Figure 1.
Diet identification using DNA barcodes.
First we assembled a DNA barcode library containing sequences of all potential host plants (A). After collecting insect herbivores in the field (B), we extracted plant DNA from gut contents (C). Host plant identifications were performed by comparing DNA sequences extracted from insect herbivores to sequences in the DNA barcode library using the BLAST algorithm and default search parameters (D).
Figure 2.
A comprehensive survey of rolled-leaf beetles and their associations with Zingiberales at La Selva Biological Station, Costa Rica.
A. Interactions recorded for two years during rainy and dry seasons (October 2008 - February 2009 and October 2010– February 2011). Each matrix element represents an association between an insect herbivore species (rows) and a host plant species (columns). Interactions in red were recorded during the second year of this study and selected for diet analyses. B. Sampling effort and accumulation curves of plant and insect herbivore species and their interactions at La Selva (Mean ± SD). Total number of host plants censused = 3092. Total number of insect herbivore records = 7359. Host plant species abbreviations: Heliconiaceae. Him = Heliconia imbricata. Hir = H. irrasa. Hla = H. latispatha. Hmr = H. mariae. Hmt = H. mathiasiae. Hpo = H. pogonantha. Hum = H. umbrophila. Hwa = H. wagneriana. Zingiberaceae. Ral = Renealmia alpinia. Rce = R. cernua. Rpl = R. pluriplicata. Costaceae. Cbr = Costus bracteatus. Clae = C. laevis. Clim = C. lima. Cmal = C. malortieanus. Cpu = C. pulverulentus. Marantaceae. Ccl = C. cleistantha. Ccr = C. crotalifera. Cgy = C. gymnocarpa. Cha = C. hammelii. Cin = C. inocephala. Clas = C. lasiostachya. Cle = C. leucostachys. Clu = C. lutea. Cma = C. marantifolia. Csi = C. similis. Cve = C. venusta. Cwa = C. warscewiczii. Iel = Ischnosiphon elegans. Iin = I. inflatus. Ppr = Pleiostachya pruinosa. Cannaceae: Ctu = Canna tuerckheimii.
Table 1.
Percent of success extracting plant DNA from gut contents and identification success of the resulting DNA sequences for the DNA barcodes rbcL and ITS2.
Figure 3.
Identification of insect-host plant associations using DNA extracted from rolled-leaf beetle gut contents.
Diet identification was performed using the molecular markers: A. rbcL and B. ITS2. Each matrix element represents the associations between a rolled-leaf beetle species (rows) and a host plant (columns). N = interaction failed to be identified by the molecular marker. Taxonomic resolution of successful host plant identifications: O = Order, F = Family, G = Genus, S = Species. Total of sequences = 403 (DNA sequences extracted from insect gut contents are included in Supplement S1). Plant species abbreviations as in Figure 2.
Figure 4.
Reconstruction of a tropical plant-herbivore network using DNA extracted from insect gut contents.
Rectangles represent insect herbivore and host plant species. Lines connect insect herbivores to their host plants. Line colors represent the taxonomic resolution at which each host plant association was identified. Rectangle size is proportional to its number of interactions. Host plant associations were inferred from rbcL and ITS2 DNA fragments. Fragments were compared to host plant DNA barcode libraries containing sequences of all potential hosts in the study area. Total of insect species = 19. Total of plant species = 28. Total of interaction = 74. (see matrix of associations in Table S1).
Figure 5.
Sampling effort and successful identification of insect herbivore host plants using two molecular markers (Mean ± SD).
Diet identifications were performed by comparing DNA sequences from insect gut contents with DNA barcode libraries containing sequences of all potential host plants present in the study area (identification probabilities used to estimate sampling efforts are included in Table 1). A. rbcL DNA fragments allowed the identification of host plants to the family and genus taxonomic levels. B. ITS2 sequences identified insect hosts to the genus and species taxonomic levels.