A Ramble at Wildflower Preserve Nov. 12, 2010

It is interesting and amazing how sometimes a small amount of time spent outdoors yields such a profusion of wildlife encounters. In a one hour visit to Wildflower Preserve (WF) near our Winter home in Englewood, FL, yesterday late afternoon, I had such an experience.

There were two beautiful buckeyes (see photo of one) nectaring on Spanish needles. After previously consulting with the primary authority on buckeye evolution (Dr. Jeff Marcus -strangely enough at the Univ. of Manitoba in Canada, but he got his PhD at Duke) I am now sure that these are mangrove buckeyes, a much rarer species than the more widespread,common buckeye. I will also attach a photo of a common buckeye for comparison; this was taken at our farm in VA. Can you see some slight but distinctive differences? Note the different colors that surround the large eyespot on the forewing (mostly orange in mangrove vs white in common buckeye), and the relative differences in size of the two eyespots in the hind wing (there is less difference in the mangrove)? Such “sibling species” are genetically and morphologically quite similar, but distinct in some ways. Here is a quote from Dr. Marcus regarding his research findings:

“What seems to be going on in Florida is that there was a resident species (common buckeye), that hybridized with invading species as they arrived (the invaders probably got to Florida from the Caribbean), replacing the invader’s mitochondria with it’s own. In the case of the Mangrove buckeye, this happened a long time ago–using molecular clock estimates: some 250 thousand years ago–the common buckeye mitochondria have actually evolved inside of the mangrove buckeye cytoplasm which is how we can date the event. In the case of the tropical buckeye, it’s happened since the 1960’s when the first tropical buckeyes apparently arrived in Florida. Pretty much all mangrove buckeyes on mainland Florida carry mitochondria derived from common buckeyes, but some mangrove buckeyes in the keys retain their original mitochondrial genotypes.”

Isn’t it remarkable what modern genetic techniques can allow us to understand or not, depending on your background in biology! But this goes to show that buckeyes in S FL have interbred but likely maintain their distinct species due in part to habitat selection. The major food plant of mangrove buckeyes is black mangrove which is only found in coastal areas of warm temperate to subtropical climates. The major food plants of common buckeyes are Gerardias, toadflax and plantain.

A beautiful green tree frog was hanging out on the stem of a Spanish needles nearby (see photo) and maybe thinking of having a butterfly for supper. Although these are fresh water frogs in general, they often breed in ponds of low salinity. We used to spend summers on Chincoteague Island, VA, and the calling of the green tree frogs from estuarine ponds was so loud it was difficult to sleep. So it will be fun to do some frog calling surveys in the summer at WF.

A female scarlet skimmer dragonfly was also perched in the Spanish needles (see photo). The male scarlet skimmer is appropriately named and this is actually an exotic dragonfly that tends to be found in disturbed habitats. Consider how different in coloration the sexes are (yellow vs red). Such a gaudy male normally would indicate that males are competing for the affections of the females, and the females get to choose! Is this a feminist’s dream or what? Supposedly the prettiest males are the strongest and will likely father the best progeny. This is rather interesting behavior for a “primitive” insect.

Finally we had an up close and personal encounter with a juvenile black-crowned night heron (BCNH) just at dusk. There were a number of both juveniles and adults flying around and I see them regularly along the creek. This is a general indicator of the estuarine character of the creek system since BCNH are normally found at much lower salinities than yellow crowned night herons (YCNH). BCNH feed more generally on frogs, fish, reptiles, etc., whereas YCNH are specialists on crustaceans (crabs mostly but will eat crayfish in fresh water habitats). In fact there is a rookery of YCNH in downtown Winston Salem, NC, in Miller Park, far from the coast where most of their kind are found. Bird watchers are chronically arguing about how to separate juvenile BCNH and YCNH; the partly yellow beak of the BCNH is distinctly different from the all-black and heavier beak of the juvenile YCNH. Does it seem strange that the adults of these two species are so different, yet the juveniles are hard to discriminate? Could this be related to separation of the breeding behavior of these two species by distinctive adult coloration?

So get out and enjoy nature wherever you happen to be today and marvel at the wonders you find there.

Bill Dunson, Englewood, FL & Galax, VA
wdunson@comcast.net