Ecological fits, mis-fits and lotteries involving insect herbivores on the invase plant, Bunias orientalis
Harvey, J.A. ; Biere, A. ; Fortuna, T.F.M. ; Vet, L.E.M. ; Engelkes, T. ; Morriën, W.E. ; Gols, R. ; Verhoeven, K.J.F. ; Vogel, H. ; Macel, M. ; Heidel-Fischer, H.M. ; Schramm, K. ; Putten, W.H. van der - \ 2010
Biological Invasions 12 (2010)9. - ISSN 1387-3547 - p. 3045 - 3059.
enemy release hypothesis - pieris-rapae - specialist herbivore - host-specificity - evolution - deterrents - community - larvae - associations - coevolution
Exotic plants bring with them traits that evolved elsewhere into their new ranges. These traits may make them unattractive or even toxic to native herbivores, or vice versa. Here, interactions between two species of specialist (Pieris rapae and P. brassicae) and two species of generalist (Spodoptera exigua and Mamestra brassicae) insect herbivores were examined on two native crucifer species in the Netherlands, Brassica nigra and Sinapis arvensis, and an exotic, Bunias orientalis. Bu. orientalis originates in eastern Europe and western Asia but is now an invasive pest in many countries in central Europe. P. rapae, P. brassicae and S. exigua performed very poorly on Bu. orientalis, with close to 100% of larvae failing to pupate, whereas survival was much higher on the native plants. In choice experiments, the pierid butterflies preferred to oviposit on the native plants. Alternatively, M. brassicae developed very poorly on the native plants but thrived on Bu. orientalis. Further assays with a German Bu. orientalis population also showed that several specialist and generalist herbivores performed very poorly on this plant, with the exception of Spodoptera littoralis and M. brassicae. Bu. orientalis produced higher levels of secondary plant compounds (glucosinolates) than B. nigra but not S. arvensis but these do not appear to be important factors for herbivore development. Our results suggest that Bu. orientalis is a potential demographic ‘trap’ for some herbivores, such as pierid butterflies. However, through the effects of an evolutionary ‘lottery’, M. brassicae has found its way through the plant’s chemical ‘minefield’.
Explorative research into quality of slurry manure from dairy farms with different feeding strategies
Reijs, J.W. ; Meijer, W.H. ; Bakker, E.J. ; Lantinga, E.A. - \ 2003
Netherlands Journal of Agricultural Science 51 (2003)1-2. - ISSN 0028-2928 - p. 67 - 89.
rundveemest - rundveedrijfmest - stikstof - diervoedering - grasbestand - fytotoxiciteit - grassen - klavers - biotesten - melkveehouderij - cattle manure - cattle slurry - nitrogen - animal feeding - herbage - phytotoxicity - grasses - clovers - bioassays - dairy farming - cress lepidium-sativum - seed-germination - sewage-sludge - cattle feces - growth - mineralization - decomposition - netherlands - deterrents
To assess cattle slurry manure quality in relation to feeding strategy, a field experiment and a bio-assay were carried out with slurries from four dairy farming systems that used diets differing in protein content and digestibility. Several quality aspects were evaluated. In the field experiment the effects of slurry manure type on herbage rejection by grazing heifers and herbage yield on undisturbed plots under cages were studied for a grass monoculture and a grass/clover mixture. The bio-assay, consisting of a cress (Lepidium sativum L.) seed germination test, was used to study differences in phytotoxicity between the slurry types. After five weeks of undisturbed growth at equal amounts of applied inorganic nitrogen (N), the herbage yields differed statistically for the different slurries. This was probably due to immobilization of N in the case of the two slurries from farming systems in which straw was fed and used as bedding material. Herbage rejection by grazing animals was significantly shown for all slurry types and was significantly and positively correlated with the NH3/NH4 +-N content of the slurry. The slurries showed large differences in phytotoxicity to seeds and seedlings in the bio-assay. Ammonia and electric conductivity appeared to be the most important slurry parameters with inhibiting effects. The slurries with a high C/N ratio showed lowest phytotoxicity. Phytotoxicity in the cress seed germination test did not account for reduced herbage yields in the field experiment. On the contrary, when the slurries were ranked according to their phytotoxicity the order was the same as the ranking on the basis of undisturbed herbage yield. It was concluded that there is a need for other laboratory tests that show greater resemblance with what is observed in the field to assess slurry quality.