02882nas a2200157 4500008004100000022001400041245014000055210006900195260001600264520227600280100002602556700001902582700002302601700001902624856008102643 2020 eng d a0305-736400aSelective pollination by fungus gnats potentially functions as an alternative reproductive isolation among five Arisaema species0 aSelective pollination by fungus gnats potentially functions as a cFeb-12-20203 a

Interspecific difference in pollinators (pollinator isolation) is important for reproductive isolation in flowering plants. Species-specific pollination by fungus gnats has been discovered in several plant taxa, suggesting that they can contribute to reproductive isolation. Nevertheless, their contribution has not been studied in detail, partly because they are too small for field observations during flower visitation. To quantify their flower visitation, we used the genus Arisaema (Araceae) because the pitcher-like spathe of Arisaema can trap all floral visitors.We evaluated floral visitor assemblage in an altitudinal gradient including five Arisaema species. We also examined interspecific differences in altitudinal distribution (geographic isolation) and flowering phenology (phenological isolation). To exclude the effect of interspecific differences in altitudinal distribution on floral visitor assemblage, we established ten experimental plots including the five Arisaema species in high- and low-altitude areas and collected floral visitors. We also collected floral visitors in three additional sites. Finally, we estimated the strength and contribution of these three reproductive barriers using a unified formula for reproductive isolation.Each Arisaema species selectively attracted different fungus gnats in the altitudinal gradient, experimental plots and additional sites. Altitudinal distribution and flowering phenology differed among the five Arisaema species, whereas the strength of geographic and phenological isolations were distinctly weaker than those in pollinator isolation. Nevertheless, the absolute contribution of pollinator isolation to total reproductive isolation was weaker than geographic and phenological isolations, because pollinator isolation functions after the two early-acting barriers in plant life history.Our results suggest that selective pollination by fungus gnats potentially contributes to reproductive isolation. Since geographic and phenological isolations can be disrupted by habitat disturbance and interannual climate change, the strong and stable pollinator isolation might compensate for the weakened early-acting barriers as an alternative reproductive isolation among the five Arisaema species.

1 aMatsumoto, Tetsuya, K1 aHirobe, Muneto1 aSueyoshi, Masahiro1 aMiyazaki, Yuko uhttps://academic.oup.com/aob/advance-article/doi/10.1093/aob/mcaa204/601730002759nas a2200217 4500008004100000020002300041245011500064210006900179260001300248300001400261490000800275520204800283100002202331700002702353700002202380700002102402700002102423700002302444700001702467856005702484 2014 eng d a0305-73641095-829000aCaught in the act: pollination of sexually deceptive trap-flowers by fungus gnats in Pterostylis (Orchidaceae)0 aCaught in the act pollination of sexually deceptive trapflowers  c2014/03/ a629 - 6410 v1133 a

BACKGROUND AND AIMS PTEROSTYLIS: is an Australasian terrestrial orchid genus of more than 400 species, most of which use a motile, touch-sensitive labellum to trap dipteran pollinators. Despite studies dating back to 1872, the mechanism of pollinator attraction has remained elusive. This study tested whether the fungus gnat-pollinated Pterostylis sanguinea secures pollination by sexual deception.

METHODS: The literature was used to establish criteria for confirming sexual deception as a pollination strategy. Observations and video recordings allowed quantification of each step of the pollination process. Each floral visitor was sexed and DNA barcoding was used to evaluate the degree of pollinator specificity. Following observations that attraction to the flowers is by chemical cues, experimental dissection of flowers was used to determine the source of the sexual attractant and the effect of labellum orientation on sexual attraction. Fruit set was quantified for 19 populations to test for a relationship with plant density and population size.

KEY RESULTS: A single species of male gnat (Mycetophilidae) visited and pollinated the rewardless flowers. The gnats often showed probing copulatory behaviour on the labellum, leading to its triggering and the temporary entrapment of the gnat in the flower. Pollen deposition and removal occurred as the gnat escaped from the flower via the reproductive structures. The labellum was the sole source of the chemical attractant. Gnats always alighted on the labellum facing upwards, but when it was rotated 180 ° they attempted copulation less frequently. Pollination rate showed no relationship with orchid population size or plant density.

CONCLUSIONS: This study confirms for the first time that highly specific pollination by fungus gnats is achieved by sexual deception in Pterostylis. It is predicted that sexual deception will be widespread in the genus, although the diversity of floral forms suggests that other mechanisms may also operate.

1 aPhillips, Ryan, D1 aScaccabarozzi, Daniela1 aRetter, Bryony, A1 aHayes, Christine1 aBrown, Graham, R1 aDixon, Kingsley, W1 aPeakall, Rod uhttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC3936588/02913nas a2200277 4500008004100000245009500041210006900136300001400205490000700219520206900226653002402295653002802319653002202347653002702369653002402396653001202420653001602432653002202448653001602470653002102486653001402507653002102521100002102542700002102563856005102584 2005 eng d00aPseudocopulatory Pollination in Lepanthes (Orchidaceae: Pleurothallidinae) by Fungus Gnats0 aPseudocopulatory Pollination in Lepanthes Orchidaceae Pleurothal a763–7720 v953 a• Background and Aims: Lepanthes is one of the largest angiosperm genera (>800 species). Their non-rewarding, tiny and colourful flowers are structurally complex. Their pollination mechanism has hitherto remained unknown, but has been subject of ample speculation; the function of the minuscule labellum appendix is especially puzzling. Here, the pollination of L. glicensteinii by sexually deceived male fungus gnats is described and illustrated. • Methods: Visitors to flowers of L. glicensteinii were photographed and their behaviour documented; some were captured for identification. Occasional visits to flowers of L. helleri, L. stenorhyncha and L. turialvae were also observed. Structural features of flowers and pollinators were studied with SEM. • Key Results: Sexually aroused males of the fungus gnat Bradysia floribunda (Diptera: Sciaridae) were the only visitors and pollinators of L. glicensteinii. The initial long-distance attractant seems to be olfactory. Upon finding a flower, the fly curls his abdomen under the labellum and grabs the appendix with his genitalic claspers, then dismounts the flower and turns around to face away from it. The pollinarium attaches to his abdomen during this pivoting manoeuvre. Pollinia are deposited on the stigma during a subsequent flower visit. The flies appear to ejaculate during pseudocopulation. The visitors of L. helleri, L. stenorhyncha and L. turialvae are different species of fungus gnats that display a similar behaviour. • Conclusions: Lepanthes glicensteinii has genitalic pseudocopulatory pollination, the first case reported outside of the Australian orchid genus Cryptostylis. Since most species of Lepanthes have the same unusual flower structure, it is predicted that pollination by sexual deception is prevalent in the genus. Several morphological and phenological traits in Lepanthes seem well suited for exploiting male fungus gnats as pollinators. Correspondingly, some demographic trends common in Lepanthes are consistent with patterns of male sciarid behaviour. 10aBradysia floribunda10aLepanthes glicensteinii10aLepanthes helleri10aLepanthes stenorhyncha10aLepanthes turialvae10amimicry10aOrchidaceae10aPleurothallidinae10aPollination10apseudocopulation10aSciaridae10asexual deception1 aBlanco, Mario, A1 aBarboza, Gabriel uhttp://aob.oxfordjournals.org/content/95/5/76300433nas a2200133 4500008004100000245005000041210004800091300001200139490000600151520005400157100001900211700002000230856004900250 1895 eng d00aFlowers and insects in Great Britain. Part I.0 aFlowers and insects in Great Britain Part I a227-2730 v93 aSceptonia nigra and Boletina sp. visiting flowers1 aWillis, J., C.1 aBurkill, I., H. uhttps://sciaroidea.myspecies.info/node/23200