Image copyright Darpan Basak Image caption "Mating": Two frogs caught in the act on a lotus leaf - one of three photos shortlisted for Young Photographer of the Year

The Royal Society of Biology has announced the shortlist for its Photographer of the Year awards.

In the main category there are seven photos by amateur photographers, as well as three shots shortlisted for Young Photographer of the Year.

These were taken by Darpan Pasak, Timofev Zubarev and Oliver Tidswell - aged 12, 13 and 17 respectively.

Image copyright Timofey Zubarev Image caption "Loneliness and stubbornness": Sea rocket clinging to a dune on the Curonian Spit in Russia - another image on the young photographer shortlist

The society invited submissions from around the world, on the theme of "conflict and survival".

The shortlisted photos include squabbles for food and mates between seabirds and muskox, as well as insects, plants and snails struggling against the environment and other species.

The winners will be announced at a ceremony in London on October 15, during Biology Week.

Image copyright Oliver Tidswell Image caption "Little one": A flowering plant at an altitude of 5,550m in the Pensi La Pass, India, also makes the young photographer shortlist

Image copyright Fabio Pupin Image caption "Headbutts": Two male muskox in Dovrefjell, Norway, engage in a prolonged series of head-to-head clashes until one of them yields

Image copyright Paddy Ryan Image caption "All, all alone": A tiny juvenile anemone fish finds a place of refuge in the ocean off the Philippines

Image copyright Debdatta Chakraborty Image caption "The herons": Stilt fishermen in the south-western beaches of Sri Lanka, perched on their "pettas", make the best of meagre pickings

Image copyright Davide Gaglio Image caption "The last sardine": Two seabirds on Robben Island in South Africa are unwilling to gamble on whether or not there are, in fact, plenty more fish in the sea

Image copyright Barbara Stanley Image caption "Impala fighting": In Namibia, male impala battle for dominance and to determine their place in the breeding hierarchy

Image copyright Beverley Brouwer Image caption "Double trouble": These two snails are both playing host to parasitic flatworms, which develop in the snail's stomach and then invade its antennae, putting on a caterpillar-like display to attract birds