Ten ant species (Hymenoptera: Formicidae) from three subfamilies feed on honeydew excreted by nymphs of the leafhopper Balclutha punctata (Hemiptera: Cicadellidae). This relationship is facultative for the partners. Preliminary field observations suggest a mutualistic interaction that represents an intermediate stage in the spectrum of formicid-hemipteran mutualisms. Behavioural adaptations of the leafhopper (no escape reaction) and the ants (no predation of leafhoppers, protection from spiders) are evident, but characters of advanced facultative mutualism such as physical contact between the partners or ant-triggered excretion of honeydew were not observed.
The influence of cucumber offered as a host plant either alone or with Aphis gossypii Glover (Hemiptera: Aphididae) was studied on the various life table and biological characteristics of the predatory bug Macrolophus pygmaeus Rambur (Hemiptera: Miridae). The nymphal development was studied at 15, 20, 25, 30 and 35°C while adult performance was assessed at 15, 20, 25 and 30°C, using a 16L : 8D photoperiod and 65 ± 5% r.h. Nymphs completed their development at all temperatures except at 35°C. Nymphal development took significantly longer time in the absence than in the presence of prey at 20 and 25°C, but the reverse was true at 15°C. Nymphal mortality was highest at 15°C in the presence of prey and it was mainly recorded at the first and second stages. Females oviposited a small number of eggs at all temperatures but not at 30°C in the absence of prey. The average number of eggs per female was almost similar with or without prey, being highest at 20°C, and adult longevity was highest at 15°C. The results concerning population parameters clearly showed that cucumber with or without prey can not support a population increase of M. pygmaeus. However, it seems that A. gossypii on cucumber inhibits development of M. pygmaeus more than when this aphid species is not present. This adverse effect on this host plant-prey system possibly results from the particular aphid genotype on cucumber, leading to high nymphal mortality, reduced fecundity and short adult life-span of M. pygmaeus.
Plant chemical composition is an important determinant of host plant-insect interactions. For many insects sugars are the main factors determining the acceptability of a plant. This study investigated changes in plant chemical composition and differences in sugar composition of different host plants induced by the feeding of Coccus hesperidum L. (Hemiptera: Sternorrhyncha: Coccoidea). Present in plant extracts and honeydew there were three monosaccharide sugars: glucose, fructose and arabinose, and one disaccharide - sucrose. Arabinose was only found in extracts of Ficus benjamina plants. The sugar content of the honeydew was greater than in the extracts of control plants and lower than that in the extracts of infested plants. The honeydew collected from C. hesperidum feeding on the three plant species differed significantly in sugar content. Extracts of coccid infested plants of the three species used in this study contained more sugar than the un-infested control plants. The results show that honeydew composition of scale insects differ and the differences reflect the chemical composition of the host plants. and Katarzyna Golan, Agnieszka Najda.
The aphid Tuberculatus quercicola (Matsumura), a non host-alternating species, lives on Daimyo oak, Quercus dentata Thumberg, and other species of oak. In summer there was a significant reduction in the total amino acid concentration in phloem sap of the host plant and fecundity of the aphids. There are two phenotypes of Q. dentata: one produces flush leaves in mid-July and the other does not. This study investigates the effect of the flush leaves produced by Q. dentata in summer on the density, fecundity and honeydew excretion by T. quercicola. Of 20 shoots on each of the study trees, 6-13 (average 8.8 shoots) produced secondary shoots with flush leaves. The number of aphids on flush leaves sharply increased by two-fold compared to that on mature leaves. The aphids reared on flush leaves were significantly larger and had a larger embryo number compared to those on mature leaves. These results suggest that the phloem sap of flush leaves has a high nutritive quality for aphids. However, in mid-summer and early autumn T. quercicola went into reproductive diapause regardless of whether it was reared on flush or mature leaves. Aphid colonies persisted until October even on trees that did not produce secondary leaves. These observations suggest that this aphid does not depend on secondary leaf production. Thus, the use of flush leaves does not enable T. quercicola to avoid nutritional stress in summer and the need for reproductive diapause.
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.
Host-plant mediation in ant-hemipteran mutualisms requires three conditions. First, hemipteran attractiveness to ants should vary with plant quality. Second, ants should preferentially tend those Hemiptera that produce the most nutritious attractant. Third, increased ant attendance based on a richer food reward should have a significant effect on some measure of hemipteran fitness. A field experiment is used to test these conditions. This is the first study to simultaneously test these three conditions, and the first to test the effect of plant flowering status on the ant-derived benefits for a honeydew-producing hemipteran. It is hypothesized that membracids (Guayaquila xiphias) feeding on plants (Didymopanax vinosum) with flowers ingest phloem sap of higher quality (higher sugar concentration), produce a higher-quality honeydew and, as a result, are attended by more ants and are better protected compared to those on plants without flowers. Total nitrogen content of the phloem sap of plants with or without flowers did not differ significantly, whereas the sugar concentration was higher in the sap of plants with flowers. Honeydew sugar concentration, honeydew production, and ant tending levels did not vary significantly with flowering status. Membracid survival increased, and natural enemy abundance decreased when ants were present. Plant flowering status did not affect the ant-derived protection afforded to treehoppers, but plants with flowers accumulated more natural enemies through time than plants without flowers. The results suggest that a trade-off between feeding on a higher-quality food and running increased risk of predation on flowering plants could underlie this ant-hemipteran interaction. Based on the parameters measured in this study it is concluded that host-plant mediation does not occur in the ant-Guayaquila system. The results suggest, however, that the way in which the host-plant could affect ant-Guayaquila interactions is complex and likely to involve other species.
1_The arboricolous dolichoderine ant Liometopum microcephalum (Panzer, 1798) is considered to be mainly predatory, although there are some reports of it tending aphids. The main objective of the present study was to confirm that this ant has a trophobiotic relationship with aphids and assess seasonal differences in its utilization of honeydew. We hypothesized that the worker ants on trees where they have their nest (nest tree) and trees where they are foraging (foraging trees) should differ in gaster mass and sugar content depending on their direction of movement, and that both should be highest in spring. From spring to summer 2009, ascending and descending workers were collected from nest and foraging trees at a locality in South Moravia, Czech Republic. Mass of their gasters and their content of total and reducing sugars were measured using chemical (photometric) methods. Differences in gaster mass confirmed the flow of liquid food from foraging to nest trees, but there were no significant between-month differences. Contents of total and reducing sugars were positively correlated with gaster mass. The gasters of workers descending from foraging trees contained significantly more reducing sugars than those of workers descending or ascending nest trees. The content of reducing sugars was lowest at the beginning of the ants’ activity period in April and highest in June, with a non-significant drop in July. Results for total sugars were similar, with the decrease in July being significant. The concentration of sugars in the gasters of workers ascending and descending nest trees did not differ significantly but the absolute content of total sugars was higher in the gasters of ascending ants., 2_Results from foraging trees confirmed that the ants collected the honeydew from these trees. Possible reasons for the ambigous results for nest trees are discussed. We conclude that trophobiosis is an important component of the nutritional biology of L. microcephalum., Jiří Schlaghamerský ... []., and Obsahuje seznam literatury