The Axolotl Newsletter Contents Issue number 28 August, 2000 The Axolotl Newsletter is prepared at the Indiana University Axolotl Colony, Bloomington, Indiana 47405. The Newsletter is distributed online free of charge and is supported, in part, by funds from the National Science Foundation. Axolotl Art....................................................2 Peter Van Eeten I.U. Axolotl Colony Axolotl Colony News ....................................2 Director: George M. Malacinski Assistant Director: Susan T. Duhon Food for Urodela ..........................................3 Curator: Sandra J. Borland Henk Wallays Assistant Curator: Margaret M. Newberry Editor, Axolotl Newsletter: Susan T. Duhon Communicating with the Axolotl Colony Telephone: (812) 855-8260 Raising Metamorphosed Juveniles ............10 Henk Wallays Fax: (812) 855-6705 Practical Axolotl .........................................17 Email: [email protected] Sandra Borland World Wide Web: Instructions for Contributors ....................22 http://www.indiana.edu/~axolotl Mailing address: IU Axolotl Colony © Peter Van Eeten 2000 1001 E. Third Street Bloomington, IN 47405-3700 Printed copies of back issues 1-27 of the Newsletter are available. Single issues cost $1.50. Unless indi- Raising Metamorphosed Juveniles ............10 vidual numbers are requested, issues 1-9 and 11-14 Henk Wallays are sent reduced in size and bound together. The set containing issues 1-9 costs $10, and the set con- Practical Axolotl.........................................17 taining issues 10-14 costs $5. Contents are listed Sandra Borland on our Web site. Indices for numbers 1-15 are in issue 15 and for numbers 16-20 in issue 20. Issue 25 contains indices for issues 21-25. Beginning with Instructions for Contributors ....................22 issue 26, the Newsletter is available free online at the Axolotl Colony Web site. Copyright 2000, The Trustees of Indiana University Axolotl Newsletter Number 28 © Peter Van Eeten 2000 Axolotl artwork by Peter Van Eeten, Melbourne, Australia Axolotl Colony News Grant Renewal! The National Science Foun- Thomas & Son International Co., to assist us dation grant that, along with user fees, sup- with international shipments. This company ports the Axolotl Colony was renewed this acts as our agent in Chicago (the port of ex- year for three years. We want to thank all our port) and makes sure that all of our packages users and others who have put in a good word get inspected and go out with the proper pa- for us and supported our efforts over the perwork and on time. Although the additional years. fee (usually about $60) makes the material more expensive for the user, we have been New Staff Member. We have added an assis- saved a world of trouble with lost packages, tant curator to the colony staff. Her name is unstamped paperwork, and delayed delivery Meg Newberry, and she will be working closely that made international shipments so frus- with Sandi and Susan to improve animal trating before for everyone concerned. stocks and deliver better service to you, the user. Meg has her B.S. degree in biology from Services. In addition to supplying live axolotl IU, and she has experience as an animal care- material, remember that we are able to pro- taker and laboratory assistant. Her help is vide other research services as well, including especially appreciated because, since May, early embryo injection (dyes, mRNA) and fix- Susan has been working in the colony only ing and freezing of staged embryos. Charges halftime. for these services are by the hour, plus the usual charge for the embryos. For more infor- International Shipments. As some of you mation, contact the Axolotl Colony. know, we now use a freight forwarder, Phil 2 August 2000 worms normally don’t fit into their diet. Ex- Food for Urodela amples are the mid-American tree salaman- ders of the genera Bolitoglossina or Oedipus. Other little salamanders have such a narrow Henk Wallays mouth that worms simply don’t fit in them (for Ter Goedingen 40 example, Plethodon cinereus). One of the ma- 9881 Bellem (Aalter) jor points (for any food resource) is to choose Belgium the size of the prey in relation to that of the [email protected] predator. The general idea is that the sala- mander eats the worm and not that the worm Worms strangles the salamander. Worms are rich in calcium and thus impor- Most salamanders are crazy about worms. tant for growth. Feeding juvenile axolotls There are several species of worms around, solely on earthworms resulted in 15-cm long however, and not all of them are equally ap- axolotls in one year, a length they failed to preciated by our salamanders. reach when I fed them solely with blood- Worms that live on animal-waste products worms. On the same feeding schedule, young are best avoided since—through their feed- Hynobius dunni doubled their size in only two ing—they can contain toxic products. Some months. Urodeles that readily accept worms salamanders such as Pachytriton and include species belonging to Salamandra, Am- Paramesotriton species will refuse to eat them. bystoma, Pseudotriton, Gyrinnophylus, They will first smell them, eventually take a Cynops, Paramesotriton, Neurergus, Necturus, first bite, and then spit them out again. When and Taricha. buying worms in pet stores, you will probably get tropical compost worms. These are ac- Slugs cepted by some species, but not by all. The trouble with them is that when attacked they When gardening among my hosta, fern, and will excrete a milky secretion, which is not bamboo, I’m always happy to discover that I appreciated by all of our tailed friends. have a garden that’s very rich in slugs. My There also exist a lot of insect-eating sala- wife—who is an enthusiastic plant lover— manders, such as the Plethodontidae, and doesn’t share this sentiment with the same ©Henk Wallays Northwestern salamander (Ambystoma gracile) enjoying an earthworm meal. 3 Axolotl Newsletter Number 28 ©Henk Wallays Axolotl (Ambystoma mexicanum) and bloodworms. enthusiasm, however. The slugs congregate in Enchytraeids the shadowy damp places of the garden, un- derneath stones and, especially, wood or plas- These little white worms are quite easy to tic. I offer them to most of my Amercan mole breed and keep at room temperature (20 °C). salamanders, who chase them with much ap- Whereas Daphnia are the main source of food petite. Remarkably enough, they are left un- for aquatic young, enchytraeids have an im- harmed by most of the Hynobius species. Am- portant place in the feeding of terrestrial juve- bystoma maculatum and A. macrodactylum, niles. I culture my enchytraeids in plastic pots especially, are true slug chasers. In older lit- filled with composted soil, on top of which I erature (Lacerta, Holland) we also read a story lay a piece of newspaper (to create a layer of that tries to link fertility with feeding with darkness and humidity). The ground is quite slugs. moist, but not swampy. When I need worms, I mix a large spoonful of rolled oats into the Tip. An easy way to catch slugs is to put a soil. At a temperature of about 17°C, it takes sheet of newspaper for a few minutes into a about a week to have large masses of little dish with beer, and then put the beer-soaked white worms ready to offer to your precious paper outside in a shady place underneath young. The worms can also be offered to some stones. It’s common knowledge that aquatic-stage larvae, since they tend to move slugs are attracted by beer. You can harvest around quite a while (hours) and thus attract them each morning. the attention of the larvae. Rearing enchytraeids with the usual milk and cheese Aphids method yields worms that contain much fat, which, when offered frequently, are said to In the middle of the summer, when the usual cause liver trouble. I offer enchytraeids espe- food resources were getting scarce, I once took cially to young Ambystoma, Cynops, an aphid-infested leaf from a rosebush and Neurergus, and Hynobius. placed it in the raising tank of my juvenile Cynops pyroghaster. After two days, the quite Tip. If you want to start a fresh culture, here’s starved Cynops showed off a nicely filled belly a tip for catching them. Find a convenient again. However, if you plan on feeding aphids, compost heap and put in a slice of bread in a take care to cut only branches of trees or damp place by the heap. Leave it there for two shrubs that you are sure have not been days, then dig it up: normally, you will find treated with insecticide. lots of enchytraeids underneath the bread. 4 August 2000 Bloodworms jelly layers in order the reach the egg, on which they feed. One ends up having eggs Whereas earthworms are the main dish for the that look like they have imploded; the eggs terrestrial adults, bloodworms play an impor- shrink day by day. If this sounds familiar, tant role in the diet of larvae and aquatic ani- start checking the underside of the stones. So mals. In Belgium, we have three sorts of mos- far I have not found a method for eliminating quito larvae: translucent white, black, and only the planaria from the tank, without red. The red form is most suitable: they move harming the other inhabitants. Raising the more and have a striking coloration, making salt level in the tank seems to work well, but them easy for larvae or adults to discover the mortal limit of planaria will also harm the them. Especially at night, you will be able to urodela, which are not too keen on brackish see them dancing around through the pursu- water, either. A simple solution is to clean the ing salamanders. They can be purchased at a entire tank by hand.