The cowl does not make the monk: scarab beetle pollination of the Neotropical aroidTaccarum ulei(Araceae: Spathicarpeae)

Abstract

Taccarum ulei (Araceae, Spathicarpeae) is a seasonal geophytic aroid, native to north‐eastern Brazil, that flowers during two months of the rainy season. Patterns of floral thermogenesis, pollination biology, and floral traits associated with pollination syndromes were studied and compared with those of other Araceae. Two species of cyclocephaline scarabs (Scarabaeidae, Cyclocephalini) were recognized as effective pollinators: Cyclocephala celata and Cyclocephala cearae. Larvae of an unidentified species of fruit fly (Melanoloma spp., Richardiidae, Diptera) were also frequently observed in inflorescences at various maturation stages, feeding on the connectives of male florets and fruits, and thus lowering the reproductive success of individual plants. Beetles were attracted by odoriferous inflorescences in the early evening of the first day of anthesis, during the female phase. The emission of attractive volatiles was coupled with intense thermogenic activity in the entire spadix, unlike other aroids in which only certain zones of the spadix heat up. Pollen release, which marks the beginning of the male phase on the subsequent evening, was not related to floral thermogenesis. Comparative multivariate analysis of the floral traits of T. ulei points to a beetle‐pollinated aroid, although some of the observed traits of the species are not common to other taxa sharing this pollination strategy. Such incongruence might be explained by the evolutionary history of the tribe Spathicarpeae and potential pollinator shifts. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ••, ••–••.

A New Female Elytral Character for the Tribe Cyclocephalini (Coleoptera: Scarabaeidae: Dynastinae) and an Observation of its Possible Function

“…In contrast, only one genus, Cyclocephala, has been recorded from dicot flowers (Figure 1). Experimental and observational studies have demonstrated that cyclocephalines can act as pollinators in Nymphaeales, Magnoliales, Arecales, Pandanales, and Alismatales ( Figure 1; Table 2) (Cramer et al 1975;Beach 1982;Beach 1984;Young 1986;Young 1988b;Gottsberger 1989;Dieringer et al 1999;Hirthe and Porembski 2003;Maia et al 2012). In these early diverging plant groups, a wide set of floral traits and floral pollination syndromes indicate a correlation with cyclocephaline beetles (large pollen grains with sticky exudates, sturdy and funnelshaped inflorescences or large disc-shaped flowers, timing of anthesis, and thermogenesis) (Thien et al 2009;Gibernau et al 2010).…”

“…Some cyclocephaline/flower associations are mutualistic (Cramer et al 1975;Beach 1982;Beach 1984;Young 1986;Young 1988b;Gottsberger 1989;Dieringer et al 1999;Hirthe and Porembski 2003;Maia et al 2012). Ervik and Knudsen (2003) provide a compelling argument that scarab pollination of the Nymphaeaceae (Nymphales) is a mutualistic relationship that dates to the early Cretaceous.…”

“…It is less clear how cyclocephalines species, which often mate inside inflorescences, maintain sexual isolation in close proximity to multiple congenerics. A single infloresence may host large crowds of beetles, often more then 30 individuals (Maia et al 2012). Sexual isolation may be maintained due to interspecific mating morphology (Moore 2012).…”

“…Cyclocephalines are important economically and ecologically as root pests (larvae) and pollinators (adults) (Ratcliffe 2003;Ratcliffe and Paulsen 2008). Adult cyclocephaline beetles can be found within the inflorescences of early diverging angiosperm groups (the family Nymphaeaceae, magnoliid clade, and monocots; Figure 1) and have been shown to contribute to pollination in the Annonaceae, Araceae, Arecaceae, Cyclanthaceae, Magnoliaceae, and Nymphaeaceae (Cramer et al 1975;Beach 1982;Beach 1984;Young 1986;Young 1988b;Gottsberger 1989;Dieringer et al 1999;Hirthe and Porembski 2003;Maia et al 2012). Studies of these interactions indicate that some early diverging angiosperm groups offer rewards to cyclocephalines in the form of mating sites, food, and metabolic boosts associated with floral thermogenicity in return for pollination services (Gottsberger 1986;Young 1986;Seymour et al 2009).…”

Aroid scarabs in the genus Peltonotus Burmeister (Coleoptera, Scarabaeidae, Dynastinae): key to species and new distributional data

“…Adult beetles use inflorescences as sites for mating and feeding, and they serve as pollinators (Moore and Jameson in press, Maia et al 2012). Species in the genus are intimately tied to host aroids and their forest habitats, and we predict that many species await discovery.…”