Mayflies emerging from a river in Mato Grosso do Sul, Brazil

Unveiling the Mayflies of Mato Grosso do Sul: A Guide to Aquatic Biodiversity

Mira Elwood in Science & Nature December 2025 • 4 min read.

"Discover the underappreciated world of Ephemeroptera and their vital role in Brazil's aquatic ecosystems."

Mayflies, scientifically known as Ephemeroptera, are a crucial part of freshwater ecosystems. These insects, found in both still and flowing waters, play a key role in nutrient cycling and energy flow. Their sensitivity to environmental changes also makes them valuable indicators of water quality.

In the state of Mato Grosso do Sul, Brazil, knowledge of mayfly diversity has been limited. Previous records listed only thirteen species. However, dedicated researchers are now working to expand our understanding of these insects in the region.

This article highlights the current state of mayfly research in Mato Grosso do Sul, emphasizing their ecological significance and ongoing efforts to document their diversity. It aims to shed light on these often-overlooked creatures and encourage further exploration of Brazil's rich aquatic biodiversity.

Why Mayflies Matter: The Ecological Role of Ephemeroptera

Mayflies emerging from a river in Mato Grosso do Sul, Brazil

Mayflies are more than just insects; they are essential components of aquatic food webs. As nymphs (juvenile stage), they feed on plants and decaying matter, processing organic material and making it available to other organisms.

Furthermore, mayfly nymphs serve as a vital food source for many predators, including fish and other aquatic insects. This position in the food chain makes them a key link between primary producers (plants) and higher-level consumers.

Nutrient Cycling: Mayflies actively participate in breaking down organic matter, releasing essential nutrients back into the water.
Food Source: They are a primary food source for various aquatic animals, supporting the entire ecosystem.
Water Quality Indicators: Their sensitivity to pollution makes them valuable indicators of environmental health. A decline in mayfly populations can signal water quality issues.

Another unique aspect of mayflies is their subimago stage, an intermediate winged form between the nymph and the adult. These subimagos are less active than adults and often rest near the water's edge before molting into their final adult form. The presence of this stage highlights the complex life cycle of these fascinating insects.

Gaps in Knowledge and Future Research

Despite their importance, mayflies in the Central-West region of Brazil, including Mato Grosso do Sul, remain understudied. The current understanding of their distribution and diversity is far from complete. Many areas lack comprehensive surveys, and the knowledge is fragmented across different regions.

To address these gaps, researchers are focusing on several key areas: integrating taxonomic, geographic, and ecological data; expanding phylogenetic knowledge; and conducting faunistic surveys in unexplored regions. Encouraging the training of specialists and creating identification keys specific to Brazil are also crucial steps.

By continuing to explore and document the mayfly fauna of Mato Grosso do Sul, we can gain a better appreciation for the region's aquatic biodiversity and develop effective strategies for its conservation. Further research will not only enhance our scientific understanding but also contribute to the sustainable management of these valuable ecosystems.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1590/1678-4766e2017116, Alternate LINK

Title: Checklist De Ephemeroptera Do Estado De Mato Grosso Do Sul, Brasil

Subject: Animal Science and Zoology

Journal: Iheringia. Série Zoologia

Publisher: FapUNIFESP (SciELO)

Authors: Fábio Henrique Da Silva, Frederico Falcão Salles

Published: 2017-01-01

Everything You Need To Know

What are mayflies (Ephemeroptera), and where are they found?

Mayflies, scientifically classified as Ephemeroptera, are insects critical to freshwater ecosystems. They are found in both still and flowing waters. They are fundamental in nutrient cycling and energy flow within these environments. Their sensitivity to changes in water quality makes them useful indicators of environmental health. The article emphasizes their role within the aquatic ecosystems of Mato Grosso do Sul, Brazil, highlighting the need for further research.

Why are mayflies important in aquatic ecosystems?

Mayflies are important because they are a vital part of aquatic food webs. As nymphs, they consume plants and decaying matter, which processes organic material and makes it available to other organisms. They are a primary food source for many predators such as fish and other aquatic insects. They also participate in breaking down organic matter and releasing nutrients back into the water, thus, helping to support the entire ecosystem. Their presence or absence can also signal water quality issues.

What is the significance of the subimago stage in a mayfly's life cycle?

The subimago stage is a unique phase in a mayfly's life cycle. It is an intermediate, winged form that comes between the nymph and the adult. The subimago is less active than the adult and often rests near the water's edge before molting into its final adult form. The presence of this subimago stage underscores the complexity of mayflies' life cycle.

What is the current state of mayfly research in Mato Grosso do Sul?

The current state of research shows that knowledge of mayfly diversity in Mato Grosso do Sul is limited. Previously, only thirteen species were documented. However, researchers are actively working to broaden the understanding of these insects in the region. There are significant gaps in knowledge and that current research aims to address these gaps, underscoring the need for more comprehensive surveys and documentation.

What are the goals of ongoing research concerning mayflies in Mato Grosso do Sul?

Ongoing research is aimed at expanding the understanding of mayfly diversity and distribution in Mato Grosso do Sul. This includes conducting more surveys, documenting different species, and understanding their ecological roles. These efforts help to shed light on the often-overlooked creatures and encourage further exploration of Brazil's rich aquatic biodiversity. It seeks to address the fragmented knowledge and lack of comprehensive surveys that exist in the Central-West region of Brazil.