Spatial fragrance patterns within the flowers ofRanunculus acris (Ranunculaceae)

The role of pollen odour in the attraction of pollen beetles to oilseed rape flowers

“…In some plant species, different floral parts contribute different volatile components to the wholeflower odour (Dobson et al, 1990;Knudsen & Tollsten, 1991;Pichersky et al, 1994;Bergström et al, 1995). To determine whether a specific part of the oilseed rape flower was involved in the attraction of the pollen beetle to whole flowers, and to investigate whether pollen odour played a role in this attraction, beetle responses to the odours of different floral samples with and without anthers were tested against a blank air control.…”

“…This was done to reduce differences between the volatile profiles of samples caused by wounding that would otherwise occur if intact flowers with their anthers were compared with those with their anthers excised. Changes in the volatile profile of flowers may occur following excision or damage (see Bergström et al, 1995) and such changes can affect the responses of phytophagous insects to their host plant volatiles (Dicke & van Loon, 2000).…”

“…Each floral structure may release a different blend of volatiles that contributes to the whole-flower odour (Dobson et al, 1990;Knudsen & Tollsten, 1991;Pichersky et al, 1994;Bergström et al, 1995). The contribution from anthers and from pollen itself is usually quantitatively small, but in many species, both are chemically distinct from those of the other floral structures Dobson et al, 1990;Bergström et al, 1995;Dobson et al, 1996). Pollen odour may therefore be used by pollen-seeking insects to locate this important protein source.…”

“…Although the attraction to host plant floral odour has been demonstrated in many flower-visiting insects (reviewed by Williams, 1983;Dobson, 1994), the origin of the attractive odour has rarely been investigated. Each floral structure may release a different blend of volatiles that contributes to the whole-flower odour (Dobson et al, 1990;Knudsen & Tollsten, 1991;Pichersky et al, 1994;Bergström et al, 1995). The contribution from anthers and from pollen itself is usually quantitatively small, but in many species, both are chemically distinct from those of the other floral structures Dobson et al, 1990;Bergström et al, 1995;Dobson et al, 1996).…”

Analysis of protein content in pollen loads produced in north-west Spain

“…Honey bees visit some plants surrounding the beehive to obtain pollen and nectar, while others plants are not visited. It seems that in the floral "preference" made by the honey bee, the chemical composition of the pollen plays preponderant role in relation to the presence of volatile compounds and to the nutritional value as measured by the protein content (Dobson, 1987;Pacini & Juniper, 1979;Dobson et al, 1990;Bergström et al, 1995).…”