Igneous Glade in the Ozarks

Digging around in piles of soft rotting wood is like a treasure hunt, each layer revealing hidden gems like purple iridescent rove beetles and flat-backed millipedes. After flipping a large piece of bark, a yellow thread hung above me, twisting slowly to maintain its grip. Despite their small size, ringneck snakes (Diadophis punctatus) are among the flashiest colubrids of North America. They are a brindle gray color on the dorsum but possess brilliant yellow-orange hues on the belly with symmetrical black spots that look as if they have been painted. When touched directly, ringnecks will flip the posterior part of their body over to reveal their colors and raise the tail into a coiled spiral. This deep orange-red region is thought to serve as a diversion tactic, whereby a predator will aim its attacks to the more expendable tail while the snake’s head is tucked away underneath the body. The photo above was taken after handling [4] to show the colors, and just a few seconds later it concealed its head and slipped under the leaf litter. The bright tail was the last part of the snake to finally flip back over.

There is some support for the tail serving as a decoy; wild populations of ringnecks have a higher incidence of tail damage than other co-occurring species that lack tail colors. Another explanation could be that it serves as a deimatic display, which may induce a startle response in a predator and increase the snake’s probability of escape. Alternatively, the tail could be aposematic if ringnecks are unpalatable or pose a threat, but this seems unlikely given the variety of predators that regularly consume them and relatively weak venom in the rear fangs. The function of flashy tail color in ringnecks remains uncertain, and more behavioral work needs to be done in the context of predator-prey interactions.

Virginia pine (Pinus virginiana)
Small-eyed click beetle (Alaus myops), found atop the same wood pile as the ringneck [1]
Wood violet (Viola palmata) along a shallow stream
Spiny lizards (Sceloporus consobrinus) were active throughout the southern pine forests, foraging in sunlit patches for flies [2]
Female (left) and male (right) five-lined skinks (Eumeces fasciatus) in courtship [2]

The pine forest we explored was reminiscent of habitats I am familiar with in Missouri, but things began to change as we approached an igneous glade. Canopy cover and understory greenery became patchy, and reddish lichenous rocks haphazardly spread out throughout the landscape. These rocks are composed of rhyolite and granite, formed more than a billion years ago during volcanic eruptions. Because of the higher light intensity and temperature in glades, they provide starkly different microhabitats for a host of flora and fauna that are adapted to more arid conditions. For this reason, I was surprised to lift a rock to find an eastern narrowmouth frog (Gastrophryne carolinensis) next to a hatched clutch of snake eggs. This species belongs to a strange family of frogs called Microhylidae, characterized by stout bodies and proportionally small angular faces that seem almost squished by having a skin fold on the top of the head. Their tiny mouths prevent them from eating large prey items and most specialize on ants and termites. In this spot I found numerous ant colonies under the rocks, so together with a cool humid soil layer, it is actually an ideal spot for narrowmouths despite the glade’s exposed surface.


It wasn’t until years after finding my first microhylid that I read about their toxicity. Birds will bite only to toss them aside and many reptile predators regurgitate them. It’s unusual to think of an uncolorful burrowing frog as toxic, but it makes sense when thinking of their foraging habits. Ant colonies are some of the most hostile places to intrude upon, and while some avoid detection through chemical mimicry, an alternative strategy is to become so unpalatable that you deter counterattacks by the colony. For microhylids, another interaction that has gained popularity is their cohabitation with tarantulas in burrows. It is speculated that the two may be mutualistic. The frog benefits from taking refuge in the spider’s constructed burrow, and the spider’s eggs experience lower mortality from ants due to the frog’s chemical defense. Of course, a prerequisite would be that the frogs themselves do not become a tasty meal for the spiders, and yes, it seems like the frog’s toxicity then plays a dual role. To date, these associations have been documented in the Great Plains narrowmouth, and a few genera in South America (Chiasmocleis, Hamptophryne) and Asia (Kaloula, Uperodon).. the latter which dwells with a scorpion!

Vertical gaps and misalignments across the larger rock faces look almost as if split by a sword; they are the result of fractures from cooling magma followed by long periods of erosion and uplifting.
Striped bark scorpion (Centruroides vittatus) [4]
Photographed after uncovered [2]

Lifting another rock, I was thrilled to find one of the tiniest snakes I have seen in my life (excluding blind snakes!)— a juvenile flat-headed / centipede snake (Tantilla gracilis). Adults of T. gracilis attain lengths of up to 20 centimeters, but this individual was probably half that size. The genus Tantilla comprises 67 species of diminutive fossorial snakes in the New World. Of the species studied, they are known to specialize on hunting centipedes, spiders, scorpions, beetle larvae, and snails. Prey items like centipedes and arachnids must sound like quite the challenge for a tiny snake, but Tantilla is well-equipped with recurved teeth and rear fangs to take hold and immobilize. If you take a closer look at the photo above, you’ll notice the snake’s tail is wrapped around a few beige leathery pouches, one of which has been completely torn. These structures are egg sacs of a huntsman spider (Sparassidae), and it’s possible I interrupted the Tantilla from consuming the trio. As far as I know, predation on egg sacs has not been reported in this species, and that would be difficult to surmise solely from stomach content analysis. For many of these secretive fossorial snakes, much about their ecological habits remains to be observed.

Iridescent ground beetle (Dicaelus purpuratus) [5]

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