Impact of introduced honey bees on native pollination interactions of the endemic Echium wildpretii (Boraginaceae) on Tenerife, Canary Islands

Abstract

The aim of this study was to investigate effects of introduced honey bees (Apis mellifera) on native pollination interactions of Echium wildpretii ssp. wildpretii in the sub-alpine desert of Tenerife. We selected two study populations, one dominated by honey bees, while the other was visited by many native insects. During peak activity period of insects, nectar was nearly completely depleted in flowers of the first, but not the latter population. Thus, a high abundance of honey bees may have suppressed visitation by native animals due to exploitative competition. Honey bees stayed longer and visited more flowers on the same inflorescence than native bees, thus potentially promoting self-pollination of the plants. Level of seed set and viability was similar in the two study populations. However, we cannot rule out long-term changes in genetic population structure due to changes in gene-flow patterns caused by foraging behaviour of honey bees vs. native flower-visitors. .

Reproductive ecology of the threatened "star cactus" <em>Astrophytum ornatum</em> (Cactaceae): a strategy of continuous reproduction with low success

“…In addition, the fruit and seed set values from the control treatment were low compared to the artificial cross-pollination treatment, which suggests pollinator scarcity, as has been reported in A. asterias (Strong & Williamson 2007). Even though our data set for floral visitors only included those who arrived at midday, the high percentage of the exotic bee Apis mellifera may be contributing factor to the low success (Dupont et al 2004).…”

Impact of honeybee (Apis mellifera L.) density on wild bee foraging behaviour

“…They found no negative relationship between the densities of honey-bee colonies and abundance or species richness of wild bees. Dupont et al (2004) Hudewenz & Klein (2013) in Germany when they observed the visitation rate on flowers of Calluna vulgaris; while no such evidence was found regarding overall reproductive success. On the other hand, Goulson, Stout & Kells (2002), exploring the competitive foraging behaviour of bumblebees and honey bees to native bees in Tasmania, found that sites where honey bees were absent supported greater numbers of native bees than sites where honey bees occurred.…”

“…Pollinator efficiency, and therefore, pollination effectiveness, is strongly related to the compatibility between flowers and their pollinators. Honey bees (Apis mellifera L.) are extremely polylectic insects (Cane & Sipes, 2006) visiting and pollinating a variety of species (Crane, 1990;Free, 1993;Vaughton, 1992;Gross, 2001;Dupont et al, 2004). In addition, honey bees have been widely and successfully used as pollinators in crop systems (Free, 1993;Morse & Calderone, 2000;Artz, Hsu & Nault, 2011).…”

“…The great majority of the studies were carried out in areas where honey bees were introduced relatively recently (Wils, Lyons & Bell, 1990;Schwarz, Gross & Kukuk, 1991;Bailey, 1994;Roubik, 1996;Paton, 1999;Gross, 2001;Goulson, Stout & Kells, 2002;Inoue, Yokoyama & Washitani, 2008). There are a comparatively small number of studies from Europe and even fewer from the Mediterranean area, where there is a long history of beekeeping (Pechhacker & Zeillinger, 1994; Ingolf & Tscharnkte, 2000;Dupont et al, 2004;Shavit, Amots & Ne'eman, 2009;Hudewenz & Klein, 2013). In this study, we gradually increased the number of honey-bee hives and observed the bee foraging behaviour in the same sites before and after the introduction of the hives.…”

Impact of alien terrestrial arthropods in Europe. Chapter 5

“…In the Canary Islands, Dupont et al (2003) showed that the introduced honeybees depleted nectar of a native plant, which reduced visitation by native pollinators and may have consequences on pollination. Th e bumblebee, Bombus terrestris, another important pollinator in Europe, is threatened by the importation of sub-species from the Middle East (B. t. dalmatinus) and Sardinia (B. t. sassaricus) introduced in Europe as pollinators of greenhouse crops.…”