Bee populations have been declining worldwide and this week, European trials have new evidence that the neonicotinoid insecticides are part of the problem. In the mammalian kingdom, scientists have been looking at the differences between male and female mice. The results have huge repercussions for drug testing which mostly use male mice. From the world of health - Brazilian scientists are grappling with the shortage of yellow fever vaccines and asking if they cut the dose to make stocks go further, would it still work? And could a reduction in the number of new brain cells we grow explain some cases of depression? It is early days but some hope that this idea could lead to the discovery of new drugs. A virtual reality exhibition is making its way from the Sheffield Doc/Fest in England to South America. From here, we are space-bound as we look to the beauty and mystery of a single star recorded by the poet Byron two hundred years ago. Finally, we turn to an age-old question that pre-dates this lyricist: Do we think in words, images, or abstract concepts? (Picture credit: A bee gathers pollen from a flower on a gooseberry bush © Yuri Kadobnov/AFP/Getty Images) The Science Hour was presented by Roland Pease with comments from Jonathan Amos, BBC Science Correspondent Producer: Graihagh Jackson