Wingless flight: An update on spider ballooning and an analysis of the terminology

Ballooning is an aerial dispersal mechanism commonly used by spiders, primarily observed in small adults and juveniles of some species. Spiders can navigate through the air by deploying silk threads, covering varying distances. During the last decades, there has been increased attention to spider aerial dispersal studies, and different use of terminologies associated with ballooning. We surveyed research literature on aerial dispersal studies from 1966 up to 2024 to assess the variances in the number of studies on these topics and analyse the use of pre-ballooning and ballooning terms. We found a total of 216 research articles containing pre-ballooning behaviour terms such as ‘tip-toe’/ ‘tiptoe’/ ‘tiptoeing’ (n = 17), ‘drop on dragline’/ ‘dropping on dragline’ (n = 15) and terms such as ‘ballooning’ (n = 146), ‘rappel/rappelling/bridging’ (n = 74), ‘aerial dispersal’ (n = 104), ″aerial dispersion″ (n = 15), or ″aeronautic behaviour″ (n = 7). These studies were distributed into 192 research articles, 9 reviews, 3 book chapters, and 7 into other categories. Spider families with the most reports of ballooning were Linyphiidae, Theridiidae, and Araneidae. Tiptoeing is considered an indicator of ballooning behaviour; however, according to our results, there are some differences in the use of the concepts ‘drop on dragline/dropping on a dragline’ and ‘rappelling’ as pre-ballooning, ballooning or non-ballooning behaviours. We discuss the importance of fine-scaled behavioural descriptions of ballooning and the need to homogenize the criteria to smooth the way for future studies of this phenomenon in spiders.