Bombus dahlbomii

It is a robust bee: workers measure 16 to 23 mm, males 17 to 22 mm and queens 26 to 33 mm.

It is covered in thick orange hair, which can vary in shade, and has yellowish-brown wings.

In Chile it ranges from the Coquimbo region to Magallanes, including Chiloé Island and Tierra del Fuego, and it also lives in southern Argentina.

It occurs from the coast to the Andes and has been seen above 3,200 m.

Its colonies are small compared with those of other bumble bees.

Its life cycle is seasonal: queens start nests early in the growing season and colonies end in autumn.

Colonies nest underground in well-protected spots, using holes dug by other animals or natural cavities in the soil.

It has been recorded on 84 plant species from 42 families, about 75 percent of them native, and native bumble bees in Chile prefer native plants.

Over the last 20 years it has disappeared from much of its former range, with a decline of more than 50 percent in 10 years.

Two European bumble bees were introduced to Chile: Bombus ruderatus in 1982 to 1983 and Bombus terrestris in 1997, to pollinate greenhouse tomatoes.

Wherever Bombus terrestris spreads, Bombus dahlbomii disappears, although the exact reasons are still unclear.

The parasite Apicystis bombi was not found in samples of B. dahlbomii and B. ruderatus collected before B. terrestris arrived, but afterwards it was present in all three species.

Six parasite species have been found in it, and these may be among the main causes of its rapid disappearance.

Chile's species classification committee rated it Endangered in 2015, based on a population fall of more than 50 percent in 10 years.