9/17/2021: Mysterious Arenivaga of the Chiricahuas

Jumping back into the serialized blog post game with a whammy: sand roaches in the mountains? More likely than you think.

My first trip to the Chiricahuas was in 2016; my first self-planned and self-propelled collecting trip and the beginning of what would become a love-hate-lust relationship with visiting Arizona. With a crew of 4 bug folks we were able to turn every leaf, stone, and stick in search for bugs; this led to the find that contrary to the reportings of many learned and professional Arenivaga collectors, it was indeed possible to find them just about anywhere suitable microclimates existed. Rodent burrows, under stones, free living in leaf litter, beneath concrete slag, in beetle frass piles, and even (much to my immense amusement) in piles of kicked-out rodent nest refuse. Indeed, Arenivaga adult females are one of the most undersampled insects, and further sampling may alter current perceptions on their taxonomy…

Regardless, it is very reliable to find Arenivaga in rodent burrows and nests, and finding a good and messy one beneath a piece of lumber or toppled sign in the Southwestern US almost always produces a glob of Arenivaga.

This unassuming life style coupled with the assumed widespread ability of many species’s nymphs and adult females to absorb atmospheric water from air of fair humidity has allowed them to persist and speciate in places that are… for a lack of more artistic language, relatively boring and unappealing to other insects. Dry leaf litter accumulations that have been forming for centuries may also yield quantities of Arenivaga, living out generations of rather unexciting time nibbling and burying into a reliable substrate made of poor quality food that other insects are unable to exploit due to their nutritional needs and lack of proper physiology/body flora to utilize. The Arenivaga at Cave Creek Canyon in the Chiricahuas seem to do just this, with a bit of a twist.

The Sunny Flat Campground is located at about 5,000 feet and surrounded by the towering, rainbow-colored walls of the mountains. The foliage is oak scrub at lower elevations and turns into alpine grassland with a myriad of colorful wildflowers and shrubs, many endemic to the area. Our little Arenivaga can be found from the base of these slopes up to about 7,000 feet; it is likely they range further up, but I usually run out of energy flipping things before getting a chance to climb higher.

In years past we have found Arenivaga in a few ways. Alan Jeon and I originally scoured the leaf litter near our campsite with fair to poor results, finding a few adult females. The following trip, things were more interesting; the Arenivaga were very abundant throughout the leaf litter on the low slopes, but very strongly associated with the frass from beetle larvae (Alan suggested they were Xyloryctes sp.). This trip, I once again sought out the Arenivaga as my colony had long since crashed (my husbandry for Arenivaga now refined, I feel confident in continuing the strain). The beetle larvae were nowhere to be found (most likely deeper in the soil preparing to pupate), but I did find a reasonable number of Arenivaga through the litter in the driest areas. Southeast Arizona has received a lot of rain this monsoon season and everywhere we visited including the Chiricahuas was completely overgrown. This coupled with abundant mosquitos made collecting at the site very frustrating. The Arenivaga are very hydrophobic and the few I did find in moister material were adult females, probably desperate to eat enough material to produce their last oothecae for the summer.

Without males we have little idea what species these could be, however just as it’s likely the life history of whatever species they are hasn’t been documented, given their location it’s very possible they are new to science. Traveling east just out of the mountains is a very different habitat, and a bare minimum of two for-sure different species can be found in the grasslands/deserts there. Once the colony is established enough to produce males, myself and a few other interested people will be working on keying them out. The females are an attractive purple and very dark green with some yellow highlights; the nymphs have a mosaic pattern across their body but are not quite as vividly colored and patterned as some other species, notably sp. “Texas Canyon” and “Bowlin’s Old West Trading Post”.

Thanks for reading! The next post will likely contain more Arenivaga nuttiness!

-Kyle