Can plant–microbe–insect interactions enhance or inhibit the spread of invasive species?

Abstract

Summary 1.Invasive species are one of the great challenges facing the world leading to great economic losses. Increasing numbers of species introductions are also increasing the likelihood of new species interactions -particularly between plants, microbes and insects. 2. Frequently discovered interactions between plants, microbes and insects are giving rise to a new field: plant-microbe-insect (PMI) interactions. This paper focuses on novel PMI interactions created from the introduction of new plant, insect and microbe species. In particular, this paper asks: Do novel PMI interactions promote or inhibit invasive plants, microbes and insects? And can we predict whether novel PMI interactions are likely to become invasive? 3. While we might predict that novel PMI interactions are likely to be simple additive interactions due to their relatively short period of interaction, instead this review demonstrates that most novel PMI interactions are actually nonadditive. This manuscript shows that there are a great number of instances where invasive species are promoted by novel PMI interactions. By contrast, the studied cases where PMI interactions limit invasive species are predominantly biocontrol PMI interactions. 4. Future research on novel PMI interactions should focus on predicting future novel PMI interactions that promote invasive species. Given that many novel PMI interactions involve plant pathogens and their insect vectors, this novel PMI interaction deserves more focus. New research should also focus on non-novel PMI interactions that could be manipulated to hinder the spread of invasive plant, microbe and insect species.

Third-party mutualists have contrasting effects on host invasion under the enemy-release and biotic-resistance hypotheses

“…For the ERH, not only were initial similarity of the herbivore and the microbe to the plant significant factors in determining plant invasion success, but the interaction between microbe and herbivore was as well. This mirrors empirical studies that have found non-additive affects when investigating PMI interactions (Morris et al 2007;Bennett 2013). This is most likely related to the plant having a harder time invading because benefits gained from being similar to the microbe are canceled by the increased similarity to the herbivore under the BRH.…”

The community ecology of invasive species: where are we and what's next?

“…Many introduced species rely on multi‐trophic mutualisms in their new habitats to become naturalized (Traveset and Richardson ). Mutualisms can be important at all stages of the introduction‐naturalization‐invasion continuum: 1) for establishment via symbioses between plant roots and microbiota (Pringle et al , Dickie et al , Rodríguez‐Echeverría , Bennett ) or plant–ant protection (Ness et al ), 2) for reproduction via animal‐mediated pollination (Burns et al ), and 3) for dispersal via animal seed dispersers (Sun et al , Traveset and Richardson ). Invasive species may also benefit from predator or parasite release in the invaded ranges (Van Kleunen et al , Hill and Kotanen , but see Levine et al ), or compete with the native species via the sharing of mutualistic partners (Burns et al , Gibson et al ).…”

Invasive mutualisms between a plant pathogen and insect vectors in the Middle East and Brazil

“…This is a key result of our study, where it demonstrates that an invasive vector gains fitness benefits in a completely asymptomatic infection. A ‘silent’ infection is particularly threatening as it can allow the pathogen to spread more effectively and go unnoted, and can be particularly problematic when a pathogen-range shifts to regions where the infection becomes symptomatic [22]. It can also contribute to the spread of the invasive vector and potentially other invasive pathogens.…”

“…WBDL is a devastating disease, which has spread across the Middle East and resulted in the destruction of more than 50% of the cultivated lime area and 75% loss in production [19,20]. Yet our understanding of this pathosystem and its extent remains limited; WBDL appears to be restricted to the Middle East [17], but with the invasive nature of these vectors [14,21], there is a strong likelihood that these pathogens and pests will increase in importance in other lime markets [22,23]. …”

“…To begin, (i) we tested whether D. citri and H. phycitis could act as vectors of the phytoplasma between individuals of C. aurantifolia in Oman. Then, in the light of accumulating evidence that vector species increase in fitness when vectoring pathogens such as phytoplasmas [22,27,28], we examined (ii) the performance of the invasive species D. citri on phytoplasma-infected C. aurantifolia compared with healthy plants in both Brazil and Oman. We then studied (iii) the potential for some local weed species in Oman to act as reservoirs for ‘ Ca .…”