Morphometrical properties of different parts of the salivary glands in nymphs and adults of the stripped bug, Graphosoma lineatum (L.) (Hem., Scutelleridae)
In most Heteroptera, the salivary glands complex consists of two principal and two accessory glands. Principal glands are structurally bilobed and are divided into anterior and posterior lobes. They are located at the thorax on each side of the midgut. Accessory glands are of two types: tubular and vesicular. In the present study, we investigated the sizes of different parts of the salivary glands of second to fifth instar nymphs and newly emerged, 10-days old, and 30-days old adults of the stripped bug, Graphosoma lineatum (L.), including the length of the salivary gland, length of anterior and posterior lobes, width of anterior and posterior lobes, and width of accessory gland. All sizes were measured by using a calibrated micrometer and a stereomicroscope. Experiments were carried out as factorial in CRD. With each instar and stage, gland size grows larger, whereas the ratio of its length to the body length decreases. Both in nymphs and adults, the effect of salivary glands situation on the size of its different parts was not significant which shows that the shape and size of right and left salivary glands of nymphs and adults are completely similar to each other. In the case of nymphs, the effect of instar was significant at 1% level which shows that an increase in developmental stages significantly increases the length of their salivary glands. In the case of adults, the effects of sexuality and adults’ life span were significant at 1% level. These show that the sizes of different parts of the females’ salivary glands are greater than that of the same age males and an increase in the adults’ life span would increase their salivary glands length.