Mapping ignorance to uncover shortfalls in the knowledge on global Orthoptera distribution

Understanding the spatiotemporal distribution of species is fundamental for ecology, evolution and conservation. However, this and other aspects of biodiversity knowledge suffer from shortcomings and biases. Quantifying and mapping biodiversity knowledge shortfalls is therefore crucial to ascertain the current quality and completeness of biodiversity data, prioritize sites for (re)sampling, or plan conservation interventions. Here, we compile a comprehensive dataset of Orthoptera occurrences, and use it to create a global ‘ignorance map’ based on taxonomic, survey and temporal completeness, and on survey and temporal evenness of the inventories. We hypothesize that knowledge of Orthopteran biodiversity is relatively poorer in tropical regions compared to temperate regions, and in the south compared to the northern hemisphere. Due to biocultural factors, we expect regions in the tropics and the Global South to have lower levels of completeness and evenness in time and space for all the studied aspects of biodiversity information. Our findings show gaps in the knowledge of orthopteran distributions, which are characterized by low survey and temporal evenness in tropical regions, but also in many temperate regions (e.g., most of the countries in temperate Asia). The combination of multiple dimensions of biodiversity knowledge (taxonomic, spatial and temporal) reveals that biogeographic interpretations based on only one component can lead to an illusion of completeness. We believe that the novel framework used in our study can guide future research towards building more accessible maps of biogeographical ignorance for entire groups.