Fruit set and the diurnal pollinators of the invasive Lantana camara and the endemic Lantana peduncularis in the Galapagos Islands

Abstract

Fruit set is highly relevant to a plant's reproductive success. Fruit set can vary due to predation on flowers, pollinator services and/or resource availability. Reproductive success, measured as the fruit set of the invasive Lantana camara and the endemic Lantana peduncularis in the cool-dry season and the warm-wet season of the Galapagos Islands, was studied. Also, autonomous self-pollination ability and seed viability were probed for both species. Furthermore, flower visitors and their activity were registered for both species during the warm-wet season. Lantana peduncularis produced fewer flowers per inflorescence, but had a higher fruit set in the cool-dry season, compared to the warm-wet season. In contrast, the fruit set in L. camara did not change seasonally. The fruit set in L. camara was higher than in L. peduncularis in the warm-wet season. Moreover, ∼18% of the bagged flowers of the invasive Lantana produced fruits by autonomous self-pollination, while for the endemic Lantana, the rate of autonomous self-pollination was very low. More than 80% of the fruits for both species had at least one viable seed per fruit. The number of pollinators and their frequency, inflorescence-and flower-visiting rates and the duration of the visit per flower were higher in the invasive Lantana than in the endemic one. The endemic Lepidoptera Urbanus galapagensis (the main pollinator of both Lantana species) and the introduced Hymenia perspectalis were observed pollinating both Lantana species. These results indicate that the alien L. camara is more attractive to pollinators and it has reproductive advantages regarding fruit set in comparison with L. peduncularis, factors that contribute to the colonization pattern of this invasive species.

Polistes versicolor (Hymenoptera: Vespidae), an Introduced Wasp in the Galapagos Islands: Its Life Cycle and Ecological Impact

“…(Malvales: Sterculiaceae) (Hervías-Parejo and Traveset 2018). In another study in the Galapagos Islands, P. versicolor was recorded getting nectar and biting the inflorescence peduncles and fruits to get liquid of the introduced Lantana camara L. (Lamiales: Verbenaceae) shrub (Carrión-Tacuri et al 2014). Flower visitation of a broad range of plant species has also been recorded in Brazil (Köhler 2008).…”

The two faces of secondary contact on islands: Introgressive hybridization between endemics and reproductive interference between endemics and introduced species

“…Image sources: Argyranthemum , conservatoire.brest at Wikimedia; Geospiza , Harvey Barrison at Wikimedia; Urbanus , image from Carrión‐Tacuri et al. (2014).…”

Foraging and pollination activity of Papilio demodocus (Lepidoptera : Papilionidae) on the flowers of Lantana camara (Verbenaceae) at Dang (Ngaoundéré, Cameroon)

“…This table shows that: a) P. demodocus ranks first with 26.32% of visits in 2016 and 18.54% in 2017; b) the difference between these two percentages is very highly significant (χ 2 = 108.08 ; df = 1; P < 0.001) (Table 1). On the Galápagos Islands [1,21] , the Urbanus galapagensis butterfly is the most frequent forager on the flowers of L. camara. In Queensland, the bee Apis mellifera is the most abundant visitor on the flowers of this plant [22] .…”

“…Before our research, the published data on the relationships between L. camara and flowering insects were collected in Costa Rica [20] and in the Galapagos Islands [1,21] where its main flower visitors are Lepidoptera and in Queensland (Australia) [22] where bees are the most abundant visitors on its flowers. None of these studies deals with the effectiveness of Papilio demodocus on this Verbenaceae.…”