In places a univoltine species, flying from June to August. Gogala (2013) states that the species is bivoltine (it has two generation per year) in Slovenia (and in other southern locations), the first generation flies from June to August, and the second in August and September. Stanisavljević (2000) lists records from Serbia from June to September
Data extracted from Pittioni et al (Accessed: 2017.10.19) record female activity from May to September. In Cyprus, both sexes are active in late October (S. Roberts, 2016, pers. obs).
Parasites: The bee Coelioxys afer (Megachilinae) is cited as a cleptoparasite of this species (Banaszak & Romasenko, 1989; C. Praz pers. comm. 2014).
Range expansion: Megachile pilidens was reported for the first time from the Netherlands in 2004 and 2005, from Nordrhein-Westfalen in Germany in 2003 and Luxembourg in 2001 (Peeters, Raemakers, vd Nieuwegiessen & Kuper, 2007).