(gentle music)
-: Our climate is changing.
Whether it's increased temperatures, altered
precipitation patterns or elevated carbon dioxide,
we know the world we're experiencing today
is not the same as it was 100 years ago.
Nor will it be the same 100 from today.
To that end, we can work on predicting and evaluating
how our species interactions and ecosystems might change.
For the purposes of today's talk, I'll focus on
one environmental factor - temperature.
Now in general we have this blanket statement,
that by the year 2100, there will be a two to four
degree increase in our global mean temperatures.
Now we know that global does not always translate
to regional or local.
For example, here in Starkville, Mississippi,
we're actually seeing an increase in our night time
temperatures while we're seeing no change in our
day time temperatures.
Why is this important?
Consider yourself a nocturnal predator, or something
that's active at night.
If I increase the day time temperature, this may not
have much of an effect on you.
However, if I increase the night time temperature
and you're active at night, this could have
a huge effect.
Let's take a broader class of organisms - insects.
Insects temperature can regulate their performance.
We see that here on a temperature performance curve.
If we start down at the bottom, we're talking about
a critical thermal minimum, or a minimum temperature
at what these organisms can survive and reproduce.
We rise slowly to a thermal optimum and then
we drop off quickly to a critical thermal maximum.
This is the maximum temperature at which they can survive
and reproduce.
Now let's add temperature onto the night time.
If we add two degrees onto that minimum temperature,
we're getting closer to the thermal optimum,
which should be positive for performance.
Alternatively, if we add those two degrees onto the
day time temperature, we're getting closer
to the maximum, which has a negative effect on performance.
Now this is very broadly what I study.
I look at the effects of day time vs. night time warming
on ecosystems.
Specifically, I work in agro eco-systems, where I use
fava bean as my plant.
I use a common insect pest, aphids, and then a common
biological control for those aphids - lady beetles.
And I asked the question "Are Beetles Ladies of the Night?"
Well, so far, my research suggests that aphid
populations are gonna grow regardless of temperature.
However, when we look at lady beetle suppression
of those aphids, we're seeing a higher amount of
suppression in our night time vs. our day time treatments.
What does this suggest?
When we're doing climate change experiments, we need to
not be looking at a global level, but we need to be
focused on regional and local variation.
Thank you.
(gentle music)