A. tumida pupae are free pupae (pupa
libera), which means that their extremities such as legs and wing sheaths
are, in contrast to pupa obtecta, not glued to the body (Fig. 3). Pupae
in early stages (Fig. 3a) are pearly-white with a series of characteristic
projections on the thorax and the abdomen, but darken as they develop (Fig. 3b)
and their exoskeleton hardens, with pigmentation first appearing in the eyes
and then the under wings (Lundie, 1940). Depending on soil temperature pupation
time varies between 15 – 74 days (Neumann et al., 2001a), but may take
up to 100 days in cold periods (Stedman, 2006). During eclosion, the puparium
bursts and the adult beetle emerges (Fig. 3c).
Fig. 3. Small hive beetle pupae and adults: a. early pupal stage; b. late pupal stage; c. adult ready to emerge from pupation chamber; d. adult on honey bee comb (dorsal view) with typical antenna and short elytra. Photos a-c: Anna Röttger; d: Nelles Ruppert.