It’s been quite a while so there is lots of good news on the aphid front! First of all, aphid casualties have decreased substantially thanks to improved transfer methods. We have now been using a paint brush to gently disturb and brush the aphids into a petri dish (upon the suggestion of Dr. George E Heimpel). This is far less traumatizing for the aphids and survival has skyrocketed from 20% to around 50%!
Also, fortunately for us, apparently all aphids at this time of the year are gravid, so we only need to select mature individuals for transferring. This was an exciting discovery since we spent a while with a microscope trying to figure out which ones were gravid before this revelation. We also officially decided to use two founders for each transfer to improve chances of survival.
Hillary and I are looking forward to checking out the preliminary data soon!
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So the weekend is upon us, summer is already beginning to slip away, and aphid abundance is on the rise. Mine and Lauren’s aphid specialization experiment is still being tweaked to perfection. We set up 5 preliminary aphid transfers on B genotype plants (the offspring of between site echinacea crosses) in order to practice appropriate aphid transfer methods and make sure that we can get aphid establishment on plants that we know aphids are found on (aka to ensure that our transfer methods do not result in aphid squashing and death). This proved perhaps more difficult than expected. I single-handedly destroyed the greater part of several aphid colonies before determining that trying to remove aphids from their leafy homes with a tooth pick was just not going to work. Eventually I settled on disturbing the leaf/gently poking at one aphid (which, it turns out, causes some species of aphid to release an alarm pheromone so all the other aphids on the leaf stop sucking phloem, withdraw their stylets and start moving around). Apparently many Aphis species do not have this alarm pheromone, but when I starting messing with the aphids/the aphids’ leaf they started running around in frantic disarray, so whether or not they release a pheromone, poking them seems to work. After instigating a mass aphid exodus, I attempted to herd several confused individuals onto the flat side of a twist tie. This was also more difficult than you might expect it to be, and was rather time consuming. When we set up our actual experiment we will knock the disturbed aphids into a petri dish, which will be a much more efficient method and will probably result in a significantly less aphid mortality. We had initially planned on using a single alate (winged) aphid as our population founder, because these are the individuals that would colonize new plants. However, this particular aphid morphology is not nearly as common as the apterous aphids (lacking wings). After conferring with Dave Andow, an entomologist from the U of M, we determined that using apterous aphids is fine, as we are testing plant suitability rather than aphid preference (ie CAN aphids colonize a certain plant, not which plant would a aphid PREFER. And anyway, preference will probably manifest itself somewhat in the form of population success and growth rate). We also discussed the important question of one founder aphid or two. If we can have lots of replicates we could have only one founder. If we are worried about aphid success rate and have fewer replicates, Dave suggested that we have two founders and just record whether one or both birth their aphid babies within the first one or two days of the experiment. Dear readers: Comments or suggestions about aphid founders are encouraged! One problem: whatever sort of aphid we use, we need to introduce gravid ones to our plants or there will be no population growth whatsoever and our experiment will fail epically. Thus it is now necessary for Lauren and I to be able to identify gravid aphids. Hmm. Apparently this is possible, and this is something we are going to have to figure out before our actual experiment can start. Again: comments or suggestion are encouraged! I think that covers most of the updates in the glorious and exciting world of me, Lauren, and aphids. Over and out! Hi I’m Lauren Hobbs. I am from a town in Wisconsin almost as small as K-town (aka Williams Bay). I attend UVA and am a psych major. Hence I am learning a lot already!! Fortunately, I found a friend here to work with! Hi! My name is Hillary Lyons and I am from Olympia, WA. I am a biology major from Carleton College. I really like muskoxen. As per a request from Daniel, here is a presentation I gave to Team Echinacea way back at the beginning of the summer. Enjoy reliving the magic! So, I know I have been missing from the flog lately, but that is only because I was saving up all my flog posts to make one huge, wonderful one! But this is not that post. First of all, This still lacks the transect searches that we will do next week, at which time I shal post an updated version. Note that even though this says Final version, this is just where I save all the final versions of my tables, as opposed to the working versions I use to sort out the tables. Here is an outline of the form needed for doing the aphid searches: Rosette Count Leaf Count Length of Longest leaf – cm Ant Presence – Yes/No Size of Aphid Infestation (Required Field) – Categories 0, 1, 2-10, 11-80, >80 Count of Leaves with Aphids Spittlebug Presence – Yes/No Distance from Plant to Spittlebug – 0 if on the Echinacea Plant itself So, in an attempt to fit as many sampling needs as possible, here are the sites that we will be sampling for aphids, juvenile plants, and some tissue samples, along with the sampling strategies: We will use a couple different sampling strategies for the different remnants in order to try and randomize them as much as possible. These should accomodate Daniel’s, Amy’s and a portion of Jennifer’s project. Note: All belt transects are 1/2 m unless otherwise noted. Staffanson – Select 3 random locations in both the burned and unburned plots using randomly selected ULM coordinates, and find them using the Trimble GPS. Then, choose a random compass direction and run the belt transect roughly 10 m in that direction. Landfill – Choose 3 random locations on the East Hill (Trimble again), choose a random direction, and do a 3-5 m belt transect in that direction. If more plants are needed, go a little further KJ’s – Choose 3 random locations, choose a random direction, and do a 3-5 m belt transect. Go further if needed. Nessman – Since this is a roadside remnant, choose 5 random points along the road edge, and extend the belt perpendicular from the road to the cornfield. East Riley – choose 5 random points along the road edge, and extend the belt perpendicular from the road to the edge of the remnant Steven’s Approach – Choose a bunch of random points along the road, and inspect to see if there are plants present. If not, go to the next point. Northwest of Landfill – choose 5 random points along the road edge, and extend the belt perpendicular from the road to the edge of the remnant. Randt – Choose a bunch of random points along the road, and inspect to see if there are plants present. If not, go to the next point. East of Town Hall – Select random points used for seedling search, and look for plants there. This file lists places to look for spittlebug spittle masses in the CG. At the top there are rows in the 99 garden and the 99S garden sorted randomly. Then all bigbatch rows (noted with end positions) are listed in a random order. Enjoy your search! |
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