Sugar Composition Of Honeydew Research Articles

Sugar, amino acid and inorganic ion profiling of the honeydew from different hemipteran species feeding on Abies alba and Picea abies.

Several hemipteran species feed on the phloem sap of plants and produce large amounts of honeydew that is collected by bees to produce honeydew honey. Therefore, it is important to know whether it is predominantly the hemipteran species or the host plant to influence the honeydew composition. This is particularly relevant for those botanical and zoological species from which the majority of honeydew honey originates. To investigate this issue, honeydew from two Cinara species located on Abies alba as well as from two Cinara and two Physokermes species located on Picea abies were collected. Phloem exudates of the host plants were also analyzed. Honeydew of all species contained different proportions of hexoses, sucrose, melezitose, erlose, and further di- and trisaccharides, whereas the phloem exudates of the host trees contained no trisaccharides. Moreover, the proportions of sugars differed significantly between hemipteran species feeding on the same tree species. Sucrose hydrolysis and oligosaccharide formation was shown in whole-body homogenates of aphids. The type of the produced oligosaccharides in the aphid-extracts correlated with the oligosaccharide composition in the honeydew of the different aphid species. The total contents of amino acids and inorganic ions in the honeydew were much lower than the sugar content. Glutamine and glutamate were predominant amino acids in the honeydew of all six hemipteran species and also in the phloem exudates of both tree species. Potassium was the dominant inorganic ion in all honeydew samples and also in the phloem exudate. Statistical analyses reveal that the sugar composition of honeydew is determined more by the hemipteran species than by the host plant. Consequently, it can be assumed that the sugar composition of honeydew honey is also more influenced by the hemipteran species than by the host tree.

Aphid Genotype Determines Intensity of Ant Attendance: Do Endosymbionts and Honeydew Composition Matter?

Abstract Ant—aphid interactions are well-studied mutualisms, but surprisingly, the intraspecific variation in the degree of ant attendance of aphids has been less appreciated than interspecific variation. Honeydew composition is a key factor in determining aphids' traits in relation to the intensity of ant attendance, and composition may be altered by endosymbiotic bacteria. Here, we evaluate relationships among the intensity of ant attendance, honeydew composition, and aphids' endosymbionts. We found differences in the intensity of ant attendance and endosymbiont composition between clones of cowpea aphids (Aphis craccivora Koch). To investigate whether aphid genotype, endosymbionts, or both, influence honeydew composition, and the relative influence of these factors on the intensity of ant attendance, a secondary symbiont of the aphid, Arsenophonus, was removed from the clone exhibiting a lower degree of ant attendance. Then, the sugar and amino acid composition of honeydew were compared between different aphid genotypes and between same genotype with and without Arsenophonus. The experiments demonstrated that there was a difference in the sugar composition of honeydew between clones, but that Arsenophonus did not influence this difference. Furthermore, the intensity of ant attendance of the clone did not change after removing Arsenophonus. These results suggest that variation in the degree of ant attendance of this aphid is caused by aphid genotype, not by endosymbionts.

A novel member of the trehalose transporter family functions as an h(+)-dependent trehalose transporter in the reabsorption of trehalose in malpighian tubules.

In insects, Malpighian tubules are functionally analogous to mammalian kidneys in that they not only are essential to excrete waste molecules into the lumen but also are responsible for the reabsorption of indispensable molecules, such as sugars, from the lumen to the principal cells. Among sugars, the disaccharide trehalose is highly important to insects because it is the main hemolymph sugar to serve as a source of energy and carbon. The trehalose transporter TRET1 participates in the transfer of newly synthesized trehalose from the fat body across the cellular membrane into the hemolymph. Although transport proteins must play a pivotal role in the reabsorption of trehalose in Malpighian tubules, the molecular context underlying this process remains obscure. Previously, we identified a Tret1 homolog (Nlst8) that is expressed principally in the Malpighian tubules of the brown planthopper (BPH). Here, we used the Xenopus oocyte expression system to show that NlST8 exerts trehalose transport activity that is elevated under low pH conditions. These functional assays indicate that Nlst8 encodes a proton-dependent trehalose transporter (H-TRET1). To examine the involvement of Nlst8 in trehalose reabsorption, we analyzed the sugar composition of honeydew by using BPH with RNAi gene silencing. Trehalose was detected in the honeydew as waste excreted from Nlst8-dsRNA-injected BPH under hyperglycemic conditions. However, trehalose was not expelled from GFP-dsRNA-injected BPH even under hyperglycemic conditions. We conclude that NlST8 could participate in trehalose reabsorption driven by a H+ gradient from the lumen to the principal cells of the Malpighian tubules.

Effects of honeydew sugar composition on the longevity of Aphidius ervi

AbstractFeeding on sugar‐rich foods such as nectar and honeydew is important for survival of many adult parasitoids. Especially in agricultural systems, honeydew is often the most prevalent carbohydrate source. However, relative to plant nectar, honeydew may be relatively unsuitable, as a result of an unfavourable sugar composition or the presence of secondary plant compounds. We studied survival of the aphid parasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae) on honeydew collected from various aphid species feeding on potato (Solanum tuberosum L., cv. Desiree) (Solanaceae), wheat (Triticum aestivum L., cv. Bobwhite) (Poaceae), or artificial diet, as well as the sugar composition of the different honeydews. Honeydews from the tested aphid species on potato, wheat, or artificial diet were found to be relatively suitable food sources for adult A. ervi, although not always as suitable as a 2 M sucrose solution. There were differences in honeydew sugar composition among the different aphid species on the various host plants. Multivariate statistics showed that the factor ‘aphid species’ had a significant influence on the sugar composition of the honeydew, explaining 27% of the variation in the potato system and 89% in the wheat system. When exploring the relationship between carbohydrate composition of the honeydews from aphids on potato and wheat plants, and their nutritional value for A. ervi, data revealed that differences in parasitoid longevity can to some extent be explained by carbohydrate composition. Furthermore, our results confirm that sucrose and its hexose components glucose and fructose are very suitable carbohydrate sources for hymenopteran parasitoids and show that parasitoid survival on an equimolar solution of the two monosaccharides glucose and fructose does not exceed performance on the disaccharide sucrose.

Seasonal variation in honeydew sugar content of galling aphids (Aphidoidea: Pemphigidae: Fordinae) feeding on Pistacia: Host ecology and aphid physiology

We investigated the possibility that seasonal variation in host-tree sap quality was reflected in aphid honeydew sugar content. Aphids (Homoptera) feed on the phloem sap of their host plants and excrete sugar-rich honeydew. We compared the sugar composition of honeydew excreted by four species of closely related aphids (Pemphigidae: Fordinae ) inducing galls on Pistacia palaestina (Anacardiaceae). Samples were collected four times a year in 1997 and 1998. Samples from one species feeding on the roots of a secondary host, a perennial herb, were also included in the study. More than 20 sugars were detected in the honeydew. Sugars that were present in more than 40% of the samples were analyzed quantitatively in a hierarchical manner. The mean proportions of each sugar of the total sugar content in different species were not significantly different, but samples taken at different dates contained significantly different proportions of the sugars. The most frequent sugars in all species were glucose and fructose. Generally, the proportion of glucose exceeded fructose, but in honeydew from aphids feeding on the roots of the secondary host the reverse was true. We suggest possible explanations for the observed patterns, and discuss a possible contribution of Fordinae honeydew to the food web in the micro-ecosystem. Wir untersuchten die Möglichkeit, dass sich die saisonale Variation der Saftqualität des Wirtsbaumes im Zuckergehalt des Honigtaus der Aphiden widerspiegelt. Die Aphiden (Homoptera) ernähren sich vom Phloemsaft der Wirtspflanzen und scheiden zuckerreichen Honigtau aus. Wir verglichen die Zuckerzusammensetzung des Honigtaus von vier Arten nahverwandter Aphiden (Pemphigidae: Fordinae), die Gallen auf Pistacia palaestina (Anacardiaceae) induzieren. Die Proben wurden viermal jährlich 1997 und 1998 gesammelt. Darüber hinaus wurden Proben einer Art in die Untersuchung mit einbezogen, die sich auf den Wurzeln eines Sekundärwirtes, eines perennierenden Krautes, ernährt. Es wurden mehr als 20 Zucker im Honigtau festgestellt. Die Zucker, die in mehr als 40% der Proben vorkamen, wurden quantitativ in hierarchischer Weise analysiert. Die mittleren Anteile eines jeden Zuckers am Gesamtzuckergehalt der unterschiedlichen Arten waren nicht signifikant verschieden, aber die Proben, die zu unterschiedlichen Daten genommen wurden, enthielten signifikant unterschiedliche Anteile der Zucker. Die häufigsten Zucker bei allen Arten waren Glukose und Fruktose. Im Allgemeinen war der Anteil der Glukose größer als der der Fruktose. Im Honigtau der Aphiden, die sich auf den Wurzeln des Sekundärwirtes ernährten, war jedoch das Gegenteil zutreffend. Wir schlagen Erklärungen für die beobachteten Muster vor und diskutieren einen möglichen Beitrag der Fordinae zum Nahrungsnetz im Mikro-Ökosystem.

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

The black bean aphid, Aphis fabae, is polyphagous and its life cycle involves seasonal migration between summer and winter host plants. The aphids are regularly tended by honeydew-collecting ants. This study investigates whether differences exist in honeydew production and honeydew sugar composition for A. fabae subspecies feeding on various host plants and whether such differences reflect differences in the intensity of ant-atttendance (Lasius niger).A. f. fabae feeding on the perennial summer host, Tanacetum vulgare, produced twice the amount of honeydew (ca. 110 µg per aphid . h-1) than when feeding on the annual host plants Vicia faba or Chenopodium album. Honeydew production of A. f. cirsiiacanthoides feeding on the creeping thistle Cirsium arvense was the highest measured in this study (ca. 150 µg per aphid . h-1). Total sugar concentration in the honeydew of A. f. fabae did not differ when feeding on various summer hosts, whereas the honeydew of A. f. cirsiiacanthoides on C. arvense contained a significantly higher amount of total sugars. The trisaccharide melezitose was the dominant sugar in all the honeydew samples, except for the honeydew of A. f. fabae and A. f. evonymi feeding on the woody winter host plant Evonymus europaeus. The highest proportion of melezitose (80% of total sugars) was found in the honeydew of A. f. cirsiiacanthoides feeding on C. arvense. In this subspecies, the intensity of ant-attendance was also highest. The results confirm our hypothesis, that the sugar richness of the honeydew (rate of honeydew secretion × total sugar concentration) along with the presence of the attractant sugar melezitose are the critical factors in determining the extent of ant-attendance.In A. f. fabae feeding on the spindle tree E. europaeus, the total sugar concentration of the honeydew as well as the sugar composition differed significantly between generations.

Age-specific patterns in honeydew production and honeydew composition in the aphid Metopeurum fuscoviride: implications for ant-attendance

The intensity of the mutualistic relationship between aphids and ants depends mainly on the composition and amount of honeydew. We used the model system Tanacetum vulgare– Metopeurum fuscoviride to study age-related differences in honeydew production and composition and its effect on the mutualism between M. fuscoviride and the ant Lasius niger. First and second instar larvae of M. fuscoviride produced only half of the amount of honeydew as older larvae or adults. There were, however, no differences between age classes in the total honeydew sugar concentration, which averaged approx. 80 μg sugar/μl honeydew. Honeydew sugar composition also did not differ between age classes, and melezitose was the dominant sugar (59% in all classes). The amino acid concentration, by contrast, increased significantly with aphid age, reaching 22.6 nmol per μl honeydew in adult M. fuscoviride. This increase was mainly caused by asparagine and glutamine, while there were no differences in the concentrations of the five other regularly detected amino acids and cystine, respectively. The intensity of ant-attendance was significantly lower in colonies of first and second instar larvae than in colonies of older age classes. Ant-attendance correlated with the amount of honeydew produced, and not with the total amino acid concentration.

Host plant and ants influence the honeydew sugar composition of aphids

Summary Honeydew composition is an important factor in mediating ant–homopteran mutualisms. The trisaccharide melezitose is especially significant in this interaction. Honeydew of threeChaitophorusaphids (Homoptera: Aphididae), reared on two species ofPopulus(Salicaceae), was analysed to investigate factors that may influence honeydew composition. Honeydew ofChaitophorus populialbaeandC. populeticontained high proportions of the melezitose. These species are typically tended by ants. In contrast,C. tremulaehoneydew contained low proportions of melezitose. This species is typically untended. Chaitophorus populetiandC. populialbaeproduced higher proportions of melezitose when reared onPopulus tremulathan onP. alba. Chaitophorus populetiandC. populialbaereduced their production of melezitose when reared in the absence of ants. The reverse was true inC. tremulae. These results show that honeydew composition differs not only between aphid species but also within aphid species. They support known differences in ant preference for the different aphid species, and produce further predictions for ant preference for aphids on different host plants. In particular they show for the first time that ant tending may itself influence honeydew composition. They suggest that maintaining a honeydew composition attractive to ants may incur metabolic costs on aphids.

Ant-aphid mutualisms: the impact of honeydew production and honeydew sugar composition on ant preferences.

The honeydew composition and production of four aphid species feeding on Tanacetum vulgare, and mutualistic relationships with the ant Lasius niger were studied. In honeydew of Metopeurum fuscoviride and Brachycaudus cardui, xylose, glucose, fructose, sucrose, maltose, melezitose, and raffinose were detected. The proportion of trisaccharides (melezitose, raffinose) ranged between 20% and 35%. No trisaccharides were found in honeydew of Aphis fabae, and honeydew of Macrosiphoniella tanacetaria consisted of only xylose, glucose and sucrose. M. fuscoviride produced by far the largest amounts of honeydew per time unit (880 μg/aphid per hour), followed by B. cardui (223 μg/aphid per hour), A. fabae (133 μg/aphid per hour) and M. tanacetaria (46 μg/aphid per hour). The qualitative and quantitative honeydew production of the aphid species corresponded well with the observed attendance by L. niger. L. niger workers preferred trisaccharides over disaccharides and monosaccharides when these sugars were offered in choice tests. The results are consistent with the ants' preference for M. fuscoviride, which produced the largest amount of honeydew including a considerable proportion of the trisaccharides melezitose and raffinose. The preference of L. niger for B. cardui over A. fabae, both producing similar amounts of honeydew, may be explained by the presence of trisaccharides and the higher total sugar concentration in B. cardui honeydew. M. tanacetaria, which produced only low quantities of honeydew with no trisaccharides was not attended at all by L. niger.

Homopteran honeydew sugar composition is determined by both the insect and plant species

1. 1. The sugar content of honeydew from three species of whitefly (Aleyrodidae) and four species of aphid (Aphididae) was determined by high performance liquid chromatography. 2. 2. More than 20% of the sugar in honeydew from the whitefly Bemisia tabaci was found to be oligomers larger than disaccharides. 3. 3. Honeydew from two species of the whitefly genus Trialeurodes contained more than 20% turanose. 4. 4. It was established that the insect species is important in determining the sugar composition of homoptera honeydew.

Claviceps africana sp. nov.; the distinctive ergot pathogen of sorghum in Africa

Stromata arising from ergot sclerotia from sorghum in Zimbabwe were different in colour and texture from those of Claviceps sorghi from sorghum in India, compounding other differences in the dynamics of the early stages of parasitism, the sugar composition of honeydew, the quantitative expression of secondary conidiation and the morphology of sclerotia. The distinctive sexual stage forms the basis of describing the African material as a new Claviceps species which also uniquely elaborates a group of dihydrogenated ergot alkaloids that are biosynthetic intermediates leading to the principal product dihydroergosine.