Reproductive isolation between two sympatric simultaneous hermaphroditic shrimp,Lysmata wurdemanniandL. boggessi

Abstract

To investigate pre-and post-zygotic isolation between two sympatric and phylogenetically related species of Lysmata shrimp, two assays were conducted in the laboratory: (1) no specific mate choice where mating between the two species was 'forced'; (2) specific mate choice or preference where a female had a choice between conspecific and heterospecifc males. Behavioural studies reveal that female L. wurdemanni accepted only conspecific male shrimp, whereas L. boggessi females would mate with an interspecific male if there was no conspecific male present. When males of both species were present, L. boggessi females always mated with the conspecific male. Male L. boggessi in general did not respond to the sex pheromones secreted by female L. wurdemanni and did not display any pre-copulatory behaviour to newly moulted female L. wurdemanni. On the other hand, some male L. wurdemanni responded to female L. boggessi. Although mating was successful between male L. wurdemanni and female L. boggessi, the resulting embryos lived at most for 10 days and failed to hatch. The results indicate that the two species are both pre-zygotically and post-zygotically isolated. Behavioural observation suggests that chemical cues are most likely responsible for pre-zygotic isolation.

Simultaneously Hermaphroditic Shrimp Use Lipophilic Cuticular Hydrocarbons as Contact Sex Pheromones

“…The design of the behavioral assay [23] was to test the bioactivity of the hexane-extractable cuticular compounds. To ensure the test animals were receptive to potential sex pheromones, only MP shrimp were used and no individual was used more than once to avoid potential habituation.…”

“…We use recent behavioral evidence that suggests the existence of both distance and sparingly water-soluble contact pheromones in Lysmata wurdemanni and L. boggessi [22], [23] to examine the chemical identity of the contact pheromone. The reproductive system of Lysmata species is rare among decapod crustaceans [24]: a shrimp first matures as a male (male phase - MP), but with growth may change into a euhermaphrodite.…”

“…In this study, we examined the hypothesis that contact pheromones on the female body surface of the hermaphroditic shrimp Lysmata boggessi are lipophilic in nature, and as such, resemble insect cuticular hydrocarbon contact cues [1] , [6] . We use recent behavioral evidence that suggests the existence of both distance and sparingly water-soluble contact pheromones in Lysmata wurdemanni and L. boggessi [22] , [23] to examine the chemical identity of the contact pheromone. The reproductive system of Lysmata species is rare among decapod crustaceans [24] : a shrimp first matures as a male (male phase - MP), but with growth may change into a euhermaphrodite.…”

Social Behaviour and Recognition in Decapod Shrimps, with Emphasis on the Caridea

“…Both species are protandric simultaneous hermaphrodites in which juveniles mature as males (male phase) and later become simultaneous hermaphrodites that resemble and function as females (female phase) but have male function; we will refer to these two phases simply as MP and FP, respectively. Zhang et al (2009) and Zhu et al (2012a) found that reproductive isolation of the two species are due to differences in the molecular composition of sex pheromones leading to asymmetric mate recognition. MP L. boggessi rarely mate with FP L. wurdemanni because males cannot recognize the soluble sex pheromones from those FPs.…”

Marine chemical ecology in benthic environments

“…Further research with two species of Lysmata shrimp, which are protandric simultaneous hermaphrodites, tested the factors that might contribute to conspecific selection during mating. 184 Behavioral experiments showed that conspecifics would always mate, but male L. boggessi would not mate with female L. wurdemanni. However, female L. boggessi would copulate with male L. wurdemanni if no L. boggessi males were present, and this interspecific mating was more frequent when the shrimp were held in the dark.…”