Last year, from its beginning until the end of April 2012, I had recorded the following numbers of insect species and other invertebrates in RBGE: 3 butterflies; 13 bees, wasps and ants (Honey Bee, 6 bumblebee species, 3 solitary bees, 2 wasps, 1 ant); 11 hoverfly species; 5 other flies; 2 bugs; and 1 beetle (Pine Ladybird) – a total of 35 species.
What of this year? March and April have both been almost unrelentingly chilly. This has had a tremendous adverse effect on the insect biodiversity in the Garden compared with the same period last year. From 1 January – 30 April 2013, I have recorded only the following: 1 butterfly; 7 bee species (Honey Bee, 5 bumblebees, 1 solitary bee – no wasps or ants seen so far); 5 hoverfly species; 3 other flies; no bugs; and Pine Ladybird – a total of 17 species, just less than half the 2012 total for the same period.
It gets worse … most of those 17 species have been seen only since 22 April, or roughly in the last week of this month. Before 22 April, I had only seen FIVE insect species in the Botanics this year, whereas last year I had seen all 35 species before 22 April and recorded nothing extra in the last week of the month!
The reason of course is that the late spring has meant that trees have come into leaf much later and many flowers are blooming much later than normal. No leaves means no food for the insects; no insects means a dire time for birds that are now trying to nest but are lacking insect food for their nestlings; and plants are not getting pollinated because so few insects are around to pollinate them.
Let’s hope that May brings warmer weather and more insects!