Data from: Reproductive interference and fecundity affect competitive interactions of sibling species with low mating barriers: experimental and theoretical evidence
Gebiola, Marco, University of Arizona
Kelly, Suzanne E., University of Arizona
Velten, Lennart, Humboldt University of Berlin
Zug, Roman, Humboldt University of Berlin
Hammerstein, Peter, Humboldt University of Berlin
Giorgini, Massimo, National Research Council
Hunter, Martha S., University of Arizona
Published Aug 10, 2017 on Dryad.
Cite this dataset
Gebiola, Marco et al. (2017). Data from: Reproductive interference and fecundity affect competitive interactions of sibling species with low mating barriers: experimental and theoretical evidence [Dataset]. Dryad. https://doi.org/10.5061/dryad.8v739
When allopatric species with incomplete prezygotic isolation come into secondary contact, the outcome of their interaction is not easily predicted. The parasitoid wasp Encarsia suzannae (iES), infected by Cardinium inducing cytoplasmic incompatibility (CI), and its sibling species E. gennaroi (EG), not infected by bacterial endosymbionts, may have diverged because of the complementary action of CI and asymmetric hybrid incompatibilities. Whereas postzygotic isolation is now complete due to sterility of F1 hybrid progeny, prezygotic isolation is still incipient. We set up laboratory population cage experiments to evaluate the outcome of the interaction between ES and EG in two pairwise combinations: iES vs. EG and cured ES (cES, where Cardinium was removed with antibiotics) vs. EG. We also built a theoretical model aimed at exploring the role of life history differences and asymmetric mating on competitive outcomes. In three of four cages in each treatment, ES dominated the interaction. We found evidence for reproductive interference, driven by asymmetric mating preferences, which gave a competitive edge to ES, the species that better discriminated against heterospecifics. However, we did not find the fecundity cost previously shown to be associated with Cardinium infection in iES. The model largely supported the experimental results. The finding of only a slight competitive edge of ES over EG in population cages suggests that in a more heterogeneous environment the species could coexist. This is supported by evidence that the two species coexist in sympatry, where preliminary data suggest reproductive character displacement may have reinforced postzygotic isolation.
We examined the relative longevity of parental species vs. hybrid progeny. We isolated 20 female pupae of EG, iES, cES and hybrids (produced by mating EG and cES wasps in both directions) in 1.2 ml vials, and at emergence we fed the adults with a small drop of honey, and kept them at a constant temperature of 27°C. Vials were checked daily, honey was added when necessary, and the date of female death was recorded.
We compared fecundity of 3 longstanding laboratory colonies (1st exp) and of 2 longstanding lab colonies and colonies recently established from field collected individuals (2nd exp). Female wasps were individually paired for 24 h in small vials with a conspecific male. Females were then placed individually in arenas with leaf disks bearing about 80 whitefly nymphs. The leaf disks rested on a layer of agar in ventilated 35 mm agar Petri dishes. Females were transferred to new whitefly-infested arenas every other day until day eight. At day 4, we provided females with the opportunity to mate again to avoid the risk of sperm depletion by introducing a male into the arena for 24h. Arenas were kept at 27°C, 16L:8D, and 65% RH. After females were removed on day 8, arenas were incubated for approximately 10 more days. At the end of this period, we recorded the number of progeny pupae, a proxy for adult emergence, as a measure of fecundity.
High Resolution Melting data
For each cage of each generation, we randomly selected 24 females among those stored in ethanol at the end of each generation by pipetting without observation. The number of parental species and hybrid progeny per cage per generation as identified by the High Resolution Melting assay is presented here.