Multiple Mating, Paternity and Complex Fertilisation Patterns in the Chokka Squid Loligo reynaudii.

Polyandry is widespread and influences patterns of sexual selection, with implications for sexual conflict over mating. Assessing sperm precedence patterns is a first step towards understanding sperm competition within a female and elucidating the roles of male- and female-controlled factors. In this study behavioural field data and genetic data were combined to investigate polyandry in the chokka squid Loligo reynaudii.

Isolation and characterization of highly polymorphic microsatellites in the chokka squid, Loligo reynaudii.

The chokka squid, Loligo reynaudii, is the target of a commercially valuable fishery in South Africa, but little information is available on population structure and mating system. We developed 11 polymorphic microsatellite markers using both standard nonenrichment and enrichment protocols. Numbers of alleles per locus ranged from 11 to 30, and levels of expected heterozygosity ranged between 0.

Adaptable night camouflage by cuttlefish.

Cephalopods are well known for their diverse, quick-changing camouflage in a wide range of shallow habitats worldwide. However, there is no documentation that cephalopods use their diverse camouflage repertoire at night. We used a remotely operated vehicle equipped with a video camera and a red light to conduct 16 transects on the communal spawning grounds of the giant Australian cuttlefish Sepia apama situated on a temperate rock reef in southern Australia.

Evidence for biased use of sperm sources in wild female giant cuttlefish (Sepia apama).

In species where females store sperm from their mates prior to fertilization, sperm competition is particularly probable. Female Sepia apama are polyandrous and have access to sperm from packages (spermatangia) deposited by males onto their buccal area during mating and to sperm stored in internal sperm-storage organs (receptacles) located below the beak. Here, we describe the structure of the sperm stores in the female's buccal area, use microsatellite DNA analyses to determine the genetic diversity of stored sperm and combine these data with offspring genotypes to determine the storage location of paternal sperm.

Behavioural ecology: transient sexual mimicry leads to fertilization.

Sexual mimicry among animals is widespread, but does it impart a fertilization advantage in the widely accepted 'sneak-guard' model of sperm competition? Here we describe field results in which a dramatic facultative switch in sexual phenotype by sneaker-male cuttlefish leads to immediate fertilization success, even in the presence of the consort male. These results are surprising, given the high rate at which females reject copulation attempts by males, the strong mate-guarding behaviour of consort males, and the high level of sperm competition in this complex mating system.