An extract of head ganglia and retrocerebral complexes of nondiapausing and diapausing Leptinotarsa decemlineata was prepared to characterize regulatory neuropeptides involved in adult diapause by Using a differential peptidomics approach. To reduce sample complexity both extracts were roughly separated by means of an identical chromatographic step. MALDI-TOF MS led to the identification of proctolin. an adipokinetic hormone, and Short neuropeptide F I and 11 in the extract of nondiapausing beetles. In combination with nano-ESI-Q-TOF MS2 evidence was found for the presence of three pyrokinins, the first to be identified in a coleopteran species. Pyrokinins, involved in the induction of embryonic diapause in Bombyx mori, were present in both physiological conditions suggesting that they are or minor importance in the regulation of adult diapause in the Colorado potato beetle. A striking difference. detected by the differential peptidomics approach, between both neuropeptide profiles was the absence of ions corresponding to the short neuropeptide F (sNPF) related peptides. also known as Led-NPF-I and -II ill the extract of diapausing animals. Therefore. we postulate that "short NPFs" are involved in the regulation of adult diapause, displayed by the Colorado potato beetle. (C) 2004 Elsevier Inc. All rights reserved.