A little secret for those wanting to see carnivorous plants in action: whether it’s in the wild or in captivity, the absolute best time is in late autumn. Firstly, most carnivores are at their greatest size and best color in order to attract insects before they go dormant, storing the nitrogen and phosphorus gathered in those final days in preparation for reemerging in spring. (This is way beyond my abilities at the moment, but any enterprising biology and botany students looking for ideas on a paper likely to get lots of popular and professional news coverage should look at the sheer number of insects caught in Sarracenia pitchers and ascertain whether the plant absorbs nutrients during its normal dormancy or if the plant only accesses and processes the insect stew inside the old pitchers after it starts to bloom. Either would help explain why so many Sarracenia pitchers remain green throughout the winter, only dying off after new pitchers start up again during the next growing season.) Secondly, the potential insect population is at its height, and it’s hungry. The normal sources for nectar and sap for insects such as flies, wasps, bees, and moths trickle dry by the middle of autumn, and those insects are determined to stave off dying of starvation for as long as they can. With many, it’s going for unattended soda or margaritas, but a lot go for the voluminous nectar secreted by various carnivorous plants, and they get frantic for what usually becomes their last meal.
The resultant arthropod feeding frenzy made showing carnivores at the Autumn at the Arboretum exhibition at the Dallas Arboretum particularly, erm, riveting. It’s one thing to discuss dispassionately how carnivores attract and capture insect prey. It’s something different when a crowd of twenty to thirty people watch different insects at different plants to see which one falls into a pitcher first, complete with cheers and groans when a big fly or sweat bee succumbs to the promise of more nectar in a pitcher float and doesn’t reemerge.
A little aside that the Arboretum attendees didn’t get to experience: driving a van full of pitcher plants back to the gallery on a Sunday evening and listening to the angry buzzes of insects trying to escape their impending tombs. One of these days, I’ll have to record audio: the only thing creepier is when the Sarracenia leucophylla pitchers first emerge and open toward the middle of May, only to fill with click beetles. I can only imagine a field of leucos with every pitcher loaded with click beetles, all thumping the inside of the pitchers as the sun comes up and the pitchers start warming in the sun.
To be continued…