Insects on an April lawn
6th April 2008, SundayI admit that I usually regard short mown lawns as rather dull garden features, but there is an exception. In Northiam lawns that are cut short, and particularly those on a south facing banks, attract a fascinating community of insects. The key species is a mining bee, Andrena flavipes. The photo below shows a freshly emerged male sitting on a piece of paper a couple of days ago, when the weather was quite different to the snow storms of today!
These bees swarm over suitable lawns in April, with a second generation later in the summer. I remember a neighbour coming up to me a few years ago and saying “You know about insects. How do I kill these bees?” What did he think a conservationist was likely to say?
A sympathetic response was not forthcoming because these bees are a key species for a whole community of insects. Although females make solitary nests, where a lawn offers plenty of warm bare soil (see photo of suitable habitat below) then the numbers of bees can really proliferate. Fortunately they are harmless and they repay careful study.
These bees are the host of a number of other species. The dark-edged, or common bee-fly Bombylius major and the dotted bee-fly Bombylius discolor are frequently photographed on this website in earlier posts. Both have been sighted in our garden this weekend. These attractive insects hover over bare soil flicking their eggs over the ground in the hope that some will find their way into the nests of the mining bee. On hatching the larvae search for and then devour the solitary bee larvae. These are not the only enemies of the solitary bees. A rather attractive cleptoparasitic cuckoo bee Nomada fucata also deposits its eggs in their nests where they feed on the pollen provisioned by the solitary bee.
In keeping with their parasitic nature the fortunes of the nomad bee and the bee-flies fluctuate with the abundance of their host. Both the dotted bee-fly and the cuckoo bee are listed as nationally scarce, and the latter species was until recently listed on the UK Biodiversity Action Plan, but both seem to have increased in numbers recently and are frequently seen in our area. Who would have thought a patch of short grass could be so interesting? By looking after your bees you can help conserve a whole community of fascinating insects
