The Dangers of Dwarf White Isopods in Egg Laying Reptile Setups

While a safe, trustworthy cleaner for reptiles of all sizes, when it comes to breeding these reptiles, keepers have been reporting issues with housing dwarf white isopods in their breeding reptile setups. Dwarf whites have been developing a reputation for eating some reptile eggs. The typical argument is that dwarf white isopods only eat eggs that are duds or dead and leave fertile eggs alone. The thought behind this occurrence is that healthy eggs are calcified enough that it is too difficult for the isopods to eat through the shell, so they don’t bother. However, many keepers are reporting finding dwarf white isopods eating eggs in their setups. This is a tricky mystery to unravel, as there are many factors that affect this ovivorous diet.

One of our male PI chahoua

The community reporting the most issues are the chahoua keepers, which are unique from other geckos in a variety of ways. Chahoua eggs are very different from other geckos in that the eggshells are thinner, and often “glued” to tank décor, and not in the dirt at all. If the eggs are laid in moist substrate, the eggs may be more prone to softening, making them more readily available for the isopods to consume. This is an event that has also been noticed by crested and Eurydactylodes gecko keepers, as well as rarer terrestrial geckos that thrive in moist setups.

A piece of decor we pried from the background after one of our chahoua thought it was a great nesting spot

Many keepers still haven’t noticed any issues; for us personally the eggs we’ve noted that have been devoured are by first year females, alarmingly under-calcified, or just not healthy looking eggs at all. We’ve conducted tests with our own personal species and cultures, offering shells of healthy, hatched geckos, eggs that have failed (but not yet rotten), eggs that are already rotting, and eggs so decayed that they are swarming with springtails. We’ve yet to see dwarf whites eat shells of healthy hatched eggs, and the only decaying eggs we’ve placed directly in their setup that have been eaten are the rotten ones.

A rotten dud egg 4 days after we offered it to a dwarf white culture.

A frequent occurrence with dwarf white eating eggs is that the female has been paired for the first time. In these cases, even a healthy female can lay unfertilized, or even just strange looking eggs while her body works out what is happening. Eggs that are unfertilized, under-calcified, or poorly developed will absorb moisture quickly and be eaten by isopods. Even females that have been proven breeders, laying healthy clutches years before, can occasionally lay a bad egg.

Heat is also a possible factor for dwarf whites – warmer temperatures causes a higher metabolism and a larger amount of activity. A higher metabolism causes a higher drive to feed and find resources, which may motivate dwarf white isopods to eat through egg shells. The instances of dwarf whites eating eggs typically occur in collections that are kept at an ambient temperature between 75F and 80F.

Tiny, but voracious.

Another factor is the nutrition available to the isopods themselves in the setup. The instances of isopods eating eggs occurs the least often in setups with nutritious soil (such as potting soils), or with additives such as cuttle bone for calcium and other protein sources. In nearly every occurrence of isopods eating healthy eggs, keepers used very little or no leaf litter at all. While dwarf whites are fantastic cleaners that will eat shed skin and other animal waste, even a very nutritious soil cannot substitute what isopods need from leaves.

To best prevent isopods from eating eggs, we can recommend a couple of interventions. First is to check for and remove eggs frequently; because if the eggs aren’t there, the isopods cannot eat them. Next, is to make sure that the substrate used is a nutritious substrate that will satisfy the dietary needs of isopods, even going as far as to add calcium and protein components (things like blood meal and shrimp meal can be mixed in for protein). After that, be sure to use a thick layer of leaf litter throughout the entire setup- we recommend at least 1”. Finally, if the population is getting very large, removed at least half of the substrate and replace with fresh substrate that doesn’t contain any isopods. This way, the isopods are less likely to prey on eggs with a smaller population and are refreshed with a new food source.

A big thanks to our friends at Oklana Zoological, The Chahoua Chamber, and The Gecko King for sharing with us their experiences with dwarf whites eating eggs in setups.