Jan. 8/09 The Death of John...

Two days ago (Jan 6) John died...
Along with his death I noted the absence of almost all crickets in the system. I believe the cause for this, and the cause for John's death, is due to the rise and then rapid fall in the number of crickets.
Sometime in December, I noted that there were juvenile crickets in the tank, meaning that they were successful in breeding. That means that the number of crickets rose. The crickets seem to eat the plants. Both dead and alive, meaning that the more crickets there are, the less cover there is. Consequently, the lizards would be able to hunt them far more effectively and before the grass could regrow enough cover, the crickets were gone.
With not enough crickets to sustain both lizards, the bigger one, Philipa, took control of the fern (most likely the last good hiding place for the crickets and the lizards alike) and forced John to look elsewhere. This explains why John was always visible and why Philipa was almost never out.
Since John's death Philipa has been making herself far less scarce, which leads me to believe that the main reason for her hiding was to defend her territory. either that, or she is eating too many crickets, still, and soon the tank will be dead. However I will not let another lizard die. I'm going to intervene next time if this happens again, now that I know what to look for.
If her past hiding was to defend her territory, then that opens up a whole new set of questions and possibilities about the psychology and social behavior of these lizards.

If I have a repeat of what happened over the Christmas Break, instead of trying the same technique again, I'm going to rearrange the tank so that there are more ferns, since the fern seems to be the focal point of almost all the lizards' behaviors.