[meteorite-list] Honeybees Defy Dino-Killing 'Nuclear Winter'

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri Nov 5 16:09:13 2004
Message-ID: <200411052109.NAA29802_at_zagami.jpl.nasa.gov>


News Release 5 November 2004
GSA Release No. 04-31

Contact: Contact: Ann Cairns
Phone: 303-357-1056; Fax: 303-357-1074


Honeybees Defy Dino-Killing "Nuclear Winter"

The humble tropical honeybee may challenge the idea that a post-asteroid
impact "nuclear winter" was a big player in the decimation of dinosaurs
65 million years ago.

Somehow the tropical honeybee, Cretotrigona prisca, survived the
end-Cretaceous extinction event, despite what many researchers believe
was a years-long period of darkness and frigid temperatures caused by
sunlight-blocking dust and smoke from the asteroid impact at Chicxulub.

The survival of C. prisca is problematic and telling, asserts
paleontology graduate student Jacqueline M. Kozisek of the University of
New Orleans. Late Cretaceous tropical honeybees preserved in amber are
almost identical to their modern relatives, she says. If no modern
tropical honeybee could have survived years in the dark and cold without
the flowering plants they lived off of, Kozisek reasoned, something must
be amiss with the nuclear winter theory.

"It couldn't have been that huge," says Kozisek of the Chicxulub-related
temperature drops asserted by other researchers.

Kozisek will present her work on Monday, 8 Nov., at the Geological
Society of America annual meeting in Denver.

Modern tropical honeybees have an optimal temperature range of 88 to 93
degrees F (31-34 ?C) in order to maintain vital metabolic activities,
according to entomological research, says Kozisek. That's also the range
that's best for their food source: nectar-rich flowering plants.

Based on what is known about the Cretaceous climate and modern tropical
honeybees, Kozisek estimates that any post-impact winter event could not
have dropped temperatures more than 4 to 13 degrees F (2-7 ?C) without
wiping out the bees. Current nuclear winter theories from the Chicxulub
impact estimate drops of 13 to 22 degrees F (7-12 ?C) - too cold for
tropical honeybees.

"I'm not trying to say an asteroid impact didn't happen," says Kozisek.
"I'm just trying to narrow down the effects."

To do this, Kozisek took a novel approach for a paleontologist - instead
of looking at what died out, she dug through the literature to find out
what survived the massive extinction event.

"I made a list of all survivors and picked those with strict survival
requirements," said Kozisek. She determined that those survival
requirements were by calling on studies of the closest modern
analogues - which wasn't always easy for some species, she pointed out.
There was, for instance, a very early primate that crawled out of the
Cretaceous alive, but there is really no comparable small primate around
today with which to reliably compare, she said.

On the other hand, a good number of tropical honeybees haven't changed a
lot in 65 million years and a great deal is known about modern tropical
honey bees' tolerances to heat and cold. What's more, amber-preserved
specimens of the oldest tropical honey bee, Cretotrigona prisca, are
almost indistinguishable from - and are probably the ancestors of - some
modern tropical honeybees like Dactylurina, according to other studies
cited by Kozisek.

Survival and Its Implications: Tropical Honeybees (Hymenoptera: Apidae:
Meliponini) and the Cretaceous-Tertiary Boundary
Monday, 8 November, 10:30-10:45 a.m., CCC 605
Abstract may be viewed at:

    Jacqueline M. KozisekUniversity of New Orleanscamel80_at_yahoo.com

During the GSA Annual Meeting, 7-10 November, contact Ann Cairns at the
GSA Newsroom, Colorado Convention Center, Denver, for assistance and to
arrange for interviews: 303.228.8570.

Geological Society of America
116th Annual Meeting
7-10 November 2004
Colorado Convention Center
Denver, CO, USA

Geological Society of America

Received on Fri 05 Nov 2004 04:09:11 PM PST

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