Invasive plants impact amphibians by altering habitat, altering species interactions, and releasing potentially toxic secondary chemicals. Despite being costly and having the potential to affect nontarget wildlife, chemical management is commonly used to control invasive plants. Prior research has indicated that individual effects of invasive plants or herbicides can be harmful to aquatic organisms; however, information is lacking on the combined effect of these factors on amphibians. A laboratory experiment was performed to assess the impact of leachates of the invasive plants Eurasian watermilfoil (Myriophyllum spicatum) and European buckthorn (Rhamnus cathartica), the herbicide Renovate 3 (triclopyr [3, 5, 6-trichloro-2-pyridinyloxyacetic acid]), and the combined effects of each plant leachate and the herbicide on the growth, morphology, and survival of northern leopard frog (Lithobates pipiens) tadpoles. No effects of treatment on survival were observed. Tadpole exposure to M. spicatum reduced body mass by 17%, exposure to R. cathartica increased body mass by 36%, and exposure to R. cathartica + low herbicide increased body mass by 38% (although only early in the experiment). Exposure to Renovate 3 induced a 16% and 29% decrease in tadpole size in lower (0.22 mg triclopyr active ingredient [a.i.]/L) and higher (0.92 mg triclopyr a.i./L) concentration treatments, respectively. Results from the present study highlight the importance of considering both individual and combined effects of invasive plants and herbicides because they may have different outcomes for tadpole growth and development. Environ Toxicol Chem 2017;36:2958-2964. © 2017 SETAC.

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Previous studies have demonstrated that genetic identity between interacting perennial plants results in more effective defense when emitter and receiver neighbors have greater genetic similarity. However, the effects of both genetic relatedness and presence of herbivores on fitness-related responses of neighboring plants have not yet been explored. Our aim was to examine how manipulating these two important factors genetic and environmental factors can influence indirect plant-plant communication in the annual crucifer Arabidopsis thaliana. Plants of a single genotype (receivers) were exposed to volatile emissions of neighboring emitter plants with a similar or different genotype, and either intact or damaged by larvae of a specialist herbivore for ten days. Each of the four treatments was isolated in separate environmental chambers and the full experiment was replicated twice. Receiver plant growth and reproductive-related traits were measured ten days after exposure to treatments, and at senescence. Results showed that the effect of herbivory and plant genotype of emitter plants influenced responses related growth and reproduction in receiver plants. Receiver plants grew taller, had more inflorescence branching, and produced more fruits (60% more) when exposed to undamaged emitters of a different genotype than receivers exposed to the other emitter plant treatments. Therefore, genotype identity and environmental context (presence of herbivory) may be important factors influencing indirect plant-plant communication, which could, in turn, result in selection for genotypes showing increased fitness-related responses.

Local adaptation is an important process that drives the evolution of populations within species, and it can be generally expressed by the higher fitness of individuals raised in their native habitats versus in a foreign location. The influence of local adaptation is especially prominent in species that subsist in small and/or highly isolated populations. This study evaluated whether the federally endangered Karner blue butterfly, Lycaeides melissa samuelis (Lepidoptera: Lycaenidae) is locally adapted to its exclusive larval host plant, the wild lupine (Lupinus perennis). To test for local adaptation, individuals from a laboratory-raised colony were reared on wild lupine plants from populations belonging to either their native (Indiana) or a foreign (Michigan and Wisconsin) region. For this purpose, lupine plants from the different populations were grown in a common garden in growth chambers, and one Karner blue larva was placed on each plant. Fitness traits related to growth and development were recorded for each butterfly across populations. Days from hatching to pupation and eclosion showed gender-specific significant differences across wild lupine populations and plant genotypes (within populations). The percent survival of butterflies (from hatching to eclosion) also differed among plants from different populations. These results indicate that wild lupine sources can affect some developmental traits of Karner blue butterflies. However, growth-related traits, such as pupal and adult weight of individuals reared in plants from native populations did not differ from those of foreign regions. The apparent absence of local adaptation to wild lupine suggests that, at least, some individuals of this species could be translocated from native populations to foreign reintroduction sites without experiencing decreased fitness levels. However, future studies including more populations across the geographical range of this butterfly are recommended to evaluate other environmental factors that could influence adaptation on a wider spatial scale.How to cite this paper: Handel, K. and Gabriela Bidart, M.

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