WEBVTT 1 00:00:00.471 --> 00:00:03.054 (gentle music) 2 00:00:09.224 --> 00:00:11.098 Our climate is changing. 3 00:00:11.098 --> 00:00:13.482 line:15% Whether it's increased temperatures, altered 4 00:00:13.482 --> 00:00:16.037 line:15% precipitation patterns or elevated carbon dioxide, 5 00:00:16.037 --> 00:00:19.065 line:15% we know the world we're experiencing today 6 00:00:19.065 --> 00:00:21.071 is not the same as it was 100 years ago. 7 00:00:21.071 --> 00:00:23.615 Nor will it be the same 100 from today. 8 00:00:23.615 --> 00:00:26.601 To that end, we can work on predicting and evaluating 9 00:00:26.601 --> 00:00:30.311 how our species interactions and ecosystems might change. 10 00:00:30.311 --> 00:00:32.343 For the purposes of today's talk, I'll focus on 11 00:00:32.343 --> 00:00:35.198 one environmental factor - temperature. 12 00:00:35.198 --> 00:00:37.397 Now in general we have this blanket statement, 13 00:00:37.397 --> 00:00:40.003 that by the year 2100, there will be a two to four 14 00:00:40.003 --> 00:00:43.224 degree increase in our global mean temperatures. 15 00:00:43.224 --> 00:00:45.467 Now we know that global does not always translate 16 00:00:45.467 --> 00:00:47.054 to regional or local. 17 00:00:47.054 --> 00:00:49.583 For example, here in Starkville, Mississippi, 18 00:00:49.583 --> 00:00:51.952 we're actually seeing an increase in our night time 19 00:00:51.952 --> 00:00:54.602 temperatures while we're seeing no change in our 20 00:00:54.602 --> 00:00:56.510 day time temperatures. 21 00:00:56.510 --> 00:00:57.853 Why is this important? 22 00:00:57.853 --> 00:01:00.095 Consider yourself a nocturnal predator, or something 23 00:01:00.095 --> 00:01:01.523 that's active at night. 24 00:01:01.523 --> 00:01:03.968 If I increase the day time temperature, this may not 25 00:01:03.968 --> 00:01:05.560 have much of an effect on you. 26 00:01:05.560 --> 00:01:08.044 However, if I increase the night time temperature 27 00:01:08.044 --> 00:01:09.920 and you're active at night, this could have 28 00:01:09.920 --> 00:01:11.467 a huge effect. 29 00:01:11.467 --> 00:01:14.280 Let's take a broader class of organisms - insects. 30 00:01:14.280 --> 00:01:17.880 Insects temperature can regulate their performance. 31 00:01:17.880 --> 00:01:20.256 We see that here on a temperature performance curve. 32 00:01:20.256 --> 00:01:22.496 If we start down at the bottom, we're talking about 33 00:01:22.496 --> 00:01:25.312 a critical thermal minimum, or a minimum temperature 34 00:01:25.312 --> 00:01:28.125 at what these organisms can survive and reproduce. 35 00:01:28.125 --> 00:01:31.176 We rise slowly to a thermal optimum and then 36 00:01:31.176 --> 00:01:34.357 we drop off quickly to a critical thermal maximum. 37 00:01:34.357 --> 00:01:36.600 This is the maximum temperature at which they can survive 38 00:01:36.600 --> 00:01:37.985 and reproduce. 39 00:01:37.985 --> 00:01:40.353 Now let's add temperature onto the night time. 40 00:01:40.353 --> 00:01:43.368 If we add two degrees onto that minimum temperature, 41 00:01:43.368 --> 00:01:45.816 we're getting closer to the thermal optimum, 42 00:01:45.816 --> 00:01:47.732 which should be positive for performance. 43 00:01:47.732 --> 00:01:50.828 Alternatively, if we add those two degrees onto the 44 00:01:50.828 --> 00:01:52.743 day time temperature, we're getting closer 45 00:01:52.743 --> 00:01:56.499 to the maximum, which has a negative effect on performance. 46 00:01:56.499 --> 00:01:58.454 Now this is very broadly what I study. 47 00:01:58.454 --> 00:02:01.328 I look at the effects of day time vs. night time warming 48 00:02:01.328 --> 00:02:02.389 on ecosystems. 49 00:02:02.389 --> 00:02:05.447 Specifically, I work in agro eco-systems, where I use 50 00:02:05.447 --> 00:02:07.611 fava bean as my plant. 51 00:02:07.611 --> 00:02:10.912 I use a common insect pest, aphids, and then a common 52 00:02:10.912 --> 00:02:14.027 biological control for those aphids - lady beetles. 53 00:02:14.027 --> 00:02:17.857 And I asked the question "Are Beetles Ladies of the Night?" 54 00:02:17.857 --> 00:02:19.612 Well, so far, my research suggests that aphid 55 00:02:19.612 --> 00:02:22.714 populations are gonna grow regardless of temperature. 56 00:02:22.714 --> 00:02:25.447 However, when we look at lady beetle suppression 57 00:02:25.447 --> 00:02:28.301 of those aphids, we're seeing a higher amount of 58 00:02:28.301 --> 00:02:31.725 suppression in our night time vs. our day time treatments. 59 00:02:31.725 --> 00:02:33.109 What does this suggest? 60 00:02:33.109 --> 00:02:35.655 When we're doing climate change experiments, we need to 61 00:02:35.655 --> 00:02:38.385 not be looking at a global level, but we need to be 62 00:02:38.385 --> 00:02:40.750 focused on regional and local variation. 63 00:02:40.750 --> 00:02:42.014 Thank you. 64 00:02:42.014 --> 00:02:44.597 (gentle music)