such as stumps, pebbles, wood, weeds, grass blades and low tree branches. Males assume an alert posture, ready for a challenge from another male, or from a predator. One study by a behavioral ecologist, John Alcock, showed that a large majority of the marked wasps returned to the same perch day after day, and two males swapped between two different sites. The species rarely perches on the ground. It shares the same nesting biology as S. speciosus. All cicada killers are ground-nesting insects and nest aggregations can contain up to hundreds of nests, each with a single provisioning female. Their tunnel is mainly made in well-drained, bare sandy soil, frequently under sidewalks, but is generally in full sunlight. Approximately 90% of its life is spent underground as a larva. It rarely infests grounds that are rich in vegetation in order for them to get more sun. Mounds are easily recognizable by their distinctive U-shaped digging entrance. Feeding and hunting habits Sphecius grandis has very similar nesting and feeding habits to other members of its genus, most notably Sphecius speciosus. As with S. speciosus, the female hunts for cicadas in low tree trunks, helped by the calls of the cicada males, and paralyses the insect by piercing the central nervous system with her stinger. She drags the cicadas back to her nest to place them in brood cells in which she eventually lays one egg per cell. Females carry cicadas that are on average 88% heavier than their own body mass. It has been hypothesised that cicada killers may also have the ability to capture cicadas mid-flight. There are approximately two or more cicadas to each brood cell. When the larvae hatch, the cicada provides nutrition for the offspring to feed on. The wasps preferentially hunt for female cicadas because they have more consumable tissue, but male cicadas are easier to locate, which explains the systemic bias towards male kills. They chiefly hunt for Tibicen duryi, Tibicen dealbata and Tibicen parallela. Cicada killers are capable of thermoregulation, which allows them to hunt for cicadas during the day, when the cicadas are most prominent. The species is mostly harmless to humans. Some males when emerging early fly into the trees to feed on sap, and the species has been known to feed on nectar. Stings of this species received a lethality rating of 46 LC measured by LC= (LC="lethal capacity", μg="venom in