The season is picking up and the first pollinators are already out, scouting for nesting sites and food, writes Athayde Tonhasca. It’s a harsh start, as cold spells may be deadly and flowers are still scarce. The orange-tailed mining bee, also known as the early mining bee (Andrena haemorrhoa) is one of the first bees to emerge in the spring. The female bee has bright, rusty red hairs covering her thorax – hence the inspiration for the species name, which derived for the Greek haima (blood) and rheo (flow); the same roots as ‘haemorrhage’. There is a tuft of red hairs at the tip of the abdomen as well, which helps distinguish this bee from others of similar colour.
Andrena haemorrhoa © Pauline Smith.
The orange-tailed mining bee in found in a variety of habitats, and like other mining bees, it nests underground. This bee is not picky at all: it will excavate its nest in parks, playing fields, gardens lawns, paths, roadsides – any open, dry spot with light soil will do, especially on south-facing slopes and banks. A little pile of spoil around a hole in the ground is a tell-tale sign of a nest. Several bees may nest next to each other, but that’s because they are all making use of a suitable nesting site: each bee will build its own nest and ignore the others.
A mining bee nest entrance.
At this time of the year you may find orange-tailed mining bees visiting the few spring-flowering plants such as dandelions, blackthorn, willows and gorse, but its diet will expand as the season progresses. In fact, this bee is one of the most frequently recorded species on flowering crops grown in the UK. It is also one of the pollinators of the Lady’s slipper orchid (Cypripedium calceolus), which is critically endangered in many countries.
But it’s not all rosy for this pollinator: a fork-jawed nomad bee (Nomada ruficornis) may be lurking, flying close to the ground in search of an orange-tailed mining bee nest. Once a nest is found, the nomad bee uses its sense of smell to tell whether the nest is stocked with pollen and its owner is nearby. If conditions are right, the nomad bee will invade the nest, sometimes kill the host’s offspring, lay her eggs and leave. The invading bee larvae will eat the host’s larvae if their mom has not already done so, then will eat each other until only one is left alive. This larva will then feed on the pollen and nectar stored by the host bee. This type of parasitism is known as kleptoparasitism (parasitism by theft) or brood parasitism, and these parasites are known as cuckoo bees.
Nomada ruficornis © Janet Graham, Wikipedia Creative Commons.
Over 3,700 parasitic bee species have been described (at least 850 of them from the genus Nomada). Most of them are host-specific, and some are threatened. If you are wondering why we should protect a bee-killing species, think about other loved, charismatic creatures that are no less deadly to their prey such as dragonflies, owls, eagles and wildcats. Cuckoo bees are marvellous examples of natural selection and evolution, and they do no less than their hosts to be successful and survive.
Scottish pollinators 