Study reveals surprising sexual tactics and aggression in harvestmen species

Researchers observed that female harvestmen sometimes perform oral stimulation to avoid male aggression, while males of another species coat their genitalia with a tasty fluid to encourage mating.

Scientists studying harvestmen in Slovakia discovered that female Phalangium opilio often lick the male's genital organ, a tactic that appears to defuse potential aggression and shorten mating duration. When females resisted, males displayed biting behavior that sometimes caused fractures, death, and cannibalism of four females. In a separate experiment with Leiobunum limbatum, males were found to coat their penis with a sugary, non-sperm fluid, which females repeatedly licked, resulting in higher mating rates and no observed male aggression.

The research involved feeding 230 juvenile harvestmen before pairing them for observation. Evolutionary biologist Anita Aisenberg, not involved in the work, speculated that the violent male behavior might be an overflow of male-male competition rather than a direct reproductive strategy. Pavol Prokop emphasized the novelty of these findings, noting they expand the known diversity of arachnid mating tactics.