3/18/2021: Florida Trip Rambles- Suspicious skunk roaches
Hopping right into some thoughts on the Florida trip, I’d like to focus on a very unique United States endemic roach: Eurycotis floridana!
This is a large and underrated member of the unique fauna of the southeastern United States. Upon internalizing that this is our only endemic representative of the subfamily Polyzosteriinae (which contains many beautiful and strongly admired species from Australia, such as Polyzosteria mitchelli), I decided to focus some time on the trip to round out my locality collection.
For many years, solid maroon strains were available with locality information scarcely openly mentioned, however with Eric Maxwell’s collection of stock from Big Torch Key and the coinciding color overlap with old hobby whispers of marked adult strains from Keys, the diversity of this species is just now starting to shine.
During the trip we encountered skunk roaches in many of our locations, but their abundance varied greatly. Preferred habitat was dead bark on standing pines, in rotten logs on or touching the ground, and most interestingly in a pile of rotting particle board infested with termites and carpenter ants.
I collected mixed individuals from Wimauma, Lake Placid, and Key Largo as well as a single ooth from Tampa, in addition to my pre-existing colonies of “Silver Springs”, “Hidden Lake”, and “Big Torch Key” Though the sample size of Key Largo specimens is only 3 with 2 being adult males, I have some generalized thoughts on the distribution of patterns.
It would seem that the retention of strong juvenile patterning into adulthood occurs not just in the lower keys but also on the mainland; “Hidden Lake” is located fairly far south on the peninsula and also possesses these traits. Although not all individuals in this strain or “Big Torch Key” retain the markings, they are completely absent from all other mainland localities. The “Key Largo” adults are all unmarked with no traces of pattern, but I will wait for the female to mature and for some F1s before further speculating.
“Silver Springs” is the farthest north locality in the sampling and even nymphs (especially half-grown ones) trend towards not having any thorax markings, while “Lake Placid” and “Wimauma” definitively have some.
This suggests a trend of increasing amount of markings on adults and nymphs as you move southward, though I would feel more comfortable if the in-between localities established colonies and I had more to look at.
The real question is… why? Is there some adaptive advantage to the markings that more southerly individuals need?
Another way to draw the lines would be similar to the distribution of Arenivaga floridensis (post on these coming soon!). Due to sea level and habitat changes their distribution is limited to the sand ridge that runs through central peninsular Florida and veins out in multiple directions. The unmarked adult skunk roaches seem to loosely correlate with the southernmost extent of this ridge, which could explain why those from southernmost mainland Florida look less like their other mainland counterparts. Perhaps at some point an island population of skunks survived a period of high ocean levels and was first to recolonize the Keys and southern mainland; or maybe a small population on the mainland was separated and re-colonized the Keys.
Who knows! But I’d love to one day unearth some firm answers to my questions about this charismatic and very special roach.
-Kyle