Zygoptera / Anisoptera (Insecta: Odonata) ratio as a tool to assess anthropogenic changes in Brazilian Cerrado streams.

Aquatic ecosystems are among the most affected by anthropogenic impacts, and the rapid detection and measurement of these impacts are of great importance for the maintenance of such environments. The order of aquatic insects Odonata has emerged as an important bioindicator of environmental quality due to its sensitivity to environmental changes and its ecophysiological requirements, which make them closely associated with habitat conditions. The aim of this study was to test whether the Zygoptera/Anisoptera ratio can be used as an effective tool to assess anthropogenic changes in Cerrado streams. Our hypothesis is that the proportion of Zygoptera/Anisoptera is an efficient tool for measuring environmental alterations in Cerrado streams, with a positive relationship between habitat integrity and the proportion of Zygoptera and an inverse relationship with the proportion of Anisoptera. Adults were collected in 44 streams of the Cerrado Biome in the eastern Maranhão state. The Habitat Integrity Index (HII) was used to verify the environmental gradient. Our hypothesis was corroborated, with a positive relationship between the richness and abundance of Zygoptera and HII, while an inverse relationship was observed for Anisoptera. According to our results, streams exhibiting a Zygoptera abundance of 68% or higher and richness of 58% or higher can be classified as preserved, while those showing an Anisoptera abundance and richness surpassing 31% and 41%, respectively, may be deemed altered. The patterns detected in the Cerrado were similar to those found in studies of the Amazon Biome and the Atlantic Forest, confirming the effectiveness of this method even for naturally open environments, such as the Cerrado. We conclude, therefore, that this method can be used as a tool to generate rapid results in monitoring studies, with low cost and easy application, enabling the development of mitigation, control, and conservation measures for extremely threatened environments such as those found in the Cerrado Biome.

Systematic challenges and opportunities in insect monitoring: a Global South perspective.

Insect monitoring is pivotal for assessing biodiversity and informing conservation strategies. This study delves into the complex realm of insect monitoring in the Global South-world developing and least-developed countries as identified by the United Nations Conference on Trade and Development-highlighting challenges and proposing strategic solutions. An analysis of publications from 1990 to 2024 reveals an imbalance in research contributions between the Global North and South, highlighting disparities in entomological research and the scarcity of taxonomic expertise in the Global South. We discuss the socio-economic factors that exacerbate the issues, including funding disparities, challenges in collaboration, infrastructure deficits, information technology obstacles and the impact of local currency devaluation. In addition, we emphasize the crucial role of environmental factors in shaping insect diversity, particularly in tropical regions facing multiple challenges including climate change, urbanization, pollution and various anthropogenic activities. We also stress the need for entomologists to advocate for ecosystem services provided by insects in addressing environmental issues. To enhance monitoring capacity, we propose strategies such as community engagement, outreach programmes and cultural activities to instill biodiversity appreciation. Further, language inclusivity and social media use are emphasized for effective communication. More collaborations with Global North counterparts, particularly in areas of molecular biology and remote sensing, are suggested for technological advancements. In conclusion, advocating for these strategies-global collaborations, a diverse entomological community and the integration of transverse disciplines-aims to address challenges and foster inclusive, sustainable insect monitoring in the Global South, contributing significantly to biodiversity conservation and overall ecosystem health. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'.