried out by human hand.

[40][48] B. terrestris has been commercially reared in New Zealand since the early 1990s,[49][50] and is now used in at least North Africa, Japan, Korea, and Russia, with the global trade in bumblebee colonies probably exceeding 1 million nests per year.

[53] Nonetheless, B. terrestris are key commercial pollinators in Europe, which has driven researchers to investigate the influence of agricultural land on the foraging and survival of this species.