The Remarkable Adaptability of Invasive Plants: Do Invasive Plants "Get Eaten" to Fit In? — A New Discovery Suggests Integration into the Food Web Within a Few Hundred Years

On November 11 (local time), a provocative conclusion was announced: **"Invasive plants are integrated into natural food webs faster than previously thought."** The setting is Europe. The research was led by a team from Leipzig University and the German Centre for Integrative Biodiversity Research (iDiv), and the paper was published in 'Ecology Letters'. A general explanation is available on Phys.org and through releases from the university and iDiv. Phys.org

The focus of this study was on the "consumers" that are small and niche parasites and herbivores—such as leaf miners, gall midges, and aphids, known as **microherbivores**. These creatures are often thought to have high host specificity, strongly linked to native plants. However, the data showed that over time and with the expansion of distribution, the "diversity of species" of microherbivores involved with invasive plants approaches the level of native plants. Phys.org

The key was a large dataset spanning across Europe. The research team integrated interaction records of over 127,000 involving 12,000 plant species and 26,000 microherbivore species, and tested it using statistical models combining explanatory variables such as the year of introduction, distribution range (area), origin region, and phylogenetic distance from natives. The results showed that "time since introduction" and "breadth of distribution" best explained the "diversity of consumption" of invasive plants, while origin and phylogenetic proximity were secondary. It was also suggested that on average, more generalist consumers are involved with invasive plants. Phys.org

This finding adds a time dimension to the classical **"enemy release hypothesis", which suggests that invasive species thrive by escaping natural enemies in new territories. Initially, the advantage of "no enemies" is likely to work, but over decades to centuries, generalist consumers catch up and integrate into the network**. This trend aligns with other studies suggesting that the predation pressure on invasive plants is low during the non-establishment phase but approaches native levels as they establish and expand. Wiley Online Library

However, "integration" does not mean "harmless". There have been recent reports of invasive tree species having serious impacts on native communities, soil, and fire regimes. Assessing impacts on ecosystem functions and community structures is different from how much and by whom they are consumed. Even if they reach a "native level of consumption," they can still negatively impact ecosystem services and regional uniqueness. Therefore, management requires a **"case-by-case" approach that incorporates both risk and time**. pnas.org

The university's release also touches on specific examples, such as the invasive tree **Robinia pseudoacacia, which has spread across Europe over a long period and now hosts more than 100 species of microherbivores. The caveat that **"native plants are essential for supporting high diversity of specialist consumers"** is significant. While generalist consumers quickly adapt to invasives, the rich world of specialist consumers depends on the survival of natives—in other words, the significance of native conservation becomes even clearer. uni-leipzig.de

How did social media react?

At the time of writing, articles have spread starting from the official sites of the university and iDiv and news distributions (such as EurekAlert!). Posts sharing the study as one that relativizes the simple equation "invasive = bad" stand out, while cautious opinions such as **"integration does not mean acceptance"** are also included. In the background, topics on invasive species tend to focus on "cute animals" on social media, while discussions about plants have relatively low visibility, according to recent analyses. The "data-driven discussion" of this study is also welcomed as a good opportunity to visualize topics on invasive and native plants. EurekAlert!

When looking at the reactions by content, they can be broadly divided into the following three clusters.

• Conservation on the Ground: In management sites, "eradication first" remains the priority. The importance of "early response" remains unchanged, but understanding long-term interactions is appreciated as it helps estimate management costs. EurekAlert!

• Novel Ecosystems: There is empathy for the message that **"ecosystems are more adaptive than thought."** However, there is also a caution not to overlook the quality of functions and services. Phys.org

• Methodology Enthusiasts: They highly value the scale of data involving 127,000 interactions and the statistical design that simultaneously handles time and space. Discussions progress by citing reproducible data (PubMed/PMC) and figures. PubMed

How should we interpret the "fast integration"?

1. Time can be both an enemy and an ally: Early response is urgent, but in the long term, they are absorbed into predation and parasitism networks. Therefore, it is necessary to balance **"strict initial response" and "long-term monitoring."** Wiley Online Library

2. Natives are the foundation: The diversity of specialist consumers is supported by natives. Protecting native communities enhances the resilience of the entire network. Phys.org

3. Impact assessment requires multiple axes: Do not judge the impact of invasives solely on the "how much they are eaten" index in a binary good-bad manner. It is essential to evaluate community structure, nutrient cycling, fire regimes, and other functional aspects. pnas.org

Limitations and the Next Steps

This analysis primarily used the **"number of microherbivore species encountered" as the main indicator, and did not delve deeply into the severity of damage or the breakdown of consumers (which lineages and how much), or the ripple effects on native communities. The research team itself has clearly stated this as a future challenge**. Quantifying the "intensity" of consumption and tracking studies to measure the evolutionary and adaptation speed differences of specialist consumers are the next points of discussion. Phys.org

Implications for Japanese Readers

In Japan, invasive species with a long history, such as Solidago altissima and Robinia pseudoacacia, have also spread. Applying the framework of this study suggests that the "way they are consumed" may increase with time since introduction and distribution expansion. On the other hand, it is reasonable to evaluate impacts on landscape, soil, fire, and native rare species individually by region and to base management strategies on maintaining native communities. uni-leipzig.de