Pine processionary maximum recorded of . The species flies from May to July. "T. pityocampa" is a highly social organism. Throughout its life cycle, a pine processionary will make several shelters. The first of these are flimsy and temporary, but in the third instar, they build a permanent nest. Once their permanent nest is built, the caterpillars become foragers staying in the vicinity of the nest. The nest has no openings, so caterpillars force themselves through the layers of the shelter. The waste from the larvae's diet accumulates at the bottom of the nest. The pine processionary caterpillar is responsible for most
California Office of Environmental Health Hazard Assessment against expansion of OEHHA: OEHHA's vision is to be California's leading scientific organization for evaluating risks to human and ecological health. OEHHA's goals as a governmental agency include: OEHHA assesses the risk of environmental chemicals based on health considerations alone. In contrast, risk managers consider economic and technical feasibility as factors in their decisions. This separation is essential to prevent undue political influence on the evaluation of health risks. These factors are and should remain explicitly excluded from the assessment of risk. OEHHA plays a critical and unique role that allows for the separation of risk assessment and hazard evaluation