Lowland heathland in Surrey is extremely important for invertebrates, especially insects and spiders, and many rare and characteristic species occur. Some of these, such as its diverse dragonfly fauna (including the local small red damselfly and keeled skimmer), silver-studded blue butterfly, emperor moth, bog bush-cricket and raft spider, are well known; many others, especially the wide range of Hymenoptera (ants, bees and wasps) are less known, except to specialists. Surrey is the richest county in Britain for this group, with dozens of rare species on its heaths, including the ants Anergates atratulus and Formica rufibarbis.
Characteristic species of dry heathland include the bee-fly Thyridandrax fenestratus, the sand wasps Ammophila sabulosa and A pubescens, wood tiger beetle Cicindela sylvatica, slave-making ant Formica sanguinea, mason wasp Eumenes coarctatus and many others. Dry heathland on the Lower Greensand of the Weald supports thriving populations of the hornet robberfly Asilus crabroniformis and has produced the only modern records of the rare hoverfly Chrysotoxum octomaculatum. Heathland in Surrey holds nationally important populations of grayling butterfly Hipparchia semele, a species which has declined significantly in recent decades. Surrey contains the majority of British sites for the heathland spider Uloborus walkenaerius and all the known populations of lynx spider Oxyopes heterophthalmus, found mainly on the Tertiary heaths of the county.
Many invertebrates of lowland heathland are dependent upon a warm microclimate and sheltered conditions providing ‘hot spots’. Bare sand and peat, including banks and old quarries are particularly important together with a good nectar supply from flowering plants. Locally, patches of acidic grassland or ‘grassy heath’ may be extremely important and a ground beetle Lebia cyanocephala which has recently been rediscovered in Britain is found on one such area in Surrey.
The very rare field cricket Gryllus campestris which once occurred on Surrey heathland is being re-introduced by English Nature under its Species Recovery Programme.