Breeding Feeders in Situ

For many of us, the bugs and worms we use to feed our geckos can be considered to be almost like a second “business” what with purchasing them, housing and feeding them, and trying to keep them from escaping during the transfer from their own habitat to the geckos’.  Wouldn’t it be great if we could just produce our feeders right in the geckos’ cages? 

I’ve had some experience with breeding feeders in situ and would be interested to hear of others’ experiences as well.  In some preliminary discussion on various reptile forums, the implicit and explicit “objections” to such a practice have been:

• concern about the feeders harassing the gecko
• difficulty of providing supplementation since feeders in situ can’t be dusted
• not knowing exactly what the gecko is eating since the feeders are already in the cage

Although the conventional wisdom is not to leave feeders such as crickets in the geckos’ cages (“only give the gecko as many crickets as it can eat in 15 minutes”), in my experience, leaving crickets in a healthy gecko’s cage has never been a problem.  I do have a leopard gecko with an oddly shaped regenerated tail that can never be kept in a cage with mealworms since for some reason the mealworms attack his tail, but that’s the exception rather than the usual situation.

The supplementation problem is an issue and consequently, unless the keeper is willing to remove the feeders from the enclosure to dust them, s/he will have to provide some additional, dusted feeders.

Although many keepers like to keep exact records of how much their geckos eat, poop and weigh, it’s not the end of the world to give up some of that control.  If the geckos look and act healthy, it isn’t necessarily important to be concerned about every morsel they take in or put out.

Requirements for Breeding Feeders in Situ

In order to successfully breed feeders in situ, the gecko enclosure needs to have the following conditions:

• temperatures appropriate for the feeders to breed.  This is especially true for roaches who need relatively warm temperatures to reproduce successfully and consequently may not do well in a crested gecko or Rhachdactylus gecko enclosure.
• humidity appropriate for the feeders.  Geckos that require arid or desert habitats may have enclosures that don’t support some feeders.
• food for the feeders.  In order to insure that the feeders don’t turn their dining attention to the geckos or the geckos’ droppings, they need to be provided with appropriate food.  More about this below.
• appropriate substrate.  Most feeders, especially worms, do best when they can bury themselves in a substrate.  Their eggs may require a certain amount of humidity surrounding them to hatch.  Breeding a reasonable number of feeders with a paper towel, tile or repti-carpet substrate is difficult to impossible.

Scavengers as Feeders

Many planted tanks utilize small insects or arthropods as scavengers that eat the gecko droppings and help fertilize the plants.  The most common are isopods and springtails.  These scavengers are quite small and usually buried in the substrate, but they are known to surface at night and may be tempting snacks for some of the smaller gecko species.  I’ve never seen any of my geckos eating the isopods or springtails, but on the other hand, I’ve never seen some of my geckos eat at all, yet they are thriving.  In addition to the common scavengers mentioned above, I use dermestid beetles and their worm-like larvae as scavengers in my less humid enclosures (African fat tails and one leopard gecko enclosure with a bioactive substrate).  I would guess that the geckos may eat some of the beetle larvae.

Accidental Feeder Breeding

The gecko is fed crickets and does not consistently eat all of them.  One day, you notice many tiny crickets hopping around the enclosure.  The crickets have laid eggs in the substrate (or in the lay box) and before you know it, your cage is full of pinheads.  Most of these pinheads will likely not live to adulthood since in many gecko cages they tend to dehydrate.  Higher humidity environments, such as those for day geckos and Rhacs, usually have the best chance of “growing” crickets.  It’s not unusual for me to periodically pull adult crickets out of my day gecko cages when I know I put them in there as 1/8″-1/4″ babies.
Since most of these crickets won’t survive to adulthood. they can be best used by harvesting them for geckos that eat smaller crickets.  I have had some limited success “catching” these small crickets using shot glasses to scoop them up and providing a dish of cricket food and then swooping down and covering the dish over as they’re eating.

Breeding Feeders Intentionally

If the gecko cage reproduces the conditions under which a particular feeder can breed, there seems to be no reason to prevent them doing so.  Choose a feeder that’s a good match for the geckos’ environment.  Provide a shallow dish of food, which can include powdered grain or fruit.  Feeders like crickets do exceptionally well in enclosures of geckos that eat fruit nectar since they can “share” the fruit with them. Provide a shallow water dish as well so the feeders don’t all drown in the water dish (some will; it’s inevitable).  Plan to remove some feeders if they become too numerous, to add “stock” periodically for genetic diversity and to supplement what’s already in the enclosure with some dusted specimens to ensure that the geckos are adequately supplemented.

My Experiences Breeding Feeders

My first attempt at breeding feeders in situ was with my Gold Dust day gecko.  I had seen some of the tiny crickets I put in there grow to adulthood in the enclosure.  Eventually I placed 10 or so adult crickets in enclosure, which already contained a shallow water dish, and provided a covered container of cricket food which the crickets could enter and leave at will.  For reasons I don’t entirely understand, it didn’t work (though it should have) and I gave up.
My next experiments were with accidental breeding.  The crickets would lay eggs in the geckos’ lay boxes and I’d attempt to catch the small crickets and feed them to my tiny geckos.  The most difficult part of this is catching the crickets.  I had some success, but more frustration.  Recently, I noticed some fruit fly larvae in the water crystal dishes in the enclosure where I keep my crickets.  I scooped them out and dumped them into the L. williamsi enclosure.  A few days ago, they apparently hatched. The L. williamsi are looking pretty well-fed, but since these are not the specially produced flightless fruitflies, they are a bit of a challenge to keep inside the enclosure.

My best effort has been in a 26 gallon bowfront leopard gecko enclosure which houses 2 retired female breeders on bioactive substrate (mostly coco fiber with a little desert sand mixed in and a generous helping of leaf litter).  I seeded the enclosure with dermestid beetles for cleanup since it’s too dry for isopods or springtails.  I added a jar lid of cricket food which I replenish when necessary.  Although the enclosure is generally fairly dry, the area under the water dish is damp and I mist the enclosure about once a month (it does rain sometimes, even in Pakistan and Afghanistan!).  When the larvae population gets too dense, they conveniently drown themselves in the water bowl.

In addition to the beetles and their larvae, the enclosure is a breeding ground for crickets, superworms that bury themselves before being  eaten and an occasional mealworm.  The cage is busy with crickets excavating the natural hides (one of the disadvantages of keeping feeders in the enclosure), superworm beetles trundling around, and writhing masses of dermestid beetle larvae near the cricket food and under the water dish.  I hand-feed both geckos dusted superworms (some of which escape and replenish the population) which they display interest in most of the time, and I toss in more adult crickets whenever the population seems to be getting low.  The geckos are healthy and weigh 74 and 71 grams consistently.

I have not yet had the time or energy to investigate systematically breeding feeders in a gecko enclosure that would enable it to be largely self-sustaining.  I imagine that this would work best in a large enclosure with ample hiding places for the feeders and good hunting opportunities for the geckos.  If anyone has had any experience with this technique, I look forward to reading your comments.