DOI: 10.5061/dryad.8v739
title: Data from: Reproductive interference and fecundity affect competitive interactions of sibling species with low mating barriers: experimental and theoretical evidence

description: 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.
description: Longevity
 experimentWe 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.longevity.xlsxFecundity experimentWe 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.fecundity.xlsxHigh Resolution Melting dataFor 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.HRM.xlsx