Ever since the appearance of the first lacewing hens in 1946 in a strain of lutinos [6], many conflicting breeding results have been reported all over the world. I have always been intrigued by the sex-linked varieties and started doing research on them many years ago.

It is known for a fact that lacewings usually breed true, however, in 1976 I discovered an unexpected event amongst the offspring of a normal split lacewing cock. During the first round only normal and lacewing hens were produced as expected, but in the second round one of the hens that hatched appeared to be a lutino.

During the breeding season of 1982 a short article was published by mr. Kluytmans from the Netherlands. He described similar results from a mating involving a normal split opaline-lacewing cock. As expected normal and opaline lacewing hens were born, but he also reported two lutino hens and one cinnamon opaline hen out of this mating.

In 1985 I recognized in my own aviary one normal cinnamon hen among nestlings derived from a normal split lacewing cock. All her sisters were normals and lacewings as expected.

A few years ago another Dutch breeder send me some unexpected results. He bred with an opaline split cinnamon-ino Type I cock (a Type I cock is a split cinnamon-ino, with the cinnamon gene on one Z-chromosome and the ino gene on the other one). Three lutino hens and one opaline-cinnamon hen hatched as one would expect, but also two opaline-lacewing hens appeared as an unexpected result. These events could only be explained so far, by cross-overs between the cinnamon and ino gene and therefore are consistent with the view that lacewings are cinnamon-inos.

However, conflicting results were send to me a few years ago by a Belgian breeder who claimed that he bred cinnamon hens as well as cinnamon cocks from a mating involving a normal split lacewing cock with a lacewing hen (..?). In fact he has twelve normal split lacewing cocks in his stock who all, when mated to lacewing hens, give rise to cinnamon hens and cocks as well as normal and lacewing hens. He also claimed that another wellknown Belgian breeder had the same results out of a similar mating. In 1980 he mated a cinnamon cock of unknown origin to a cinnamon-opaline hen and in the first round he found one ino hen in the offspring. During the second round, however, a lacewing hen hatched totally unexpected.
Some of the earlier results could be very well explained by cross-overs in the sex-chromosomes of the cocks involved as I stated before, because cross-over rate in the sex-chromosomes of male Budgerigars is pretty high. My testmatings with slates and opalines provided evidence for this [3]. However, the Belgian results cannot be explained by cross-overs although I have no reason to doubt the data send to me. By introducing the possibility of the reappearance of the brownwing, an autosomal recessive mutation with the same phenotype as the cinnamon, some analyses could be made in which the Belgian results might fit, but unfortunately the Belgians didn't respond to this hypothesis and a most interesting discussion ended up in a dead end street. We have to consider the possibility of the reappearance of the brownwing as well as the recessive grey, but the main problem is, will they be recognized!! If the brownwing as well as the sex-linked cinnamon both are involved in the "Belgian" matings, than we have to deal with a very complicated situation.

In the second edition of Genetics for Budgerigar Breeders [7] professor Taylor describes a "painstaking" researchproject executed by Dr. Trevor Daniels to prove that lacewings are in fact cinnamon-inos. Dr. Daniels was so convinced that this was the case that he set out to prove it by trying to provoke a cross-over between the cinnamon and ino genes. He started with an initial cinnamon x ino mating and whichever way this mating is carried out, all the cocks derived from such mating are Type I split cinnamon-inos as described earlier in this article. The original mating actually used was a lutino cock to a cinnamon-opaline hen and six normal split (cinnamon-opaline)-ino Type I cocks were among the youngsters bred from this pair. Over the following years these cocks sired a total of 27 hens and of these hens 16 were inos, 3 were cinnamons (also as a result of cross-overs), 7 were cinnamon-opalines and one was an opaline lacewing! In addition to these results data were collected from other breeders who had made similar matings and no cross-overs out of 9 hens bred were found. Adding these two sets of results, a figure of one cross-over in 36 was obtained, i.e. a cross-over value of about 3% which actually means that these genes are very tightly linked and why normal split lacewing cocks usually 'breed true' [2,7].

In april 1992 Dawn Henderson (USA) [3] reported a mating involving a clearbody cock giving rise to two lacewing hens, one clearbody hen and one ino hen. Since a cock cannot be split for both lacewing and ino at the same time, it was presumed to be a poorly marked lacewing, but in fact it is quite well possible that this bird really is a lutino.

Thanks to the research of prof. Taylor [7] and the author himself [4], we do have a better knowledge of the cross-over values of the sex-linked genes of the Budgerigar today and a chromosomal map of the Z-chromosome comes therefore within our reach. To find an explanation for the "Henderson mating" involving a clearbody / lacewing cock, I made the following analysis.

Formula COCK : Z ino^cb_cin⁺/ Z ino_cin (clearbody/lacewing cock)

Formula HEN : Z ino⁺_cin⁺/ W (normal hen)

Number of all possible combinations crossovers included: 8

Number of different genotypes : 8

1) 24.25% Z ino^cb_cin⁺/ Z ino⁺_cin⁺ (normal/clearbody cocks)

2) 0.75% Z ino_cin⁺/ Z ino⁺_cin⁺ (normal/ino cocks)

3) 24.25% Z ino_cin/ Z ino⁺_cin⁺ (normal/lacewing cocks)

4) 0.75% Z ino^cb_cin/ Z ino⁺_cin⁺ (normal/cinnamonclearbody cocks)

5) 24.25% Z ino_cin/ W (lacewing hens)

6) 0.75% Z ino^cb_cin/ W (cinnamonclearbody hens)

7) 24.25% Z inocb_cin⁺/ W (clearbody hens)

8) 0.75% Z ino_cin⁺/ W (ino hens)

According to this analysis it is easy to see that there is approximately 0.75% chance that an ino can be found amongst the youngsters of this mating. Also the results of a testmating with this ino next season can prove if such bird is a badly marked lacewing or a real ino.

To clarify some misunderstandings according to the inheritance of the sex-linked varieties finally the following.
Some people state that the "lacewing gene" appears to be an allele of the sex-linked ino locus, but unfortunately I disagree with that statement and I will explain why. If Prof. Taylor is right about the lacewing being a cinnamon-ino than a separate "lacewing gene" does not exist and the lacewing is the result of the composition of the cinnamon and the ino gene. I always supported that point of view and until now nobody in the world has ever been able to prove the opposite. That is also the reason why the lacewing was also omitted from the international list of symbols proposed by the MUTAVI research group [4].
The lacewing cannot possibly be allelic with the ino gene and with the help of the symbols and a few matings I will try to make that clear.

The first mating proposed is a cinnamon cock to an ino hen, note that an ino cock mated to a cinnamon hen would give the same results according to the young cocks.

Formula COCK : Z ino⁺_cin/ Z ino⁺_cin (cinnamon cock)

Formula HEN : Z ino_cin⁺/ W (ino hen)

Number of all possible combinations : 4

Number of different genotypes : 2

1) 50% Z ino_cin⁺/ Z ino⁺_cin (normal/ino_cin Type I cocks)

2) 50% Z ino⁺_cin/ W (cinnamon hens)

Formula COCK : Z ino_cin⁺/ Z ino_cin⁺ (ino cock)

Formula HEN : Z ino⁺_cin/ W (cinnamon hen)

Number of all possible combinations : 4

Number of different genotypes : 2

1) 50% Z ino_cin⁺/ Z ino⁺_cin (normal/ino_cin Type I cocks)

2) 50% Z ino_cin⁺/ W (ino hens)

Both matings presented here result in normal cocks in the offspring and that is the ultimate proof that the cinnamon and ino genes are separate genes. However, a cinnamon cock mated to a lacewing hen result in cinnamon split lacewing cocks with the formula Z ino⁺_cin/ Z ino_cin and an ino cock mated to a lacewing hen result in ino split lacewing cocks with the formula Z ino_cin⁺/ Z ino_cin.

If we take a good look at the outcome of the matings presented it looks like the lacewing behaves if it is allelic with both cinnamon and ino at the same time but since we know these are separate genes that is quite impossible. The only plausible explanation is that the lacewing is indeed a cinnamon-ino and that leaves us to the question why the ino gene is not able to mask the cinnamon phenotype completely. However, there might be another explanation for these complicated events in the sex-chromosomes of the Budgerigar and I would like to discuss a new hypothesis in another article where I will discuss the sex-linked clearbodies.

Consulted and cited Literature:

[1] Davis G. (1992)
    Letters to the Editor
    The Budgerigar Journal (august/sept.issue); p.p.35
[2] Daniels T. (1981)
    Understanding Cinnamon Inos
    Cage & Aviary Birds Jan.17
[3] Henderson D. (1992)
    The Clearbodies, Our American Mutations
    The Budgerigar Journal (april issue); p.p.13-15
[4] Onsman I. (1992)
    Rules for a Standard Genetic Nomenclature for Budgerigars
    The Budgerigar Journal (june issue); p.p.19-21
[5] Onsman I. (1992)
    Crossing-over in the Sex-chromosome of the Male Budgerigar
    (Melopsittacus undulatus)
    MUTAVI website
[6] Rogers C.H. (1987)
    The World of Budgerigars; p.p.103-105
    Nimrod Press, Alton, Hampshire
[7] Taylor T.G., Warner C. (1986)
    Genetics for Budgerigar Breeders; p.p.45-46
    Publ.The Budgerigar Society, England