Habitat-related differences in the pre-copulatory guarding and copulation behavior of Neohelice granulata (Brachyura, Grapsoidea, Varunidae)

Mating behavior strategies of brachyuran crabs are flexible depending on the habitat and social context. We evaluate pre-copulatory guarding in Neohelice granulata and describe the unusual copulatory behavior. Laboratory experiments were conducted to test whether factors such as male size, presence of burrows, a male-biased operational sex ratio (OSR) and female mating history affect the copulation duration in two different study areas. Females initiated a searching behavior approximately 20–26h before they became receptive by assessing large male burrows and displaying a courtship behavior (“flirting”) in its entrance. Once the female entered inside the male burrow, pre-copulatory guarding was observed until the female became receptive and successful copulation occurred immediately after. This species shows some very unusual copulatory behavior involving eyestalk grasping not seen in any other varunid crab. The copulation duration was independent of male size and the presence of burrows, although it was dependent on the study area, the OSR and the female mating history. Thus, copulation duration is a flexible character in this species which varies with habitat and biological factors such as mating history and sex ratio. •Neohelice granulata males develop pre-copulatory guarding.•Females search and assess male burrows where pre-copulatory guarding occur.•Females display a courtship behavior in the entrance of male burrows.•Copulation duration is independent of male size and the presence of burrows.•Copulation duration is dependent on location and operational sex ratio.•Copulation duration is dependent on female mating history.