Fine structure and metamorphosis of the wax gland cells in a psyllid insect, Anomoneura mori schwartz (Homoptera)

Abstract

The fine structure of the wax gland of Anomoneura nymph and its metamorphic change were investigated. In the nymph, this organ encircles the anus, and consists of two kinds of cells, derived from epidermal cells: (1) very tall, slim wax cells, which produce and secrete the wax, and (2) flat interstitial cells found among the wax cells. The whole gland is covered by a wax-secreting cuticle with a delicate surface sculpture. Each wax cell has a long, wide duct which opens at the cuticle and penetrates the entire cell. Its cytoplasm is rich in mitochondria and smooth endoplasmic reticulum while that of interstitial cells contains rough endoplasmic reticulum. During each nymphal molt, the cluster of primordial wax gland cells - derived from the epidermis - proliferates rapidly and forms the gland of the next instar. The gland of the preceding instar meanwhile degenerates. Interstitial cells play an important role in cuticle formation and shedding at each molt. These cells alone produce and deposit the new cuticle of the next instar; the wax cells, specialized for wax production, cannot produce cuticle. The apical portion of the wax cell is cut off from the main cell body by growth of the surrounding interstitial cells. Thereafter, the wax cells degenerate, resulting in the rapid disappearance of the previous instar's wax gland. Adults lack this gland entirely.

Behavioral, Ultrastructural and Chemical Studies on the Honeydew and Waxy Secretions by Nymphs and Adults of the Asian Citrus Psyllid Diaphorina citri (Hemiptera: Psyllidae)

“…However, our SEM work here provided much finer details of the wax pores and cuticular slits found on the circumanal ring of ACP females and/or nymphs. The wax pores we described here, especially in ACP nymphs, are somewhat ultrastructurally similar to openings of the wax glands, described as ‘canaliculated cuticle’, in the nymphal anal ring of the psyllid A. mori [28]. But they are considerably different from the ‘wax pores’ found on wings of the flatid planthopper Metcalfa pruinosa (Fulgoroidae) [33], or from ‘pores in the wax gland plates’ on the cuticle of some aphid species [39].…”

“…Waku [28], studied wax glands in nymphs of another psyllid ( A. mori ) by transmission electron microscopy, and indicated that these glands consisted of two kinds of cells, derived from epidermal cells: wax cells, which produce and secrete the wax, and flat interstitial cells found among these cells. Each wax cell has a long, wide duct which opens at the cuticle.…”

“…These glands were described as ‘wax glands’ in Psylla mali nymphs and adult females by Brittain [27] using light microscopy, and in the nymphs of another psyllid, Anomoneura mori , by Waku [28] using light and electron microscopy. Both authors described openings of these ‘wax’ glands in the ‘anal’ or ‘circumanal ring’.…”

Morphology and Ultrastructure of the Accessory Glands in the Female Genital Tract of the House Cricket,Acheta domesticus

“…This kind of cuticular passage by lipophilic secretions seems to be widely distributed among insects, which is also shown by previous theoretical and experimental studies (Eidmann 1922; Koeniger et al 1996). As demonstrated by numerous investigations, the release of hydrophilic substances from the producing gland cells, to the lumen always occurs by their transport through highly specific channel structures (e.g., Treherne 1957; Waku 1978; Essler et al 1992). …”

The Fine Structure of Insect Glands Secreting Waxy Substances

“…There is a space between the cuticle and the plasma membrane of each wax cell. The plasma membrane retracts from the overlying cuticle during development of the wax gland (Waku, 1978; see Figure 20B). …”