The biology and energetics of the potato aphid Macrosiphum euphorbiae, living in galls of the apple aphids Dysaphis devecta and Aphis pomi
1984
Llewellyn, M. | Hargreaves, C.E.M.
A non-gall-forming aphid, Macrosiphum euphorbiae, was reared within the galls of Dysaphis devecta and Aphis pomi which had been induced in apple seedlings. Similar aphids were also reared on ungalled seedling leaves of a similar age and also on mature leaves and in old galls. There is a weak positive linear relationship between lipid content and pre-reproductive adult dry weight, but aphids living on young galled or ungalled plant tissue have 30% lipid compared to 11% for aphids living on old plant tissue. Adult aphids gradually decline in weight, losing between 24% and 38% of their pre-reproductive biomass before death. The energy content of this loss subsidises reproduction. Reproduction of aphids feeding in old galls or on mature leaves was negligible, but on younger tissues average fecundity was 31, there being little difference between aphids living on galled and ungalled tissue. There is no simple relationship between pre-reproductive adult embryo content and fecundity. The principal factor mediating honeydew production was aphid size and this factor overrides any variation caused by different feeding sites, Honeydew production averaged 0.43 mg during a life of 30 days. Aphids successfully completing their life cycle have a life-time energy consumption of 30.58 joules of which 18% is lost as heat during respiration (R), 30% is contained in honeydew (F + U), 1% is contained in exuviae (Pe). Larval growth accounts for 17% (Pg), and adult reproduction for 34% (Pr). The P/C ratio for M. euphorbiae is 53% and is broadly comparable with aphids living on herbaceous plants.
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