Re: Insects at K/T boundary

[Gautam Majumdar <gautam@xxxxxxxxxxxxxxxxxxxx>]

"Fuller, Daryl" <Daryl.Fuller@BCHydro.bc.ca> wrote

>1) At what time of the year did the impact occur (surely there must be
>some evidence - newly formed deciduous leaves buried in the wash in
>Texas, etc.)?

See the article : Wolfe J A, Palaeobotanical evidence for June 'impact winter'
at the Cretaceous/Tertiary  boundary, Nature 1991; 352: 420-2.

Author concluded from the analysis of the sediments of Teapot dome in
Wyoming, USA, which was a lily  pond at the end of the Cretaceous period,
that there was a double bolide impact early in June.  

I really don't know what other palaeoclimatologists thought about this paper.

>2) If we know the time of year of the impact, how long does it take for
>the effects of such an event to take place? (this would help us
>determine if the insects had time to "prepare" for the theorized nuclear
>winter)?

The typical scenario is of an initial heat wave travelling round the earth over a 
few hours followed by and overlapped by fall of burning ejecta producing a
global wildfire (lasting for hours to days) followed by the "impact winter". Now
the problem starts. I have not seen any consensus about the duration of the
cold phase. It could be days, months or years depending on the setting of the 
parameters. Also have to be fitted in an initial massive tsunami, massive rain
for days as all the evaporated water comes down (what effect that will have
on the global wildfire, I wonder), acid rain for weeks to years, etc.  

For an impact of Chicxulub size no creature would have had any time to
prepare for what to come. Animals and plants prepare for the various phases
of life, including seasonal changes, according to predetermined genetic
information - no creatures other than modern humans have any foresight to
prepare for catastrophic events.

>3) If we know the answer (or at least have strong evidence of the most
>likely answers) to 1) and 2) above, then do any or most insects exhibit
>a behavior which would enable them to react within a reasonable time to
>allow adaptation to a rapid change in their environment (not as fast as
>putting them in the freezer, more like over a 1 year or one or two
>life-cycle period)?
>
Unfortunately, the answers to neither (1) nor (2) can be determined with any
degree of certainty. 

>I am not an "Impacter" nor am I a "Deccan Traps" devotee, but I do enjoy
>a good scientific discussion like this one attributed to Heinz and his
>wife's after-dinner discussion. 

Gautam Majumdar                 gautam@majumdar.demon.co.uk