Another unusual feature of the Raff lesia is that it has no leaves or
stems. It grows low to the ground, attaching itself to and burrowing
inside the tropical grapevine
Tetrastigma
. The only part of the Raff lesia
that is visible outside of the host vine is its giant five-petaled f lower.
Why does the Raff lesia attach itself to the vine in the first place?
Without green leaves, the Raff lesia cannot produce its own food
through photosynthesis. Instead, it must live as a parasite on the host
grapevine. Then the Raff lesia obtains all its nutrients from the vine it
grows on.
The dead horse arum (
Helicodiceros muscivorus
), native to the stony
islands of Corsica and Sardinia in the Mediterranean Sea, also smells
like rotting f lesh. And yes, the smell is the plant’s way of attracting
f lies—in this case blowf lies—for pollination. This plant can do
something else extraordinary: it can raise its body temperature. That’s
right, this plant has a built-in heating system! The ability to grow
warm (thermogenesis) is rare among plants, but it is part of respiration.
The dead horse arum’s warmth, along with its stench, attracts f lies to
its f lower.
Blowf lies are critical to the plant’s fertilization, which isn’t as simple
as you might think. Each dead horse arum f lower has only a two-day
window of opportunity for pollination. The female part of each f lower
can receive pollen for only one day, but on that day, the male part
is not mature enough to release pollen. On the following day, when
the male part can release pollen, the female part has already withered.
That’s where the blowf lies come in. The dead horse arum emits its
characteristic horrid odor to attract blowf lies for pollination at just the
right time. On day one, the f lies explore the plant’s f lower, looking for
a place to lay their eggs. When they reach the female portions of the
f lower, spines in the f loral chamber trap the insects inside, holding them
overnight. During this time, the f lies release pollen picked up from
earlier visits to other f lowers. The next day, the spines wilt and the f lies
are able to exit the chamber. As they leave, they pass by the male part of
the f lower, which on this day is ready to release pollen. The blowf lies
get covered in more pollen and f ly off to pollinate more female f lowers.
The one-day delay is perfect timing for the dead horse arum.
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P. U . , Yo u S t i n k !
