02759nas a2200277 4500008004100000022002500041245015400066210007100220260001600291300001400307490000800321520184900329653002102178653001702199653003602216653001702252653002002269653002302289653002202312653002102334100002202355700001702377700002302394700002402417856004002441 2023 eng d a0028-646X, 1469-813700a‘Bleeding’ flowers of Ceropegia gerrardii (Apocynaceae‐Asclepiadoideae) mimic wounded insects to attract kleptoparasitic fly pollinators0 aBleeding flowers of iCeropegia gerrardiii Apocynaceae‐Asclepiado cApr-04-2023 a1490-15040 v2393 a

Summary Kleptomyiophily, where flowers imitate wounded insects to attract ‘kleptoparasitic’ flies as pollinators, is one of the most specialized types of floral mimicry and often involves physical trapping devices. However, the diversity of pollinators and functional floral traits involved in this form of mimicry remain poorly understood. We report a novel example of kleptomyiophily in the nontrapping flowers of Ceropegia gerrardii and explore the floral traits responsible for attracting pollinators. The pollinators, reproductive biology and floral traits (including epidermal surfaces, spectral reflectance and the composition of nectariferous petal secretions and scent) were investigated. Attractive volatiles were identified using electrophysiological and behavioural experiments. Ceropegia gerrardii was predominantly pollinated by kleptoparasitic Desmometopa spp. (Milichiidae) flies. The flower corollas extrude a protein‐ and sugar‐containing secretion, similar to the haemolymph of wounded insects, on which the flies feed. Floral scent was chemically similar to that of injured honey bees. Four out of 24 electrophysiologically active compounds, all released by injured honey bees, were identified as key players in pollinator attraction. Our results suggest that C. gerrardii flowers chemically mimic wounded honey bees to attract kleptoparasitic flies and reward them with a secretion similar to the haemolymph on which they would normally feed.

10abehavioural trap10aBrachystelma10aelectroantennographic detection10afloral scent10afly-pollination10ahaemolymph mimicry10ahoney bee mimicry10akleptoparasitism1 aHeiduk, Annemarie1 aBrake, Irina1 aShuttleworth, Adam1 aJohnson, Steven, D. uhttp://dx.doi.org/10.1111/nph.1888802736nas a2200229 4500008004100000022001400041245011000055210006900165490000600234520197800240100002202218700001802240700001702258700002902275700001802304700001902322700002602341700002002367700001702387700002102404856008102425 2015 eng d a2296-701X00aDeceptive Ceropegia dolichophylla fools its kleptoparasitic fly pollinators with exceptional floral scent0 aDeceptive Ceropegia dolichophylla fools its kleptoparasitic fly 0 v33 a

Ceropegia species (Apocynaceae) have deceptive pitfall flowers and exploit small flies as pollinators, supposedly by chemical mimicry. Only preliminary data on the composition of flower scents are available for a single species so far, and the mimicry system is not yet understood in any species. We collected data on basic pollination aspects of C. dolichophylla, analyzed floral scent by gas chromatography linked to mass spectrometry (GC/MS), identified electrophysiologically active scent components by gas chromatography coupled with electroantennographic detection (GC/EAD), and determined compounds responsible for pollinator attraction in bioassays. We found that flowers of C. dolichophylla are visited by small flies of several taxa. Only Milichiidae and Chloropidae carried pollinaria and are, thus, pollinators. The pollen transfer efficiency (PTE) at two different sites was 2% and 4%, respectively. The floral scent was dominated by spiroacetals, mainly (2S,6R,8S)-8-methyl-2-propyl-1,7-dioxaspiro[5.5]undecane, n-tridecane, and N-(3-methylbutyl)acetamide. This spiroacetal and the acetamide elicited the most intense electrophysiological responses in fly antennae, and bioassays confirmed the capability of the spiroacetal in eliciting behavioral responses in pollinators. Most flies, determined as pollinators of C. dolichophylla, are kleptoparasites. They exploit insect prey of predatory arthropods as food source to which they are attracted by volatiles. 8-Methyl-2-propyl-1,7-dioxaspiro[5.5]undecane and N-(3-methylbutyl)acetamide have not been identified before as volatiles of other plants, however, they are known as insect volatiles. Both compounds occur in the venom glands of paper wasps, a potential food source for the pollinators of C. dolichophylla. We propose that C. dolichophylla shows a kleptomyiophilous pollination strategy. It mimics insect related odors to exploit the food-seeking behavior of its kleptoparasitic pollinators.

1 aHeiduk, Annemarie1 aKong, Hanghui1 aBrake, Irina1 avon Tschirnhaus, Michael1 aTolasch, Till1 aTröger, Armin1 aWittenberg, Elisabeth1 aFrancke, Wittko1 aMeve, Ulrich1 aDötterl, Stefan uhttp://www.frontiersin.org/chemical_ecology/10.3389/fevo.2015.00066/abstract