Life History of Passaloecus pictus Ribaut, 1952 (Hymenoptera, Pemphredonidae)

The nesting of <i>Passaloecus pictus</i> Ribaut, 1952 was observed in Kowalewo Pomorskie (northern Poland). The nests were built in trap nests that were placed on a windowsill facing southwest. The females used resin from <i>Picea pungens</i> Engelm., located 5 m away, to build the cell walls. The tunnel consisted of 1-7 cells. The females provided provisions for two to three cells per day. The frequency with which a female brought aphids to a nest cell varied from 1 to 7 min. No males were observed near the nest. A total of 42 cells were examined (consisting of 31 female cells and 11 male cells). On average, a female brought about 33 aphids to the female cells and 21 aphids to the male cells. The prey were <i>Macrosiphoniella millefolii</i> (De Geer, 1773), <i>Dysaphis crataegi</i> (Kaltenbach, 1843), <i>Macrosiphoniella persequens</i> (Walker, 1852) and <i>Uroleucon achilleae</i> (Koch, 1855). The nest parasites were <i>Melittobia acasta</i> (Walker, 1839). The occurrence of a second generation has been confirmed.