Atelopus frogs in most cases are Traditional Breeders, reproducing
only in streams or wetlands where they metamorphosed. Each drainage
system has its OWN variants! •Resident males and juveniles live
along streams, and adult females and subadult males roam free in the
forest. (High Andean Atelopus may vary here a little). •Only during a
short or longer breeding period (steered by mostly unknown trigger
factors), both sexes join at the edge of the stream with males calling,
spacing and defending breeding sites along the shores, often coupled
with complicated semaphoring behavior and at least four general call
types (A. reticulatus, unpublished obs., R.S.).
Basics 2 •
pair enters in amplexus, and the onriding male defends himself against
other clasping males by release calls and leg movements. •Amplexus may last one week or more than 100days! (Why Atelopus need often such a long amplexus phase is unknown).
•For egg laying, the couple looks for a shallow beach or whirlpool with backwater condition in flowing water.
•Female presses out two parallel clear egg strings, (one from each
ovary) in shallow water. Egg color is white to cream or orange, and
differs herein from other egg string types of Bufonids. •Egg numbers are from 150 in small species to several hundred in bigger species.
Egg strings are not tended out continuously in some species (A.
varius, observation and photos by Rolf Bechter, Zürich in 1982,
confirmed by R.S. with A. reticulatus). •Remember that spawning and
fertilization by the pair in amplexus must be done mostly IN FAST
FLOWING WATER, which is a very difficult condition.
Basics 4 (the most fascinating!) •
The Female pushes out a small group of eggs (6-10 from each string) into a “pool” formed with their hind legs.
•The Male presses out sperms into this pool.
•Female opens the pool and egg strings extend.
•Immediately, the female forms another pool, the male fertilizes again
and so on, until all eggs from the double string had been pressed out.
•During egg laying and “pool” forming, the couple slowly walks ahead against the current, tending out the double egg string.
•The couple then finishes the amplexus and retreat- the male to its
territory at the stream edge and the female into the adjacent forest.
If an Atelopus species has the behavior of Basics 4, parallel egg
strings show small identical GAPS (a small transparent space) between
usually white egg groups and before the next egg group comes. GAPS are
formed by the female’s opening and closing of the “leg pool”.
species that extend egg strings in standing or very slow flowing water
do not need the “Hindlegs- POOL” method, like common toads for example.
•The POOL forming is the key for a correct fertilization under often fast flowing water conditions.
The eggs in the strings hatch according to water temperature in a few
days or faster, then tiny and short white tadpoles cling to rocks and
substrate with the anterio - ventral sucker disk, a typical feature of
all Atelopus tadpoles. Later, tad’s color changes to black with
ornaments in some cases.
•They later avoid direct sunlight, but might be active by shaded daylight in the stream bed.
•They also prefer to cling to undersides of rocks in the stream
sections with highest velocity and oxygen content or are foraging on old
driftwood, dead leaves and stones or rocks.
Having hatched Atelopus tadpoles is no warrant of success: several
times in the past, hobbyists and researchers got free swimming tadpoles-
but the tadpoles later starved to death.
•The hypothesis of R.S.
after mentioning this problem in a book in 1980/1984 was, that those
tadpoles feed possibly on a special food in their original streams.
•Observing Atelopus tadpoles at our Venceremos Atelopus breeding site in
Peru (now destroyed by asphalt road construction and possibly Chytrid
fungus impact), we could obtain more details.
Basics 8 •
hazard we found a gravel bottom- roadside creek (1700 m altitude) at
Venceremos (Cordillera Oriental) that had Atelopus tadpoles YEAR ROUND
and in all stages. There was no vegetation in the 4-15 cm deep creek
with 8ºC water temperature- only reddish and yellow sandstone rock
fragments (gravel) present with some small driftwood pieces. We could
during several years (1982- 1991) visit sporadically this place with
positive results, until finally it was destroyed and amphibian declines
reached this site around 1996-99.
Basics 9 •
image in Main Exposition, two tad types present, adults UNKNOWN),
foraged on the sandstone fragments and driftwood. There had been NO
VISIBLE algae layers present- just clearest, cold water and the gravel
with some driftwood pieces in the water. If sky was cloud covered,
tadpoles came out, rasping on the stones. Under full sunlight, tadpoles
fled under stones and driftwood.
•This indicates, that a TRANSPARENT
MICROLAYER of something nutritive was on the gravel that provided a
full alimentation to the tadpoles. At this time, we had no access to a
powerful light microscope to check out those microlayers, but Detroit
Zoo made the discovery during the Golden Frog Rescue Project in Panama
and with A.zeteki: those tadpoles fed on Diatom layers.
The Venceremos breeding site also showed, that this new Atelopus
species avoided to breed in a bigger stream going parallel to the road
and preferred this tiny creek with little or no predators.
unable to transport and raise such tadpoles, because they died after a
few minutes in the transport containers because of a rising of the water
temperature in our car and possible oxygen lack. •In 2003, we made a
first hydrological survey (Dietmar Bernauer) on the other rivulets and
main stream (but without microscopic analysis and Chytrid tests yet: the
water is of highest quality.
•There is also a tiny black catfish, which imitates Atelopus tadpoles at least in juvenile stages. •Investigations are going on.
RESUME 1 •
Some (or all?) Atelopus have a very complicated breeding biology and egg laying- fertilizing method. •They need ample, shallow backwaters of (fast) flowing rivulets to breed and to tend their egg strings.
•Hatched tadpoles may need a microlayer food, which are Diatoms
(endemic???) or a similar replacement food mix film glued to a glass
carrier substrate (Detroit Zoo has the receipt!).
•Water values and
original habitat climate must be COPIED PERFECTLY to be able to breed
those species- this creates the urgent need to install data loggers into
•Local diatoms and Microlayers must be
identified and tadpoles (if ever found) should undergo microscopic
stomach-intestine content tests.
RESUME 2 •
Males are the
resident territory holders in the field- this means that previous
captive breeding attempts sexes should be kept separately and well fed -
but under IDENTICAL climate cycles copied from the original habitat
•The Male frogs come first into a reproduction test terrarium or greenhouse, later at breeding season, ripe females are added.
•Pairs getting in danger during long amplexus should be separated and run another full reproduction cycle.
•More on site original habitat field research is a MUST in the next years!!!!
•Any still surviving Atelopus species must pass today a Chytrid
screening and preventive treatment if we want to work with them in
RESUME 3 •
INIBICO recommends fully air
conditioned double foil greenhouse kits of at least 1000- 2000 square
feet for breeding experiments with two simulated rivulets in each (two
species program). Any interior decoration material and water must be
CHYTRID FREE and kept like this!
•Other tests can be made with BIG
glass terrariums with special structures and special cooling (if not
working at original climate on site).
•A climate like a “cool orchid house” with a lot of air flow is the best starting point, except for lowland species.
RESUME 4 •
Best food supply to adults must be warranted (own insect cultures).
•The tadpole substrate food mix must be developed (ask Detroit Zoo).
•Tiny juveniles (5 mm) need best springtail cultures!!
•Any Chytrid medication must be made VERY CAREFULLY and with Med. Vet. assistance! •Hormone injections might be used to induce spawning- but with Med Vet care.
Captive Breeding (CB)- Problems 1 A.)
Losses of Adults
•Reproductors die fast because of wrong keeping temperatures: the most
difficult species to keep are the ones from high altitudes!
A lot of deaths had been observed because of a wrong and
insufficient alimentation. Atelopus are able to starve some time- but
need ants, special ground termites, springtails, recently hatched
crickets and Drosophila flies in higher amounts.
Chytrid fungus, lung worms, nematodes in skin and intestine, other
fungus infections, and bacterial infections (especially during mass
CB- Problems 2 B.) Killing during amplexus
As Atelopus males can hold a very strong and extremely long amplexus
(over a month!), females might get killed by strangulation. Onriding males may die of hunger (females do feed during Amplexus - our field observation.).
CB- Problems 3 C.)
Hormonal Timing Error (both sexes)
•The most observed failure during Atelopus captive breeding is
generated by a wrong hormonal timing of the sexes: if females have ripe
eggs, the male has no ripe spermatozoids and is not in breeding mood.
•Timing of the sexes usually depends on cyclic climatic events and may
also be steered by other yet unknown factors.
CB- Problems 4 C.)
It is today possible to induce both sexes with injected special
hormones to coordinate spawning and fertilization. But this is an
emergency strategy- better is to look for the natural timers and apply
those to the terrarium conditions!
•The MOST DIFFICULT to breed species
are those of high altitudes, because their climate can’t be simulated
well in captivity.
CB- Problems 5
•The male frogs are the
resident ones- they come first in the terrarium and stay there some
weeks. Females are kept separate from males and all frogs must be fed
well. Both groups must undergo the SAME climatic steering effects: dry
season simulation, wet season simulation. This is only possible, if we
have MOST PRECISE DATA from the ORIGINAL HABITAT!
CB-Problems 6 WRONG TERRARIUM CONSTRUCTION
Egg laying and fertilization is a highly complicated process in
Atelopus frogs. A wrong terrarium design may stop any positive breeding
result. Nearly all Atelopus lay eggs and fertilize in FLOWING WATER- and
this has its needs and tricks!
CB- Problems 7 •Egg laying
in Atelopus requires space, shallow flowing special water and well
coordinated partners. In terrariums, spematozoids are washed usually
into the biofilter or water is too deep at the egg laying place. The
best design is to create a whirlpool with shallow backwaters, where
spermatozoids circulate a while before getting trapped in the filter.
•Do not overcrowd breeding test terrariums!
•The terrarium must give enough room that males can establish
territories. In the field, a male is found at 3 or 4 m distance from
another (outside of the breeding season).
•Check constantly for alimentation status and Chytrid presence.
•Sterilize or treat any decoration and the water against Chytrid presence.
•Prepare the water with Revers Osmosis (RO), but returning minerals and trace elements!
•Do not use plastic products which release softener toxins into the water or terrarium!
Bron gevonden -http://www.inibico.org/pp..._bestanden/frame.htm