LB 14-166 - CANCELLED - Uncovering the effects of reproductive interference on Caenorhabditis species coexistence

Background/Question/Methods:

Interspecific sexual interactions play a significant role in driving species coexistence between closely related species. Reproductive interference occurs when individuals of one species engage in reproductive activities with individuals of another species causing a reduction of fitness of one or both species. Although Caenorhabditis elegans has been one of the best studied organisms in biology for decades, researchers have recently established Caenorhabditis as a model to study reproductive interference. When collected from nature, multiple Caenorhabditis species can be found cohabitating on rotting fruit and flower substrates. How species interact on these ephemeral substrates is unknown. The two sexual systems within Caenorhabditis are gonochorism, males and females, and androdioecy, males and hermaphrodites that are capable of self-fertilization but cannot cross with one another. Using Caenorhabditis strains collected from Barro Colorado Island, Panama, we ask whether interspecific mating affects the reproductive output and behavior of a gonochoristic species, C. becei, and two androdioecious species, C. tropicalis and C. briggsae. We paired hermaphrodites with males of heterospecifics and then collected data on reproductive output, presence of copulatory plug, and whether animals attempted to leave the mating arena.

Results/Conclusions:

Preliminary results indicate that C. becei is capable of reducing the reproductive output of both C. tropicalis and C. briggsae. C. tropicalis and C. briggsae are less likely to cause a reduction in reproductive output to each other. C. briggsae hermaphrodites and males both attempt to leave the mating arena when paired with heterospecifics. C. briggsae hermaphrodites are more likely to have a copulatory plug from C. tropicalis than C. becei. When paired with C. tropicalis hermaphrodites, C. becei males tend to have copulatory plugs stuck to their tails and no copulatory plug is present on C. tropicalis hermaphrodites. Our results are consistent with previous studies of Caenorhabditis reproductive interference, which show that gonochoristic species reduce the reproductive output of androdioecious species.