[CH] More thoughts on C. pubescens fruit setting
Cameron Begg (begg.4@osu.edu)
Mon, 24 Aug 1998 14:57:12 -0500
Hi C-H's,
As usual, it has taken until mid- August here in the N. hemispere to set
fruit on my venerable rocoto. This is despite the fact that the first
flowers were smiling their purple beauty at the world over two months ago.
During that time I have been dutifully inserting my little paintbrush
whenever the opportunity presented itself, and until recently have been
rewarded only with a sad pile of crumpled flowers around the base of the
plant. Now there are suddenly about a dozen fruits set.
Previously I have hypothesised about day length, temperature, chemical
conditions, altitude and anything else I could think of. Still the answer
has elluded me. Until now. Maybe.
So what is different in the middle of August? I have been watching the
plant very carefully for clues and have come up with a rather obvious
answer. I noticed a brown hornet (one of the type that constructs hanging
clay nests for it's young) very systematically foraging in the flowers;
presumably for traces of nectar. Further studies revealed an irridescent
green fly about 0.3" long doing the same thing. Any entomologists on the
list?
Hypotheses: The insect vectors which pollinate these plants successfully in
S. America and Mexico are missing in Dublin OH. Some aspect of the life
cycle of the hornets prevents pollination until later in the Summer. Do
their feeding habits change? Or perhaps do only the newly adult hornets
seek nectar? Do the "green flies" only hatch out at this time of year?
And why doesn't the paint brush work? I try to do "it" carefully aided by a
10x magnifying glass, but maybe I don't have the touch. Maybe it takes a
fuzzy little insect to implant the pollen grains.
Maybe.
Regards, Cameron.