Bumblebee declines have been well publicised. It is the suite of longer tongued species that have declined most significantly. The reason is that these species need very extensive areas of flower-rich countryside to survive. The shrill carder bee Bombus sylvarum for instance, sadly lost from the RX area, is thought to require ten square kilometres of suitable flowery habitat with the appropriate food plants to maintain viable populations. Over the next few weeks I intend to highlight some of the more valuable foodplants for these insects, and encourage land managers to let them flower on their land.
Right now some of the best bumblebee forage is on the dead nettles, such as white dead nettle Lamium album.
This inhabitant of hedgerows and rough grassland is very attractive to these insects and in Rye this week the plants have been covered in the garden bumblebee Bombus hortorum, normally the least common of the widespread bumblebee species, and not restricted to gardens! English names for bumblebees are far from helpful. It would be a good plant to encourage in unmanaged areas of the nature reserves at Rye Harbour and Dungeness since it is one of the best forage plants for the scarcer species at this time of year, before we get a burst of flowering from the legumes. One of the issues with bumblebees is that they need continuity of the correct flowering plants throughout their life, and this is one of the reasons why some species need such extensive areas of habitat. When fields are cut for hay they loose that food source and they have to travel further to find food.
Bombus hortorum is a black and yellow striped bumblebee with a white tail, but if you look at the pattern of stripes on the thorax (the section of the body where the wings are attached) there are two yellow stripes, one at the front of the thorax, and one at the rear, extending onto the abdomen. Two common bumblebees in our area share this pattern, Bombus hortorum, a long tongued species with a long narrow face, and the smaller Bombus jonellus. This species though is short tongued, and has a short face, as long as it is wide. One other rare species, Bombus ruderatus, is very similar to the hortorum, but is now very rare and has not been seen recently in this area.
The other dead nettle in the area that is used by these insects is the smaller red dead nettle Lamium purpureum, a species of disturbed ground that I try to tolerate in our garden.