Where did all those insects come from? Tracking the history of insect invasion in Chile

Going through centuries-old literature, researchers compiled a database of the exotic insects established in the country.

Graphs displaying the taxonomic and biogeographic patterns of the non-native insect fauna of Chile

Guest blog post by Daniela N. López, Eduardo Fuentes-Contreras, Cecilia Ruiz, Sandra Ide, Sergio A. Estay

Understanding the history of non-native species arrivals to a country can shed light on the origins, pathways of introduction, and the current and future impacts of these species in a new territory. In this sense, collecting this information is important, and sometimes essential, for researchers and decision makers. However, in most cases, reconstructing this history takes a lot of work. Finding antique references is hard work. To add more complexities, changes in the taxonomy of species or groups could be frustrating as we try to track the moment when a species was referenced in the country for the first time, sometimes centuries ago. Of course, we only learned about these issues when, almost seven years ago, we thought that compiling a database for the exotic insects established in Chile would be interesting to people working on invasive species in the country.

Tremex fuscicornis caught in Chile. Photo by Sergio Estay

First, we collected information from physical and electronic books and journals available in our institutional libraries, but soon we noticed that we needed a more significant effort. In Chile, the National Library and The National Congress library allowed us to review and collect information from texts, in many cases, over a hundred years old. We also had to request information from foreign specialized libraries and bookstores. Sometimes, we had to negotiate with private collectors to buy antique books or documents. When we figured the first version of the database was ready, we began a second step for detecting errors, correcting the taxonomy, and completing the information about the reported species.

Ctenarytaina eucalypti individuals and damage in Chile. Photo by Sergio Estay

The analysis began when we finally completed the database. What types of questions could we answer using this data? Was the database complete enough to detect historical, biogeographic, and ecological patterns? Two competing hypotheses were the starting point for the study at this stage. On the one hand, the species that dominated the non-native insect assemblage could have come from original environmental conditions that matched Chile’s. Or, the pool of non-native insects arrived using pathways associated with the country’s economic activities, regardless of their origin.

We found records of almost 600 non-native insect species established in continental Chile. Most species corresponded to Hemiptera (true bugs and scales, among others) from Palaearctic origin and were linked to agriculture and forestry, as we initially hypothesized. These characteristics point to the central role of intercontinental human-mediated transport in structuring non-native insect assemblages in Chile. Non-native insect introductions began immediately after the arrival of Europeans to the central valley of Chile and have shown an enormous acceleration since 1950. Using data on the economic history of Chile, we can preliminary link this acceleration with the strong development in agriculture and forestry in Chile after World War II and the increase in intercontinental air traffic.

Exotic aphids in garden in Chile. Photo by Sergio Estay

The development and analysis of this database gave us some preliminary answers about the ecology of invasive insect species and opened the door to new questions. Also, this is a work in progress. We need the scientific community’s support to improve and correct the records, provide new reports and collect further references to support the database. Our data and analysis may be representative of other countries in South America. Similarities between our countries can facilitate using this information to manage recent introductions and prevent significant economic, social, or environmental damage.

Reference

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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