Relatinship Between Pllinatin Behavir f Invasive Hneybees and Native Bumblebees Carlyn Silverman Barnard Cllege, Clumbia University 7 Ec-Infrmatics Summer Institute HJ Andrews Experimental Frest Oregn State University
Mtivatin Plant-pllinatr netwrks: traditinally bipartite Ignres pssible relatinships within each grup Why d we care? Invasive hneybees may impact native bees Chice f Pllinatrs: Apis mellifera 0 species f Bmbus Ttal recrded interactins: 22.8% Apis and 9.6% Bmbus Generalist pllinatrs 2
Definitins/Ntatin mwy := meadw-watch-year (78 ttal) f := a single flwer species invlved in >9 scial bee interactins in a mwy A f := # f Apis interactins with f B f := # f Bmbus interactins with f Pssible classes fr each f interactin: Class E (Equal) := apprximately : A f t B f Class A (Apis) := at least 2: A f t B f Class B (Bmbus) := at least 2: B f t A f Observed Class and Andy Class 3
Questin : Hw are bserved classes related t Andy s expected classes? 4
Andy Class (based n flwer traits) is Related t Observed Class Observed Class Andy Class E A B Ttal E 3 68 27 08 A 3 70 0 83 B 6 0 96 2 Ttal 22 48 33 303 Pearsn s chi-squared test: X-squared = 40.4, df = 4, p-value < 2.2e-6 Prprtins by rw: Observed Class Andy Class E A B E 0.2 0.63 0.25 A 0.04 0.84 0.2 B 0.05 0.09 0.86 5
Questin 2: Hw d flwer traits and envirnmental factrs relate t Apis/Bmbus partitining f interactins? 6
Mdeling Apprach: Decisin Trees Class E Class 2 A Class 3 B.36.29.35 00% yes ExclusinVisibility = bright n.46.38.6 78% ExclusinTubePlantCde =,0,2,3,6,7.6.8.2 59% ExclusinTubePlantCde =,0,3,6,7.70.2.09 5% ExclusinTubePlantCde = 0,3,6,7.9.04.05 24%.52.36.2 27% Bim.flwr >= 7 Bim.flwr < 8.2 2.03.7.26 3% Bim.flwr < 3.00.00.00 22% 3.2.38.50 3%.95.05.00 4% 2.04.96.00 9% 3.00.00.00 3% 3.00.00.00 8% 2.00.00.00 9% 3.00.00.00 22% Decisin tree fr Andy Class based n flwer traits 7
Methd AdaBst: An ensemble methd fr classificatin Linear Cmbinatin f weighted trees Outputs relative imprtance f each variable Fit 3 mdels using AdaBst t predict the bserved and Andy class 5 decisin trees per mdel Estimate misclassificatin rate thrugh crss-validatin Plt imprtance value f each predictr (nrmalized t sum t 00) 8
Observed Class Related t Envirnmental Cvariates Mdel Predictrs: Abund := #stalks * #flws/stalk ApisPrp := Prprtin f Apis t all scial bees in the mwy Day = day f year Andy Class Predictin Errr: 47.2% Observed Class Predictin Errr: 22.4% 9
Observed Class and Andy Class bth Related t Flwer Traits Mdel 2 Predictrs: Bim.flwr = bimass per flwer Tube = cde indicating tube length and extent f exclusivity (0 levels) Visibility = bright r red/dark Bim.flwr Funct Exclusin 48 44 8 Flwer Frm Funct Exclusin Bim.flwr 52 34 5 Flwer Frm Andy Class Predictin Errr:.3% Observed Class Predictin Errr: 20.8% 0
Observed Class Best Explained by Bth Envirnmental Cvariates and Traits Mdel 3 Predictrs: Day, Abund, ApisPrp, Bim.flwr, Tube, Visibility Funct Exclusin Bim.flwr 37 36 5 Abund Day ApisPrp Flwer Frm 6 5 2 Andy Class Predictin Errr: 3.3% Observed Class Predictin Errr: 4.9%
Findings & Interpretatin Apis and Bmbus (generalist pllinatrs) rarely interact equally with a flwer species in a given mwy Avidance? Cmpetitin? Flwer Preference? Andy Class predicted very well by 3 flwer traits Implies crrelatin between traits Envirnmental cvariates and flwer traits bth play a rle in the partitining f interactins Significant relatinship between pllinatr presence and the pllinatin activity f ther species 2
Thank Yu: Julia Jnes Rebecca Hutchinsn Andy Mldenke Kate Jnes EISI Participants 3
AdaBst: An Ensemble Methd fr Classificatin AdaBst = Adaptive Bsting Linear cmbinatin f weighted weak learners create a strng classifier Mdel utputs relative imprtance f each variable based n weight and Gini Index Gini Index = degree f inequality f predictrs fr each weak classifier Figure: Paul Vila 4