General remarks about incubation

  • sort out eggs regularely from the cages and incubate them seperatly, as nymphs should be kept and raised seperately from the adults too
  • this way it is much easier to keep an overview on the various stages of developement, control the number of hatching nymphs and prevent uncontrolled, destructive overpopluation in the cages
  • overpopulated cages are very stressful for the phasmids and have a very detrimental effect on the breeding success
  • the size of the incubation boxes must be adapted to the size of the hatching nymphs
  • if the incubation boxes are too small, then the hatching nymphs will disturb each other, which will result in crippled, often non-viable nymphs (badly bent or missing legs, crippled bodies)
  • short dry periods (few days in row or a one-time delivery by mail) does not harm the eggs of most species
  • however, if the dry period lasts too long (several weeks) then the eggs may die
  • if eggs are kept dry during hatching, then the hatchling might get stuck in the egg and won't be viable
  • on the other hand, don't incubate eggs on a very moist substrate (this is a common mistake !). This does also damage the eggs, they might die and it encourages mould growth
  • moderately moistened vermiculite is well suited as incubation substrate (for details, see Cup Incubation Method below)

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Hatching

  • nymphs of different species (genera) hatch during different sections of the day
  • nymphs of many (if not most) species hatch under the veil of darkness, thus during the night
  • but there are also species (genera) which hatch during daylight hours, usually in the early morning or around noon (eg Achrioptera, Cranidium, Phyllium)
  • so that the nymphs hatch at the right time, they need to be able to perceive the time of the day. Perhaps they can "estimate" the right time by the raising temperatures in the morning. Another possibility would be, if they could perceive the light changes (night-day). But because of the often thick and dark egg shell the 2nd option seems less likely to me
  • thus it is advantageous that during incubation the eggs are subjected to a "natural" nightly temperature drop and a daily light-dark cycle
  • immediately after hatching, the hatchlings pump up their body with air, and thus they "grow" quite a bit. It is very important that the nymphs are not disturbed during this crucial phase
  • if the hatching nymphs feel disturbed during this phase, then they tend to "forget" to inflate their bodies. This can lead to sqatty, dwarfish nymphs (the so-called "Dwarf Syndrom"), because their exoskeleton hardens. Such "dwarf nymphs" often die prematurely. This problem is more common in species with long-legged, large nymphs (eg Pharnacia, Phasmotaenia, Tirachoidea) than in species with stout nymphs (eg Trachyaretaon, Dares, Mearnsiana)
  • disturbances to be avoided during this phase shortly after hatching:
    • moving the incubation box
    • too many nymphs hatching at the same time in a narrow, small incubation box
    • loud music or noise
    • commotion around the hatching boxes
    • of course, hatchlings should remain only a short time in the incubation box

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Mould

  • eggs of some species or genera (eg Phasmotaenia, Eucarchaus, Hermarchus, Phasma, Xenophasmina, Phyllium) tend to get mouldy quickly and it is difficult to beavoided. Thus eggs of such species should be kept less humid
  • the negative effects of mould on phasmid eggs is however somewhat overestimated
  • as long as mould growth is not excessively high, the hatching ratio will not be affected too much
  • but this does not mean that we are careless and reckless in dealing with mould. Finally it is also beneficial for our own health to reduce mould growth to a minimum
  • if eggs are covered with a layer of mould, then we can clean them carefully in a tea strainer under lukewarm water with a soft brush
  • if vermiculite is being used as incubation substrate, then the eggs can be covered with a thin layer of vermiculite (1 - 2 mm high). This helps to reduce mould growth, and additionaly this helps the nymphs to hatch unscathed
  • springtails (Collembola) can be used in the incubation boxes to reduce mould growth
  • but springtails can destroy eggs of some phasmid species, though this is very rare. This has been observed for Calvisia sp. "Dong Nai" eggs, a species which glues its eggs. If glued eggs are detached carelessly from the substratum they are glued to, then a part of the egg shell may break away. And this allows springtails to "crack" and destroy the egg
  • thus always just add few springtail to a incubation unit
  • more infos on springtails
  • dead eggs often burst open and serve as a food for springtail, and thus they multiply quickly. This should be avoided, by sorting out infected dead eggs from time to time, in order to keep the springtail population low
  • some breeders use isopods (Isopoda) to minimize mould growth. But it is not known to me whether isopods can "crack open" and destroy phasmid eggs

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Incubation substrate vermiculite

  • vermiculite is very suitable for egg incubation
  • vermiculite itself can't get mouldy, as it is an inorganic, biologically inert mineral
  • therefore it is better suited than sand, peat, coir, paper or cotton
  • vermiculite absorbs water very well, thus the eggs won't lie moist
  • and therefore it is also better suited than sand
  • I use fine-grained vermiculite (about 1 - 2 mm), but coarser-grained vermiculite should be equally well suitable
  • vermiculite of poor quality contains a lot of powdery material, which can hardly absorb any water. Thus the powedery material should be sift from the vermiculite before using it
  • vermiculite for incubation is kept at a medium moisture
  • too much moisture should be avoided, incubating eggs too moistly is a common mistake amongst phasmid breeders
  • how to find the right medium moisture for your vermiculite ?
    • vermiculite from different sources (or different brands) varies in it's ability to absorb water. Therefore an absorption test is needed before first using vermiculite from a new source
    • there is always some podwery material in the vermiculite, which does not absorb water effectively. This powdery portion must be sieved out with a very fine sieve
    • in order to determine the maximum amount of water your vermiculite is able to absorb, slowly add water to a known amount (dry net weight) of dry vermiculite (use a small digital letter scale), to the point where no additional water is absorbed and the surface starts to glisten moistly. This is best seen when the container is tilted a bit
    • this gives you the maximum H2O absorbtion ratio for your vermiculite
    • about 50 - 55 % of that amount of water is needed to get a medium moisture, which is good-enough for incubating eggs of species from tropical, humid areas. This will result in a humidity of about 85+% within the cup-incubation unit, and that is enough humidity for a successful incubation
    • now you know how much water you need for the specific vermiculite you are using. And you can use this figures, unless you get your vermiculite from another source ...
    • rule of thumb - vermiculite with a good-enough medium moisture feels almost dry to the touch and it does not glisten moistly
  • incubation moisture for species with different requirements:
    1. species from tropical, humid areas
      • use medium moist vermiculite
      • use about 50% of the maximum H2O amount your vermiculite can absorb
    2. for species from rather dry or moderately dry areas
      • e.g. for species like Agathemera, Bactrododema
      • use just slightly moist vermiculite
      • use about 15% of the maximum H2O amount your vermiculite can absorb
      • use a syringe with a long hollow needle (canula) or something similar, so that the water can be added to the vermiculite at the bottom in the incubation unit. Like this the vermiculite on top (on which the eggs lay) remains dry. And this helps to reduce mould growth on the eggs, as the eggs are just exposed to a slightly higher humidity but are not in direct contact with moisture
    3. for species which glue or stick their eggs onto /into leaves or twigs
      • a natural condition is that such eggs are not in direct and constant contact with humid vermiculite
      • use GET or SET method
      • use about 75% of the maximum H2O amount your vermiculite can absorb

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Cup-Incubation method

  • over the years I have tried out different incubation methods and setups
  • currently I am using a Cup-Incubation method which works very well and is very handy
  • for this 2 clear plastic cups of different sizes are used. The smaller upper cup must fit tightly into the larger lower cup (see pictures below). Two such cups then form one Cup-Incubation unit
  • I use cups made of polystyrene. Cups made of this material wedge firmly into each other, and thus the upper cup sits firmly on the lower cup
  • the upper cup shall not sit loose on the lower cup, otherwise hatching nymphs can escape through a gap between both cups
  • one can also use socalled smoothie cups (see pics below)
  • this Cup-Incubation method has a some advantages:
    • hatching nymphs have quite lot of space - thus less crippled nymphs
    • each culture hatches in seperate containers - thus cultures can be confused with each other
    • hatched nymphs are easily visible in a Cup-Incubation setup
    • nymphs can be transposed directly with the upper cup into the breeding cage (which is much less stressful for the nymphs and the breeder)
  • make some (needle) ventilation holes in the bottom of the upper cup, to avoid the formation of condensation within the cups
  • make sure that you use chlorine-free water, as chlorinated water is harmful both for humans and insects
  • at the beginning of the incubation, note the culture's full name and the total weight (cup + vermiculite + water + eggs) on an adhesive tape (yellow in the pictures below)
  • water will evaporate from the cups via the ventilation holes in the upper cup. Therefore 1th per month the vermiculite is checked, whether it is still humid enough. Use again a digital letter scale and the total weight of the unit as described above
  • in my setup, about 6 g water evaporate per month
  • during this monthly check, the vermiculite is moistened again with the appropriate amount of water 
  • eggs can be covered with a thin layer of vermiculite (2 - 3 mm high). This helps the nymphs to free themselves from the egg shell completely, and mould growth is somewhat reduced too
  • for species with very large hatchlings (eg Pharnacia, Phryganistria, Tirachoidea, Eurycnema) the cups might be too small (unless one uses very large cups). For such species an Faunabox setup in combination with the Cup-Incubation method is recommended (see below)
  • and further below a variation of the Cup-Incubation method by Pablo Valero Riquelme (Spain) is described

 

Cup-Incubation unit with freshly hatched Ph. giganteum "Tapah" nymphs

 

left: ventilation holes in the upper, smaller cup
right: many Phyllium giganteum eggs are here fully covered with vermiculite (and therefore not visible), a few lay uncovered on top

  

hatchlings are easily visible in an array of Cup-Incubation units

 

if you can not find cups similar to the ones I use, then you can easily find socalled clear smoothie cups. Such cups are equally useful

 

Fauna-Box setup
for species with big hatchlings

  • cups are prepared as described above
  • in addition a larger opening is cut into the upper cup (use a stanley knife)
  • Cup-Incubation units are placed inside a big Faunabox (or a similar cage)
  • Faunabox stands upright, and its floor is covered with wet kitchen paper
  • keep this kitchen paper constantly moist
  • the upper half of the Faunabox lid is sealed with plasticso that a higher humidity (> 75% RH) can build up within the Faunabox
  • hatching nymphs can easily escape through the hole in the upper cup into Faunabox. Thus they do not impede each other
  • as with this setup several species / cultures can hatch into the same Faunabox, one must ensure that hatchlings of similar cultures (eg pure populations from a specific provenience) can not be confused with each other. Therefore eggs of similar or closely related species / cultures must be incubated in seperate Faunaboxes

 

left: Faunabox with Cup-Incubation units for species with big hatchlings (here Phryganistria grandis "Cham Chu")
middle: hatching nymphs can "escape" from the Cup-Incubation unit through the opening cut into the upper cup
right: opening cut into the upper cup

 

an easy variation of the Cup-Incubation method

a similar method is used by Pablo Valero Riquelme (Spain). This one is particularly suitable if one can not find clear plastic cups which fit thightly into each other without any gaps (as described above). The pictures are self-explanatory