Many species of solitary bees and wasps nest in aggregations. The activity around nesting aggregations especially from males discourages predators and parasites. Some nesting aggregations can be large but none compare to the late autumn breeding ivy bees. Their aggregations can number into the thousands proving a spectacular sight around cliff faces, sandstone walls and clay banks.
The species specialises in collecting ivy pollen so the entire population of the species emerges at the same time in late September/October to coincide with ivy flowering and before it gets too cold for activity.
There are a number of large nesting aggregations in Hastings but the easiest to observe are those at the base of the sandstone exposure of Ladies Parlour on the West Hill and the sandstone walls within White Rock Gardens. As well as observing the ivy bees at their nest sites any patch of flowering ivy will have large numbers of female bees collecting pollen.