Many entomologists, who are breeding Sphingidae hybrids, have acknowledged, that in some cases, the males of the hybrids eclose, but the females do not.
Professors Dr. E. A. LOELIGER (The Netherlands) & Dr. FRIEDRICH KARRER (Switzerland) have worked on this problem. Their opinions and results are published in the paper: LOELIGER, E.A. & KARRER, F. (1996): "On the induction of metamorphosis of Lepidoptera by means of ecdysone and 20-hydroxy-ecdysone." – Nota lepid. 19 (1/2): 113-128.
My friend Dr. Habil Reinhard Predel and I were very interested in learning of this. Dr. Predel has modified the procedure of ecdysone-injection in, until now (March 11, 2006), twelve experiments (approx. 500 individuals) with good results.
A new question arose from those experiments. We wondered if we could use ecdyson to influence eclosions so that we could have Saturniidae from different continents emerge at the same time for the purposes of hybridization attempts. We recognized that, in the case of hybrids, the females may not be able to produce the metamorphosis hormone ecdysone. Thus, development in diapausing pupae might be delayed or inhibited.
Answers to these questions and a description of the procedure follow.
The following listed material was used for the procedure.
a) ecdysone C27H44O6, (2ß, 3ß, 14a, 22[R] 25 Pentahydroxy-7-cholesten-6-one),
made and supplied by Sigma, St. Louis (short-name: a-ecdysone, not ß-ecdysone!),
other deliverers are LUKA, Buchs,CH and ROHTO, Osaka,J
b) ethanol 100%
c) pure (de-ionized ) water H2O
d) paraffin solidum 54-56°C (melting point)
e) syringe for insulin-injection, calibrated, graduation line 10 µl
f) micro-cannula, size 6PK, 90mm/30g
g) ultrasound bath
How to prepare the injection-solution? The following data describe the preparation of 1 ml injection-solution.
h) Take 1mg ecdysone
i) Put it in 120 µl ethanol 100%
j) To improve dissolving use the ultrasound bath
k) Add 80 µl pure H2O
l) Use the ultrasound bath again
m) Wait approx. 10 minutes. The solution is ethanol 60%, this
concentration has the maximum power for disinfection
n) Add 800µl pure H2O
o) You have got 1 ml solution, containing 0,1% ecdysone in ethanol
12%. That means, 10µl (1 graduation line) contains 10 µg ecdysone
The necessary dose for the induction of metamorphosis was found to be 6…7 µg ecdysone per 1 g pupa-weight.
It is very important to work clean and sterile. We cleaned that part of the pupa where the injection was to be administered with 100% ethanol. We chose a dorsal location where the skin is thin between the fifth and six abdominal segments.
We did each injection very slowly with observation under a microscope. In most cases no, or only a little, body-liquid escaped. We closed each wound by using the low-temperature-melting paraffin.
The time between injection and hatching depends on the species and, of course, the storage temperature. Normally we use storage temperatures between 20 – 25°C. Generally we observe the following developmental times (some examples only):
14 days for the hybrid Smerinthus (ocellata x planus)
17 days for the hybrid Mimas (tiliae x christophi
30 days for (pure species) Marumba sperchius
22-35 days for most of the Saturniidae (pure species) and Brahmaeidae
such as Gonimbrasia tyrrhaea,
Automeris iris hesselorum, Antherina suraka, Eupackardia calleta,
Brahmaea christophi, Brahmaea hearseyi
We obtained very different results in the case of Saturniidae-hybrids. Our actual assumption is that in some cases there is another defect beyond the inability to form/create the metamorphosis hormone. Those results will be published in a subsequent paper.
Our European Sphinx ligustri normally has one generation per year only, flying in June and July. We treated pupae with ecdysone in September and obtained more than six hundred eggs from the female, considerably more than usual. Thus we we bred that Sphingid in October – November. Hybrids of Smerinthus (ocellata x planus) and Smerinthus (kindermanni X ocellata) produced the same result.
I wish to thank Rainer for putting
together this article. The implications are enormous, perhaps even
with human application. It is interesting to me that only a week
prior to receiving Rainer's article, I had reread the accounts
of Abraham and Sarah in "Genesis". It would seem that absence of a
particular hormone may block the development of eggs. I had always
thought that the slightly larger than full-sized hybrid females of
cecropia x columbia that I had observed in the wild and in
my own rearings were completely devoid of eggs. I had opened
the abdomens of at least two females to try and learn of the problem
(i.e., no egg deposition after a successful pairing). Now it seems
that the tiny egg buds are there and what is missing is the
hormone to trigger their development.
Perhaps the many women who have tried for years to get pregnant,
decide to adopt, and then suddenly find themselves pregnant,
have experienced a simple change in hormones that allows the
development and release of eggs.
I have no idea how close chemically the human fertility drugs are to
ecdyson.
I strongly advise that the inexperienced do not play with this procedure until there is a full account of dangers of any of the chemicals involved. The implications for hybrid females to carry eggs are also astounding. Perhaps all that is needed to trigger another round of speciation is a sunburst of higher radiation levels to "unlock" the blocking mechanisms.