This Year's First Mated Mexican Bush Katydid

This morning we were ecstatic to find one of our female Mexican Bush Katydids (Scudderia mexicana) carrying the prized spermatophoryx!

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It has been exactly six nights since we first put our eight Mexican Bush Katydids (four adult females and two adults males) into our outdoor enclosure on 7/17. The purpose of its design was to try to mimic natural outdoor conditions as much as possible by providing a live food plant (potted Passionflower [Passiflora mixta x manicata "Susan Brigham"]) while giving them enough sunlight and space to move around, or even fly if they choose to. In other years that we have gotten these katydids to mate, we had also put them in an outdoor enclosure with live plants (a glass aquarium tank with bean plants) so we imagined it wouldn't be too difficult this year if we attempted something similar. And it wasn't.

This morning when we went out to check on them, we noticed something somewhat odd. Only three of eight katydids were even on the plant and one of them was sixth instar nymph preparing to molt to adult. The other katydids were all scattered around on the lid, the sides, and one of the adult males was even on the ground. Something must have been going on! Upon close examination of the females, we immediately noticed that one of them (one of the two adult females on the lid) had a nice, gelatinous spermatophoryx attached to her genitalia which was eaten up by 10 AM. It is impossible to identify who this female was (where we had found it and when it molted) and which of the two males it had mated with (though we assume it was the broken legged one on the ground that molted on 6/20 since older males are more willing) but that is not important. 

What matters now is that we need to see about getting her to lay her eggs. There should be at least a hundred in that plump abdomen of hers! Mexican Bush Katydids lay their eggs exclusively in leaf sheaths (epidermal layers) based on the ovipositor shape and will probably lay their eggs in most any large leaf. The eggs overwinter in the leaf all the way until spring time of the following year, but we suppose they are hardy enough to survive should the leaf die fall off the plant (a risk even for non-deciduous trees). The Singing Insects of North America (SINA) site suggests depriving the gravid female of laying sites first, presumably to cause her to become more "desperate" and willing to lay once you reintroduce the laying sites. This is what we will attempt first, after we give her a few days to eat up the spermatophoryx and such.

- Brian