Using a botanical garden to assess factors influencing the colonization of exotic woody plants by phyllophagous insects

Abstract

The adoption of exotic plants by indigenous herbivores in the region of introduction can be influenced by numerous factors. A botanical garden in Western Siberia was used to test various hypotheses on the adaptation of indigenous phyllophagous insects to exotic plants invasions, focusing on two feeding guilds, external leaf chewers and leaf miners. A total of 150 indigenous and exotic woody plant species were surveyed for insect damage, abundance and species richness. First, exotic woody plants were much less damaged by chewers and leaf miners than native plants, and the leaf miners' species richness was much lower on exotic than native plants. Second, exotic woody plants having a congeneric species in the region of introduction were more damaged by chewers and hosted a more abundant and species-rich community of leaf miners than plants without native congeneric species. Third, damage by chewers significantly increased with the frequency of planting of exotic host plants outside the botanical garden, and leaf miners' abundance and species richness significantly increased with residence time in the garden. Finally, no significant relationship was found between insect damage or abundance and the origin of the exotic plants. Besides the ecological implications of the results, this study also illustrates the potential of botanical gardens to test ecological hypotheses on biological invasions and insect-plant interactions on a large set of plant species.

Introduced plants as novel Anthropocene habitats for insects

“…In addition to the 'degree of novelty' of a novel habitat, it is also important to consider its age (hypothesized as the length of time that a nonnative plant has existed in a region), and its geographic extent (analogous to the range size of a nonnative plant). As the range size of an introduced plant increases over time, more potential colonists are likely to encounter it and develop specialized adaptations, potentially generating a positive correlation between the time since arrival of nonnative plant species and insect herbivore species richness (Brändle et al, 2008;Kennedy & Southwood, 1984;Kirichenko & Kenis, 2016). However, the effect of time is not always apparent (Andow & Imura, 1994;Carpenter & Cappuccino, 2005) and may be overshadowed by the effect of range size once a time-richness asymptote is approached (Banerjee, 1981;Kennedy & Southwood, 1984;Strong, 1974;Strong, McCoy, & Rey, 1977).…”

Forewarned is forearmed: harmonized approaches for early detection of potentially invasive pests and pathogens in sentinel plantings

“…One main problem is that a PRA is normally only conducted once a pest or pathogen is formally described (FAO 2016). Time limitations and logistical issues restrict the ability of researchers to formally describe unknown taxa in sentinel plantings (Roques et al 2015;Vettraino et al 2015;Kirichenko and Kenis 2016). To alleviate this issue taxonomists based in the exporting countries need to be engaged through networking activities.…”

“…A sentinel arboretum ( Fig. 3) comprises a broad range of both native and non-native tree species from diverse regions around the world, which can allow testing of various ecological hypotheses on biological invasions, as possible host-shifts, one of the main barriers to establishment of alien plant pests and pathogens, can be examined (Kirichenko et al 2013;Kirichenko and Kenis 2016;Morales-Rodríguez et al 2018). Non-native species are exposed to inoculum of native, potentially pathogenic organisms harboured by native trees species growing in the same or nearby environment.…”

Spotting the pests of tomorrow—Sampling designs for detection of species associations with woody plants

“…Several studies have found that the degree of relatedness of co-occurring introduced and native plants is correlated with the amount of damage the introduced plant suffers from native herbivorous insect species (i.e. Bush, 1969;Connor, Faeth, Simberloff, & Opler, 1980;Kirichenko & Kenis, 2016;Pearse & Hipp, 2014;Strong, 1979).…”