# Exploring Potential Distribution and Environmental Preferences of Three Species of Dicranomyia (Diptera: Limoniidae: Limoniinae) Across the Western Palaearctic Realm Using Maxent

## TL;DR

This study uses Maxent to model the potential distributions and environmental preferences of three crane fly species in the Western Palaearctic.

## Contribution

The study reveals distinct environmental influences and distribution patterns among three closely related crane fly species.

## Key findings

- Dicranomyia affinis and Dicranomyia chorea share similar distributions influenced by climate, while Dicranomyia mitis is influenced by soil pH.
- High suitability for Dicranomyia affinis and Dicranomyia chorea is predicted in Mediterranean, Central, and Northern Europe.
- Dicranomyia mitis shows higher suitability in Eastern Europe and Scandinavia compared to Mediterranean regions.

## Abstract

One of the most fundamental questions in biology relates to understanding the drivers that shape observed species distributions. Various methods based on statistics and machine learning, collectively known as Ecological Niche Models or Species Distribution Models, have been proposed to address this question. These tools aim to predict distributions by using environmental information from areas where the species is known to occur and comparing them to data from areas where the species has not yet been observed. Maxent is one of the most popular and user-friendly tools for this purpose. In this study, we explore the potential distributions of three closely related species of Dicranomyia crane flies, Dicranomyia affinis, Dicranomyia chorea, and Dicranomyia mitis, in the Western Palaearctic realm using Maxent. Our results indicate that Dicranomyia affinis and Dicranomyia chorea have distributions that are very similar to each other, but different from that of Dicranomyia mitis. Additionally, there appear to be differences in the environmental variables that most influence their potential distributions. The models for Dicranomyia affinis and Dicranomyia chorea are primarily influenced by two climatic variables, while the model for Dicranomyia mitis is mostly influenced by soil pH.

Species distribution models were built for three short-palped crane fly species of the genus Dicranomyia: Dicranomyia affinis, Dicranomyia chorea, and Dicranomyia mitis. The main objective of this study was to assess potential habitat suitability in undersampled regions and explore differences in environmental space. Dicranomyia affinis was historically considered a variety of Dicranomyia mitis due to their morphological similarity. In contrast, Dicranomyia chorea is a widespread species. The biology and ecology of these species remain poorly understood. Models were developed using Maxent, a widely used tool. Our results indicate that Dicranomyia affinis and Dicranomyia chorea share highly similar predicted habitat suitability, with high suitability across the Mediterranean, Central, and Northern Europe, moderate suitability in Eastern Europe, and low suitability in Central Asia. In contrast, Dicranomyia mitis is predicted to have greater habitat suitability in Eastern Europe and Scandinavia, with lower suitability in Mediterranean regions. Analysis of variable importance revealed possible ecological differences between the species. While climatic factors primarily influenced the models for Dicranomyia affinis and Dicranomyia chorea, Dicranomyia mitis was more strongly influenced by the variable pH. These findings may provide insights into potential distributions in undersampled areas and improve our understanding of the species’ ecology.