Eresus cinnaberinus and Eresus sandaliatus are the two species sometimes called ladybird spiders. They range from the northern Mediterranean throughout the European mainland and into southern England, near Dorset. They are a protected species in Great Britain, because they nearly became extinct there due to various pressures on ladybird habitat. Agriculture, road-building, deforestation and development systematically reduced and fragmented the lowland heaths near Dorset where the last redoubts of the spider survived. Efforts have been successful to protect the spiders and repopulate the Dorset habitat.
The female builds a tube-like vertical den, generally protected by a thick, anarchic web connecting local vegetation to the ground in front of the den's entrance. Juvenile spiders remain in the birth den until adulthood. The spiders reach adulthood in under a year, when adult females seek out new dens. Adult males mate upon reaching adulthood and summarily die afterwards. Females typically live about three years and are eaten by their babies afterward.
Ladybird spiders, which prefer sunlight on the entrance of their dens, almost always construct the den on a south-facing gradient. During the day, the females will transport their egg sacs to the entrance of the den to warm them, then return them to the depth of the den at night. Ladybird spiders are remarkable hunters, with a real taste for beetles, even very large beetles, as well as other spiders. Ladybird spider dens will be in an area that's well-populated with these food sources.
In addition to south-facing gradients and a reliable food source, ladybird spiders prefer habitat that has debris and small stones. Debris is collected to wrap into the egg sacs to camouflage them, and small stones are shifted into positions around the den entrance, presumably for protection, for heat or for both. Water accumulation is a threat to ladybird spider dens, so the spiders prefer sandy, well-drained soils and spots where water doesn't pool during heavy rain.