The rusty patched bumble bee has become the first wild bee in the continental United States to gain federal protection, with the government adding it to its list of endangered and threatened species.
The bee, once widely found in the upper Midwest and Northeastern United States, was listed on Tuesday after US president Donald Trump's administration lifted a hold it had placed on a plan for federal protections proposed last northern autumn by the administration of then-president Barack Obama.
Bumble bees are key pollinators of crops such as blueberries and cranberries, and are almost the only insect pollinator of tomatoes in the US, according to the US Fish and Wildlife Service.
Conservation groups that had called for the new classification welcomed the move.
"The listing helps mediate threats for this species and for all of those other animals out on the landscape that are suffering similar setbacks," Rich Hatfield, senior biologist at the Xerces Society for Invertebrate Conservation, said.
The rusty patched bumble bee, or Bombus affinis, is one of 47 varieties of native bumble bees in the US and Canada, more than a quarter of which face risk of extinction, according to the International Union for the Conservation of Nature.
The population and range of the bee, named for the reddish blotch on its abdomen, have declined by more than 90 per cent since the late 1990s due to disease, pesticides, climate change and habitat loss, according to wildlife officials.
The agency in September proposed safeguarding the bee, but the listing was delayed by Trump's White House as part of a broader freeze on rules issued by the prior administration.
Environmental advocacy group the Natural Resources Defence Council in February sued, arguing that suspending the listing without public notice or comment violated the law. The NRDC on Tuesday said it was evaluating the next steps in its legal fight.
Government scientists said the delay, part of a standard review, was not expected to affect the insect's conservation, Interior Department spokeswoman Heather Swift said in a statement.
The agency "will work with stakeholders to ensure collaborative conservation among landowners, farmers, industry, and developers in the areas where the species is native," she added.
Bumble bees pollinate wildflowers and about a third of US crops, according to the Xerces Society. A recent study by the Centre for Biological Diversity found that more than 700 of the 4,000 bee species native to North America and Hawaii may be inching toward extinction.