Honeydew amino acids in relation to sugars and their role in the establishment of ant‐attendance hierarchy in eight species of aphids feeding on tansy (Tanacetum vulgare)

Abstract

Abstract. The ratio of the concentration of honeydew total amino acids to total sugars in the honeydew of eight species of aphids, all feeding on tansy, Tanacetum vulgare (L.), was determined and correlated with honeydew production and ant‐attendance. The honeydew of the five ant‐attended aphid species [Metopeurum fuscoviride (Stroyan), Trama troglodytes (v. Hayd), Aphis vandergooti (Börner), Brachycardus cardui (L.), Aphis fabae (Scopoli)] was rich in total amino acids, ranging from 12.9 to 20.8 nmol µL−1 compared with the unattended aphid Macrosiphoniella tanacetaria (Kalt.) with only 3 nmol µL−1. Asparagine, glutamine, glutamic acid and serine (all nonessential amino acids) were the predominant amino acids in the honeydew of all species. The total concentration of amino acids in the phloem sap of tansy was much higher (78.7 nmol µL−1) then in the honeydew samples, and the predominant amino acids were glutamate (34.3%) and threonine (17.7%). A somewhat unexpected result was the finding that those aphid species with the highest total amino acid concentration in the honeydew always had the highest concentration of sugars. The lowest amino acid–sugar combined value was 104–28.8 nmol µL−1 in the non ant‐attended species M. tanacetaria, and the highest value was an average of 270–89.9 nmol µL−1 for the three most intensely attended aphid species M. fuscoviride, A. vandergooti and T. troglodytes. There is no evidence that any single amino acid or group of amino acids in the honeydew acted as an attractant for ant‐attendance in these eight aphid species. The richness of the honeydew (rate of secretion × total concentration of sugars), along with the presence of the attractant sugar melezitose, comprised the critical factors determining the extent of ant‐attendance of the aphids feeding on T. vulgare. The high total amino acid concentration in sugar‐rich honeydews can be explained by the high flow‐through of nutrients in aphids that are particularly well attended by ants.

Resource discovery in ant communities: do food type and quantity matter?

“…8% fructose and 6% glucose in the 20% solution and 31% fructose and 25% glucose in the 80% solution) and small (mean = 0.053 g) and large (mean = 0.36 g) crickets. The sugars found in clover honey, glucose, and fructose are the main components of the honeydew and nectars exploited in natural communities (Blüthgen & Fiedler, 2004;Woodring et al, 2004) and the concentrations we used fall towards the ends of the spectrum found in nature (Blüthgen & Fiedler, 2004). The crickets were representative of the proteinaceous resources frequently exploited by ants.…”

Honeydew production and honeydew sugar composition of polyphagous black bean aphid, Aphis fabae (Hemiptera: Aphididae) on various host plants and implications for ant-attendance

“…Other species, for example Macrosiphoniella tanacetaria on tansy, contain virtually no melezitose in their honeydew, and are not usually tended by ants (Hendrix et al, 1992;Völkl et al, 1999). In a recent study on the hierarchy of antattendance in eight species of aphids feeding on tansy (Woodring et al, 2004) it was demonstrated that a combination of the sugar richness of the honeydew excreted by the aphid (rate of honeydew production × total sugar concentration in the honeydew) together with a high content of the attractant sugar melezitose determines the extent of ant-attendance. There was no evidence that any single amino acid or group of amino acids in the honeydew act as an attractant for ant-attendance in these aphids.…”

Host-plant flowering status and the concentration of sugar in phloem sap: Effects on an ant-treehopper interaction

“…However, in the current study total nitrogen concentration was the same for the phloem fluid of plants with or without flowers, and therefore we do not believe that honeydew from membracids feeding on plants with or without flowers would vary in nitrogen concentration. Although ants may assimilate amino acids from hemipteran honeydew (Woodring et al, 2004), sugar concentration and composition appear to be the most important factors mediating the interaction between ants and Hemiptera (Kiss, 1981).…”

“…Indeed, sugar concentration and composition appear to be the primary attractants for honeydew-gathering ants (Völkl et al, 1999;Fischer & Shingleton, 2001) and recent studies indicate that the amino acids in the honeydew of several aphid species do not influence ant attendance (Woodring et al, 2004; but see Lanza, 1988;Bristow & Yanity, 1999). Moreover, the main source of protein for many ants involved in these interactions, including Camponotus species, is live prey or dead animal matter (Buckley, 1987;Hölldobler & Wilson, 1990;Davidson et al, 2003, and references therein).…”

“…The quality of phloem sap (i.e., nutritional value) is expressed in terms of soluble sugar and total nitrogen. Because nitrogen concentration did not vary with plant flowering status (see below) and sugar content is regarded as an important factor in ant-hemipteran interactions, honeydew quality is evaluated in this study in terms of sugar concentration (see Kiss, 1981;Völkl et al, 1999;Woodring et al, 2004). The field experiment was designed to address the following questions: (1) Does the quality of phloem sap (sugar concentration) vary between plants with and without flowers?…”