Fly pollination of dichogamous Angelica sylvestris (Apiaceae): how (functionally) specialized can a (morphologically) generalized plant be?

Abstract

Because of the flower morphology and high number of insect visitors, plants of the family Apiaceae are regarded as generalists in terms of pollination systems. Recent studies however showed some degree of, at least, ecological specialization in some members of this taxonomical group and indicated interesting patterns of insect visitor behavior: discrimination between umbel sexual phases. To test whether this is true in case of other members of the family, over two years we studied the pollination biology of a common European umbellifer, Angelica sylvestris, a species considered by some authors as a supergeneralist. Although its flowers were visited by over 70 species of insects grouped in 10 morphospecies, only a relatively narrow assemblage of muscoid and syrphid flies, rather constant in both study years, contributed to pollination. These insects did not exhibit any preferences toward plant sexual phases. Based on our results and available literature, we discuss the concept of specialization/generalization of the A. sylvestris pollination system, especially in the context of the ''unspecialized'' floral morphology characteristic for members of the Carrot family.

Myophily in the critically endangered umbelliferous plant Ostericum palustre Besser (Apiaceae)

“…Vesp Vespidae, LS large Syrphids, SS small Syrphids, LM large Muscoid flies, MM medium Muscoid flies (Faegri and van der Pijl 1966), and, as such, may be easily visited by a wide spectrum of insects, and are thus phenotypically generalized (Ollerton et al 2007). Indeed, our study showed that they are attractive to over 81 species of anthophilous insects, a result comparable to that found in many other members of the family (Knuth 1898; Corbet 1970; Grace and Nelson 1981;Ellis and Ellis-Adam 1993;Zych 2002Zych , 2007Zych et al 2007;Niemirski and Zych 2011). Although the taxonomic spectrum of visitors to our study species extended over 5 systematic orders, most floral visitors to O. palustre flowers belonged to a small number of functional groups within a single order, since 99-100 % visits in 2009-2010 and 85 % visits in 2008 were by Diptera.…”

“…We used a slightly modified version of the observation method of Zych (2007) and Niemirski and Zych (2011). Each full study day would comprise a maximum of six rounds of observations.…”

“…Consequently, since direct methods of assessing the performance of floral visitors were impractical (Lindsey 1984;Niemirski and Zych 2011), we used a slightly modified indirect method, as described by Zych (2002Zych ( , 2007, which is based on counts of insect pollen loads and observations of insect frequency, abundance and behaviour on inflorescences:…”

“…These insects, in particular large Syrphids and large Muscoid flies, were among the most frequent floral visitors, carried the largest pollen loads, and in two out of three study years, seemed to be the key pollinating agents. If, following Niemirski and Zych (2011), the large Muscoid and medium Muscoid flies were clustered into a single functional group, namely, Muscoid flies, then, quantitatively, they would constitute the largest group of floral visitors (over 51 % of visits during both 2008 and 2009, and 73 % in 2010). However, when all parameters of insect performance are considered, they are still inefficient pollinators compared to large Syrphids.…”

“…However, even in the case of generalist species, their reproductive biology may be threatened by habitat fragmentation, as demonstrated for another endangered member of the family, namely, Seseli farrenyi Molero & Pujadas (Rovira et al 2004). Furthermore, in recent years, the pollination systems of a number of species of Apiaceae have been investigated, and these have proved to be less generalized than anticipated, exhibiting at least ecological and/or functional specialization (Lindsey 1984;Zych 2007;Carvalheiro et al 2008;Niemirski and Zych 2011). This may also be the case for O. palustre with profound effects on preservation of this rare species.…”