Daggerwings, Deadly Darts, and Monkey-Ball Trees

The last week or two has been a good “stretch” for Ruddy Daggerwing Butterflies, something right now must agree with them.   Sometimes you see Daggerwings in a shaded woods way up high bouncing in and out of the tree branch shadows.   Sometimes they come down and say hello, feeding on any of many flowers.   The larvae feed on Strangler Figs, as in my yard, likely the reason Daggerwings visit out the window during sunny morning coffee time.

The wings folded up look like leaves,  when open they are orange and tiger-striped.  The wings have a variable “swallowtail” even though Ruddies are not Swallowtail Butterflies in a taxonomic sense. Those “tails” must be useful because they have evolved multiple times.  An idea not original with me, they seem to be false antennae that orient confused predators to the rear (less vulnerable end) of the butterfly.

Movie Feature,  Rudy the ruddy finds bees bothersome:  CLICK 

Count the movie star’s legs.  Insects have 6 legs, right?  Not always; in this family (the brush-footed butterflies), only four legs are leggy, the other two reduced to sensory organs.

For the moment let’s agree with the many websites that state “the” larval host plants of the RDW to be Ficus.  Around here natively that would be mostly Strangler Fig, Ficus aurea, plus some cultivated species.   The butterfly is a “pest” on edible figs.    Fig stems and leavess ooze milky sap, which may be key to an oddity of the caterpillars.  They make a little “nest” of debris and frass probably glued with the milky goo, either fresh or after passing through the caterpillar.  I have no idea why.  As with so much of natural history….what’s up with that?

Everybody knows butterflies render themselves poisonous to predators by taking up toxins from their larval hostplants.   Now in the case of the Daggerwings, that gets interesting.  I don’t know how toxic Strangler Fig sap may be, but the butterfly extends tropically into South America where the larvae feed on a different member of the fig family called  Naucleopsis (now-clee-OP-sis).  Species of Naucleopsis in different regions are the secret sauce in lethal poison arrows and darts.   Don’t eat any Rudder Daggerwings.

The northern range of Daggerwings is of interest too.  Here in South Florida “the” larval foodplant may be strictly Ficus, but the range of the Ruddy Daggerwing extends westward and northward where no Ficus grows.   Ruddy Daggerwings are recorded historically  west beyond Texas and northward through Kansas and, decreasingly, much farther north.  Lucky for us the British Museum of Natural History maintains records, available online, tabulating every known hostplant for every butterfly.  A search there shows for Ruddy Daggerwing, not only Ficus and Naucleopsis, but also “Maclura.”   That may be significant.  When I was a kid growing up in West Virginia we used to throw ”monkey balls,” fruits of the so-called Osage-Orange tree, Maclura pomifera, yep, in the Fig Family.  Osage-Orange wood is arguably the best North American wood for making bows, as in bows and arrows.  For that reason pre-Europeans presumably moved the valuable tree around.  Humans relocating its likely northern host may have extended the range of the Ruddy Daggerwing.   I’ve always been drawn to the suspected influences of thousands and thousands of years of pre-Europeans in the modern ranges of plant species.

 Come to think of it, speaking of  bows and arrows, Daggerwings, and larval hosts the same may be true in South America for Naucleopsis.

Look at the two maps below.  One is the present range of Osage-Orange, the other is the present and historical range of the Ruddy Daggerwings.   Remember that the southern extensions into the tropics can be based on Ficus (and Naucleopsis).     The northern similarities of the Daggerwing’s present and past range and the range of Osage-Oranges are suggestive.  (The dark green dots are the area where the tree is common, the more widespread lighter dots show where it is spotty.)  Wonder why the butterfly disappeared from part of its historical distribution:  reduction in woodlands with Maclura?  Increased or changing agricultural pesticide use?  Glad we have it here.

Ruddy Daggerwing present and past distributions

Maclura. Bright green (Texas, Oklahoma, Arkansas = core of the range). Blue-green = counties where recorded but spotty.