Floral reward and insect visitors in six ornamental Lonicera species – Plants suitable for urban bee-friendly gardens

Abstract

Pollinator decline is a global threat with serious consequences to biodiversity. Mosaic structure of urban habitats and greenery areas are regarded beneficial for insects. However, for proper ‘pollinator-friendly’ management of urban areas, detailed information on floral reward offered by particular plant species is required. In this paper floral rewards of six ornamental Lonicera species (Caprifoliaceae), growing in the city of Lublin, SE Poland, were investigated. In this temperate zone, the investigated Lonicera species bloomed during May-June or May-October and could be considered as valuable food resources for pollinating insects. The mean amount of nectar sugars per shrub ranged 8.6–66.3 g (L. caprifolium - L. maackii, respectively). The mean pollen yield was 2.1–110.1 g per shrub (L. xylosteum – L. maackii, respectively). Due to considerable differences in corolla depth, Lonicera species attracted diverse groups of insect visitors, i.e. short-corolla species represented morning pattern of flower opening and attracted mainly honey bees and bumble bees, while long-corolla species opened in the evening and lured Apoidea, butterflies (mainly hawkmoths), and sporadically wasps, syrphid flies and beetles. Two high sugar- and pollen-yielding species, L. maackii and L. tatarica, are however regarded invasive in some geographical areas. Therefore, the spread of the species should be carefully monitored in urban green areas.