Care for Mantis Eggs

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Peter Clausen

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Hatching Mantis Egg Cases-

One of the most challenging parts of the mantis life cycle is caring for the oothecae (singular ootheca). In the English language we commonly call these egg-cases and less commonly egg-clusters. Both examples should probably be hyphenated, but rarely are.

There are many opinions as to the best way for promoting hatching and different species may have different requirements with regards to temperature, humidity and time. Most species that are kept as pets will hatch within a few months at room temperature.

The book "Praying Mantids Keeping Aliens", by Orin McMonigle, is a universally accepted source of information regarding all stages of the pet mantis life cycle.

Some suggestions are given below on the basis of my own experience.

Oothecae should be left alone. Many hobbyists have problems because they are too concerned about the care of their oothecae. Room temperature is just fine for most mantis species.

Research your species. There are other hobbyists who have raised this species, including perhaps the person you obtained yours from. Ask these people for help. Unless you personally collected your mantis or ootheca in the wild, it is likely that others will be happy to provide some specific instructions for your particular species.

Humidity- this is an issue that a lot of hobbyists seem to have trouble with and there are some related issues that complicate this. The amount of humidity you have in your enclosure is dependent on the amount of moisture you have in it, along with temperature and ventilation. For most mantis species a weekly spray into the enclosure should be just fine.

Don't spray the ootheca directly. If it doesn't dry out in time, it could begin to mold. Usually the mold will form right along the part of the ootheca where the mantises actually emerge. Once this happens, it is likely that the mantises will also be affected and will die if it goes unnoticed for more than a day or two (oftentimes, the mold begins within the ootheca and external mold may be a sign that it is already too late). A very mild soap-water solution and a very gentle scrubbing with your fingers will remove the mold. Allow the ootheca to air-dry completely. A bit of time in the sun will work best.

Ambient humidity is the goal here. A peat moss substrate, or coco fiber or even some paper towel works well. All of these liners for your "incubation" enclosure help to buffer the humidity by both soaking up the excess, but also in retaining it so that it remains in the enclosure for slightly longer periods of time. Both peat moss and coconut husk (shredded and re-hydrated) have antifungal properties. Paper towels will sometimes begin to show small signs of mold and should be replaced at the first sign of this (or sooner).

A gentle spray or two, perhaps one on the inner side of the enclosure and then also one into the substrate is recommended. By raising the humidity in the enclosure, you keep the mantis oothecae from drying out and this helps the mantises remain lubricated for their exit from the ootheca.

Depending on your local humidity levels, spraying may not even be necessary. It should be noted that many homes have less humidity than a desert during the cold seasons due to heating systems being constantly run. This will affect your mantids, their oothecae and even the people in the house and is one reason so many people get sick (dried out mucous membranes).

Time

Some mantis species do require a diapause. This is the over-wintering period that many temperate species (Northern latitudes) require. While tropical species do not require a diapause, the oothecae of temperate species may not hatch without it. Though it may vary from species to species, 3 weeks at 50 degrees is usually enough, though if a species is native to your area, feel free to leave it outside. A brown paper bag is often recommended. It protects the oothecae from direct exposure, but not so much that it doesn't let some important humidity through. In either case, after a minimum of a few weeks, the ootheca can be brought back indoors and set up to hatch. Alternatively, you can put them in your refrigerator for a few weeks and that will usually provide the necessary diapause.

The average ootheca takes about 2-3 months to hatch. Some species take less and some take twice that long. While nymphs of most species will all emerge from the oothecae at the same time, there are some species that will hatch out one at a time over a period of days or even months. Again, if you have questions about a particular species, please post a question on the forum or ask a known breeder of that species.

Setting up your Ootheca

The shape of the ootheca will partially determine your options for hanging it. All oothecae should be suspended from the top of an enclosure, or along the underside of a branch which has angle of between 90 and 135 degrees (see image I, below). A captive mantis does not always lay an ootheca in the most convenient place. Often, a hobbyist will have to carefully remove the ootheca from a piece of screen or break off a section of branch and re-hang the ootheca at the more appropriate angle.

Before you remove the ootheca from its original site, take care to notice the direction it was laid. Even if the perfect perch was not available for a female to lay the ootheca upon, she will usually lay it in particular direction. What is meant by this is that there is actually an upside-down and a right-side up for many oothecae. With a little bit of observation you can sometimes notice a few patterns. Running your fingers against the area where the mantises emerge, you can sometimes feel the "grain" of the area. Going one way it feels rough, the other is smoother. Try to re-hang it with respect to this. If you aren't sure, simply beat the odds by splitting the difference and hanging it parallel to the ground (if you're in the Southern hemisphere, hang it parallel to the ceiling.). ;) In either case, make sure the emergence region is pointing downward so that they can hatch with the aid of gravity.

If you've never seen a mantis ootheca hatch before, it may not immediately make sense why it is so critical to hang the ootheca a particular way (though there are many cases of mantises hatching just fine from oothecae that have fallen to the bottom of the cage or even during shipment in tiny enclosures). When an ootheca does hatch, the mantises will descend an inch or two (2 to 5 cm) on small, silk-like strings. They will look like small capsules at first, but as they wriggle out of the small membrane that surrounds them, they will spread out their legs and eventually relocate themselves to let their exoskeletons harden. At this time the hatchling mantises are referred to as 1st instar or L1 (first larval instar). After they shed their skin the first time they are then known as second instar or L2.

Superglue and glue gun are tried and true methods for affixing oothecae to various surfaces. Though brands may vary, both are considered non-toxic options. A small dab at either end of the ootheca should work well. Affix this to a branch or other structure that will place the ootheca at the aforementioned angle. Or, simply glue the ootheca to the top of the enclosure.

I've also carefully used pins to hang oothecae. If it is on a thin branch, you can snip the branch on either side. A small pin poked through the lid of your enclosure and into the twig will hold the ootheca at the proper angle. If you have a large round ootheca and observe its structure closely, you may assume that a pin poked through the very edge of the ootheca will not actually puncture any of the egg chambers within. If done correctly, this method works well.

Sometimes a combination of superglue and pins are required. Occasionally, and depending on the size/shape of the ootheca, I glue it to a thin strip of paper that is just slightly longer. Once the glue sets, you can pin the edges of the paper to the top of your enclosure's lid.

Various other methods for hanging your oothecae work just as well. You might experiment and share your experiences with the forum.

Though most of the mantids will emerge within an hour of each other, it's not too uncommon to see another few wriggle out the following day. Don't count your chickens before they hatch!

There is never any reason to give up on an ootheca, unless it has been about six months to a year (most species). If you become curious and must open a section of the oothecae, you will notice that a viable (healthy) ootheca has wet egg chambers within it. If it is dried and crystalline, the ootheca is quite dead. No amount of re-humidifying will bring it back to life.

Heat Lamps

To use or not to use? Be very careful. These WILL bake your oothecae if not used very carefully. While some hobbyists may need to use them if they keep their homes extremely cold, remember that you must be very vigilant of the humidity levels. Ootheca can dry out in a matter of days if humidity is allowed to fall while heat is maintained. Though a few species do hatch best at temperatures approximating 100 degrees F, most do not. If you can't check your humidity levels once or twice each day, a heat lamp is not recommended, especially if the bulb is held in close proximity to the ootheca. The same is true for anything else that warms up the incubation enclosure.

Patterns/Troubleshooting

Most hobbyist notice that their oothecae seem to hatch after a recent combination of spraying, a period of several hours of drying out and during the cooler temperatures of evening.

Most hobbyists that see only a few mantises hatch out of a fairly large ootheca have probably allowed the majority of the ootheca to dry out beyond the point of all the mantises being alive. It is more common for the entire ootheca to fail, than for only a few to make it. But it does happen.

If a large percentage of the mantises drop from the ootheca but fail to successfully remove themselves from the membrane that surrounds them, this suggests that current and perhaps longterm humidity levels were a bit on the low side.

If an ootheca fails to hatch, it either dried out or was unfertilized. Females will often lay oothecae even if they never have an opportunity to mate (though these oothecae are usually smaller and misshapen).

Finally, once laid, it may be best to let your ootheca harden and even dry out for a period of about a month (room temperature), spraying maybe only a couple times per week (ambient humidity). During the second/third month, try to maintain more consistent levels of humidity. At this time, you might want to move your ootheca to a higher shelf in the house where it may be a few degrees warmer. The normal day/night temperature changes are healthy for your mantises, while levels of light don't seem to play a factor in hatching.

(photos coming soon as well as edits and additions)

 
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Don L.

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Research your mantis species to find its country of origin, and if possible, the specific region, as large countries such as the US or India vary quite a bit in climate. Especially important in the temperate zones is to know in what month the nymphs would hatch, and also when they would mature and begin to make oothecae. An ootheca may require very different conditions to hatch naturally (such as those during Winter), than the mantis would experience in the Spring and Summer. At www.weather.com when you enter a city or zip code of the country of origin, you will be shown the current temperature and humidity % for that day. You should also click for the 10 day forecast to note variations. Click the Month link too when hatching oothecae, and you will be given the option to check each month of the year for its particular conditions. Very useful to check natural conditions for your other pets too!

 
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