PROJECT REPORT: International Wildlife Research Week

Transcription

1 PROJECT REPORT: International Wildlife Research Week The preferences of alpine butterflies regarding the colors and species of different flowers Anny Gora, Selina Sollberger 2 Emmy-Noether-Gymnasium, Berlin, Germany, 2 FMS Thun, Thun, Switzerland Supervised by: Irene Weinberger Date: July 27, 208 Abstract: Butterflies are really amazing animals, there are more than species of them all over the world. On a trip in the Alps we observed that different types of butterflies flew to different flowers. So we wanted to know if there is a connection between the butterfly species and the color or species of flowers. To answer this question, we counted which butterflies flew to which flowers in 4m 2 -plots in Buffalora, Switzerland. Our results show, that there is really a connection between the butterfly species and the color of the flowers as well as between the butterfly species and the species of the flowering plant. However, some butterflies seem to be flower specialists and some generalists.

2 . Introduction On our trip on the second day of the International Wildlife Research Week we saw a lot of different, interesting animals, but one of them impressed us most: the butterfly. First, we only observed the different shapes and colors of the butterflies, but then we noticed that a few butterflies, which were orange, sat often on orange flowers and brown butterflies sat on yellow ones. So, we asked if there is a relation between the species of butterflies and the species or color of a flower. In our literature research we only found the information that the caterpillars of each butterfly species prefer specific plants. Additionally, scientists in the UK showed that butterflies can be plant specialists or plant generalists (Tudor et al., 2004). However, we did not find any facts on butterfly species preferring certain colors or species of flowering plants. So, we set out to find the answer of our question on our own. 2. Material & Methods We did our research in the area of Buffalora because there are different but few flowering plant species. Buffalora is situated in the Val Mustair in the Canton Grison in Switzerland. Here, we set up 4m 2 -plots using four hooks and string (Figure ). For each plot, we counted the number of flowers with identical colors. Then we identified the flowering plant species using a plant-identification book (Spohn et al, 2008). To identify the butterfly species in the area, we caught and photographed them. To assess the relation between butterfly and plant species or flower color, we then counted all butterflies that sat on a flower in our plot for 30 minutes. We noted the species of the butterfly, the color of the flower and the plant species it sat on. Then we did it all again with other 4m 2 -plots. We took care that the plots had flowers with the same color and/or the same species or genus of the flowering plants. We then calculated the color and plant preferences for all butterflies combined and for each butterfly species. For this, we calculated the percentage of each flower color over all flowers (=availability). Then we calculated the percentage of the butterflies that sat on each flower color (=use). We then divided the use by availability and then we took the logarithm to reduce the skew. This tells us if and how much the color of the flower is preferred by the butterflies. Positive numbers mean that the butterflies prefer sitting on that flower color, while negative numbers mean that the butterflies avoid that color. We repeated the same calculation also for the selection of the butterflies for flowering plant species. 2

3 A: Identification books D A C E B: Protocols C: Butterfly net D: Chars E: String to set up the plot B F: Hooks F Figure : Material 3. Results Between July 23 and 25, we counted of butterflies and plants in 22 plots (Figure 2). All in all, we counted in 22 plots 708 flowers of 5 different genera and 462 butterflies, which we divided into 9 groups (see the groups and species in the appendix A, A2). Figure 2: Location of our plots (Source: map.geo.admin.ch) We found that, if you look at all butterflies combined, they prefer orange and yellow flowers and they were not so interested in the white, pink, violet and purple flowers. There was not any butterfly on the violet flowers at all (Figure 3). 3

4 ,2 0,8 0,6 0,4 0,2 0-0,2-0,4-0,6-0,8 orange flowers yellow flowers white flowers pink flowers purpel le flowers dark yellow flowers white flowers + yellow inside white - pink flowers violett flowers Figure 3: Selection of flower colors of all butterflies combined. Everything above 0 is positively selected, while the points below 0 are avoided. However, there was a difference between the different butterfly families/genus/species. So, the butterflies of the family, genus and species Lycanidae (orange and blue), Erebia sp., Boloria sp., Melitaea sp., Colias phicomone and Euphydryas sp. preferred nearly the same flower colors as mentioned before (at all butterflies, Fig. 3), although some of them did not flew to all flowers (Fig. 4,5 & Appendix A4). On the other hand, the butterflies of the family Lycanidae (brown and darkblue) did not sit often on the yellow or orange flowers. They both sat more often on pink flowers. The darkblue Lycanidae preferred the purple flowers (Figure 5), while the brown butterflies of this family did not flew a lot to these ones. 0,8 0,6 0,4 0,2-0,2 0-0,4-0,6-0,8 -,2 - -0,8-0,6-0,4-0,2 0 0,2 0,4 0,6 The colors of the points indicate the colors of the flowers. Figure 4 & 5: example Boloria sp. (left) & Lycanidae (darkblue) (right) 4

5 We also assessed the preference of butterfly species (or genus) for plant genus or species: There we found that, if you look at all butterflies together, they really preferred Arnica montana and they did not sit often on the Campanula rotundifolia. Additionally, we could not detect a butterfly sitting on the Erigeron sp. and the Antennaria diocia.,2 0,8 0,6 0,4 0,2 0-0,2-0,4-0,6-0,8 - Senecis abrotenifolius Arnica montana Hieracium sp. Leontodon sp. Galium sp. Achillea millefolium Erigeron sp. Crepis aurea Helianthemum sp. Taraxacum officinale Leucanthemum vulgare Trifolium sp. Antennaria diocia Campanula rotundifolia Figure 6: Selection of flowering plant species of all butterflies combined. Looking at the different flowering plants, we detected an even bigger difference between the different butterfly groups than when just looking at the colors. So, every butterfly group preferred and disliked other flowering plants (Fig 7 and 8, for other species see Appendix A4). Furthermore, there were butterfly groups, which flew about nearly the same amount to several flowers, like Boloria sp. (Fig 7) and other groups, which preferred only one flower the most, like Lycanidae (darkblue) (Fig 8). 5

6 0,8 0,6 0,4 0,2-0,2 0-0,4-0,6-0,8 -,2 - -,4 -,6,6,4,2 0,8 0,6 0,4 0,2 0 Figure 7 & 8: example Boloria sp. (left) & Lycanidae (darkblue) (right) 4. Discussion Our results show that different butterflies species prefer different colors and they also have a preference for different species/genus of flowering plants. Furthermore, we could see, that there were really flower specialists and generalists among the butterflies. Our work supports the results of Tudor et al. (2004). However, we noticed a few weaknesses of our work. One problem was that the weather was not constantly sunny but we counted the butterflies for 30 minutes regardless of the weather. When it was cloudy and windy, no butterfly was flying. Therefore, not all plots had all the time good flying weather for the butterflies. Also, the number of flowering plants differed between the plots. As an example, the Arnica montana occurred only one time in one plot and during the count in this plot it was very sunny and the grass was very flat, so that generally more butterflies flew around. During this measurement we counted 6 butterflies on the Arnica montana, which caused a high value and maybe have distorted our results. If we could do it again, we would stop counting during cloudy or windy moments and continue only when it is sunny. Additionally, we would try to find plots with nearly the same conditions. Another point is that it would be best if there are the same numbers of different flowers and butterflies because than you can compare it better. In addition, it could be also important to have a look at the different structures or forms of the flowers. For example, flowers of plants of the family Asteraceae might be preferred by butterflies because it is easier for them to land on them than on a Campanulaceae. 6

7 5. Acknowledgements There were a lot of people who helped us and we are very thankful about that. A very big thank goes to Irene. She helped, cared and gave a lot of tips to us. With her humor and funny jokes, she made us smile and our science work was easier with it. Also, a great thank to Claudia, Jonas and Arno. They had many tips for us and that was great. And not to forget our cook Gilbert. He cooked very well and he cared for us that we were not hungry. Last, we would like to say thank you to the Swiss and German Jugend forscht without them this great week and thus our project would not have been possible. We also thank the Stiftung Mercator Schweiz for funding this week. References Bühler-Cortesi T., Schmetterlinge, Tagfalter der Schweiz, Haupt Verlag AG, Bern Spohn M., Aichele D., Golte-Bechtle M. & Spohn R., Was blüht den da?, Kosmos Verlag, Stuttgart Tudor O., Dennis R.L.H., Greatorex-Davies J.N. & Sparks T.H., Flower preferences of woodland butterflies in the UK: nectaring specialists are species of conservation concern, Biological Conservation, 9 (3), map.geo.admin.ch. 7

8 Appendix: A: List of all butterflies counted during the study: total number of butterflies Erebia sp. 234 Melitaea sp. 6 Boloria sp. 58 Lycanidae (orange) 8 Lycanidae (brown) 26 Lycanidae (blue) 8 Lycanidae (darkblue) 7 Colias phicomone Euphydryas sp A2: List of all flowering plants: total number of flowers Senecis abrontenifolius 40 Crepis aurea Arnica montana Helianthemum sp. 3 Hieracium sp. 8 Taraxacum officinale 22 Leontodon sp Leucanthemum vulgare Galium sp. 2 2 Trifolium sp Achillea milleforium 30 Antennaria diocia 8 38 Erigeron sp. 9 9 Campanula rotundifolia 92 Phyteuma orbiculare

9 A3: Table of butterflies and species of the flowering plants: Senecis abrotenifolius (40) Crepis aurea (53) Arnica montana () Helianthemum sp. (3) Erebia sp Melitaea sp. Boloria sp Lycanidae (orange) 2 Lycanidae (brown) 2 Lycanidae (blue) Lycanidae (darkblue) 2 Colias phicomone Euphydryas sp. all butterflies Hieracium sp. (8) Taraxacum officinale (22) Leontodon sp. (7) Leucanthemum vulgare (78) Galium sp. (2) Trifolium sp. (56) Achillea milleforium (30) Antennaria diocia (8) Erigeron sp. (9) Campanula rotundifolia (92) Phyteuma orbiculare (6) Table of butterflies and color of the flowers: orange flowers: 93 dark yellow flowers: yellow flowers: 223 white flowers + yellow inside: 78 Erebia sp Melitaea sp. 5 Boloria sp Lycanidae (orange) 2 Lycanidae (brown) Lycanidae (blue) 6 2 Lycanidae (darkblue) 2 Colias phicomone Euphydryas sp. 2 all butterflies white flowers: 2 white - pink flowers: 56 pink flowers: 38 violett flowers: 9 purpel flowers:

10 A4: Diagrams of every butterfly species: 0

11

12 2

13 3

14 4

15 5

16 6

17 7

18 8

19 9