Gall wasp Aulacidea hieracii (Hymenoptera: Cynipidae) produces galls on a hawkweed Hieracium x robustum and feeds on gall tissues during summer. We employed in vivo resonance Raman spectroscopy to assess changes in carotenoids in living juvenile forms of this insect during its development. We revealed that the carotenoid composition in the feeding summer gall wasp larvae differs from that in the gall tissues. Non-feeding winter larvae contain more carotenoids than summer forms, despite the absence of feeding. Moreover, the carotenoid composition of winter larvae differs from that of summer larvae. We address the question, whether A. hieracii can synthesize carotenoids.