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August 2000

Worms

Most salamanders are crazy about worms.There are several species of worms around,however, and not all of them are equally ap-preciated by our salamanders.

Worms that live on animal-waste productsare best avoided since—through their feed-ing—they can contain toxic products. Somesalamanders such as Pachytriton andParamesotriton species will refuse to eat them.They will first smell them, eventually take afirst bite, and then spit them out again. Whenbuying worms in pet stores, you will probablyget tropical compost worms. These are ac-cepted by some species, but not by all. Thetrouble with them is that when attacked theywill excrete a milky secretion, which is notappreciated by all of our tailed friends.

There also exist a lot of insect-eating sala-manders, such as the Plethodontidae, and

worms normally don’t fit into their diet. Ex-amples are the mid-American tree salaman-ders of the genera Bolitoglossina or Oedipus.Other little salamanders have such a narrowmouth that worms simply don’t fit in them (forexample, Plethodon cinereus). One of the ma-jor points (for any food resource) is to choosethe size of the prey in relation to that of thepredator. The general idea is that the sala-mander eats the worm and not that the wormstrangles the salamander.

Worms are rich in calcium and thus impor-tant for growth. Feeding juvenile axolotlssolely on earthworms resulted in 15-cm longaxolotls in one year, a length they failed toreach when I fed them solely with blood-worms. On the same feeding schedule, youngHynobius dunni doubled their size in only twomonths. Urodeles that readily accept wormsinclude species belonging to Salamandra, Am-bystoma, Pseudotriton, Gyrinnophylus,Cynops, Paramesotriton, Neurergus, Necturus,and Taricha.

Slugs

When gardening among my hosta, fern, andbamboo, I’m always happy to discover that Ihave a garden that’s very rich in slugs. Mywife—who is an enthusiastic plant lover—doesn’t share this sentiment with the same

Food for Urodela

Henk WallaysTer Goedingen 40

9881 Bellem (Aalter)Belgium

henk.wallays@skynet.be

Northwestern salamander (Ambystoma gracile) enjoying an earthworm meal.

©Henk Wallays

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Axolotl Newsletter Number 28

enthusiasm, however. The slugs congregate inthe shadowy damp places of the garden, un-derneath stones and, especially, wood or plas-tic. I offer them to most of my Amercan molesalamanders, who chase them with much ap-petite. Remarkably enough, they are left un-harmed by most of the Hynobius species. Am-bystoma maculatum and A. macrodactylum,especially, are true slug chasers. In older lit-erature (Lacerta, Holland) we also read a storythat tries to link fertility with feeding withslugs.

Tip. An easy way to catch slugs is to put asheet of newspaper for a few minutes into adish with beer, and then put the beer-soakedpaper outside in a shady place underneathsome stones. It’s common knowledge thatslugs are attracted by beer. You can harvestthem each morning.

Aphids

In the middle of the summer, when the usualfood resources were getting scarce, I once tookan aphid-infested leaf from a rosebush andplaced it in the raising tank of my juvenileCynops pyroghaster. After two days, the quitestarved Cynops showed off a nicely filled bellyagain. However, if you plan on feeding aphids,take care to cut only branches of trees orshrubs that you are sure have not beentreated with insecticide.

Enchytraeids

These little white worms are quite easy tobreed and keep at room temperature (20 °C).Whereas Daphnia are the main source of foodfor aquatic young, enchytraeids have an im-portant place in the feeding of terrestrial juve-niles. I culture my enchytraeids in plastic potsfilled with composted soil, on top of which Ilay a piece of newspaper (to create a layer ofdarkness and humidity). The ground is quitemoist, but not swampy. When I need worms, Imix a large spoonful of rolled oats into thesoil. At a temperature of about 17°C, it takesabout a week to have large masses of littlewhite worms ready to offer to your preciousyoung. The worms can also be offered toaquatic-stage larvae, since they tend to movearound quite a while (hours) and thus attractthe attention of the larvae. Rearingenchytraeids with the usual milk and cheesemethod yields worms that contain much fat,which, when offered frequently, are said tocause liver trouble. I offer enchytraeids espe-cially to young Ambystoma, Cynops,Neurergus, and Hynobius.

Tip. If you want to start a fresh culture, here’sa tip for catching them. Find a convenientcompost heap and put in a slice of bread in adamp place by the heap. Leave it there for twodays, then dig it up: normally, you will findlots of enchytraeids underneath the bread.

Axolotl (Ambystoma mexicanum) and bloodworms.©Henk Wallays

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August 2000

Bloodworms

Whereas earthworms are the main dish for theterrestrial adults, bloodworms play an impor-tant role in the diet of larvae and aquatic ani-mals. In Belgium, we have three sorts of mos-quito larvae: translucent white, black, andred. The red form is most suitable: they movemore and have a striking coloration, makingthem easy for larvae or adults to discoverthem. Especially at night, you will be able tosee them dancing around through the pursu-ing salamanders. They can be purchased at alocal fish store

Problems

Egg penetration. I’ve already observed blood-worms that penetrated the outer layers ofeggs. Whether they are actually damaging theegg or not, I’ve not yet been able to verify.

Planaria. While feeding with bloodworms, onealso imports eggs of other, more harmfulthings into the tank. One of them might beplanaria. This little grey flatworm, recogniz-able by its triangle-shaped head, has an insa-tiable appetite for salamander eggs. Theyavoid direct light and start crawling aroundonly during twilight, when they leave theirhideouts (underneath a stone or leaf) andclimb on the sides of the tank. While breedingNeurergus strauchii in 1996 and 1997, I lostwell over 80% of the total egg package becauseof planaria. They intrude through the different

jelly layers in order the reach the egg, onwhich they feed. One ends up having eggsthat look like they have imploded; the eggsshrink day by day. If this sounds familiar,start checking the underside of the stones. Sofar I have not found a method for eliminatingonly the planaria from the tank, withoutharming the other inhabitants. Raising thesalt level in the tank seems to work well, butthe mortal limit of planaria will also harm theurodela, which are not too keen on brackishwater, either. A simple solution is to clean theentire tank by hand. Another practical solu-tion is to move the salamanders to anothertank and put little fish in the planaria-filledtank. Some cold-water fish will eventually eatthem (sticklebacks do).

When temperatures start to rise suddenlyduring the springtime, most bloodworms innature will metamorphose and become mos-quitos. In this short period, which most unfor-tunately always seems to coincide with thereproductive period of the salamanders,bloodworms will not be available in the shops(unless they carry imported material).

Tips for raising juveniles

Terrestrial juveniles can easily be fed withbloodworms, too. Take a piece of wet papertowel and put some bloodworms on it. The wetsubstrate will keep them alive a long time,and the wriggling red worms on the whitesubstrate are sure to attract the attention of

©Henk WallaysPlanaria

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Axolotl Newsletter Number 28

Livingstone©Biodidac

size of the larvae to be fed. This can be doneby sifting them through some fine Daphnianets, which are avail- able in varioussizes. To assure maximumuptake, it’s best to offerDaphnia the size of thelarvae’s eyes. In this way,larvae don’t waste un-necessary ef- fort or energytrying to catch and swal-low Daph- nia that aretoo large for them. Whent h e r e ’ s enough light-i n g , nonconsumedDaphnia will stay alive inthe tank, offering the advantage that theyclean up the water while feeding. On the otherhand, food stays available, and when theDaphnia reproduce, you end up having youngDaphnia in your tank year round.

Where. Daphnia can be purchased in sometropical pet shops. During the summermonths, they can be massively available instagnant water containing much plant debrisor animal waste, sometimes in such densi-ties that the water appears reddish. A smallduck pond (in a park) is a handy source.You’ll also be surprised how many Daphniayou will find if, during the winter, you netthrough waterweeds in a well-filled gardenpond (even under ice).

the young hunting salamanders. After feeding,you simply take away the paper towel, so youdon’t get the urodarium dirty. I have success-fully used this technique in raising Cynops,Paramesotriton, and Triturus species.

Cyclops

It’s best to avoid feeding larvae these littlecrustaceans, since they will attack the larvae.High densities of Cyclops can result in thedeath of the larvae and negate most of yourefforts in raising the species.

Artemia

Most people who have formerly kept tropicalfishes know about this food resource. Theeggs are for sale in the tropical fish stores andcan, through an easy process, be hatched andraised in salt-enriched water. The orangebrine shrimp can then be offered, and, despitebeing released in freshwater, they tend to stayalive for awhile. Just as with Daphnia, theseshrimp seem to contribute a lot to the red col-oration of the belly of firebellied newts.

Problems

Separating the shrimp from the remainingeggshells is quite important. After feedingsome Pleurodeles waltl larvae with Artemia,the larvae suddenly started developing gasbellies and floating around the water’s sur-face, and finally dying off. After a search witha microscope, remains of eggshells were foundin the intestines, blocking them off.

Daphnia

Feeding larvae of Asian firebellied newts(Cynops, Paramesotriton) frequently withDaphnia will enhance the red belly coloration.We frequently notice captive-bred species withorange bellies; feeding them with Daphnia justmight make a difference. Adult newts are will-ing predators on Daphnia, too. Currently, itlooks as if feeding Daphnia to Neurergusstrauchii might—surprisingly—be trouble-some. Further observations and investigationsare, however, necessary to confirm this.

Tips. For the raising of salamander larvae,Daphnia and their young play an importantrole in the early phase: they are the mainsource of food for most captive-bred species.One should choose their size in relation to the

Mysis (Freshwater Shrimp)

In some brackish water, it’s possible to findMysis. This creature looks like a little shrimpand can be eaten by various aquatic sala-manders. I have, however, not yet worked withthis food resource. It’s also not an easy task tobring home captured Mysis alive.

Fruitflies and Their Larvae

In most terrarium pet shops, you can buy thewell-known pots with fruitfly maggots. Theyare, perhaps, more commonly used by frogkeepers, but they also have a value for theurodela keeper. Some plethodonts are mainlyinsect eaters. For little species such asPlethodon cinereus, they are good-sized prey,which in no time will be discovered and cap-tured by means of a sticky tongue. Land-phase juvenile salamanders will accept bothflies and larvae. The maggots, however, aredelivered in a smelly paste, which is better notspread around the raising tank. Offering them

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in a small pot, on the other hand, carries therisk that your juveniles will fall into thisswamp and drown. For this reason, I herewithquote a nice, clean, and practical solution,which was originally worked out by HenriJanssens, Brugge, Belgium.

Take a piece of a plastic electric tubing andseal off one of the ends. Fill the tube halfwayto two-thirds full with the jelly and maggots.Cover the other end with a fine mosquito net-ting. Place the tube in the rearing tank withthe end with netting somewhat higher thenthe sealed end. When the maggots want tospin their cocoon for their metamorphosis,they will search for a dry spot and start climb-ing out the open end—where after a while theyoung salamanders will know to find them.

Waxmoths and Larvae

Waxmoths are very nutritious and fairly easyto breed and keep. There are various ways ofraising them; one is to make your own mix-ture, and another consists of keeping them onused wax combs, which you might obtainfrom someone who keeps bees as a hobby.However, in this last case, it’s better not topronounce the name of this little insect intheir hearing. One escaping waxmoth mightmean the end of their hobby.

Tadpoles

Tadpoles are frequently predated on by newtsin nature, so it must not be a shock to seethis food item on the list. I have personallyobserved predation by adult Alpestris on frogeggs. The newts started crawling over the eggmass and picked out just the eggs. After thefestival, only an empty transparent jelly re-mained. Species like Pachytriton andParamesotriton just love tadpoles and willchase them around in the tank. However, beaware that most European frog and toad tad-poles are protected by law. So you will need tobreed the frogs if you want to offer this type offood.

Fish

Some of the larger neotenic species, such asAndrias, neotenic Ambystomids, and Necturus(to name a few), will also eat live fish. Thisfeeding behavior has given mudpuppies andother species a very negative name to sportsfishermen. The overall damage mudpuppiescan do to salamander populations has been

quite exaggerated, however. But anyway, youcan readily offer little fish to these species.

Buffaloworms

You can purchase these little mealworm-likeanimals in some pet shops as food for exoticbirds. They are tinier in size than mealworms,and I have offered them to various sorts ofterrestrial urodela such as Ambystoma,Plethdontidae, and even Hynobius. Especiallywhen raising juveniles of Hynobius, Am-bystoma opacum, and Macrodactylum, such afood resource comes in handy. As in the caseof mealworms, one should not feed solelythese little worms, since they are rich in fatand are said to cause liver troubles.

Problems

Don’t feed buffaloworms in polystyrene foam(for example, Styrofoam or Tempex) boxes:they will eat their way through, making little‘ventilation holes.’ The danger with this is thatthey get eaten on the way by the salamanders,who at the same time devour the Tempex.This can lead to constipation and eventualdeath of the juveniles.

Beef heart

Beef heart can be purchased at a butchershop or at the meat counter of a grocery store.It might not look or smell appealing, but it is apowerful food resource for salamanders. Somesalamanders used for lab research are mainlyfed on this. For the larger species, it’s suffi-cient to cut the meat into little strips andmove it in front of the animals. Most of themwill react to the movement and snap at it (e.g.,Ambystoma gracile). For aquatic urodela, Icut the meat in pieces and stir it thoroughlyuntil it becomes a paste. Then I take an ice-cube tray from the freezer and divide the meatinto little portions and freeze it. From one beefheart you can get a lot of food. Fifteen min-utes before you want to start feeding you canpick out one of the cubes and let it thaw (orput it in the microwave briefly), then divide itamong the different tanks. The scent of bloodwill spread through the water and most of thenewts react to it quite soon. Streamside sala-manders, especially, are very successful inlocating the prey and can react quite aggres-sively. I have successfully tried out this foodresource with Pachytriton, Paramesotriton,Neurergus (strauchi and crocatus), Cynops,

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Axolotl Newsletter Number 28

axolotls, Triturus, and Pleurodeles, and evenaquatic Gymnophiona such as Typhlonectescompressicauda. In Oregon (USA), we evenbarehandedly caught neotenic Dicamptodonsthis way. After a short adaptation period—torecognize and appreciate the food—most sala-manders readily ate this food resource, whichmight just make the difference during theperiods of the year when other supplies areunavailable (early spring and midsummer).

Problems

Water pollution. Leftover pieces of beef heartshould be removed from the tank, since theypollute the water. This problem can beavoided by the introduction of meat-eating redwater snails. In contrast with the othersnails—who mainly devour plants—this redform prefers flesh. But, on the other hand,they might also eat some of the salamandereggs (e.g., Cynops and Neurergus). If you offerbeef heart frequently, water changes shouldbe performed on a regular basis, too.

Housefly maggots. This food resource stillmeets with much discussion; some people talkabout the danger of perforated stomachs orintestines, other people just praise it. I willnot take in a position in the debate, but canonly confirm that, over the years, I have raisedquite a lot of salamanders (Hynobius,Neurergus, Ambystoma, Triturus, Pachytriton,Cynops) on this easy and cheaply availableresource without encountering troubles. Onlythe Paramesotriton are not too crazy about it.

Tip. From a urodela meeting in the Nether-lands, I have the following practical tip fromEdo Van Uchelen for actually raising your ownmaggots "a la carte." The advantage of theprocedure is that you can raise them to anysize you need, even very handy little ones(which are generally not available in petshops).

Take some cat or dog food out of a can andput it outside in a sunny place. Be sure tokeep the food wet when placed in the sun, andwhen you have dogs or cats in the environ-ment, pay attention that they don’t run offwith all your efforts for dinner. On account ofthe odor, it’s recommended that you place thissomewhere outside. If all goes well, the flieswill soon show interest and lay their eggs.After some days, you will get a not-very-good-smelling, moving jelly of crawling larvae andhalf-eaten meat. You can dip out the neces-

sary portion of larvae daily by putting them ina little Daphnia net. By washing off the re-mains of the jelly under water (to preventfungi from flourishing) you will get pure foodfor juveniles that you can safely release in theraising tank.

Water Sow Bugs

In standing water with much plant waste, es-pecially, you’ll find a lot of these crustaceans.In my garden, I keep a large plastic container(100 liter) filled with waterweeds and swampplants. In the fall and winter these plants dieoff and pollute the water. An explosive cultureof sow bugs follows as a reaction during thelate winter and early spring. I offer these espe-cially to my Neurergus species to enrich theirdiet. If they are small enough, they will also beconsumed by the larvae.

Pill bugs, Rolypolys, Sow Bugs

These crustaceans can be found under piecesof rotten wood in humid and shady places.During the winter, I have even found a largeaggregation pressed together between theroots of still-living trees. During other sea-sons, you’ll probably find them in your owngarden under stones and in moist wood, fromwhich they are easy to remove. I feed themmainly to my land-dwelling species and evento land-phase Triturus. Since most of mytanks are configured in a natural way (withpieces of wood and ferns) and have at leastfive hours of lighting, the nonconsumed ani-mals stay around and even reproduce in theurodariums, thus offering a large variety insize. This is very practical if you have young toraise. Refreshing with newly captured animalsfrom time to time may be necessary.

Hyalella Azteca

Another good friend suggested to me a secondunusual food resource: the American speciesHyalella azteca. Some streamside sala-manders young such as Neurergus andSalamandra larvae consume large amounts ofthese crustaceans under natural conditions.

These little crustaceans are much smallerthen their European counterpart, Gammarus,which is not suited for keeping at room tem-peratures. Furthermore, transportation ofGammarus is not that easy either becausethey need much oxygen. In the USA andCanada, Hyallela is a much-used lab animal

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for testing water quality. They are found instanding or gently flowing waters, where theylive as sediment burrowers feeding on plantdebris. Under favorable conditions, they canbe present quite massively and are a goodhealthy nutrient for fish and salamanders.Adults measure from 6 to 8 mm.

Concerning Captive Maintenance

The optimal temperature is around 23°C,which, together with a 16-hour light cycle, willresult in a large reproduction. Temperatureshigher then 33°C are lethal. As food, you canoffer them fish flakes, trout pellets, and evenmaple leaves.

I recommend that you give the animals a

©Henk Wallays

Typhlonectes compressicauda and shrimp.

substrate in which they can hide. A piece ofcotton or nylon nets are suggested in the lit-erature, but some more natural substratesuch as pebbles might work as well.

Finally, in water, salamanders act like littlepredators who will hunt down anything that ismoving and soft enough to ingest, includingtheir own larvae. Some (Ambystoma) sala-manders are even the top predators in fishlesswaters. Aside from the above mentioned foodresources, there are certainly many other preythat might be useful. This list is only meant tobe a first practical step, mainly based on mypersonal experiences. As we encounter anduse other sources, I hope to extend this list. Ifanyone else has other useful ideas and tips,feel free to inform me.