Pollination by sexual deception promotes outcrossing and mate diversity in self‐compatible clonal orchids

Abstract

The majority of flowering plants rely on animals as pollen vectors. Thus, plant mating systems and pollen dispersal are strongly influenced by pollinator behaviour. In Australian sexually deceptive orchids pollinated by male thynnine wasps, outcrossing and extensive pollen flow is predicted due to floral deception, which minimizes multiple flower visitations within patches, and the movement of pollinators under mate-search rather than foraging behaviours. This hypothesis was tested using microsatellite markers to reconstruct and infer paternity in two clonal, self-compatible orchids. Offspring from naturally pollinated Chiloglottis valida and C. aff. jeanesii were acquired through symbiotic culture of seeds collected over three seasons. In both species, outcrossing was extensive (t m = 0.924-1.00) despite clone sizes up to 11 m wide. The median pollen flow distance based on paternity for both taxa combined was 14.5 m (n = 18, range 0-69 m), being larger than typically found by paternity analyses in other herbaceous plants. Unexpectedly for orchids, some capsules were sired by more than one father, with an average of 1.35 pollen donors per fruit. This is the first genetic confirmation of polyandry in orchid capsules. Further, we report a possible link between multiple paternity and increased seed fitness. Together, these results demonstrate that deceptive pollination by mate-searching wasps enhances offspring fitness by promoting both outcrossing and within-fruit paternal diversity.

Functional Significance of Labellum Pattern Variation in a Sexually Deceptive Orchid (Ophrys heldreichii): Evidence of Individual Signature Learning Effects

“…Recent investigations in the Australian sexually deceptive orchid genus Chiloglottis suggest that high levels of outcrossing may help to circumvent the costs, i.e. reduced seed germination and growth, of geitonogamous pollination [ 81 ]. Most species in the genus Ophrys possess inconspicuous labella without highly contrasting patterns.…”

Emission rates of species-specific volatiles change across communities ofClarkiaspecies: Evidence for character displacement in floral scent

“…In particular, it is critical to determine if this variation in scent has functional 448 consequences for pollinator behavior. Given that the volatiles that mediate pollinator behavior interactions at multiple scales, from specifying highly specialized interactions (e.g., Peakall and 462 Whitehead 2014; Whitehead et al 2015) to contributing to the structure of complex plant-463 pollinator interaction networks (Kantsa et al 2018(Kantsa et al , 2019. In this study, by testing for character 464 displacement in multiple trait modalities across communities that contain different numbers of 465 interacting species, we have generated new insights into the context-dependency of character 466 displacement, which may occur through multiple pathways.…”

Genetic variation and selfing rate in Lychnis flos‐cuculi along an industrial pollution gradient

“…In these populations, S estimated manually and with Mltr comprised 0.35–0.60 and 0.19–0.44, respectively, while Colony (both PLS and FPLS) inferred S of 0–0.07 through overestimation of the minimum number of sires required to explain a progeny array. This sort of bias had already been documented for the latter approach earlier (Sefc & Koblmuller, ; Whitehead et al ., ). The obtained results show that even for markers with high levels of polymorphism (sufficient for the identification of genotypes), a high proportion of genetically identical individuals in a population suffering from a strong genetic bottleneck may bring uncertainty to the estimation of mating system parameters based on genetic data.…”

“…Despite the fact that the methods used for parentage inference and estimation of mating systems using genetic marker data have become more precise in recent years (Ritland, 2002;David et al, 2007;Sefc & Koblmuller, 2009;Wang et al, 2012;Whitehead et al, 2015), the disparate estimates of S obtained in this work may be subject to bias. For example, RMES apparently tended to overestimate S in all populations, while COLONY (PLS) did so in populations with a higher genetic variation.…”