While I am, of course, concerned about the risks posed to the UK’s delicate biosystem by the inadvertent importing of harmful fauna and flora from foreign countries, your piece (Colombian tree frog found by Sheffield florist highlights invasive species threat, 17 January) left a vital question unanswered. What happened to the little tree frog?
Sallyann Halstead
Fitzhead, Somerset

Intrigued to read about the government promising a record pool in nuclear fusion (Ministers pledge record £410m to back UK nuclear fusion vigor, 16 January). Reminds me of the ancient joke: fusion, for the last 70 years, has always been 20 years in the upcoming – perhaps an experiment to prove period doesn’t exist in nuclear physics?
Dr Paul Dorfman
Chair, Nuclear Consulting throng

You update (15 January) that Rolls-Royce is banking on the achievement of tiny modular reactors. I assume the corporation is also banking on not being around to tidy up the nuclear waste.
Peter Gray
Chesterfield, Derbyshire

Your piece (14 January) reveals that the Wellcome depend paid fees of £11m for the management of its pool holdings. The profitability was 5.2%. It might have been better off putting it into a building population.
Jim Golcher
Greens Norton, Northamptonshire

I have often thought about changing my name (Letters, 16 January), but resisted and was never out of work. However, after passing by a motorcycle shop in Newport, Isle of Wight, proprietor Dave Death, I ponder sometimes it might assist.
Rowan Vuglar
London