Host plant dispersion, leaf hopper movement and disease transmission

Abstract.

• 1 The plant-to-plant movement of the corn leafhopper, Dalbulus maidis Delong & Wolcott, and the spread of the leafhopper-borne maize rayado fino virus were investigated in four patterns of maize (Zea mays) dispersion.
• 2 D. maidis was less abundant and the spread of the virus was slower in dense stands of maize than in sparse stands.
• 3 When plant density was held constant, leafhoppers were more abundant in maize stands with relatively equidistant plant spacing (uniform dispersion) than in stands with densely-sown rows (linear dispersion) or double-sown hills (clumped dispersion), but there was no difference in virus incidence among these plant dispersion patterns.
• 4 Leafhoppers were less likely to move to adjacent plants in uniform plant dispersion patterns than in either linear or clumped dispersion patterns. This result may explain the lack of higher virus incidence in uniform stands, despite higher leafhopper abundance.
• 5 Leafhopper movement was consistent with a simple rule: the shorter the distance to the next adjacent plant, the more likely a leafhopper is to move between plants.
• 6 These results demonstrate that host plant dispersion can affect the abundance and behaviour of highly mobile herbivorous insects even when plant density is constant.

     

南美斑潜蝇寄主选择性与植物次生化合物及叶毛的关系

采用非自由选择法,以刺伤孔（包括取食孔和产卵孔）数为指标,在室内测定了南美斑潜蝇对6科、16种、22个蔬菜品种的寄主选择性。结果表明,南美斑潜蝇对供试蔬菜品种的选择性存在显著差异,选择性大小依次为豆科>菊科>葫芦科>茄科>伞形科>十字花科; 菜豆和茼蒿是南美斑潜蝇最喜欢产卵和取食的寄主,而甘蓝和番茄是其选择性最差的寄主。化学分析和解剖镜观察表明,叶片单宁酸、黄酮含量及叶毛密度在供试品种间存在显著差异： 苦瓜的单宁酸含量最高,其次为豌豆、番茄和青椒,含量最低的为金丝搅瓜、茼蒿、菜豆和美国西芹; 黄酮含量最高的为甘蓝和番茄,其次为苦瓜,最低为茼蒿、菜豆和美国西芹; 南瓜和小白菜的叶毛密度最高,其次为西葫芦、金丝搅瓜和甘蓝,最低为青椒、莴苣和苦瓜。相关分析表明,南美斑潜蝇寄主选择性与叶片单宁酸和黄酮含量呈显著的负相关关系,相关系数分别为-0.4425（ P=0.0392）和 -0.5728（ P=0.0053）,而与叶毛密度相关关系不显著（ R＝-0.1807,P=0.4211）。说明黄酮和单宁酸对南美斑潜蝇产卵和取食具有明显的抑制作用。     

The influence of host plant diversity and food quality on larval survival of plant feeding heteropteran bugs

Abstract. 1. In a laboratory experiment, the influence of host plant diversity and food quality, in terms of nitrogen content, on the larval survival of two oligophagous bug species (Heteroptera, Miridae: Leptopterna dolobrata L., Notostira erratica L.) was investigated. Both species are strictly phytophagous and capable of feeding on a wide range of grass species. Moreover, they typically change their host plants during ontogenesis; it has been suggested that this behaviour is a response to the changing protein content of the hosts.
2. To investigate the importance of host plant diversity for these insects, the development of insects reared on grass monocultures was compared with that on mixtures of four grass species. In addition, the host grasses were grown under two nitrogen regimes to test whether nitrogen content is the key factor determining host plant switching.
3. Both species had a significantly higher survival rate when feeding on several host plants but only L. dolobrata showed a significant response to food nitrogen content. Furthermore, there was no correlation between the nitrogen content of the host plants and the survival rate of N. erratica larvae.
4. The study suggests that at least some Stenodemini need a variety of host plants during larval development but that the level of host plant nitrogen is not the main factor responsible for the observed diversity effect.     

Factors determining the host plant range of the phytophagous mite, Tetranychus urticae (Acari: Tetranychidae): a method for quantifying host plant acceptance

The host plant acceptance of the phytophagous mite Tetranychus urticae was experimentally quantified. Host plant acceptance is described as the proportion of adult females settling on the test plant on which they have been placed. On the other hand, the host plant suitability of T. urticae on different plant species is expressed as the mean number of eggs produced by the females within 5 days (hereafter 'fecundity'). An inbred T. urticae line was tested with regard to host plant acceptance and fecundity on 11 potential host plants. These two variables were positively correlated across host plants; host plant species on which the fecundity was low were also those on which females settled less readily compared to host plants with high fecundity. The characteristics of host plant acceptance of the T. urticae are discussed in light of their potential food resource under natural conditions.     

The evolution of diet breadth: Monophagy and polyphagy in swallowtail butterflies

Much of the world's biodiversity has resulted from specialization of insect populations onto different plant species, partially through evolution of preference in ovipositing females. Here I report an experimental analysis of how an oviposition preference hierarchy has evolved during the evolutionary diversification of an insect group to produce taxa ranging from monophagous to polyphagous. Tests on the Papilio machaon group of swallowtail butterflies show that the preference hierarchy for plant species is evolutionarily dynamic within this species complex, yet constrained among most populations within species, creating a geographic mosaic of populations differing to various degrees in patterns of host preference. The results indicate that different diet breadths can evolve within a group of closely-related species through a combination of conservatism in preference hierarchy among some populations, occasional but rare rearrangements in preference among others, correlations in preference for some plant species, and availability of similarly ranked hosts.     

Instar duration, adult consumption, oviposition and nitrogen utilization efficiencies of leafhoppers feeding on different quality food (Auchenorrhyncha: Homoptera)

Abstract. 1. Plant material of Holcus lanatus L. removed from an artificially fertilized trial was used to rear leafhoppers of three feeding types: Dicrano-tropis hamata Boheman and Ebmana sulphurella Zetterstedt, (phloem feeders), Eucelis incisus Kirschbaum (xylem feeder) and Zyginidia scutellaris Herrich-Schaeffer (mesophyll feeder).
2. In the laboratory, leafhopper instar durations, adult consumption rate, oviposition rate, and nitrogen utilization efficiency were influenced by the quality of the food consumed. Adult longevity was unaffected by the level of food quality normally found in plants.
3. Z.scutellanis consumed mesophyll contents equivalent to 72% of its body weight each day but only digested about 30% of its intake. Eincicus had a low dry weight consumption rate (12% body weight/day) but digested its food more efficiently (60%) than the other feeding types. The two phloem feeders consumed mounts equivalent to 25% of their body weight each day and digested 40–50% of their intake.
4. Each species reached maximum nitrogen utilization efficiencies at different plant nitrogen levels. This suggests that leafhopper species may be associated with a particular nitrogen concentration in the grasses.     

Vector-pathogen-host plant relationships of chrysanthemum yellows (CY) phytoplasma and the vector leafhoppers Macrosteles quadripunctulatus and Euscelidius variegatus

Chrysanthemum yellows (CY) phytoplasma is a plant-pathogenic mollicutes belonging to the 16Sr-IB genetic group which infects a variety of dicotyledonous plants and is transmitted in nature by some species of Cicadellidae Deltocephalinae. The transmission characteristics of CY and the factors influencing the vector efficiencies of the leafhoppers Macrosteles quadripunctulatus Kirschbaum and Euscelidius variegatus Kirschbaum are described in the present study using transmission experiments and phytoplasma-specific polymerase chain reaction (PCR) assays. Vector insects were allowed to acquire CY under different experimental conditions and then transferred to healthy test plants for inoculation and/or sampled for DNA extraction and amplification. The transmission efficiency of CY was very high and almost all the leafhoppers became infective following acquisition on CY-infected daisies. The latent period in the vector ranged from 16 to 20 days after the start of the acquisition and infectivity lasted, in general, for life. The PCR assay was successful in detecting CY phytoplasmas in the insects well before they became infective (5 versus 16–18 days) and was used to estimate the proportion of infective insects. When analysed for CY presence by PCR, all the leafhoppers fed for 7–18 days on source daisy reacted positively while, following one day of acquisition, some insects failed to provide amplification. Host-plant species influenced CY acquisition, and daisy appeared a more efficient source for both leafhoppers compared to periwinkle. Life stage did not appear to be critical for CY acquisition, although newly-hatched nymphs of E. variegatus acquired CY less efficiently than fifth instar nymphs.     

Influence of feeding guild on insect response to host plant fertilization

Abstract.

• 1 The densities of insect herbivores in fertilized and unfertilized field plots of goldenrods, Solidago altissima (Compositae), were monitored over a period of 4 years.
• 2 A total of seventeen insect taxa occurred on the plots over the course of the study, including sap feeders, leaf chewers, leaf miners, leaf gallers and stem gallers with multiple representatives in each of these feeding guilds.
• 3 Nine of the seventeen taxa significantly increased in density on fertilized plots in at least one year of the study, two taxa showed marginally significant increases on fertilized plots, two significantly decreased in density on fertilized plots in at least one year, and the remaining taxa were unaffected by the fertilizer treatment.
• 4 The effects of fertilization on the insects were not strongly related to feeding guild; the group of insects that increased on fertilized plots was functionally diverse, and for the most part members of the same guild did not respond to the fertilizer treatment in consistent ways.
• 5 Differences between fertilized and unfertilized plots were greatest in the fourth year. The insects that showed delayed responses to fertilizer treatment may have been affected by changes in microclimate that developed slowly over the course of the study, suggesting that long-term studies may be necessary to detect effects of host plant stress on insect herbivores.

     

Trichome‐based host plant resistance of Lycopersicon species and the biocontrol agent Mallada signata: are they compatible?

Trichome‐based host plant resistance of Lycopersicon (Solanaceae) species offers the potential to reduce pesticide use in tomato production, but its compatibility with biocontrol agents is largely unknown. The effect of trichome‐based host plant resistance on the lacewing biocontrol agent, Mallada signata, was assessed for five accessions of L. cheesmanii, four accessions of Lycopersicon hirsutum, two accessions of Lycopersicon pennellii, and one Lycopersicon esculentum cultivar. An intact leaf was isolated from the whole plant using Tangletrap to coat the petiole and 20 green peach aphids [Myzus persicae (Sulzer) (Homoptera: Aphididae)] were placed on the leaf surface. After 24 h, 10 lacewings were placed on the leaf. The numbers of dead, trapped by exudates, untrapped and predated lacewings and aphids, and the numbers that had left the leaf were recorded a further 24 h later. Differences in insect designations between accessions were analysed using ANOVA. A General Linear Model (GLM), consisting of the densities of each trichome type and leaf area, was fitted to the data to determine the role of trichomes on the observed effects on lacewings and aphids. Lacewing mortality was greater on one accession of L. pennellii and one accession of L. hirsutum than on L. esculentum. The GLM indicated that type IV trichomes decreased the numbers of aphids predated, and increased cannibalism and, along with type III trichomes, increased entrapment‐related predator mortality. Although there were no differences in the numbers of predated aphids, with the majority predated for all accessions, the compatibility of trichome‐based host plant resistance of Lycopersicon species and the biocontrol of aphids by lacewings is questionable.     

Temporal host plant use in three polyphagous Heliothinae,with special reference to Helicoverpa punctigera (Wallengren) (Noctuidae: Lepidoptera)

Abstract Potential host plants of the polyphagous lepidopteran Helicoverpa punctigera (Wallengren) were surveyed in two ways. A broad survey, conducted in southern Queensland and northern New South Wales, indicated that H. punctigera larvae were present on relatively few plant species. A detailed survey of host plant use in a non-cropping area in which H. punctigera was numerous demonstrated restricted host plant use by this species. The density of H. punctigera on its principal host in the area, the indigenous daisy Ixiolaena brevicompta F. Muell., was much higher (as measured per unit of time searched) than on other plant species available. Also, I. brevicompta was used regularly by H. punctigera after rainfall events. Ixiolaena brevicompta represents a new host record and on the basis of the pattern of its use by H. punctigera should be considered a ‘primary host plant’ of this noctuid. In cropping areas sampled, usually more than one plant species hosted H. punctigera regularly and in large numbers. Usually a crop species was included (e.g. cotton and chick pea). Alternative hosts in cropping areas were Sonchus oleraceus L. (sowthistle) and possibly the native legume Sesbania cannabina (Retz.) Poiret. Our results imply that the polyphagy of H. punctigera is probably not as extensive as previously claimed. The criteria for inclusion of a plant species as a primary host for H. punctigera need to include the regularity of use of that species and the relative abundance of eggs and larvae on it. We suggest that an understanding of the host-searching mechanism of this species will be best achieved through study of the interaction of H. punctigera with its indigenous primary hosts. The surveys also yielded information on host plants of two other heliothine noctuids, H. armigera (Hübner) and Australothis rubrescens (Walker), and this is also presented.     

寄主植物-蚜虫-天敌三重营养关系的化学生态学研究进展

综述了寄主植物－蚜虫－天敌三重营养关系的化学生态学研究,重点阐述了3个研究热点：①植物挥发性物质在蚜虫及其天敌选择寄主行为过程中的作用;②蚜虫信息素和蜜露对蚜虫天敌寄主选择行为的影响;③植物挥发性物质对蚜虫信息系作用的影响。对寄主植物－蚜虫－天敌三重营养关系的全面了解,将为蚜虫的综合治疗提供新思维。     

Altered ecosystem carbon and nitrogen cycles by plant invasion: a meta-analysis

Plant invasion potentially alters ecosystem carbon (C) and nitrogen (N) cycles. However, the overall direction and magnitude of such alterations are poorly quantified. Here, 94 experimental studies were synthesized, using a meta-analysis approach, to quantify the changes of 20 variables associated with C and N cycles, including their pools, fluxes, and other related parameters in response to plant invasion. Pool variables showed significant changes in invaded ecosystems relative to native ecosystems, ranging from a 5% increase in root carbon stock to a 133% increase in shoot C stock. Flux variables, such as above-ground net primary production and litter decomposition, increased by 50-120% in invaded ecosystems, compared with native ones. Plant N concentration, soil NH+4 and NO-3 concentrations were 40, 30 and 17% higher in invaded than in native ecosystems, respectively. Increases in plant production and soil N availability indicate that there was positive feedback between plant invasion and C and N cycles in invaded ecosystems. Invasions by woody and N-fixing plants tended to have greater impacts on C and N cycles than those by herbaceous and nonN-fixing plants, respectively. The responses to plant invasion are not different among forests, grasslands, and wetlands. All of these changes suggest that plant invasion profoundly influences ecosystem processes.     

寄主植物对乌桕黄毒蛾取食量及生长发育的影响

【目的】研究乌桕黄毒蛾Euproctis bipunctapex(Hampson)对5种不同科寄主植物(天仙果Ficus erecta var.beecheyana、拐枣Hovenia acerba、苦槠Castanopsis sclerophylla、杨梅Myrica rubra和杜英Elaeocarpus decipiens)叶片的取食量以及不同寄主植物对乌桕黄毒蛾生长发育和繁殖的影响。【方法】在恒定条件[温度(26±1)℃,相对湿度80%,光周期12L︰12D]下,设置5个处理组,每处理分别投喂不同寄主植物叶片,测定取食量、幼虫历期、存活率、繁殖力等指标。【结果】乌桕黄毒蛾对不同寄主植物的取食量差异显著,苦槠饲喂组最高(2 588.15 mg),杜英饲喂组最低(1 971.33 mg);但对不同植物的日取食量总体趋势相同,随时间呈指数增长,4龄起进入暴食期,4龄、5龄和6龄幼虫取食量占总取食量的80.68%~85.91%。取食不同寄主植物的乌桕黄毒蛾生长发育差异显著,天仙果饲喂组的个体幼虫历期(34.35 d)最短,存活率(60.20%)最高,产卵量(281.33粒/雌)最多,而杜英饲喂组的个体幼虫历期(41.36d)最长,存活率(38.78%)最低,产卵量(215.83粒/雌)较少。【结论】乌桕黄毒蛾虫害防治适期是4龄之前,苦槠和杨梅受乌桕黄毒蛾取食最多,天仙果是乌桕黄毒蛾生长发育的最适寄主植物。     

跳甲的食性及食性分化

跳甲隶属于鞘翅目叶甲科跳甲亚科,是一类具有重要经济意义的植食性昆虫。本文对跳甲食性及食性分化的研究进展进行了综述,诠释了寄主植物的概念,分析了昆虫食性专化发生的原因。跳甲亚科的寄主植物的范围虽广,但有85%的属为专食性属。一般认为,专食性的跳甲亚科和萤叶甲亚科是由食性较广的叶甲亚科进化而来的,食性分化在其中可能起了重要作用。广食性代价推动了食性分化的发生,广食性代价假说受到越来越多的实验支持。有关食性分化方向的观点倾向于寄主植物转向化学物质相似的植物,表现为寄主转移、寄主扩张和形成寄主型等;食性分化推动了同域物种形成。跳甲食性分化的研究对于丰富研究昆虫与植物相互关系的协同进化理论也有重要作用。     

Ecology of the aphid pests of protected pepper crops and their parasitoids

Myzus persicae, Macrosiphum euphorbiae, Aphis gossypii and Aulacorthum solani (Homoptera: Aphididae) are principal pests of protected pepper crops in southeastern Spain. Our goal was to determine the incidence of aphids on pepper crops and the role of vegetation surrounding greenhouses as a source of aphids and their parasitoids. The population dynamics were followed in six commercial greenhouses during 3 years. Another 82 greenhouses and their surrounding vegetation were surveyed occasionally. Myzus persicae had the highest incidence in pepper greenhouses followed by M. euphorbiae and A. solani. Parasitism of all aphid species in greenhouses was low, Aphidius matricariae and Aphidius colemani being the most abundant parasitoids. Myzus persicae and Macrosiphum euphorbiae were the most abundant and polyphagous aphids, being present on 77 and 55% of the plants sampled outside greenhouses, respectively; species of Brassicaceae were the main hosts for both aphids. Aulacorthum solani was only present on Malva parviflora and at low numbers. Outside greenhouses, A. matricariae was the most common parasitoid of M. persicae, followed by Diaeretiella rapae and A. colemani. Aphidius matricariae was the most polyphagous, being present in 10 out of 22 aphid species. Macrosiphum euphorbiae and A. solani were both parasitised by A. ervi and Praon volucre. Aphelinus asychis was found on A. solani. Parasitoids were found in other aphids not attacking pepper. The role of natural vegetation as a reservoir of aphid pests of pepper and of parasitoids is discussed.     

昆虫唾液成分在昆虫与植物关系中的作用

近年来,人们对于植食性昆虫唾液的深入研究,揭示出其在昆虫与植物的相互关系和协同进化中起到非常重要的作用。植食性昆虫唾液中含有的酶类和各种有机成分,能诱导植物的一系列生化反应,而且这些反应有很强的特异性,与为害的昆虫种类甚至龄期有关。鳞翅目幼虫口腔分泌物（或反吐液）中含有的β-葡糖苷酶、葡萄糖氧化酶等酶类和挥发物诱导素等有机成分,已经证明可以诱导植物的反应; 刺吸式昆虫的取食也可以刺激植物产生反应,但其唾液内的酶类,如烟粉虱的碱性磷酸酶, 蚜虫的酚氧化酶、果胶酶和多聚半乳糖醛酸酶, 蝽类的寡聚半乳糖醛酸酶等是否发挥作用,目前还没有直接的证据。寄主植物对昆虫的唾液成分也有很大的影响,可能是昆虫对不同植物营养成分和毒性成分的适应方式。对昆虫唾液蛋白的分析表明,具有同样类型口器、食物类型接近的昆虫,唾液成分有更多的相似性。研究植食性昆虫的唾液成分,对于阐明昆虫和植物的协同进化关系、昆虫生物型的形成机理、害虫的致害机理,以及指导害虫防治等,有着一定的理论和实际意义。     

唾液成分在刺吸式昆虫与植物关系中的作用

近年来,人们对刺吸式昆虫唾液成分的研究,揭示出其在刺吸式昆虫与植物关系中的重要作用。对多数刺吸式昆虫而言,他们取食时会分泌胶状和水状两种唾液,其中胶状唾液会在取食早期分泌形成唾液鞘来围绕并保护口针,通过直接和间接的作用来帮助取食;而水状唾液中则包含了果胶酶、纤维素酶、多酚氧化酶、过氧化物酶、碱性磷酸酯酶、蔗糖酶等组分,来帮助刺吸式昆虫对植物穿刺、消化食物、解毒次生物质并破坏植物的防御反应。有趣的是,唾液成分同时还可以诱导植物的防御反应,包括诱导植物的伤信号引起直接防御反应和诱导植物产生挥发物吸引植食者的天敌引起间接防御反应。并且,许多刺吸式昆虫取 食能够特异性地引发植物的病理反应,有研究推测刺吸式昆虫唾液中多聚半乳糖醛酸酶、碱性磷酸酯酶、蔗糖酶、多酚氧化酶等成分可能是某些植物特定病理反应的激发子,但是目前还没有定论,同时许多刺吸式昆虫唾液中的氨基酸和蛋白酶还是引起植物虫瘿的原因之一。 迄今的研究表明,刺吸式昆虫会根据不同的寄主植物和不同的生理需要,通过唾液组分的改变,来达到取食和发育的目的。对刺吸式昆虫唾液成分和作用机理的研究,可以为揭示刺吸式昆虫致害机理特别是传毒机理、指导害虫有效治理、阐明其与植物的协同进化等提供一定的思路。     

丛枝菌根真菌与根围促生细菌相互作用的效应与机制

丛枝菌根(arbuscular mycorrhiza,AM)真菌是植物活体营养专性共生菌,广泛存在于陆地各生态系统中.研究表明,AM真菌与根围促生细菌(plant growth promoting rhizobacteria,PGPR)之间的相互作用,尤其是它们之间的协同作用不仅影响植物养分吸收利用、病原物发生发展、土壤理化特性与生物修复等,而且对于可持续农、林、牧业生产、稳定生态系统都具有十分重要的意义.因此,近年来给予众多关注和研究.综述了AM真菌与PGPR之间的相互影响及其可能的作用机制,以及AM真菌与PGPR协同改善植物营养和生长、协同抑制病原菌、协同修复土壤方面的作用,旨在总结AM真菌与PGPR相互作用的效应与机制方面的最新研究进展,为今后研究发展提供依据.     

Acquisition and allocation of resources in two waterlogging-tolerant grasses

This study focuses on the following questions: (i) whether reductions in root:shoot ratio have a cost in terms of nutrient balance of the plant, and (ii) whether changes in resource-allocation patterns are proportional among different resources. Our approach was to analyse the variations in the allocation pattern induced by soil waterlogging. A pot experiment was conducted to analyse the effects of waterlogging on biomass, phosphorus (P) and nitrogen (N) accumulation of Paspalum dilatatum and Danthonia montevidensis , two waterlogging-tolerant grasses. When changing from oxic to anoxic conditions, a common response of these and other waterlogging-tolerant grasses is a reduction in allocation to below-ground resources. It was observed that (i) the reduction in root:shoot ratio caused by waterlogging did not have a cost in terms of capacity for nutrient uptake; (ii) resource partitioning within aerial parts was less sensitive to treatments than partitioning between roots and shoots; and (iii) biomass does not appear to be a useful currency for evaluating nutrient-allocation patterns, as the allocation of P and N was inadequately represented by biomass. The results presented here indicate that the existence of compensation mechanisms reduces the predictive value of the partition of resources for the capacity of plants to acquire resources. Data on the allocation of nutrients in relation to biomass suggest that the assumptions of independence in the allocation pattern between biomass and limiting nutrients under the effects of environmental factors can be extended.     

Influence of flowering cover crops on Anagrus parasitoids (Hymenoptera: Mymaridae) and Erythroneura leafhoppers (Homoptera: Cicadellidae) in New York vineyards

Abstract 1 We tested the hypothesis that providing nectar‐producing cover crops will enhance the biological control of grape leafhoppers (Erythroneura spp.) by Anagrus wasps in commercial vineyards in New York, U.S.A. 2 We established three cover crops between vine rows in a commercial vineyard: buckwheat (Fagopyrum esculentum (Moench)), clover (Trifolium repens L.) and mowed sod (Dactylis glomerata L.). 3 There was no effect of cover crop on adult Anagrus in 1996, whereas in 1997 adults were more abundant within edge vines with buckwheat compared to vines with clover or sod; adults were more abundant at the vineyard edge, especially early in the season. 4 Parasitism of ‘sentinel’ leafhopper eggs was higher on vines with buckwheat compared to parasitism on vines with clover or sod in 1996; a similar, non‐significant trend, was observed in 1997. 5 Neither the abundance nor the distribution of leafhoppers was influenced by cover crops, although in 1997 there was a trend toward greater numbers of nymphs on edge vines with buckwheat. 6 In a cage experiment, parasitism by Anagrus of leafhopper eggs on grapes was greater when adults had access to flowering buckwheat rather than buckwheat without flowers. 7 In a laboratory study, longevity of female Anagrus was increased when provided with honey or sugar water compared to water only or nothing. 8 Our results suggest that parasitism of grape leafhoppers by Anagrus may be enhanced by providing floral resources within vineyards in New York, although it is unclear whether this will produce meaningful reductions in pest abundance.