Species Richness and Host Specificity among Caterpillar Ensembles on Shrubs in the Andes of Southern Ecuador

Abstract

Caterpillar ensembles were sampled on 16 species of shrubs from the family Asteraceae and the genus Piper (Piperaceae) in open and forest habitats in the Andean montane forest zone of southern Ecuador between August 2007 and May 2009. Trophic affiliations of caterpillars to the host plants were confirmed in feeding trials. Overall, species richness of herbivorous caterpillars was high (191 species across all plants), but varied strongly between ensembles associated with different plant species (2-96 lepidopteran species per shrub species). Ensembles on Piper species were characterized by low effective species numbers and high dominance of one or two species of the Geometridae genus Eois Hübner. Low species number and high dominance were also found on latex-bearing Erato polymnioides, whereas ensembles on two other Asteraceae species were far more diverse and less strongly shaped by a few dominant species. The observed diversity patterns fit well to the concept that anti-herbivore defenses of plants are the major factors regulating associated insect ensembles. Local abundance and geographic range of host plants appear to have less influence. Lepidopteran species feeding on Asteraceae were found to be more generalistic than those feeding on Piper species. We conclude that caterpillar ensembles on most, but not all, studied plant species are defined by a small number of dominant species, which usually are narrow host specialists. This pattern was more distinct on Piper shrubs in forest understory, whereas Asteraceae in disturbed habitats had more open caterpillar ensembles.

The value of targeted reforestations for local insect diversity: a case study from the Ecuadorian Andes

“…Further circumstantial evidence suggests that herbivore densities might have been higher before the drought. Bodner et al (2012;personal communication) recorded considerably higher caterpillar abundance and species richness on three species of Asteraceae shrubs growing on successional habitat similar to our pasture sites in the Rio San Francisco area. Similarly, Plath et al (2012) reported higher diversity of arboreal Coleoptera for a 2-yearold, low-land timber plantations that was notably similar to the present design in species selection (i.e.…”

“…Sample treelets were not uniform with regard to leaf area and larger treelets may conceivably have harbored more individuals, thereby potentially biasing the slope of the curves. Following Bodner et al (2012), we therefore re-scaled the x-axis of each accumulation curve by multiplying the original sample count with the average leaf area of a sample treelet belonging to that respective group. In addition to habitat and host-species level richness estimates provided by the species accumulation curves above, we used generalized linear models (GLM) to compare treelet-level a-diversities across tree species and habitat types for each of the four insect groups.…”

“…cattle pasture, secondary fern-shrub vegetation and a Pinus patula plantation; Aguirre 2007;Günter et al 2009). Although selected insect groups have been extensively studied in the region (Lepidoptera: Bodner et al 2012;Fiedler et al 2008;Hilt and Fiedler 2008;soil microfauna: Illig et al 2010), insect-plant interactions for tree species of silvicultural interest and the prospective conservation value of reforestations for local arthropod diversity have so far not been examined. Arthropods play a vital role in the regulation of ecosystem functioning (e.g.…”

Caterpillar assemblages on Chusquea bamboos in southern Ecuador: abundance, guild structure, and the influence of host plant quality

“…Detritivorous caterpillars are not restricted to the leaf litter layer, but may also occur above‐ground on herbaceous or woody plants, where they feed on dead plant biomass (Bodner et al ., ). Epiphyll grazing caterpillars scrape algae, mosses, and lichens from leaves (Moskowitz & Westphal, ; Bodner et al ., , ). Even though non‐herbivorous feeding associations have been described in many caterpillar species, genera, or more inclusive groups, their role in ecosystems has rarely been studied.…”

First host plant records for Iridopsis hausmanni Vargas (Lepidoptera, Geometridae) in the coastal valleys of northern Chile

“…On one hand, their most commonly acknowledged function is herbivory, because their abundance levels may be high among the external chewers of some plants (Bodner et al 2012). On the other hand, they may be also extremely important as prey for insectivorous organisms (Matthews & González 2004;Marconato et al 2008).…”