Hirano Kohji, 1981

A new marking method using a sewing needle: effects on survival rate of twenty-eight-spotted lady-beetles, Henosepilachna vigintioctopunctata Fabricius (Coleoptera: Coccinellidae) //

Applied Entomology and Zoology, Vol. 16, No. 3, P. 264-270.

Kohji Hirano

Laboratory of Applied Entomology and Nematology,
School of Agriculture, Nagoya University, Nagoya 464, Japan

ABSTRACT: Adults of the twenty-eight-spotted lady-beetle were marked by piercing their elytra with a sewing needle. Sixteen of the twenty-eight natural spots seen on the elytra were used as piercing points. Marking-and-recapture experiments made in the field suggested that there was no significant difference between the mortality rates of needle-marked and unmarked adults. Marking with a needle seemed to have no harmful effect on the number of recaptures. No difference between survival rates of needle-marked and lacquer-marked individuals was seen in a field-cage experiment.


Piercing method. The adults have twenty-eight black spots on the elytra. Marking was made using 16 of these spots, as shown in Fig. 2-a. Coding was made with a 1-2-4-7 marking system (Southwood, 1978) which allowed us to describe all the numerals from 1 to 9 with one or two spots. Marking was made by piercing the centre of these spots with a sewing needle (0.4 mm in diameter). By this system we can identify up to 9,999 individuals. On catching adults by hand, the elytra were opened wide with the fingers while piercing to avoid wounding the hind wings. Beetles were not anaesthetized, but there was no sign of any nervous action after their release.

In a routine census, since teneral adults (two or three days after emergence) were difficult to mark with this method, they were first marked with lacquers and piercing was done when they were recaptured after maturation.

Paint method. Four places on the elytra were marked with spots of lacquer paint of nine different colours (Fig. 2-b), which indicated numerals from zero to eight. 'Nine', 'ninety', etc. were discarded in coding. Thus, by this method we could identify up to 84 (4096) individuals. As the marking system included a zero-class, we could know the rate of loss of marks when we found an individual with less than four spots.

Fig. 2. Method of marking twenty-eight-spotted lady-beetles.
a: Marking points with a needle. Piercing was made at centre of natural spots.
b: Marking points with lacquer paint (see text for further explanation).