Alder Leaf Beetle Research Articles

Feeding of leaf beetle to two species of alder grown under two different soils in a free-air CO2 enrichment

ABSTRACT The effects of elevated CO2 concentration on the defensive ability of two Alnus species (A. maximowiczii, A. hirsuta) against herbivory attacks (alder leaf beetle; Agelastica coerulea) were investigated using a free-air CO2 enrichment. Elevated CO2 significantly affected consumed leaf area index (CLI) of A. maximowiczii but soil fertility did not, while more significant effects on CLI of A. hirsuta were found in both CO2 and soil fertility. As found in natural conditions, A. hirsuta was grazed five times more than A. maximowiczii in both CO2 levels, which was explained with the low condensed tannin (CT) concentration of the leaves. The value of leaf mass per area in fertile soil was 10 g m−2 lower than that in infertile soil under ambient CO2 in July. Leaf C/N ratio was not affected by elevated CO2 for both species but that of A. hirsuta was little higher in infertile soil when compared to fertile soil in July. CT of A. maximowiczii tended to increase in September under elevated CO2. CT of A. hirsuta was higher in infertile soil than in fertile soil in July and showed an overall decrease in September compared to July. Nitrogen-fixing activity by a nodule of Frankia sp. on A. maximowiczii was higher in elevated CO2 treatments than in ambient CO2 independent of soil fertility. As a result of changes in these parameters, except for fertile soil, the peak of the herbivorous damage was later in elevated CO2 for the Alnus species than in the control.

Resistance and Resilience of Hyrcanian Mixed Forests Under Natural and Anthropogenic Disturbances

Biological disturbances are integral to forest ecosystems and have pronounced effects on forest resistance, resilience, and diversity. The Hyrcanian mixed forest, in northern Iran, is at risk of declining resistance, resilience, and diversity due to ongoing pressure from land use change, harvesting, and biological disturbances. We analyzed the resistance and resilience of this area under two biological disturbances (i.e., oak charcoal fungus, Biscogniauxia mediterranea, and alder leaf beetle, Galerucella lineola) and in concert with proposed harvesting. We used a simulation modeling approach whereby we simulated 12 combinations of biological disturbances and harvesting scenarios using the LANDIS-II landscape change model. We estimated the correlation between forest resistance and resilience and tree species diversity to harvesting and biological disturbance. We analyzed the full species composition and age class for 30 and 100 years after disturbances in order to assess resistance as the change in species composition over time. We considered resilience as the ability to recover from a disturbance back to a similar initial state. Results indicate a positive effect of biological disturbances and harvesting on diversity. Our simulations resulted in a negative relationship between diversity-resistance and diversity-resilience within high diversity areas. Our simulation of the Hyrcanian forest reveals that harvesting and biological disturbances, as tested, fulfill the goal of maintaining forest diversity. However, increasing diversity does not always follow by increasing forest resistance and resilience. Scenarios with oak charcoal fungus, both with and without harvesting indicate the lowest decrease in resilient and resistant.

Food Resource Sharing of Alder Leaf Beetle Specialists (Coleoptera: Chrysomelidae) as Potential Insect-Plant Interface for Horizontal Transmission of Endosymbionts.

Recent studies suggest that endosymbionts of herbivore insects can be horizontally transferred to other herbivores feeding on the same host plants, whereby the plant acts as an intermediate stage in the chain of transmission. If this mechanism operates, it is also expected that insect communities sharing the same host plant will have higher chances to share their endosymbionts. In this study, we use a high-throughput 16S rRNA metabarcoding approach to investigate the presence, diversity, and potential sharing of endosymbionts in several species of leaf beetles (Coleoptera: Chrysomelidae) of a local community specialized on an alder diet in North America. Rickettsia and Wolbachia were predominant in the sample, with strong evidence for each species having their own dominant infection, of either or both types of bacteria. However, all species shared a much lower proportion of a particular Wolbachia type, compatible with the same strain dominant in one of the species of leaf beetles. Crucially, the same 16S rRNA haplotype of Wolbachia was found on alder leaf extracts. The combined evidence and the absence of this strain in a syntopic species of leaf beetle feeding on a different host plant support the hypothesis that at least the initial stages of the mechanism that would allow horizontal transmission of endosymbionts across species feeding on the same plant is possible. The accessibility and characteristics of endosymbiont associations of this system make it suitable for deeper analyses of their diversity and transmission in natural conditions.

Diet-mediated modulation on the development and phenoloxidase activity in the Alder leaf beetle larvae, Agelastica alni (L., 1758) (Coleoptera: Chrysomelidae)

Food-induced changes in the phenoloxidase activity and development of Agelastica alni (L.,1758) (Coleoptera: Chrysomelidae) larvae reared on unbalanced artificial diets were examined. The study was conducted between 2015- 2016. Food quality had an impact on the phenoloxidase activity and growth performance of alder leaf beetle. The maximum pupal mass was recorded in the 0.5:1 P:C (protein:carbohydrate) diet and the minimum pupal mass was recorded from the larvae fed on the 3:1 P:C diet. The amount of carbohydrate consumed affected the pupal mass positively, whereas the amount of protein consumed negatively affected the pupal mass. The highest amount of pupal lipid was found in the 0.5:1 P:C diet and the lowest pupal lipid amount in the 1:3 P:C diet. Also, imbalance diets affected phenoloxidase activity. There was a positive relationship between P ratio of the diet and phenoloxidase activity. Phenoloxidase activity decreases as the amount of carbohydrate consumed by larvae increases. As a result, unbalanced diet affects the immune system of larvae. Carbohydrate also has a significant effect on immune defenses as much as protein. In addition, larvae increase their body size with excessive consumption of carbohydrate.

The Effect of Nutrient-Allelochemicals Interaction on Food Consumption and Growth Performance of Alder Leaf Beetle, Agelastica alni L. (Coleoptera: Chrysomelidae)

In this study, the effects of secondary metabolites on the feeding preference and growth of generalist caterpillars, Agelastica alni L., were investigated. Feeding experiment has been applied with a total of 11 diet; 6 of which were prepared by adding different concentrations of gallic acid (1, 3, 5 %) and quinine (0.125, 0.25, 0.5 %) to the control diet, 3 diet of which prepared by adding different concentrations of gallic acid and quinine. According to the results, the amount of gallic acid consumed did not affect the food consumption and the amount of pupa lipids. However, the amount of gallic acid consumed positively affects the pupal mass and the pupal crude protein. In addition, the amount of quinine consumed negatively affected the developmental performance of larvae except for the food consumption. As the count of secondary metabolites in the diet increases, the pupal mass and the pupal crude protein decrease. Overall, during the co-evolution processs, A. alni larvae may be able to adapt to gallotannins. However, quinine, an alkaloid, is a feeding deterrence and growth suppressor for larvae.

Efficacy of native entomopathogenic nematodes from Turkey against the alder leaf beetle, Agelastica alni L. (Coleoptera: Chrysomelidae), under laboratory conditions

The alder leaf beetle, Agelastica alni L. (Coleoptera: Chrysomelidae), is one of the most defoliator pests of oak and alder trees. In the present study, the efficacies of three native strains of entomopathogenic nematodes, Heterorhabditis bacteriophora (ZET35), Steinernema feltiae (ZET31), and Steinernema websteri (AS-1), were tested against pre-pupae and adults of A. alni. Experiments were conducted by four concentrations under laboratory conditions in 2015. Four different temperature regimes were tested at concentration of 1000 infective juveniles (IJs)/ml under laboratory conditions. It was observed that pre-pupae were more sensitive than adults in all tests. Based on screening tests, S. websteri was the most effective isolate on both pre-pupae and adults of A. alni at concentration of 1000 IJs/ml with 79.17 and 71.11% mortality, respectively. It caused the highest mortality values at all temperatures, except for 30 °C against pre-pupae and adults. Results of the present study suggested that S. websteri and H. bacteriophora had significant potentials against A. alni.

A new biopesticide from a local Bacillus thuringiensis var. tenebrionis (Xd3) against alder leaf beetle (Coleoptera: Chrysomelidae).

Use of chemical pesticides in agriculture harms humans, non-target organisms and environments, and causes increase resistance against chemicals. In order to develop an effective bio-pesticide against coleopterans, particularly against Agelastica alni (Coleoptera: Chrysomelidae) which is one of the serious pests of alder leaf and hazelnut, we tested the insecticidal effect of 21 Bacillus isolates against the larvae and adults of the pest. Bacillus thuringiensis var. tenebrionis-Xd3 (Btt-Xd3) showed the highest insecticidal effect based on screening tests. For toxin protein production and high sporulation of Xd3, the most suitable medium, pH and temperature conditions were determined as nutrient broth medium enriched with salts, pH 7 and 30 °C, respectively. Sporulated Btt-Xd3 in nutrient broth medium enriched with salts transferred to fermentation medium containing soybean flour, glucose and salts. After fermentation, the mixture was dried in a spray dryer, and spore count of the powder product was determined as 1.6 × 1010c.f.u.g-1. Moisture content, suspensibility and wettability of the formulation were determined as 8.3, 86% and 21s, respectively. Lethal concentrations (LC50) of formulated Btt-Xd3 were determined as 0.15 × 105c.f.u.ml-1 for larvae at laboratory conditions. LC50 values were also determined as 0.45 × 106c.f.u.ml-1 at the field condition on larval stage. Our results showed that a new bio-pesticide developed from B. thuringiensis tenebrionis (Xd3) (Btt-Xd3) may be valuable as a biological control agent for coleopteran pests.

How to Spoil the Taste of Insect Prey? A Novel Feeding Deterrent against Ants Released by Larvae of the Alder Leaf Beetle, Agelastica alni

Chemical defense of leaf beetle larvae (Chrysomelidae) against enemies is provided by secretions containing a wide range of deterrent compounds or by unpalatable hemolymph constituents. Here we report a new, very strong feeding deterrent against ants released by larvae of the alder leaf beetle Agelastica alni when attacked. The larvae release a defensive fluid from openings of pairwise, dorsolaterally located tubercles on the first to the eighth abdominal segments. The fluid, consisting of hemolymph and probably a glandular cell secretion, has previously been shown to contain a very stable, non-volatile feeding deterrent. The major deterrent component was isolated by repeated HPLC separation and analyzed by NMR and MS. The compound proved to be gamma-L-glutamyl-L-2-furylalanine (1), a novel dipeptide containing the unusual amino acid L-2-furylalanine. This amino acid, although synthetically well known, has not previously been reported from natural sources. The absolute configuration of the natural compound was elucidated by enantioselective gas chromatography after derivatization. The structure of the dipeptide was verified by the synthesis of several isomeric dipeptides. In bioassays a concentration of 1 microg microL(-1) was sufficient to deter polyphagous Myrmica rubra ants from feeding.

Insecticidal effects of some biological agents on Agelastica alni (Coleoptera: Chrysomelidae)

The alder leaf beetle (Agelastica alni L., Coleoptera: Chrysomelidae) causes approximately 10% of total economic damage to hazelnut product per year in Turkey. A. alni larvae are susceptible to several pathogens indigenous to the area in which these insects occur in Turkey. In the present study, in order to find a more effective and safer biological control agent against this common pest, we evaluated the various biological agents’ insecticidal activity during the four hazelnut seasons from 2002 to 2005 on the larvae of the alder leaf beetle collected from the vicinity of Trabzon, Turkey. The tested agents are 25 insect-originating bacteria, 2 bacterial toxins and 1 viral preparation. The results showed that the highest insecticidal activity was obtained by bacterial isolates at 1.8 × 109 bacteria/mL dose, within ten days on the larvae of A. alni. These are 90% for Bacillus thuringiensis biovar tenebrionis (4AA1), Bacillus sphaericus (Ar4, isolated from Anoplus roboris L., Col.: Curculionidae), and Bacillus thuringiensis (Mm2, isolated from Melolontha melolontha L., Col.: Scarabaeidae). Our results indicate that these isolates may be valuable as biological control agent.

The biopesticide market for global agricultural use

The biopesticide market for global agricultural use

Energy metabolism and metabolic rate of the alder leaf beetle Agelastica alni (L.) (Coleoptera, Chrysomelidae) under aerobic and anaerobic conditions: a microcalorimetric study

In early fall, adult alder leaf beetles (Agelastica alni L.) retreat, for overwintering, to the top layer of the soil near their forage trees where the ground gets easily waterlogged so that the beetles will be submerged and cut off from atmospheric oxygen. Hence, unlike most other adult insects, alder leaf beetles encounter hypoxia/anoxia in their natural habitat and this may occur at moderate temperature. Exposing beetles to pure nitrogen gas at 20°C had similar behavioral and metabolic effects as submerging them in water, causing rapid immobility and increasing the content of lactate about sevenfold to some 5μmolg−1 body weight during 10h anoxia. Recovery from 10 h hypoxia/anoxia in pure nitrogen was complete within about 90min.Hypoxia/anoxia triggered a marked decrease in metabolic activity in the beetles (microcalorimetry at 21.7°C) as indicated by a precipitous drop in their heat flow rate, from 1.39±0.27 to 0.08±0.04mWg−1 body weight, i.e. by about 94%, when the flow of gas through the calorimeter was switched from air to pure nitrogen. Post-anoxic recovery was accompanied by a peak in heat flow rate that exceeded the basal normoxic rate by about 50%. The homoeostasis of adenine nucleotides in Agelastica is lost when oxygen is wanting. Submergence at 15°C for three days caused a dramatic fall in ATP, to less than 2% of the normoxic value, and a marked increase in AMP, while the total contents of adenine nucleotides decreased by almost two-thirds. Reduced metabolic activity, combined with the capacity to regenerate ATP after readmission of air, is regarded as a key factor for surviving transient lack of oxygen in alder leaf beetles.

Defoliation of alders (Alnus glutinosa) affects herbivory by leaf beetles on undamaged neighbours.

The effects of defoliation of alder (Alnus glutinosa) on subsequent herbivory by alder leaf beetle (Agelastica alni) were studied in ten alder stands in northern Germany. At each site, one tree was manually defoliated (c. 20% of total foliage) to simulate herbivory. Subsequent damage by A. alni was assessed on ten alders at each site on six different dates from May to September 1994. After defoliation, herbivory by A. alni increased with distance from the defoliated tree. Laboratory experiments supported the field results. Not only leaf damage in the field, but also the extent of leaf consumption in laboratory feeding-preference tests and the number of eggs oviposited per leaf in another laboratory test were positively correlated with distance from the defoliated tree. Resistance was therefore induced not only in defoliated alders, but also in their undamaged neighbours. Consequently, defoliation of alders may trigger interplant resistance transfer, and therefore reduce herbivory in whole alder stands.

Identification of Volatiles Responsive to the Alder Leaf Beetle ( Agelastica coerulea) from its Host Plant, the Japanese Alder ( Alnus glutinosa)

Electroantennography (EAG) and gas chromatography coupled with electroantenno-graphic detection (GC-EAD) were used to identify volatiles from Alnus glutinosa attractive to Agelastica coerulea. Seven compounds (3-cyclohexene-1-methanol, 2-cyclohexen-1-ol, 5-methyl-2-(1-methylethyl)-cyclohexanol, 5-alpha-androstan-17-beta-ol, 3-ethyl-3-hydroxy-androstan-17-one, (Z)-2-(9-octadecenyloxy)-ethanol, and hexadecanoic acid) showed responsiveness to the antenna of A. coerulea. In bioassays, adults and larvae of A. coerulea were attracted to volatiles from A. glutinosa.

Primary and secondary host plants differ in leaf-level photosynthetic response to herbivory: evidence from Alnus and Betula grazed by the alder beetle, Agelastica alni.

Field-grown trees of Alnus incana (L.) Moench, Alnus glutinosa (L.) Geartner and Betula pendula Roth displayed pronounced differences in responses of light-saturated net photosynthesis (Asat ) to herbivory by the alder beetle (Agelastica alni L., Galerucinae), a specialized insect which primarily defoliates alders. We found that photosynthetic rates of grazed leaves increased following herbivory in Alnus but not in Betula. Area- and mass-based Asat of grazed leaves declined linearly with increasing amount of leaf perforation in B. pendula, by as much as 57%. By contrast Alnus glutinosa and Alnus incana increased area-based rates of Asat by 10-50% at all levels of leaf grazing. Given increased Asat in the remaining portion of grazed leaves, a net reduction in photosynthesis per leaf occurred only when the proportion of leaf area grazed exceeded 40% for Alnus incana and 23% for Alnus glutinosa. Since vein perforation by Agelastica alni was observed much more frequently in leaves of Betula than in Alnus, we hypothesized that declining Asat in herbivorized Betula was related to this disruption of water transport. A field experiment with artificial leaf perforation demonstrated a greater decline in Asat in vein-perforated Betula leaves than perforated leaves with midrib veins intact. However, regardless of leaf perforation regime, birch never showed post-perforation increases in Asat . In all species, rates of transpiration of grazed leaves linearly increased and water-use efficiency decreased with increased amount of leaf perforation. In grazed Alnus incana leaves, increasing leaf area consumption by Agelastica alni resulted in an increase of total phenols, a reduction in starch content and no changes in nitrogen concentration in the remaining portion. The increase in photosynthesis in Alnus incana might be related to declining leaf starch concentration or increasing stomatal conductance, but was unrelated to leaf nitrogen concentration. These gas exchange and leaf chemistry measurements suggest that in contrast to B. pendula, Alnus incana and Alnus glutinosa, which are the major host species for Agelastica alni, possess leaf-level physiological adaptations and defence mechanisms which can attenuate negative effects of herbivory by the alder leaf-beetle.