Lipid‐enhanced pollen and lipid‐reduced flour diets and their effect on the longevity of honey bees (Apis mellifera L.)

Abstract

As eucalypt pollens contain low concentrations of lipid, enhancing pollen diets with fatty acids was hypothesised to improve honey bee longevity. Different concentrations of linoleic and oleic acid added to eucalypt pollen were trialled in small cages containing approximately 1400 bees each. Bees fed diets of redgum (Corymbia calophylla (Lindl.) Hill & Johnson, formerly Eucalyptus calophylla) pollen had the lowest mortality of 22 diets tested for 6 weeks and had life spans (50%) greater than 42 days. Linoleic acid mixed with a redgum diet in concentrations >6% corresponded to life spans of 24-25 days. Bee longevity appeared to be more sensitive to oleic acid as life spans decreased to 15-21 days when diets had concentrations >2%. The life spans of bees fed soya bean flour were 26 days on low (0.6% lipid) fat, 19 days on defatted and 20 days on full-fat diets. Bees fed lupin flour had a life span of 23 days. Adding redgum pollen to lupin flour caused increased mortality, but addition of pollen to soya bean flour was beneficial. Thus, beekeepers who choose to utilise soya bean or lupin flours as protein substitutes to pollen will have bees with reduced longevity. Bees fed redgum pollen that had been dried, crushed, irradiated and hermetically stored in a cool room for several years had similar longevity to bees fed fresh-collected and frozen redgum pollen.

Nutritional Effect of Alpha-Linolenic Acid on Honey Bee Colony Development (Apis Mellifera L.)

“…Studies have shown that fatty acids can inhibit fatty acid synthase activity (Mersmann et al, 1973). In this experiment, successive lipase activity decreased when ALA levels increased from 0 to 6%, which is consistent with the results of previous studies (Herbert et al, 1980;Manning et al, 2007), but interestingly, when the amount of ALA continued to increase to 8 and 10%, the lipase activity increased rapidly. Currently, no reports are consistent with this finding.…”

“…Many studies have demonstrated that dietary fatty acid levels are closely related to honey bee longevity. A study by Manning et al (2007) found that diets high in oleic acid significantly reduced the life of bees. This finding may possibly be because the high oleic acid diet was toxic to bees, and diets high in linoleic acid also reduced the lifespan of bees.…”

“…Information regarding the protein and amino acid requirements of honey bee colonies and individuals, is plentiful (De Groot, 1953;Barker and Lehner, 1972;Kim and Smith, 2000;Afik et al, 2006;Weiner et al, 2010;Hendriksma et al, 2014;Paoli et al, 2014), but data regarding lipid or fatty acid requirements are scarce. Nevertheless, lipids, among then fatty acids, play an important role in the honey bee diet (Loidl and Crailsheim, 2001;Manning et al, 2007). In general, linolenic acid (C18:3), linoleic acid (C18:2), and palmitic acid (C16:0) predominate in pollen, and the proportion of them is roughly 1.0: 0.65: 0.83 (Saa-Otero et al, 2000;Manning, 2001;Manning et al, 2007).…”

“…Nevertheless, lipids, among then fatty acids, play an important role in the honey bee diet (Loidl and Crailsheim, 2001;Manning et al, 2007). In general, linolenic acid (C18:3), linoleic acid (C18:2), and palmitic acid (C16:0) predominate in pollen, and the proportion of them is roughly 1.0: 0.65: 0.83 (Saa-Otero et al, 2000;Manning, 2001;Manning et al, 2007). Alpha-linolenic acid (ALA) is an n-3 polyunsaturated fatty acid (PUFA).…”

“…When bees do not have access to pollen, they can utilise their protein for brood rearing until their protein content drops to 20% of their body weight (Black, 2006). At the same time, the queen bee stops laying eggs, and the colony population weakens (Manning et al, 2007). In this case, the colony may be offered a pollen substitute, which is food intended to completely replace pollen.…”