Research Article |
Corresponding author: Sergio A. Estay ( sergio.estay@gmail.com ) Academic editor: Victoria Lantschner
© 2023 Daniela N. López, Eduardo Fuentes-Contreras, Cecilia Ruiz, Sandra Ide, Sergio A. Estay.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
López DN, Fuentes-Contreras E, Ruiz C, Ide S, Estay SA (2023) A bug’s tale: revealing the history, biogeography and ecological patterns of 500 years of insect invasions. NeoBiota 81: 183-197. https://doi.org/10.3897/neobiota.81.87362
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The arrival of Europeans to the Americas triggered a massive exchange of organisms on a continental scale. This exchange was accelerated by the rapid increase in the movement of people and goods during the 20th century. In Chile, scientific and technical literature contains hundreds of records of non-native insect species established in different parts of the territory, from the hyperarid Atacama Desert to the Magallanes Region. Here, we analyse temporal trends, taxonomic diversity, biogeographic origin and main impacts of these species on different sectors in Chile from the European arrival to the present. Our task includes a review of old records in museum catalogues, libraries, collections, expedition records and catalogues. Almost 600 species of non-native insects have been reported to be established in Chile. Introductions started with the very arrival of Europeans to the central valley of Chile and underwent a huge acceleration in the second half of the 20th century. The order Hemiptera was the most prevalent amongst non-native insects. Most species are linked to agriculture and forestry. Species are of Palearctic origin in more than 50% of the records. In terms of temporal trends, the rate of established non-native species shows an abrupt increase at the beginning of the 1950s. This change may be associated with the strong development in agriculture and forestry in Chile after World War II and the increase in intercontinental air traffic. We believe that the understanding of past patterns of introductions is an important component in the design of current policies to minimise the impact of invasive insects.
biological invasions, Chilean fauna, insect pests, invasive species, non-native insects
The advance of civilisations, human migration and the proliferation of trade between different regions have led to a strong increase in species movement (
Social and economic factors are key components in the increase in propagule pressure or species introductions (
In a similar vein, it is not only the species’ identities that can reflect different processes structuring the non-native assemblages. Diversity of orders or families may or may not respond to ecological factors. Non-native insect assemblages can be a reflection of the global richness of these groups, with the representation of orders or families being proportional to their world richness or the non-native richness may be biased towards a group associated with some particular pathway, socioeconomic or ecological variables (
In the Americas, the arrival of Europeans triggered a massive exchange of organisms on a continental scale. Accidental and intentional introductions of plants and animals promoted the establishment of new insect species, especially those associated with crops of foreign origin (
In Chile, the scientific and technical literature contains hundreds of records of non-native insect species in different parts of the territory, from the hyperarid Atacama Desert to the Magallanes Region. Using this information, here we analyse the biological patterns of establishment of non-native insects to Chile from the first European arrival to the present. In particular, we analyse temporal trends, taxonomic diversity, biogeographic origin and main sectors impacted by each species. Through the description of these patterns, we can obtain a better understanding of the process involved in biological invasions over a timescale of centuries.
We collected records of non-native insects established in continental Chile from scientific articles, museums, libraries, collections, Chilean governmental reports, expedition records and catalogues. A primary online search using the words “exotic insect”, “invasive insect”, “insect pests” and “Chile” and their equivalents in Spanish was performed in Google Scholar. However, this search provided few results. For example, the Alien Species First Records Database 1.2 (
First, we estimated several descriptive statistics. We calculated the percentage of insects belonging to each order and family of non-native insects and also the distribution of orders as a function of the dominant realm of origin. We compared the frequency distribution of the number of species per order of non-native insects with the proportional number of insect orders in the world and Chile. For world data of insect richness, we used
We used the common species-time approach to examine temporal trends in insect dates of first report (e.g.
Our review identified 591 non-native insect species established in Chile. Three of them were eradicated after establishment (see Suppl. material
Taxonomic and biogeographic patterns of the non-native insect fauna of Chile a proportional representation of species belonging to each order and family b proportional representation of the biogeographic realms of origin of orders of the species c Heatmap showing the bivariate distribution (%) of orders and origins of the species.
When comparing the relative richness of the non-native insects established in Chile and world richness of species per Order, we observed a disproportionate representation of orders Hemiptera and Hymenoptera and a strong underrepresentation of the orders Coleoptera, Diptera and Lepidoptera (Fig.
Comparison of the frequency distribution of insect orders in the a World fauna and b Chilean fauna, with the pool of non-native insects established in Chile.
Percentage of non-native insect species established in Chile with the impact on each category of human activity, according to global literature. Unknown categories are not shown. Overlap areas correspond to the percentage of species with more than one category of impact (n = 565).
When we analysed temporal trends of the total accumulated number of non-native species, the best model was the segmented regression (Table
Results for models fitted to the total number of accumulated non-native insects in Chile considering all species and the main orders separately.
All orders | ||||
---|---|---|---|---|
Model | Formula | Parameter | R2 | BIC |
Linear | S = a+b*t | a = -6216; b = 3.310 | 0.90 | 1472.7 |
Exponential | S = a*exp(b*t) | a ≈ 0; b = 0.017 | 0.99 | 1107.1 |
Segemented | Si = ai+bi*t, with i= 1,2 | a1 = -2797; b1 = 1.512; a2 = -11260; b2 = 5.854 | 0.99 | 1031.3 |
Coleoptera | ||||
Linear | S = a+b*t | a = -1160; b = 0.624 | 0.87 | 1136.0 |
Exponential | S = a*exp(b*t) | a ≈ 0; b = 0.015 | 0.99 | 837.0 |
Segemented | Si = ai+bi*t, with i= 1,2 | A1 = -399.7; b1 = 0.221; a2 = -2010; b2 = 1.054 | 0.99 | 746.0 |
Hemiptera | ||||
Linear | S = a+b*t | a = -2104; b = 1.126 | 0.82 | 1363.2 |
Exponential | S = a*exp(b*t) | a ≈ 0; b = 0.019 | 0.99 | 933.6 |
Segemented | Si = ai+bi*t, with i= 1,2 | A1 = -661.0; b1 = 0.3611; a2 = -4411; b2 = 2.291 | 0.99 | 1006.4 |
Hymenoptera | ||||
Linear | S = a+b*t | a = -6216; b = 3.310 | 0.71 | 1267.1 |
Exponential | S = a*exp(b*t) | a ≈ 0; b = 0.017 | 0.99 | 831.4 |
Segemented | Si = ai+bi*t, with i= 1,2 | a1 = -2797; b1 = 1.512; a2 = -11260; b2 = 5.854 | 0.99 | 788.2 |
Lepidoptera | ||||
Linear | S = a+b*t | a = -6216; b = 3.310 | 0.89 | 825.2 |
Exponential | S = a*exp(b*t) | a ≈ 0; b = 0.017 | 0.98 | 619.0 |
Segemented | Si = ai+bi*t, with i= 1,2 | a1 = -2797; b1 = 1.512; a2 = -11260; b2 = 5.854 | 0.98 | 557.9 |
Temporal trend of the accumulated number of non-native species in Chile (S) a total number of species. Points correspond to observed data, the black line corresponds to the fit of the regression model and the dashed lines indicate the 95% confidence interval for the break-point in the segmented regression b number of species of the most abundant orders c number of species identified as biological control agents.
The history of insect invasion in Chile follows the common trend observed all around the world (e.g.
Our results show that the composition of non-native insect fauna in Chile is strongly biased to groups associated with agriculture and forestry. This is a common situation in other parts of the world (
In terms of the origin of the non-native insects, most of them show a Palearctic origin. Again, this situation has been observed in other parts of the world.
We detected an abrupt increase in the rate of introductions recorded around 1950. Many studies have shown an exponential increase in the rate over years, especially in the last century (see examples in
Nowadays, climate change has acted as a promoter of the range expansion of many insect species. For non-native species, ongoing and future climate change could facilitate the short distance dispersal of non-native insects across national borders (
In this study, we reconstructed the main patterns of insect introductions to Chile. The order Hemiptera was the most prevalent amongst non-native insects, with species linked to agriculture and forestry industries. Species are of Palearctic origin in more than 50% of the records. Temporal trends show an abrupt increase at the beginning of the 1950s. This change may be associated with the strong development in agriculture and forestry in Chile after World War II and the increase in intercontinental air traffic. We believe that the understanding of past patterns of introductions is an important component in the design of current policies to minimise the impact of invasive insects. This database is the first attempt to compile this information, but this is essentially a work in progress. It has to be updated and improved by governmental agencies, academics and specialists for a better understanding of it. We think that some of the results presented in this study may be representative of other countries in South America. Similarities with other regions suggest that the processes behind insect introductions are common around the world and their detailed description can be a fundamental tool for managing current introductions and preventing major economic, social or environmental damage.
The authors were supported by ANID PIA/BASAL FB0002 and Fondecyt 1211114.
Database: exotic insects of Chile
Data type: table (excel file)
Explanation note: Excel file containing records of exotic insects in Chile.