Researchers leveraged iNaturalist, a crowdsourced observation platform, to trace how parental care evolved in harvestmen spiders, according to a study published in the Zoological Journal of the Linnean Society.
Harvestmen, also called daddy longlegs, are arachnids known for their long legs and small bodies. Unlike most spiders, some harvestmen species exhibit paternal guarding, where males protect eggs laid by females. This behavior is unusual in arthropods and represents a valuable window into understanding how parental investment evolves.
The research team analyzed thousands of observations submitted to iNaturalist by citizen scientists worldwide. The platform's extensive photographic records allowed researchers to document which harvestmen species display parental care and which do not. By mapping this behavior across the evolutionary tree of harvestmen, the scientists identified patterns in how and when paternal guarding originated and spread through different lineages.
Citizen science proved essential here because harvestmen are small, cryptic organisms that rarely attract professional entomological attention. iNaturalist's global network of amateur naturalists captured observations that would otherwise go unrecorded, creating a dataset large enough to support comparative evolutionary analysis.
The findings reveal that parental care in harvestmen evolved through specific evolutionary pathways and provides clues about the selective pressures favoring paternal investment. Understanding these mechanisms helps biologists grasp why males in some species remain with eggs while males in others abandon them immediately after mating.
This work underscores how citizen science bridges gaps in professional research by aggregating observations from millions of users. iNaturalist has become particularly valuable for studying organisms too small, too numerous, or too geographically scattered for traditional field surveys. The harvestmen research demonstrates that amateur naturalists contribute substantively to published science, not merely as data collectors but as essential partners in biological discovery. The