Like or dislike: Response of rodents to the odor of plant secondary metabolites

Abstract

Rodents, including common voles (Microtus arvalis) and house mice (Mus musculus) cause immense pre‐harvest and post‐harvest losses. Therefore, developing methods that mitigate these losses while maintaining their role in ecosystems is a priority. Several plant secondary metabolites (PSM) which significantly reduce food intake of both species under laboratory conditions have been identified. However, before these can be used in rodent pest management, they must be tested under more natural conditions where other food sources are available. In this study, the odors of 4 PSMs were evaluated for their repellent effects in experiments conducted in semi‐natural enclosures. Soil treated with PSMs or untreated soil (experimental control) was placed in an underground box containing food (rolled oats). We quantified the number of visits to each box and could demonstrate that all 4 PSMs reduced the number of visits to treatment boxes in both rodent species. For common voles the combination of methyl nonyl ketone + black pepper oil was the most repellent PSM. House mice made fewer visits to all PSM boxes; boxes with the anthraquinone were visited least. Furthermore, house mice consumed less food from boxes containing soil treated with all 4 PSMs. Our results suggest that PSMs are repellent in murid and microtine rodents under semi‐field conditions. In addition, the future use of PSM odors for repelling both pest species, especially house mice, seems promising. Further investigations with other PSMs, different concentrations as well as alternative application methods are needed to repel common voles from attractive crops.

Dietary shifts influenced by livestock grazing shape the gut microbiota composition and co‐occurrence networks in a local rodent species

“…In our study, for these three dominant plant species, there exist huge differences in secondary compounds, digestible nutrients and fibre. Properties of plant quality could affect the feeding behaviour and modulate the gut microbiota of voles, which influenced the growth and health of voles (Hansen, Stolter, Imholt, & Jacob, ). For example, silica in plant leaves has a detrimental effect on voles by wearing tooth, inducing intestinal abrasion and reducing plant palatability and digestibility (Wieczorek, Zub, Szafranska, Ksiazek, & Konarzewski, ).…”

“…In our study, for these three dominant plant species, there exist huge differences in secondary compounds, digestible nutrients and fibre. Properties of plant quality could affect the feeding behaviour and modulate the gut microbiota of voles, which influenced the growth and health of voles (Hansen, Stolter, Imholt, & Jacob, 2017 , 2017). Evidence indicated that the gut microbiota can also be affected by the fructose-to-glucose ratios of diets (Noble et al, 2017) and dietary tannins (Kohl et al, 2016) in diets.…”

Time allocation to resources by three species of rats (Rattus spp.) in a radial arm maze

“…They also found that rats preferred foods with high carbohydrate content and that rats were less neophobic to foods with high sugar content. In Germany, Hansen et al (2016Hansen et al ( , 2017 found that some rodents (house mice (Mus musculus) and voles (Microtis arvalis)) were attracted to some plant secondary metabolites, whereas other plant secondary metabolites had a repellent effect. In the United Kingdom, Inglis et al (1996) found wide variation in Norway rat responses to new foods, but also to new food containers.…”

Pine chemical volatiles promote dauer recovery of a pine parasitic nematode, Bursaphelenchus xylophilus

“…When the vector beetle feeds on pine trees, the volatile concentrations from the pine increase rapidly (Su et al ., 2008; Niu et al ., 2012; Zhao et al ., 2014; Chen et al ., 2018). The accumulation of volatiles in response to herbivore or pathogen attack is an important component of host defence (Lewinsohn et al ., 1991; Keeling and Bohlmann, 2006; Hansen et al ., 2017). However, B. xylophilus might take advantage of these volatile accumulations for its survival (Figs 4 and 5).…”