Citizen scientists have helped researchers uncover how parental care evolved in harvestmen, a group of spider like arachnids, by contributing observations through the popular nature platform iNaturalist. The findings, published in the Zoological Journal of the Linnean Society, reveal that parental guarding behavior has appeared, disappeared, and evolved again multiple times over the group's evolutionary history.
By combining nearly 30 years of field research with observations submitted to iNaturalist, an international team led by a University of São Paulo scientist more than doubled the number of documented examples of parental care in harvestmen. The expanded dataset also allowed researchers to reconstruct, for the first time, how both maternal and paternal care evolved within the superfamily Gonyleptoidea.
Citizen science reveals the evolution of parental care
The analysis showed that parental guarding behavior has not followed a simple evolutionary path. Instead, it has emerged repeatedly, been lost in some lineages, and later reappeared.
Researchers found that maternal care evolved only from species that showed no parental care, matching patterns previously observed in insects. Paternal care, however, followed two different evolutionary routes. It arose either directly from species with no parental care or from species in which females already guarded the eggs. This suggests that different evolutionary pressures shaped the development of maternal and paternal care.
