Distribution and endemicity patterns of Mexican dragon- and damselflies (Insecta: Odonata).

Distribution patters are important because they illustrate the history, in terms of time and space, of living organisms. The importance of the interaction between life, time and space, has been summarised by Léon Croizat: “Earth and life evolve together”. Much can be gained by investigating the distribution patterns of living organisms in nature, because one may find the explanations to the constant repetition of their distributions.

Biogeography studies the distribution (in time and space) of living organisms. It also investigates the causes and processes that determine such patterns. In 1820, de Candolle proposed the system of biogeographic regions. He based his observations on plants, the composition of regions and their relationships to climate. He also recognised a number of taxa that exclusively occupy a region; these taxa are known as ‘endemic taxa’. In other words, endemic taxa are restricted to a region, due to reproductive- or geographic isolation, or both.

Ecological niche models are robust tools used to predict the potential distribution of a given species, or that of a group of taxa. In order to estimate a potential distribution, these models use the presence records of a given species, as well as data on the location and date of observation of each individual.

Biogeography models have been used to plan conservation strategies, since they can be used to identify biodiversity hotspots or areas in need of protection. This is why it is important to identify the patterns of distribution of endemic taxa.

Freshwater is one of the most diverse ecosystems on the planet. One of the main reasons for the high levels of diversity of freshwater ecosystems is the way in which these are arranged: as ‘islands’. In such arrangement, islands are separated both by distance and altitude, which promotes diversification and speciation. Nowadays these ecosystems are severely threatened by human activities and climate change (among other reasons).

Dragon- and damselflies are insects of the order Odonata. These insects depend on freshwater ecosystems in order to reproduce and to develop from larvae to adults. Once the adult emerges, it leaves the water, develops two pairs of wings and tries to mate: males usually patrol the ponds or streams in search for females, or defend areas to which females are attracted, while the latter will come near the water in search for males. Once the females mate, they will fertilise their eggs before dropping them in the water or inserting them into a plant’s tissue.

Lucía del Carmen Salas Arcos is a first year MSc student at the Centro Tlaxcala de Biología de la Conducta (Universidad Autónoma de Tlaxcala, Mexico). She is supervised by Martín Alejandro Serrano-Meneses and by Enrique González Soriano (Universidad Nacional Autónoma de México, Mexico). Lucía’s work aims to determine the distribution patterns of endemic dragon- and damselfly taxa of Mexico, as well as their potential distribution (using ecological niche models).

The current information on the distribution of endemic Odonata of Mexico is mostly circumstantial. Therefore Lucía will gather data and produce results that will highlight not only the distribution of fragile taxa, but also those areas in need of desperate conservation efforts. To this end, Lucía will (i) elaborate an updated listing of endemic Odonata of Mexico, (ii) elaborate distribution maps of these taxa (using Diva GIS 7.2.3) by superimposing vegetation, weather and temperature layers, and (iii) model, along with Miguel Rivas Soto, the potential distribution of taxa, as estimated under the ecological niche criteria. Taken together, the information produced by Lucía’s study will be used to implement future, more focused and efficient conservation plans.