Table 1.

Digestion score and appearance description of adult mites

Digestion score	Appearance description
0	The body of the mite is red and full of blood, no distinct transparent region was observed.
1	The trunk is mostly bright red or dark red, with only a small portion of intestines (especially midgut) being transparent.
2	Three pairs of caeca and hindgut have blood, most centre parts of the hinder body are transparent. The intestinal profile can be clearly recognized.
3	Most of the body is transparent, only a small amount of blood remains in the intestine. The intestinal structure cannot be clearly recognized.
4	The body is almost completely transparent or white, and no blood remains in it.