Ecologically relevant levels of multiple, common marine stressors suggest antagonistic effects.

Stressors associated with global change will be experienced simultaneously and may act synergistically, so attempts to estimate the capacity of marine systems to cope with global change requires a multi-stressor approach. Because recent evidence suggests that stressor effects can be context-dependent, estimates of how stressors are experienced in ecologically realistic settings will be particularly valuable. To enhance our understanding of the interplay between environmental effects and the impact of multiple stressors from both natural and anthropogenic sources, we conducted a field experiment.

Environment-dependent variation in selection on life history across small spatial scales.

Variation in life-history traits is ubiquitous, even though genetic variation is thought to be depleted by selection. One potential mechanism for the maintenance of trait variation is spatially variable selection. We explored spatial variation in selection in the field for a colonial marine invertebrate that shows phenotypic differences across a depth gradient of only 3 m.

Propagule size and dispersal costs mediate establishment success of an invasive species.

Bio-invasions depend on the number and frequency of invaders arriving in new habitats. Yet, as is often the case, it is not only quantity that counts, but also quality. The process of dispersal can change disperser quality and establishment success.

Copulatory wounding and traumatic insemination.

Copulatory wounding (CW) is widespread in the animal kingdom, but likely underreported because of its cryptic nature. We use four case studies (Drosophila flies, Siphopteron slugs, Cimex bugs, and Callosobruchus beetles) to show that CW entails physiological and life-history costs, but can evolve into a routine mating strategy that, in some species, involves insemination through the wound. Although interspecific variation in CW is documented, few data exist on intraspecific and none on individual differences.

Cephalo-traumatic secretion transfer in a hermaphrodite sea slug.

Mating rituals in the animal kingdom are often quite extraordinary, in particular when mating is traumatic. We here describe the exceptional traumatic mating behaviour of the currently undescribed sea slug, Siphopteron sp. 1.

Functions, diversity, and evolution of traumatic mating.

Copulation can involve the wounding of the mating partner by specialised devices. This type of mating, which we term traumatic mating, has been regarded as exceptional. Its prevalence, however, has not been compared across taxa, nor have its functions and putative evolutionary pathways.

Female fitness optimum at intermediate mating rates under traumatic mating.

Traumatic mating behaviors often bear signatures of sexual conflict and are then typically considered a male strategy to circumvent female choice mechanisms. In an extravagant mating ritual, the hermaphroditic sea slug Siphopteron quadrispinosum pierces the integument of their mating partners with a syringe-like penile stylet that injects prostate fluids. Traumatic injection is followed by the insertion of a spiny penis into the partner's gonopore to transfer sperm.

Population density and group size effects on reproductive behavior in a simultaneous hermaphrodite.

Background: Despite growing evidence that population dynamic processes can have substantial effects on mating system evolution, little is known about their effect on mating rates in simultaneous hermaphrodites. According to theory, mating rate is expected to increase with mate availability because mating activity is primarily controlled by the male sexual function. A different scenario appears plausible in the hermaphroditic opisthobranch Chelidonura sandrana.