Many of us have enjoyed watching parades of leafcutter ants, such as
can be seen in Bustamante Canyon in northern Mexico. Don't think they
get very far into Texas. Here's a curious things from Jim Conrad's
Naturalist Newsletter about leafcutter bees, which I'd never heard of
before.
You can sign up to get his e-mail weekly newsletter at
www.backyardnature.net/news/natnat.php
Very rarely anything about caves, but lots of interesting nature
stuff, especially about plants and birds. -- Mixon
JIM CONRAD’S NATURALIST NEWSLETTER
Issued from the woods not far from Natchez, in
southwestern Mississippi, USA
April 1, 2012
*****
LEAFCUTTER BEES
On my last day in the Yucatán I untied the rope that
for so long had been suspending my backpack from the
hut's ceiling, hopefully out of mind for nest-seeking
rats and mice, and took my old backpack in hand. Ashes
from daily campfires had settled all over it so I
stepped outside and gave it a good whack. The
resulting cloud was half ash and half green tatters of
dried, coiled-up leaf-parts stuck together into tube-
like affairs. The leaf tatters surprised me.
But, I knew what they were, for back in 2006 during my
stay at Genesis Retreat in Ek Balam, Yucatán, the Maya
staff there had showed me the same thing. You can read
about that encounter and see the leafy, tube-like item
at http://www.backyardnature.net/yucatan/jo_olon.htm
A young Maya woman had told me that the green leaf-
tube was a collection of nests stuck end-to-end, and
that the tube construction itself was known by a
special Maya name, which was pa'ak. The creature
inside the cocoon was Jo'olon. I was told that a bee
made the nest, but I hardly believed it.
But, now I believe her, for once I had disturbed all
those nests in my roof-suspended backpack, hoards of
bees came complaining, thumping against me and
entangling themselves in my hair but never stinging.
And they were surely the most unusual bees I've ever
seen, for instead of carrying clumps of pollen on
their back-leg "baskets," they transported it on hairs
covering the entire bottoms of their abdomens. With
their golden-yellow abdomen bottoms they look like
dimly lit fireflies. You can the pollen-dusted lower
abdomen on a bee entering its pa'ak cocoon, one
stuffed into one of my backpack's looped belt-tips, in
the hut's dim light, so it's a grainy picture, at
http://www.backyardnature.net/n/12/120401be.jpg
A rear view of the same bee showing golden pollen
stuffed inside a green pa'ak tube is shown at
http://www.backyardnature.net/n/12/120401bf.jpg
So, this was my last Yucatán identification challenge
for volunteer IDer Bea in Ontario. Here's what she
came up with: It's a Leafcutter Bee. Many times we've
spoken of leafcutter ants, but this was something new.
Leafcutter Bees, I find, are members of the genus
MEGACHILE, and despite my ignorance of its existence
that genus is one of the largest among bees, home to
well over 500 species and over 50 subgenera. A list of
insects of Río Lagartos, Yucatán includes eight
species of Megachile leafcutter bees, but I can't say
which species is shown here.
Of leafcutter bees I read that, exactly as we see with
our pa'ak tubes, Megachile nests typically are
composed of single long columns of cells constructed
from cut-out leaf sections. Females place pollen or a
pollen/nectar mix in each cell as food for the egg
laid there, then the cell is capped so that a wall
separates that cell from the next one. The larva
hatching from the egg eats the food supply and after a
few molts and maybe a period of hibernation spins a
cocoon and pupates, emerging from the nest as an adult
bee. Males are typically smaller than females and
emerge before them. Males die shortly after mating but
females survive for several weeks, building new nests.
What a fine last discovery to end my Yucatán days!
----------------------------------------
The winner of the rat race is still a rat.
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