The lady-bird beetle, Harmonia axyridis PALLAS is a highly variable species. The author experimented on the inheritance of the color pattern and also on that of the presence and absence of a transverse ridge on the elytra.
The elytral color patterns may be classified into six types as follows:
1. s type (succinea)-(Fig. 1-a, b, c)
2. A type (aulica)-(Fig. 1-d, e)
3. S type (spectabilis)-(S1 subtype-Fig. 1-f. S2 subtype-Fig. 1-g)
4. AS type-(Fig. 1-h, i)
5. C type (conspicua)-(C1 subtype-Fig. 1-j. C2 subtype-Fig. 1-k)
6. AC type-(Fig. 1-l, m)
Each of s, A, S and C types is determined by a factor which shows inheritance as follows:
1. s is largely recessive to any of the other types.
2. AS is the hybrid between A and S.
3. AC is the hybrid between A and C.
4. S is a simple recessive to C.
5. The subtype S1 is the homozygote, while the subtype S2 is the heterozygote of S and s. The subtype C1 is the homozygote or the heterozygote of C and S, while the subtype C2 is the heterozygote of C and s.
Genes p, PA, PS, and PC which determine the appearance of s, A, S and C respectively constitute a set of quadruple allelomorphs and are autosomal.
Hence, genic constitution of the six phenotypes may be designated follows:
A type-PAPA, PAp
S type-S1 subtype-PSpS,
C type-C1 subtype-PCPC or PCPS
Tan and Li's interpretation (Amer. Nat. 1934, 68: p 252-265) on the inheritance of pattern types of the same beetle which is based on mutually independent genes seems inadequate.
The presence (Fig. 2-a) or absence (Fig. 2-b) of a ridge on the elytra is also inherited on the monohybrid basis.
The factor (R.) for presence is dominant to the factor (r.) for absence.