Salivary glands

honey bee salivary glands

Dissected salivary glands (also called labial glands) of honey bee worker. After Snodgrass (1956, fig. 21cde) [1], Cruz-Landim (1967) [2]. (scale bar = 1 mm)

HGld - head salivary gland (also called postcerebral gland or cephalic salivary gland)
Res - reservoir of thoracic salivary gland
slDct - common salivary duct
ThGld - thoracic salivary gland

The salivary gland system comprises two pairs of exocrine glands, one in the head (head salivary glands) and one in the thorax (thoracic salivary gland). The glands are connected by common salivary duct to salivary pocket (salivarium) at the base of labium (see also side view of salivary glands). The head and thoracic glands differ in protein expression [3].

Salivary glands are well developed in queens and workers; in drones they are small [4][5][6][7]. Salivary glands of workers are more active when they are foraging [8][7][9] see also [10]. Head salivary glands of queens become more active when they start egg laying [7][9]. In drones head salivary glands degenerate when they become sexually mature [7][11].

Head salivary glands produce oily secretion [12][13] which contains mixture of hydrocarbons [14][8], imaginal disc growth factor 4 [3]. It was suggested that it is used to: soften wax [15] and lubricate mouthparts [12]. The head salivary glands can be a source of cuticular hydrocarbons [8][7]. The secretion can be added to royal jelly [3].

[16][17][18][19][20]

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