Bombus Maxillosus vs. Bombus Pensylvanicus

Attribute	Bombus Maxillosus	Bombus Pensylvanicus
Common Name	Large Carpenter Bee	American Bumblebee
Coloration	Black with yellow stripes	Black with yellow stripes
Size	Large	Medium
Range	Eastern United States	North America
Habitat	Forests, woodlands	Grasslands, meadows

Physical Characteristics

Bombus maxillosus, also known as the large-headed bumblebee, is easily distinguished by its large head and robust body. It has a black thorax with yellow stripes and a black abdomen with yellow bands. In contrast, Bombus pensylvanicus, or the American bumblebee, has a more slender body with a black thorax and yellow stripes. Its abdomen is also black with yellow bands, but the overall appearance is more streamlined compared to Bombus maxillosus.

Behavior

When it comes to behavior, Bombus maxillosus is known for its aggressive nature. It will defend its nest vigorously against any perceived threats, including other insects or animals. This species is also known to be more territorial compared to Bombus pensylvanicus. On the other hand, Bombus pensylvanicus is generally more docile and less likely to engage in aggressive behavior. It is more focused on foraging for nectar and pollen rather than defending its territory.

Foraging Habits

Bombus maxillosus has a preference for flowers with deep corollas, as its long tongue allows it to access nectar from these types of flowers. This species is also known to be a more efficient pollinator due to its ability to reach the nectar in hard-to-reach flowers. On the other hand, Bombus pensylvanicus tends to forage on a wider variety of flowers, including those with shallow corollas. While it may not be as specialized as Bombus maxillosus, Bombus pensylvanicus plays an important role in pollinating a diverse range of plant species.

Nesting Behavior

Both Bombus maxillosus and Bombus pensylvanicus are ground-nesting bumblebees, meaning they build their nests underground. However, there are differences in their nesting behavior. Bombus maxillosus tends to build larger nests with more workers compared to Bombus pensylvanicus. This species is also known to have a longer active season, allowing it to produce multiple generations of workers throughout the year. In contrast, Bombus pensylvanicus typically has smaller nests with fewer workers and a shorter active season.

Range and Habitat

Bombus maxillosus is primarily found in the eastern United States, with a range that extends from Maine to Florida. It prefers open grasslands and meadows as its habitat. On the other hand, Bombus pensylvanicus has a wider distribution across North America, ranging from the eastern United States to the western states and parts of Canada. This species can be found in a variety of habitats, including forests, prairies, and urban areas.

Conservation Status

Both Bombus maxillosus and Bombus pensylvanicus face threats to their populations due to habitat loss, pesticide use, and climate change. Bombus maxillosus is considered to be of least concern in terms of conservation status, as it has a relatively stable population size. However, Bombus pensylvanicus is listed as a species of special concern in some regions due to declining populations. Conservation efforts are underway to protect both species and ensure their continued survival.