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Leaf Miner Species (leaf_miner + species)
Selected AbstractsWeak parasitoid-mediated apparent competition between two Phyllonorycter (Lepidoptera: Gracillariidae) leaf miner species on a deciduous oak Quercus dentataENTOMOLOGICAL SCIENCE, Issue 3 2009Takashi NAKAMURA Abstract Parasitoid assemblages and the rates of parasitism on tissue-feeding larvae of two Phyllonorycter leaf miner species, P. persimilis and P. leucocorona, were studied from the autumn generation in 2002 to the summer generation in 2005 to understand whether parasitoids mediate interactions between the two leaf miner species. Fourteen species of parasitoids emerged from P. persimilis and 11 emerged from P. leucocorona. The parasitism rate was high: 24.1,92.6% in P. persimilis and 58.9,81.7% in P. leucocorona. Thus, parasitism was a major mortality factor in the present Phyllonorycter species. The parasitoid composition was distinctly different between the two host species, although most parasitoids were able to parasitize both leaf miner species. The analysis based on the quantitative parasitoid overlap revealed that the present parasitoids could mediate interactions between the present leaf miner species, but their effects would be weak. This is attributable to parasitoid's preferential uses of either of the leaf miners as a host. [source] Competition as a structuring force in leaf miner communitiesOIKOS, Issue 6 2009Ayco J. M. Tack The role of competition in structuring communities of herbivorous insects is still debated. Despite this, few studies have simultaneously investigated the strength of various forms of competition and their effect on community composition. In this study, we examine the extent to which different types of competition will affect the presence and abundance of individual leaf miner species in local communities on oak trees Quercus robur. We first use a laboratory experiment to quantify the strength of intra- and interspecific competition. We then conduct a large-scale field experiment to determine whether competition occurring in one year extends to the next. Finally, we use observational field data to examine the extent to which mechanisms of competition uncovered in the two experiments actually reflect into patterns of co-occurrence in nature. In our experiment, we found direct competition at the leaf-level to be stronger among conspecific than among heterospecific individuals. Indirect competition among conspecifics lowered the survival and weight of larvae of T. ekebladella, both at the branch and the tree-level. In contrast, indirect competition among heterospecifics was only detected in one out of three species pairs examined. In the field experiment, the presence of a given moth species in one year affected the relative abundance of leaf miner species in the next year. Nevertheless, patterns of competition observed in these experiments did not translate into repulsion among free-ranging leaf miners: conspecific larvae of four leaf-mining species were aggregated on the same trees, shoots and leaves. In contrast, heterospecific larvae were only aggregated at the tree-level. We propose that despite the fact that leaf miners do compete and that such effects extend through time, the incidence and strength of competition is relatively small at realistic densities. Hence, competition will likely be of minor importance in shaping the distribution of leaf miners in a natural setting. [source] | ||||||||||