Fireweed

Senecio madagascariensis

Fireweed is utilised by bees as a pollen source in the winter and spring on the NSW North Coast. (Clemson, p.210)

It is not a high quality pollen as its crude protein ranges from 13% to 17%, and the two amino-acids valine and iso-leucine are below the required amount. As a result the digestibility of the protein in fireweed pollen would only be 60% to 70%. This gives the available crude protein of 8% to 11%. (Table 17)

Fireweed produces large quantities of pollen in winter and early spring. This can keep bees ticking over while waiting for clover, stringybark, forest red gum or dillwynia to flower. For this reason, fireweed is appreciated by beekeepers. Fireweed also produces a little nectar, which keeps the hives stimulated and breeding.

The feeding of protein in the form of soyflour and or pre-collected pollen to the bees when they are working fireweed, would be a good management practice, if there are prospects for an early honey crop. The extra protein supplement would allow the bees to develop higher body-protein levels, required for the spring build-up. However, there is no need to feed the bees if there are no prospects for an early honey crop.

Fireweed is not an ideal floral source on which to overwinter bees. Bees would need access to other forms of pollen such as clover or forest red gum before they would breed satisfactorily.

However, the spread of fireweed onto agricultural land of the north coast is reducing the dependence of coastal beekeepers on heath and melaleuca swamps for overwintering bees.

Fireweed, due to its low crude protein level, would not be good as a feedback pollen.

Table 17: Fireweed Senecio madagascariensis

Amino-acid
Minimum % of Amino-Acid from De Groot (1953)
Casino

June 1985

Bentley

Sept 1985

Woodburn

Sept 1986

Casino

Aug 1987

Woodburn Sept 1986
Threonine 3.0 4.28  3.54  3.39  4.39 3.8 
Valine 4.0 4.18  2.82* 3.30* 3.74* 3.8*
Methionine 1.5 2.05  1.53  1.67 1.17  1.4 
Leucine 4.5 6.16  4.93  4.89  5.97  5.7 
Iso-leucine 4.0 3.46* 2.33* 2.22* 3.24* 3.9*
Phenylalanine 2.5 3.97  3.46 2.96 3.47  3.4 
Lysine 3.0 6.16  6.13 6.26 8.38  7.3 
Histidine 1.5 4.07  3.99 5.08 6.76  3.6 
Arginine 3.0 5.95  4.98 5.62  6.34  5.0 
Tryptophan 1.0 - - - - -
Crude protein - 13.3% 15.2% 17.3% 12.65% 11.8%

* Low level of this amino-acid


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