As promised in the previous Newsletter you'll find my observations on the male mating strategy of Hynobius dunni included (bottom), along with some updates on my breeding results. We are still searching for adequate stud book software... any help would be welcome.
New Version of this Newsletter
I'm slowly starting to think about adding images to this Newsletter (little jpegs of about 10-15 K). Since I know that some of you have emails that do not support graphics, I would have to split up the Newsletter in 2 forms : an 'imaged' or 'plain text' version. Without reaction from your side I will continue to mail the plain text version. If you are interested in the pictured version, please contact me.
Breedings
Only a short update on this side. We have finally started (re)counting the Hynobius breedings.
Hynobius retardatus
All the Hynobius retardatus are now on land, most of them are looking very fine: they are not only brown as their parents, but they also have brass-colored patterns on their back, which makes them shine really beautifully in the sunlight. Like Aneides ferreus, this coloration is not easy to photograph, since both with the flash and under sunlight it seems to loose some of its depth. Anyway, I have counted 42 slender looking animals. In contrast with other Hynobius species, this species is quite bold: you can find them from time to time out in the open, sitting on top of a stone or bark. The other Hynobius species have a far more hidden life-style. Another contrast is that juvenile H. retardatus are quite picky eaters, whereas H. dunni really act like little vacuum cleaners, inhaling anything they can put their mouth around. I have written down my experience with this species in a Dutch article, which I will propose for the book of the 20th anniversary of the Dutch Royal salamander circle.
Hynobius dunni
Finally the larvae have started metamorphosing. Once the larvae reach the length of 3 cm they are very hardy and as such drop-outs after that period are rare. Over the former 3 breeding years I have had my share of troubles in raising them, but I seem to have solved this now. The larvae were distributed among 12 separate heavily planted rearing tanks, which made counting quite impractical. The general idea was to raise them as successfully as possible. As they metamorphose, I now am moving them over into wet terraria (as described in Axolotl Newsletter 28). Currently I already have 177 juveniles on land and there are still 102 large larvae (close to metamorphosis) swimming around. So this does look like I have been able to raise 279 animals and as such I will probably get stuck with a surplus for quite some time. (They are very hardy.) However I thought that the signal that Hynobius dunni needn't be too difficult to raise also has its value, especially since this species has been put on the red data list of Japan as a 'sensitive' species (meaning that they are in the stage of becoming a threatened species). Currently about 8 -12 more animals metamorphose per day. Perhaps needless to say, next year I will probably not be rearing offspring of this species in such masses again.
Tylototriton
The juveniles from the last breeding have already been on land for quite a while and are doing well. In particular, the large metamorphosed ones (over 6 cm) are the easiest group to raise: there are no drop-outs. Animals that are metamorphosing below that length need more care and... even with that, one still looses some of them anyway. With the weather getting warmer over here, I have decided to set these animals outside in one of my underground rearing terraria (see pd. version of the Axolotl Newsletter). They are doing great and have grown considerably in that period. One important thing to add is that the more decaying wood is present in the tank, the better thesalamanders seem to thrive in it: it holds down humidity well and attracts possible prey-animals. Due to this positive outcome, I have also decided to set outside my T. taliangensis and so far the results are fine. They seem to eat well and grow, but this species is no match with the growth rate of the ever-hungry T. verrucosus. The 3 young T. shanjing are also doing fine in their indoor enclosure. This species is kept in a quite dry tank, which gets misted from time to time. Any other salamander species would not like this dry area, but they just seem to love it.
Currently my T. verrucosus females have started breeding again in different waves. I have set aside 10 eggs from the first batch and now recently some 30 more. The first batch have meanwhile turned into larvae. The eggs are kept at 22°C. The adult animals are currently kept in an aquarium with a little land area and 15 cm of water. The tank is partly filled with Fontinalis sp. between which the females like to lay the eggs. Some of the eggs are also laid on land. I have also observed the clasping of the female by a male , quite similar to the behavior of the closely related Pleurodeles waltl . Two days after that behavior, the egg-depositions started. At first, looks like the gravid female wants to break out of the tank, she starts to swim vigorously and tries to crawl out of the tank (especially active in the corners). The next day the egg deposition started. One female started laying the eggs and practically as soon as they were laid another female came after her and started 'cleaning up' the eggs. Lucky enough this deposition started on Saturday and I was able to intervene each 2 hours. About 20 eggs were thus saved...
Neurergus
Here the news is less positive: in the N. crocatus group it looks like trouble is really starting to set in. The second adult male is rapidly loosing weight, whatever I try. I had this same phenomenon occurring last year in the first male. I have meanwhile lost this specimen due to that trouble. So unless a miracle occurs, this will mean a temporary stop to my breeding results of this species for 2 years (the time for the juveniles to become adult).
The females on the other hand are doing fine. The remaining group of juveniles (15) will thus be a key factor in the further captive propagation of this species. In the event of a future re-breeding I will certainly try keeping them outdoors since this seems to go far better.
Taricha granulosa
Around the end of March, I had discovered some eggs in the parental tank. Since I intended to leave soon for the Oregon / California trip, I chose to set out the eggs in the (escape-proof) outdoor pool... and after that totally forgot about them. Now this weekend I decided to clean up the pool and found 4 juvenile Taricha granulosa. The animals still had gills, but already showed the corrosive skin... so they were close to metamorphosis. In a way, this comes out as an unexpected breeding, which we will of course try to rear for the best now. Although I cannot really say that I have done much for this breeding I'm still quite happy with the final result since this is my first captive breeding of this species. They will first be raised up until they are semi-adult in order to see the gender since I would need some more females to calm down the ever clasping males... (getting the other females off the hook).
WebPages
This time this topic will be perhaps be slightly immodest since I now point out a Russian site, which also holds some of my articles. I hope you will enjoy this.
http://www.callisto.ru/amphibia/henk/hwpage.htm
Alexandre Tsoukanov is a Russian amphibian keeper who has built up an interesting site. You will find good information on various species. Especially the article on the Hynobidae holds my personal interest. Alexandre has also done the painstaking work to set up a Moscow oriented webpage on my behalf with articles (+ images) on 'Pachytriton C', 'Food for salamanders', 'Raising techniques for metamorphosed juveniles' and the first part of my Oregon trip reports (still need to write down the second report).
Remark : This site seems to have troubles when not addressed through Internet Explorer!
Miscellaneous
T. asperrimus & T. wenxianensis
Xie Feng and Max Sparreboom have mentioned that they will study T. asperrimus ( and its 'related' T. wenxianensis) so I hope that I will be able to report more on this when this sees the light of publication.
Slide scanners
Currently my slide collection has grown to considerable size ( > 2000 items) and I am considering buying a slide scanner. As such, I have been diving into some technical literature and have read some interesting reports. Although there are many different slide scanners on the market, it looks quite like the Nikon Coolscan series are unbeaten masters at this game. Currently (2 months ago, I think) this firm has released their new Coolscan IV or 4000 which should be top of the line for the serious amateur and even for professional use. The dpi density of the images is up to print quality...
size="2" Whereas the IV (US$850-900) can scan in one slide at a time, the 4000 (approx. $1500) has a slide mounter. Also the dpi of the 4000 is slightly higher... but altogether these differences do not seem to add up to the price difference (personal note). They also have a Coolscan 8000 available, but the price of this beauty is (unfortunately) out of proportion to my needs (I think it is around $3000-4000).
Articles
Currently I'm in the final process of finishing 4 articles, which I will submit for the former mentioned book of the 20th Anniversary of the Dutch Royal Salamander circle. They will be send out by the end of this week, and for now I have no idea if any will be published. These articles concern my observations and breeding reports on H. dunni ,H. retardatus, and N. crocatus plus a general article on Hynobius species. This last article is in fact a literature overview on various taxonomical and ecological reports (with some minor personal additions). After publication, I will try to translate them into English.
The next project after this will be to re-vitalize the so far unedited 'Tales on Asian tales' story that I had once written down (almost 3 years ago). It concerns an article that discusses the 'Asian fire-bellied newts (Pachytriton , Cynops & Paramesotriton)' with tips on how to keep, breed, raise, sex, and feed them. So this article really talks about Chinese/Japanese newts. In the time-lapse of 3 years, some new information has become available on these animals and thus I really need to revise it.
Currently I'm trying hard to dig in a little deeper into resources on the lesser known Chinese Cynops species (like C. chengongensis, the extinct C. orphicus and C. cyanurus). This last species is currently kept by a small group of European keepers, but it's still a species that has not given up all of its secrets. Breedings are irregular, raising of the larvae troublesome, and there's still an unusual apparent preference for warmer temperatures (which is somewhat puzzling for what is considered to be a high altitude newt). Personally I have not been successful keeping this newt at all.
Hynobius dunni: male breeding strategy
Installation of the tank
The tank is 80 by 60 cm long, water depth was 15 to 20 cm. The back of the tank consists of broken stones, with loads of gaps. In between and on top of the stones, there's about 10 cm of moss which by its capillary function creates various degrees of humidity. The animals like to hide in between the gaps of the stones especially in the quite wet places (Wallays 2000). In the front of the tank we introduced branches of trees in order to obtain spawnings and to be able to follow the mating-strategy of the males.
Observations
In contrast with the other years, we were able to observe the major part of the mating strategy of the males. On one of the first/few sunny afternoons in a long-lasting winter and an unusually cold spring, 3 males started to get active around 13:00 (18 march 2001). In former years, this activity had started as much as 2 months earlier. We noticed one little (C) and one large animal (B). The middle male (A) had the most pronounced white coloration on his throat, and this animal also proved to be our key player.
1.Males
At first all the males are walking around on the bottom of the tank (wandering phase) and were quite interested in the introduced branches. From time to time they started climbed on them (climbing phase), most of their interest was clearly focused upon those branches which were placed horizontally just underneath the water surface. Unlike the other 2 animals, male A did not only wander and climb, he also had a peculiar spot to which he seemed to return from time to time (spot A). This branch was oriented horizontally and just situated underneath the water surface. (There were other spots like this). He kind of hooked himself laterally onto it with one hindlimb and started tail waving. Through the high positioning of the branch, the upper side of his tail broke the water surface while fanning, which made the standing water move in ripples. At the same time, he oriented his throat downwards and kind of blew up his already thickened throat. I call this behavior of fanning and blowing up the attraction phase.
When none of the females reacted upon this phase, male C let himself either glide back onto the ground, restarting the wandering /climbing phase, or started rubbing his cloaca on the same spot where he had been tail fanning. I call this behavior the marking phase. When there was no reaction to that phase, he fell back to the wandering phase. He did not always go from attraction phase to marking phase.
The whole cycle (wandering, climbing, attraction, and marking phase) were repeated many times without success. About every 10 to 15 minutes the attraction phase was displayed.
2. Males & females
During some moments gravid females did walk by and when they did, they took the interest of the males. Especially when one of them started climbing onto the branches (their body is so thick with eggs that they have difficulty swimming) all the males came closer. Because I was trying to shoot slides at some of these moments, I did loose some part of the overview, but at a given point I always ended up having 4 animals in a square of at most 10 cm. In that phase, the males behaved nervously and most of the times their nervous behavior ended up pushing the female off the branches (by accident, off course)
3. Interested female
At a certain quiet moment, male C again started to display the attraction phase. In the direct visible environment there were no females (30 cm around). The male had just but started to tail wave when all of a sudden a female reacted upon this. Her time of reaction was, considering the distance, kind of unrealistically quick. She came from underneath the stones onto the branches and climbed on them towards the male. Almost undistinguishable the other males had also started to get closer (again) and in this hectic moment the female was again pushed down by the over-active males. In this heated moment, I have also seen one male threatening another with a wide-open mouth. I have only observed this once aggression once.
Around 15:15 I had to stop my observations. At that time, I had witnessed 7 failed approaches of the females. When I arrived home 3 hours later I found a fresh laid, rumpled egg sac attached at point A. In the following week, 2 more egg sacs were laid; they were also attached in the direct environment of point A.
Considerations
Apart from that one time aggression, I could not witness territorial behavior like it is described by Tanaka (Hynobius naevius, Hynobius nebulosus), Thorn (Hynobius nebulosus) and T. Kusano (Hynobius tokyoensis). I am aware of an article by Mashiba on reproduction of Hynobius dunni, but I have not been able to obtain it so far and even when I get it there's still the matter of the translation to consider (it's entirely written in Japanese).
In contrast with Tanaka's findings, it was not the largest male which played the key role in this story. But since these observations were done on a small group of animals, we really should try to re-observe this behavior next year. At that point, 24 extra animals (F-1 1999) will be sexually mature. The voluntarily disturbance of the water surface by a tail fanning male has also been described with H. nigrescens (Usuda, 1995). Thorn also mentions that H. retardatus has a similar preference for a horizontally oriented rhizome.
The whole cycle has been photographed (slides), with the sole exception of that single instance of aggression. Next year we will try to record the observations with means of a (motion sensored?) video camera.
This observation is part of a larger article on the captive husbandry of this species. The other observations consider the installation of the tank, the results of 4 consecutive breeding years, and some considerations/differences of this species in relation to the breeding of my other Hynobius species. As a result of the 2001 egg depostion, we have raised the larvae: at least 150 to 200 juveniles will make it into metamorphose.
Literature
Kusano, T. 1982. Postmetamorphic growth, survival, and age at first reproduction of the salamander Hynobius nebulosus tokyoensis Tago in relation to a consideration on the optimal timing of first reproduction. Researches on Population ecology 24(2) : 329-344
Tanaka K. 1986. The territorial behavior of Hynobius takedai in the breeding season (Amphibia : Hynobiidae). Japanese Journal of Herpetology 11(4) : 173-181.
Tanaka T. 1987. Body Size and Territorial behavior of male Hynobius takedai in Breeding Season (Amphibia :
Hynobiidae). Japanese Journal of Herpetology 12(2) : 45-49.
Thorn R, 1986, Propos sur le comportement sexuel et sur la reproduction en captivité chez quatre éspeces de Salamandres de la famille des Hynobiidés (Amphibia, Caudata), Bull. Soc.Nat. luxemb. 86 : 67-74
Thorn R, 1991, Observations et notes sur diverse especes dce Salamandres (Amphibia, Caudata), Bull. Soc. Nat. Luxemb. 92 : 79-83
Wallays H, 2000, Raising metamorphosed juveniles, Indiana university Axolotl Newsletter 28 : 10-17
If anyone has information judged useful for this newsletter, please feel free to contact me.
Best wishes,
Henk Wallays
Henk Wallays
Ter Goedingen 40
B-9881 Bellem (Aalter)
Belgium