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Hybrid and pure-line (inbred) rice (Oryza sativa L. (Poaceae)) varieties have distinct physiologies, particularly as related to their nutrient requirements. These differences could confound the results and interpretation of experiments that compare rice varieties grown in pots for their resistance and responses to herbivores. In this study, a series of experiments was conducted to identify potentially confounding interactions between pot size (soil volume), fertilizer regime, and the use of acetate insect cages with rice line type (hybrid, fertile parental inbred, and male sterile inbred) during bioas- sayswiththebrownplanthopper,Nilaparvatalugens(Stal)(Hemiptera: Delphacidae). Thegrowthof hybrid rice was often limited (relatively low biomass and low grain production) compared to fertile inbred lines even in large pots (7 200 ml) and when grown without added fertilizer. Several interac- tions between theeffects ofgrowth conditions andline typewere detected. Acetatecages causeda sig- nificant reduction in grain yield in hybrids, but not in inbreds, mainly resulting from a cage-induced decrease in grain weight (smaller grains). Hybrids and male sterile lines often had higher root or above-ground biomass in the largest caged pots compared with fertile inbred lines, but biomass was similar in smaller pots, indicating that the large pots allowed longer unimpeded growth of fertile in- breds, but not other line types. There were no interactions between the presence or absence of plant- hoppers with line type or experimental conditions. All line types were equally susceptible to planthoppers. Often the effects ofplanthopper feeding on plantfitness (i.e., tolerance) were apparent when plants were grown in large pots but not in small pots, particularly for hybrid lines and under highnitrogenregimes.Onthebasisoftheseresultswerecommendthatresearchersensurethatplants are not unequally stressed by inadequate growth conditions during comparative studies with herbi- vores on physiologically distinct rice varieties or rice species. We recommend the use of large pots (soil volume) and lower fertilizer levels with young, non-reproductive plants during comparative bioassays with planthoppers. Field cages are recommended for hybrid-inbred comparisons during older plant stagesbut thesearesubjecttoa rangeofotherconfoundingvariables.

Highlights ► We determine the permeability of cropping systems to commercial bumble bees. ► We quantify the prevalence of pathogens in bumble bees adjacent to greenhouses. ► Up to 97% of pollen returning to commercial bumble bee hives was non-crop pollen. ► The prevalence of two gut parasites was greatest within 2 km of greenhouses. ► Pathogen spillover in this system compels national and international regulation., Worldwide, wild bumble bees (Bombus spp.) are experiencing marked declines, with potentially up to 11% of species currently under threat. Recent studies from North America suggest that disease transmission from commercially reared bumble bees to wild populations has led to marked range contractions in some species. In Europe, data on the prevalence of pathogen spillover from commercial to wild bumble bee populations is lacking, despite the widespread production and transport of hives within the EU since the early 1980s. We determined the permeability of cropping systems to commercial bumble bees, and quantified the prevalence of four pathogens in commercial Bombus terrestris hives and adjacent conspecific populations at increasing distances from greenhouses in Ireland. Commercial bumble bees collected from 31% to 97% of non-crop pollen, depending on the cropping system, and hives had markedly higher frequencies of two gut parasites, Crithidia spp. and Nosema bombi, compared to adjacent populations, but were free of tracheal mites. The highest prevalence of Crithida was observed within 2 km of greenhouses and the probability of infection declined in a host sex- and pathogen-specific manner up to 10 km. We suggest implementing measures that prevent the interaction of commercially reared and wild bumble bees by integrating the enforcement of national best management practices for users of commercial pollinators with international legislation that regulates the sanitation of commercial hives in production facilities.

For over 50 years, host-plant resistance has been regarded as an efficient method to reduce yield losses to rice caused by delphacid and cicadelid hoppers. Already a number of resistant rice varieties have been developed and deployed throughout Asia. To date, over 70 hopper resistance genes have been identified in rice; however, less than 10 genes have been deliberately introduced to commercial rice varieties. Currently, due to recent brown planthopper (Nilaparvata lugens [Stål]) and whitebacked planthopper (Sogatella furcifera [Horvath]) outbreaks occurring at an unprecedented scale, researchers are working toward a second generation of resistant varieties using newly identified gene loci and applying new molecular breeding methods. This paper reviews advances in the identification of resistance genes and QTLs against hoppers in rice. It collates all published information on resistance loci and QTLs against the major rice planthoppers and leafhoppers and presents information on gene locations, genetic markers, differential varieties, and wild rice species as sources of resistance. The review indicates that, whereas progress in the identification of genes has been rapid, considerable tidying of the information is required, especially regarding gene nomenclature and resistance spectra. Furthermore, sound information on gene functioning is almost completely lacking. However, hopper responses to resistance mechanisms are likely to be similar because a single phenotyping technique has been applied by most national and international breeding programs during germplasm screening. The review classifies genes occurring at two chromosome regions associated with several identified resistance loci and highlights these (Chr4S: BphR-R and Chr12L: BphR-R) as general stress response regions. The review calls for a greater diversity of phenotyping methods to enhance the durability of resistant varieties developed using marker-aided selection and emphasizes a need to anticipate the development of virulent hopper populations in response to the field deployment of genes. © 2013 Copyright Taylor and Francis Group, LLC.

Meloidogyne minor, first reported on potatoes in the Netherlands in 2004, is an emerging nematode pest in Europe. It damages turfgrass, particularly creeping bentgrass (Agrostis stolonifera) grown on sandy soils such as those of golf greens. However, little is known of the nematode's life history and pathology. In this study, the spatial and temporal distribution of M. minor on a creeping bentgrass green in Ireland was determined over a 15 month period. Cores were taken on transects across yellowing patches of grass caused by nematode damage. Second-stage juveniles (J2) were absent from the soil from November to February, when soil temperatures were below 10°C. Both galls and egg masses were present throughout the year but were more abundant in late summer and early autumn. More J2, galls and egg masses were present in the top 10 cm of soil than at a depth of 11-20 cm. The nematode population tended to decrease as distance from the centre of the yellow patches increased. The diameter of visual symptoms (yellow patches) was also recorded over the 15 months. The mean diameter of five sampled patches increased from 23·7 cm in June 2003 to 45·2 cm in August 2004. There were 158-193 galls per 100 cm3 soil at the margin of the visible infested area, indicating that this could be the threshold level for visible symptoms. © 2012 British Society for Plant Pathology.

A series of experiments was set up to examine the effects of nitrogen on rice (Oryza sativa L.) resistance against Nilaparvata lugens (Stål) and Sogatella furcifera (Horváth). Egg laying by N. lugens was reduced on the indica variety IR60. Nymph biomass (N. lugens and S. furcifera) was also lower on IR60: this was associated with low honeydew production and a high proportion of xylem-derived honeydew in N. lugens but not in S. furcifera. Nitrogen increased egg-laying by S. furcifera and increased N. lugens nymph biomass on all varieties tested. Oviposition and egg mortality in both planthopper species were examined on plants at 15, 30 and 45 days after sowing (DAS). Sogatella furcifera laid more eggs on plants at 15 DAS, but laid few eggs during darkness; N. lugens continued to lay eggs on older rice plants (30 DAS) and during darkness. Egg mortality was high on cv. Asiminori, highest at 45 DAS, and higher for S. furcifera than for N. lugens. Mortality of S. furcifera eggs was associated with lesions around the egg clusters. These were more common around clusters laid during the day and suggested induction by Asiminori of an ovicidal response. Egg mortality declined under higher soil nitrogen levels. Results are discussed in the light of improving rice resistance against planthoppers and reducing rates of planthopper adaptation to resistance genes., Highlights • The effects of nitrogen on planthoppers has focused mainly on antibiotic resistance against nymphs. • IR60 and Asiminori had strong to moderate resistance against Nilaparvata lugens and Sogatella furcifera, respectively. • Nitrogen reduced resistance in both varieties. • Asiminori exhibited induced ovicidal response to S. furcifera eggs that decreased under high nitrogen. • Resistant rice varieties require proper nutrient management to avoid planthopper adaptation.

The social-ecological systems of rice terraces across Southeast Asia are the result of centuries of long-term interactions between human communities and their surrounding ecosystems. Processes and structures in these systems have evolved to provide a diversity of ecosystem services and benefits to human societies. However, as Southeast Asian countries experience rapid economic growth and related land-use changes, the remaining extensive rice cultivation systems are increasingly under pressure. We investigated the long-term development of ecosystem services and the adaptive capacity of the social-ecological system of rice terrace landscapes using a case study of Banaue (Ifugao Province, Northern-Luzon, Philippines). A set of indicators was used to describe and assess changes in the social-ecological state of the study system. The resilience of the rice terraces and the human communities that maintain them was examined by comparing the current state of the system with results from the literature. Our findings indicate that, although the social-ecological system has not yet shifted to an alternative state, pressures are increasing and some cultural ecosystem services have already been lost.

This study examines the possibility of horizontal and vertical transmission of virulence (the ability to tolerate a given resistant plant or resistance gene) between individuals from brown planthopper, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), populations with distinct feeding abilities when their populations share the same feeding sites (virulence acquisition hypothesis). We created optimal conditions for intraspecific interactions on the same rice, Oryza sativa L. (Poaceae), plants between planthoppers from populations with different feeding histories: an ‘avirulent’ population that was continually reared on a susceptible variety, and a ‘virulent’ population that had been selected over several generations on the resistant variety IR62, that possesses the Bph3 gene. We noted that planthoppers attained highest weights on rice plants that had previously been attacked by conspecifics from the IR62-selected population. We also tested the ability of planthoppers to feed on IR62 and the susceptible cv. Taichung Native 1 (TN1) after interacting with individuals from the IR62-selected population on a tolerant rice cultivar (Triveni). Feeding by avirulent planthoppers on both IR62 and TN1 improved after feeding on the same rice plants with virulent planthoppers. Furthermore, the effects were carried over to planthopper progenies. Our preliminary results indicate that feeding by mixed populations that include individuals adapted to feed on resistant varieties potentially accelerates adaptation by N. lugens to rice resistance.

In the inter-Andean valleys of central Perú, two species of tuber moth, Phthorimaea operculella (Zeller) and Symmetrischema tangolias (Gyen), often occur simultaneously in stored potatoes. Traditional farming communities in the region produce a variety of native potatoes for local consumption. These include Solanum tuberosum subsp. andigena, the presumed predecessor of commercial potatoes, S. tuberosum subsp. tuberosum. In this study, we examined resistance against P. operculella in ten native Peruvian potato varieties (Casa blanca, Chispiadita, Madre de vaca, Mamaco negro, Misha, Chorisa, Mamaco rosado, Occa papa, Vacapa jayllo, and Yana tornasol). We also compared resistance in the first five of these varieties against S. tangolias. Varieties with pigmented periderms showed moderate resistance (30-40% against P. operculella in Mamaco negro, Mamaco rosado, and Yana tornasol and 55% against S. tangolias in Mamaco negro). All the other varieties were susceptible to both moth species. Small tubers tended to be the most resistant to the attack by both moths; however, this was not related to the availability of food for developing larvae, since pupal weight and development time were unaffected by the size of tubers. Similar responses by the two moths to native potatoes indicate that tuber resistance could be used to control the complex of tuber moths that damage potatoes in the Andes. We suggest that native potatoes, which are often easily introgressed with commercial potatoes, are a potential source of resistance against tuber moths.

Despite over 30 years of deployment, varieties with the Bph3 gene for resistance to the brown planthopper (BPH), Nilaparvata lugens (Stal) (Hemiptera: Delphacidae), are still effective in much of the Philippines. In the present study, we determined the effects of adaptation to one resistant variety, IR62 – assumed to possess the Bph3 gene – on (1) resistance against a series of varieties with similar biotypical responses (presumed to contain the same major resistance genes), and (2) a differential variety with the bph4 gene that occurs at the same chromosome position as Bph3. We also examined the effects of high soil nitrogen on the effectiveness of Bph3. Feeding, planthopper biomass, and development times were reduced in a wild BPH population when reared on IR62 compared with the susceptible standard variety TN1. However, nitrogen application increased the susceptibility of IR62. After 13 generations on IR62, BPH had adapted to the plant’s resistance. Virulence of the adapted BPH against the variety ‘Rathu Heenati’ supports the idea that Bph3 is present in IR62. Across similar IR varieties (IR60, IR66, IR68, IR70, IR72, and IR74), feeding, planthopper biomass, and development rates were generally higher for IR62-adapted than for non-adapted BPH; however, contrary to expectations, many of these varieties were already susceptible to wild BPH. Fitness was also higher for IR62-adapted BPH on the variety ‘Babawee’ indicating a close relation between Bph3 and bph4. The results indicate that the conventional understanding of the genetics behind resistance in IR varieties needs to be readdressed to develop and improve deployment strategies for resistance management.

The brown planthopper, Nilaparvata lugens, shows considerable geographic and temporal variability in its response to varieties of cultivated rice. N. lugens has repeatedly " adapted" to resistant rice varieties; however, the physiological changes underlying planthopper adaptation are poorly understood. Endosymbionts within planthoppers, such as yeast-like endosymbionts (YLS) could play a role as they produce essential amino acids for planthoppers. We used a full factorial study to determine how natal rice variety, exposed rice variety, YLS presence, and the number of reared generations affected nymphal development, planthopper total nitrogen content, and planthopper hydrolyzed amino acid profiles. Nymphal development was strongly influenced by a four-way interaction between the exposed rice variety, natal rice variety, number of reared generations, and YLS presence. While symbiosis improved nymphal performance in the 8th generation, it appeared to be a drain on nymphs in the 11th generation, when the aposymbiotic nymphs actually showed higher performance than the symbiotic nymphs. This suggests that the symbiotic relationship may be acting beneficially in one generation while acting as a drain during another generation. Aposymbiotic planthoppers reared for 11 generations had a higher proportional concentration of rare amino acids than those reared for 8 generations, indicating that the planthopper itself appears to improve its ability to acquire rare amino acids. Therefore, the change in amino acid composition of planthoppers suggests an underlying change in protein expression or amino acid metabolism over time. © 2011 Elsevier Ltd.

In 2007, an invasive paropsine beetle, Paropsisterna nr. gloriosa Blackburn, caused severe defoliation of Eucalyptus in mixed-species foliage plantations in south-west Ireland. At many of the plantations, Eucalyptus parvula L.A.S. Johnson & K.D. Hill was the most heavily damaged species while Eucalyptus pulverulenta Sims was generally resistant to the beetle. However, at the most heavily damaged site beetles moved to feed on E. pulvarulenta presumably during periods when suitable foliage (new leaves) of E. parvula had been severely depleted. The present study examines factors underlying shifts in oviposition from the preferred to non-preferred host. In choice and no-choice experiments, P. nr. gloriosa laid more eggs directly on new E. parvula foliage compared with new E. pulverulenta foliage. However, in choice experiments where new E. parvula foliage was unavailable (but old foliage available), more eggs were laid on new E. pulverulenta foliage. The potential for prior feeding damage to stimulate or deter oviposition on either host was also examined. Prior damage to new and old E. parvula leaves increased egg-laying directly on the damaged foliage; however, prior damage to E. pulverulenta may have inhibited oviposition. The results suggest that in mixed-species plantations, facilitation of oviposition on preferred hosts through prior feeding damage helps maintain the relative resistance of E. pulverulenta against P. nr. gloriosa, even under high beetle densities. However, the vulnerability of E. pulverulenta will increase where suitable age-classes of preferred-host foliage are severely depleted or unavailable.

An exotic, paropsine beetle ‐ Paropsisterna nr. gloriosa Blackburn ‐ occurred at high densities in south-west Ireland in 2007. In bioassays, adults and larvae fed on foliage from a variety of eucalypt species. Eggs and neonates occurred only in association with new foliage. Despite their ability to consume old foliage, adult beetles had a high preference for new leaves with low specific leaf weights (softer leaves). In choice tests, adults that depleted new foliage of their preferred host, moved to new foliage of a second host but not older foliage of the preferred host. A 2008 survey of southern Ireland indicated that P. nr. gloriosa was restricted to County Kerry, largely associated with foliage plantations in that county. The distribution of damage suggests that the initial spread of the beetle was facilitated by foliage-trade activities. Eucalyptus parvula L.A.S. Johnson & K.D. Hill was the most heavily damaged species at many plantations. Eucalyptus pulverulenta Sims and Eucalyptus cordata Labill. were highly resistant to the beetle as indicated by low levels of damage in the field and reduced fitness of larvae in feeding trials. Nevertheless, at the plantation with the highest overall levels of damage, adult beetles moved to feed on E. pulverulenta. A progressive dispersal from plantations also caused slight damage to neighbouring ornamental eucalypts. Clear preferences by P. nr. gloriosa for new foliage, irrespective of eucalypt species, suggests that pollarding ‐ the removal of top branches to produce dense juvenile foliage ‐ accelerated population build-up during 2007.

Tuber resistance can contribute to current management strategies against the potato tuber moth, Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae), in field and stored potatoes. Wild potatoes represent a potential source of novel resistance traits against the moth. We assessed resistance in three wild potato species, Solanum multiinterruptum Bitt., Solanum sparsipilum (Bitt.) Juz. & Buk., and Solanum wittmackii Bitt. against neonate and developing tuber moth larvae. All three species had high levels of resistance but accessions of S. sparsipilum and S. wittmackii were significantly more resistant. Resistance in S. multiinterruptum was generally concentrated in the tuber periderm, whereas in S. sparsipilum and S. wittmackii resistance was mainly cortex-based. Unidentified cortex-resistance factors in all three species reduced survival and increased larval and pupal development times, but had no apparent effects on the pupal weights of survivors. A high proportion of larvae abandoned or died within tubers of S. wittmackii, which has particularly high levels of unidentified cortex-based defenses. Resistance decreased in S. multiinterruptum and S. sparsipilum as tubers sprouted but was more stable in S. wittmackii. Periderm-based resistance was more stable than cortex-based resistance in S. multiinterruptum during sprouting. In contrast, cortex-based resistance was stable in tubers of S. wittmackii as these sprouted, and resistance may have increased on some older sprouting tubers. Solanum multiinterruptum and S. sparsipilum are proposed as potential sources of resistance against the potato tuber moth.

Digitonthophagus gazella, un escarabajo coprófago de origen Indoafricano fue inicialmente introducido en el continente Americano en 1970. Desde ese momento su rango de distribución se ha incrementado debido a introducciones deliberadas en nuevas regiones y por procesos naturales de dispersión en ausencia de barreras geográficas. Esta especie ha continuado expandiendo su rango de distribución ayudado por el efecto antrópico producido por la tala de bosques. Se presenta el primer reporte de D. gazella para el Perú, indicando que esta especie se constituye en el escarabajo coprófago más ampliamente distribuido en pastizales tropicales y subtropicales

This study examines the effects of deforestation, and the habitat value of coffee and regenerated forest for tropical dung beetles, a functionally significant insect group. Pitfall trapping was conducted at 22 sites in a montane region of central Peru during April and November/December of 2002. Sites included primary and secondary forest, shade-coffee, regenerated forest and open farms (mainly with banana, yuca, and corn). Ordination techniques indicated that beetle assemblages in forests, regenerated forest and coffee were relatively similar. However, assemblage compositions in forested areas differed even at similar altitudes under the influence of biogeographical factors, and the assemblages at disturbed sites (farms/coffee) were influenced by beetle dispersal from adjacent forests. During dry months, when beetle activity is low, communities at all habitat types tended to converge because fewer unique species were recorded in forests at that time and habitat/season generalists were dominant. Preliminary results also indicate that beetles in shady crops such as bananas responded to plant growth: as the banana canopy closed-in, producing more shade, open-habitat specialists retreated and forest/shade specialists invaded the sites. Chronosequence data at two of the sites demonstrate the rapid and dramatic changes in species richness and assemblage composition caused by deforestation. As forests become increasingly fragmented, and open farms continue to expand, dung beetles will become more restricted to the remaining fragments and reserves. In the mosaic landscape studied here, shade crops, like coffee, act as habitat and corridors for many dung beetle species. Small farm size and the consequent magnitude of edge effects, likely contributed to beetle movement between habitat types and determined the apparent generalist nature of many of the dung beetle species in this study.

Plants allocate resources between defence, reproduction, maintenance, and growth. This can lead to detectable allocation and ecological costs expressed as trade-offs between distinct plant functions. It could also lead to trade-offs between a plant's defences to different kinds of herbivores or a plant's defences to herbivory on different plant parts. We examined the hypothesis that allocation to defence in leaves is inversely related to allocation to defence in tubers of two distinct trichome-bearing morphotypes of the wild potato, Solanum berthaultii Hawkes (Solanaceae). This species has been widely used in potato breeding programs aimed at acquiring foliage resistance to Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae) and other herbivores. Phthorimaea operculella lays eggs in the soil and neonate larvae generally initiate host attack. We exposed leaves and tubers from multiple wild potato populations to neonate P. operculella. For both plant morphotypes, survival of neonate larvae placed on foliage was negatively correlated with the survival of neonate larvae placed on tubers, suggesting a trade-off between the levels of herbivore defence in these plant tissues. These results suggest that the evolution of tuber resistance and trichome-mediated foliage resistance to herbivores may not be independent, and that potato-breeding programs that select for resistance in one tissue might compromise resistance in another.

The diversity and abundance of herbivores often decreases with increasing altitude. Plants are expected to respond to reduced herbivore pressure by allocating fewer resources to anti-herbivore resistance at higher altitudes. This study uses a greenhouse experiment and parallel bioassay to examine population variability in trichome-mediated defenses across a range of accessions of Solanum berthaultii Hawkes and S. tarijense Hawkes that originated from different altitudes. S. berthaultii bears two types of glandular trichomes, type A and type B, whereas S. tarijense has type A trichomes only, and hairs resembling type B trichomes that are eglandular. Both type A and type B glandular trichomes on S. berthaultii deterred ovipositing female Phthorimaea operculella (Zell.) (Lepidoptera: Gelechiidae). The density of type A, but not type B trichomes decreased with increasing altitude of origin in S. berthaultii populations. The ratio of type A to type B trichomes on the abaxial surface of S. berthaultii negatively affected oviposition and was inversely related to altitude of origin. In S. tarijense, type A trichomes deterred, but eglandular leaf hairs stimulated oviposition. Consequently, the ratio of type A trichomes to eglandular leaf hairs was negatively related to the number of eggs laid. The total numbers of trichomes per leaf generally increased with increasing altitude of origin in S. tarijense whereas the ratio of type A trichomes to eglandular hairs declined. In the oviposition bioassay, we found no direct relationship between resistance and altitude of origin, which may have been due to differences in leaf area at the time of the bioassay. Nevertheless, the results suggest that populations of both plant species that originated from higher altitudes were generally more susceptible to ovipositing P. operculella.

Under EC Council Directive 2007/33/EC member states of the European Union are recommended to take soil samples ranging from 100 mL to >1500 mL to monitor populations of potato cyst nematodes [PCN] (Globodera spp.) in targeted fields. This study examines the effects of varying sample size on sample processing and cyst extraction using two widely used laboratory methods. Cyst recovery was stable using the Fenwick can from 100 mL up to the physical limits of the can. Recovery was significantly lower for low density 50 mL samples; however, this was partly due to a statistical artefact since higher numbers of cysts were lost from successively larger samples with constant cyst numbers (i.e. decreasing densities). The Schuiling centrifuge had functional limits of 500 mL. Outside this range, cyst recovery from low density samples was significantly reduced. Cyst recovery from samples of varying size, but with equal numbers of cysts was only constant above 100 mL. However, samples ranging from 200-500 mL were optimal for the Schuiling centrifuge. Cyst extraction efficiency was similar using both methods for samples ranging from 150 mL to 1500 mL, where larger samples were divided into

This study examines the functional attributes of Neotropical dung beetles, and, based on the analysis, evaluates the role of dung beetles in pastures and tropical dry forest in El Salvador. Dung beetle diversity was lower in pastures than in forests. However, the total biomass of beetles at similarly-sized dung baits was frequently higher in pastures. Diversity loss followed structured patterns: (1) carrion and fruit feeding beetles were well represented (species number) in the forests but were largely absent from pastures; (2) large ball rollers and small fast tunnellers were present in forests but were absent from pastures; (3) large fast tunnellers and small slow tunnellers were poorly represented in pastures compared to forests but the few species that survived in pastures attained extremely high populations; and (4) each functional group in the species-poor pasture assemblages was divided almost equally into day and night active species. Substrate and habitat generalists that were present in both the forests and pastures were attracted to fruit and carrion in forested habitat but not in open pastures. In open habitats, flies and other insects may be the principal decomposers of decaying fruit and carrion.

The trichome-bearing wild potatoes Solanum berthaultii (Hawkes) and Solanum tarijense (Hawkes) (Solanaceae) have noted resistance to leaf-feeding insect herbivores; however, little is known about their resistance to tuber-feeding herbivores. This study evaluates resistance in tubers of these two species to attack by the potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae). Tu bers from a range of accessions were presented to recently emerged neonate tuber moth larvae. Resistance to neonates varied between accessions and was generally higher in accessions of S. tarijense . The contribution to observed resistance of periderm vs. cortex factors was assessed by perforating tuber periderm in paired-tuber experiments. Across species and accessions, an average of 62% of resistance was attributed to periderm-related factors. All larvae entered tubers through the eyes. Unidentified cortex-related factors affected larval development time and pupal weight. Sprouting compromised resistance by reducing the protective value of the periderm. The degree of sprouting also decreased larval development times and increased pupal weights in one of two accessions examined. These results demonstrate the potential of S. berthaultii and S. tarijense as sources of tuber-resistance and identify accessions of both species with notably high periderm-based protection. Levels of periderm resistance were not correlated to levels of cortex resistance and represent an independent resistance source compatible with the food value of crop potato.

This study examines the response of tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), during the initial stages of attack, to variability in trichome density and composition on foliage of Solanum berthaultii (Hawkes) and Solanum tarijense (Hawkes) (Solanaceae). Solanum berthaultii bears two types of glandular trichome (type A and type B) that together reduced oviposition by the moth. Females were often completely deterred from ovipositing on foliage with >300 trichomes per cm 2 . In contrast, neonate establishment on S. berthaultii was generally positively related to trichome densities, indicating that trichomes may be a poor defense against P. operculella when the moth oviposits in soil and neonate larvae select the host plant. Solanum tarijense has only one type of glandular trichome (type A) and eglandular hairs. Most eggs were deposited on the adaxial leaf surfaces that had lower trichome densities. Although the density of type A trichomes was negatively related to oviposition, high densities of hairs on the abaxial and adaxial leaf surfaces appeared to stimulate oviposition, leading to stronger positive relations between hair densities and oviposition. Larvae generally established on the abaxial surface where hair densities were greatest. Relationships between the abaxial densities of leaf hairs and neonate establishment on S. tarijense were positive. The results indicate that the responses by P. operculella to the types and density of trichomes are complex. Whereas type A and type B trichomes may act synergistically to reduce oviposition by the moth, leaf hairs do not defend against oviposition and neither leaf hairs nor type A and B trichomes reduce neonate establishment by this herbivore species.

This study examines the spread of synanthropogenic dung beetles (species favoured by human activities) in pasture landscapes in Central America, and evaluates the role of forest fragments and regenerating patches of native vegetation in maintaining beetle diversity. Pitfall trapping was carried out at nine locations in El Salvador and seven in Atlantic Nicaragua that included both pasture and remnant or regenerating native vegetation. More dung beetle species occurred in forest fragments than in pastures. Community composition differed considerably between forest fragments from El Salvador and Nicaragua with many species restricted to either the Caribbean or Pacific regions. In contrast, dung beetle community composition and structure were largely the same in the pastures of El Salvador and Nicaragua, regardless of region or original habitat-type, and were similar to published results from pastures in Mexico and elsewhere on the Isthmus. Very small patches of native shrubs and tree stands (

The genetic structure of the earth bumblebee (Bombus terrestris L.) was examined across 22 wild populations and two commercially reared populations using eight microsatellite loci and two mitochondrial genes. Our study included wild bumblebee samples from six populations in Ireland, one from the Isle of Man, four from Britain and 11 from mainland Europe. A further sample was acquired from New Zealand. Observed levels of genetic variability and heterozygosity were low in Ireland and the Isle of Man, but relatively high in continental Europe and among commercial populations. Estimates of Fst revealed significant genetic differentiation among populations. Bayesian cluster analysis indicated that Irish populations were highly differentiated from British and continental populations, the latter two showing higher levels of admixture. The data suggest that the Irish Sea and prevailing south westerly winds act as a considerable geographical barrier to gene flow between populations in Ireland and Britain; however, some immigration from the Isle of Man to Ireland was detected. The results are discussed in the context of the recent commercialization of bumblebees for the European horticultural industry.

This study examines the three-way interaction between symbionts, insect herbivores and their host plants during adaptation to resistant crop varieties. We conducted a long-term selection study (20 generations of continuous rearing) with a monophagous phloem-feeder, the brown planthopper [Nilaparvata lugens (Stål)], on several resistant rice (Oryza sativa L.) varieties. Planthopper fitness and the abundance of yeast-like symbionts (YLS) were monitored throughout the selection process. N. lugens populations collected from six regions in the Philippines adapted to the resistant varieties as noted by increasing body size and increased egg-laying. Adaptation was partially through physiological and behavioral changes apparent during feeding: Planthoppers on resistant plants had relatively high levels of xylem feeding compared with planthoppers on susceptible plants. YLS densities were highly dependent on the host rice variety. However, there were no consistent trends in YLS density during host plant switching and virulence adaptation: Compared to densities in planthoppers on the standard susceptible variety Taichung Native 1 (TN1), YLS densities were consistently higher on PTB33 (resistant), similar on IR62 (resistant) and IR65482 (moderately resistant) but lower on IR22 (susceptible). Furthermore, YLS densities often remained the same despite improved planthopper fitness over generations. Our results do not support the hypothesis that changes in YLS density mediate planthopper adaptation to resistant varieties. However, slight reductions in YLS densities toward the end of selection on TN1, IR22 and IR62 may indicate that YLS have lower functional significance where varieties and environmental conditions are constant between generations.

Copyright: © 2015 Schmidt et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Decomposers provide an essential ecosystem service that contributes to sustainable production in rice ecosystems by driving the release of nutrients from organic crop residues. During a single rice crop cycle we examined the effects of four different crop residue management practices (rice straw or ash of burned straw scattered on the soil surface or incorporated into the soil) on rice straw decomposition and on the abundance of aquatic and soildwelling invertebrates. Mass loss of rice straw in litterbags of two different mesh sizes that either prevented or allowed access of meso- and macro-invertebrates was used as a proxy for decomposition rates. Invertebrates significantly increased total loss of litter mass by up to 30%. Initially, the contribution of invertebrates to decomposition was significantly smaller in plots with rice straw scattered on the soil surface; however, this effect disappeared later in the season. We found no significant responses in microbial decomposition rates to management practices. The abundance of aquatic fauna was higher in fields with rice straw amendment, whereas the abundance of soil fauna fluctuated considerably. There was a clear separation between the overall invertebrate community structure in response to the ash and straw treatments. However, we found no correlation between litter mass loss and abundances of various lineages of invertebrates. Our results indicate that invertebrates can contribute to soil fertility in irrigated paddy fields by decomposing rice straw, and that their abundance as well as efficiency in decomposition may be promoted by crop residue management practices.

The ‘aggregation model of coexistence’ predicts that a strong and independent aggregation of species across ephemeral resource patches promotes species coexistence and maintains diversity. This study examines the role of aggregation in maintaining tropical dung beetle diversity and the effects of deforestation on aggregation patterns and diversity loss. Using clusters of pitfall traps, dung beetle aggregation was quantified in natural and disturbed habitat at nested temporal and spatial scales in central Peru. The results indicate that dung was colonized by a greater number of species, many of which were large, leading to a higher total beetle biomass in forest habitat than in deforested, farm habitat. Beetles were intraspecifically aggregated at each spatial scale examined. Habitat-type (forest/deforested) had no effect on the intensity of intra- or interspecific aggregation. Analyses of aggregation patterns revealed that dung beetle assemblages in forest habitat were generally saturated whereas in deforested habitat they were unsaturated. In general, interspecific aggregation was too weak relative to intraspecific aggregation to explain the high diversity of species in forest habitat. Other mechanisms, including resource partitioning are likely to play a greater role in maintaining the diversity of dung beetle assemblages in the region. These results also indicate that the loss of species from disturbed habitat has not been due to a breakdown in the aggregation mechanism.

Dung beetles play a major role in nutrient cycling in the tropics. While a number of studies have indicated decreasing diversity of dung beetles as a result of deforestation, scant information exists on the implications of this for decomposition. This study compares dung beetle assemblages at forest and deforested sites on the eastern slopes of the Peruvian Andes and examines the importance of species richness and assemblage biomass in the decomposition of standardized dung pats. Results from pitfall trapping indicated that species richness, assemblage biomass and the number of beetles arriving at dung pats were greater at forest sites than at deforested sites. Although dung removal was generally faster at forest sites, between 50 and 100% of each 100 ml pat was removed within 3 days at all sites. Dung remained attractive to beetles for longer at forest sites, where it remained moister, than at the deforested sites. Dung beetle activity significantly reduced the number of flies emerging from dung. In an observation of decomposition of 96 separate dung pats, dung disappearance after 24 h was more frequently and more closely related to total assemblage biomass than to species richness. This study indicates that deforestation results in a reduced efficiency in decomposition by dung beetles that can be attributed mainly to reduced assemblage biomass at individual dung pats.

This study examines the effects of resource distribution on colonisation, intra- and interspecific aggregation, and the occurrence of low-density, competition refuges for tropical dung beetles. In field experiments from central Peru, using dung pats (resource patches) of different volumes, the numbers of interacting species and total beetle biomass at individual pats increased with increasing pat volume. In two of three separate experiments (including an experiment that also varied patch density), this represented a decrease in the biomass of beetles per unit volume (biomass-density) at larger patches. The numbers of interacting tunneller species and tunneller biomass-density were also related to the distance between pats (patch density) in one of two experiments with constant numbers of pats. Closely positioned pats had generally fewer interacting species and a lower biomass-density of beetles. For the most abundant Dichotomius species, interspecific associations increased as distances increased between dung pats. The numbers of interacting species and biomass-density declined linearly under the combined effects of increasing patch density and local patch abundance in 25 m 2 plots. In experimentally placed grids with large numbers of pats, colonisation of pats at the edge of the grids was generally higher than at the centre of the grids for tunnellers and Eurysternus spp. but not for ball rollers; however, at least tunnellers did not readjust to avoid patches with high densities of competitors. These results indicate that an aggregated distribution of dung and natural variability in patch size contribute to species coexistence by creating low-density refuges for weaker competitors.

1. This study combines the results of laboratory experiments using representative assemblage components and pitfall trapping over a large geographical area to examine the hypothesis that ongoing interspecific competition structures Neotropical dung beetle assemblages. 2. From Guatemala to Panama assemblages of large to medium-sized, fast-tunnelling dung beetles include a single large, nocturnal dichotomiine species, Dichotomius annae (Kohlmann & Solis, 1997). In competition experiments, this species out-competed the medium-sized coprine species, Copris lugubris Boheman and Phanaeus demon Laporte-Castelnau, for dung and nesting space, in spite of earlier colonisation by the diurnal species, P. demon. 3. Differences in the abundance of D. annae at Central American sites did not affect total fast-tunnelling dung beetle assemblage richness over the rainy season. However, D. annae rank order was directly related to the probability of interspecific encounters (Hurlbert's Δ1) among species. These trends were also observed when species lists from published and unpublished studies of other large allopatric dichotomiine species, with a more northerly distribution, were included in the analyses. 4. The results obtained suggest that where large dichotomiine species are abundant, their efficient pre-emption of a considerable proportion of available resources drives all, or most, other fast-tunnelling species to a lower population density, thereby decreasing assemblage diversity.

A field study was carried out to determine whether small hypogaeic beetles prey on winter moth (Operophtera brumata [L.]) pupae. Small invertebrates were responsible for ca. 28% of pupal mortality at sites in British Columbia in 1991. Using a new trap design, adult Staphylinidae and beetle larvae were shown to actively search for buried pupae as indicated by significantly higher catches in hypogaeic traps baited with pupae than in unbaited, control traps. Baited and unbaited pitfalls were largely ineffective at capturing predatory larvae when compared to the baited hypogaeic traps. Many previous studies of predation on the soil-dwelling stages of insect herbivores may be biased towards the epigaeic component of the predator assemblage because they use pitfall traps alone. A combination of traps that includes hypogaeic traps should be considered for future studies.

This study describes assemblages of predatory ground beetles in native birch forest and derived blueberry farms on the Lower Mainland of British Columbia and investigates their role in the successful biological control of winter moth ( Operopthera brumata L.) by the parasitoid Cyzenis albicans Fallen. Pitfall traps at four sites in 1991 and 1992 indicated that natural birch forest was dominated by native carabid species, while open blueberry was dominated by introduced species and some native xerophilous species. Predation by generalist invertebrates was an important mortality factor for both winter moth and C. albicans at all sites and was greatest in the first 2 weeks after pupation. Ground beetles including Harpalus affinus (Schrank) and Pterostichus spp. consumed winter moth pupae in arenas but adult beetles rarely consumed C. albicans pupae. Much of the overall predation was due to smaller invertebrates including beetle larvae. Predators actively searched for buried pupae and selected among pupal types based on condition (dead, parasitised or healthy) and size. Prey-selection differed among sites but C. albicans pupae were preferred at three of the four sites. At the remaining site, an organic blueberry farm, over 90% of both parasitised and healthy pupae were consumed. High levels of predation did not affect the levels of parasitism by C. albicans at the sites. This herbivore–parasitoid–predator system demonstrates the importance of naturally occurring predatory invertebrates for successful integrated pest management, even where they prey upon a biological control agent.

The occurrence of dung beetles in the diet of hooded crows (Corvus corone cornix L.) was examined in order to identify possible biases in predation that could influence the structure of local dung beetle assemblages. Pellets and gizzards collected in southern Ireland indicated that crows fed largely on insects between March and September, and dung beetles (particularly Aphodius prodromus (Brahm)) were the most common insects in the diet in March and April. An abundance of alternative prey items, including Carabidae and Curculionidae, may have protected late summer dung beetles from intense crow predation. Small beetles (i.e. Hydrophilidae < 2mm body length) did not occur in the pellets or gizzards and may be ignored or avoided by foraging crows. Field observations and diet analyses suggest that crows prefer to forage from fresh equine dung rather than fresh cattle dung. We suggest that such predation biases could play a role in determining dung beetle assemblage structures at microhabitat (dung type) and macrohabitat scales. Finbarr G. Horgan (corresponding author e-mail: f.horgan@unb.ca), Department of Biology, University of New Brunswick, Fredericton, New Brunswick, E3B 6C2, Canada; Simon D. Berrow, Department of Zoology and Animal Ecology, Lee Maltings, University College, Cork, and Shannon Dolphin and Wildlife Foundation, Merchants Quay

Since its introduction in the mid-2000s, the apple snail, Pomacea canaliculata (Lamarck) has spread throughout Ecuador's southern lowlands. This paper collates information from government surveys, farmer interviews and roadside mapping to track the distribution and rate of spread of the snail. The paper also examines the impact on the rice (Oryza sativa L.) sector of the snail invasion and farmers' preferred management practices in response to high snail densities. Since its initial introduction, and following severe flooding in Guayas and Los Rios Provinces during 2008, the snail has invaded most of Ecuador's major rice-growing regions. The snail invasion of Ecuador has been fundamentally different from other regional invasions because of the presence of a specialized snail predator, the snail kite, Rostrhamus sociabilis Vieillot. Snail kite densities increased in response to the snail invasion, but snail densities have remained high, particularly in areas of 'stepped rice' - where rice is planted to floodplains in response to natural receding of water levels. The Ecuadorean government responded to the snail invasion by investing in data collection, farmer training and molluscicide distribution. Farmers have overwhelmingly opted to control the snails using insecticides and molluscicides despite training in alternative control methods; however, farmers have experienced increased rice damage from insects and diseases that may be associated with high pesticide use. Farmers perceive snail kites as beneficial predators, but have not been pro-active in enhancing kite numbers or their efficiency. We present a series of recommendations for sustainable apple snail management in Ecuador. © 2014 Elsevier Ltd.

Several cultural methods are known to reduce the densities of exotic apple snails (Pomacea spp.) and the damage they cause to rice in Asia. However, one aspect of seedling production - seedbed seed-density - has been largely overlooked and could compromise popular cultural control methods such as delayed transplanting. We conducted experiments to examine the effects of seedbed seed-density on hill survival in snail-infested paddy fields in the Philippines and to examine the interactions between seedbed seed-density and other cultural methods (delayed transplanting, 3 seedlings per hill and hand-picking). Seedbed seed-density determined seedling weight and stem thickness at the time of transplanting. Hill survival was highest where cultural methods (delayed transplanting and 3 seedlings per hill) were combined with low seed-density seedbeds (60-120gm-2). Furthermore, reduced seedbed seed-density was directly related to increased hill biomass in field plots 32 days after transplanting. Hand-picking of snails together with delayed transplanting and 3 seedlings per hill eliminated hill mortality due to snail herbivory. Farmers adopting cultural snail control methods, but without adhering to low seedbed seed-densities risk increased losses due to snails because of poor quality seedlings. We suggest that seedbed seed-densities should not exceed 120gm-2 with better results at even lower densities. © 2014 Elsevier Ltd.

In the late 1980s, a new outbreak of the introduced winter moth, Operophtera brumata (L.), occurred in Richmond, on the lower mainland of British Columbia. This was accompanied by the introduced parasitoid, Cyzenis albicans (Fallen). Populations were monitored at 2 birch woodlands and 2 blueberry plots between 1989 and 1993. Parasitism by C. albicans and predation by generalist predators were important mortality factors during the outbreak. Predation of moth pupae increased at all sites between 1989 and 1990. Parasitism by C. albicans caused significant mortality each year reaching a maximum in 1991 and remaining high through to 1993 at birch sites. The winter moth populations collapsed simultaneously in 1992 at all study sites, despite different levels of parasitism and 2 very different host plants. As the outbreak collapsed at Richmond, the moth continued to increase in numbers and cause severe defoliation of birch at new sites in southern Vancouver where parasitism remained low. C. albicans is unable to prevent the initial outbreak of winter moth even when the 2 species are introduced simultaneously. The parasitoid requires high density host populations before becoming well established, but may contribute sufficient additional mortality to prevent subsequent prolonged outbreaks. The control of high density winter moth populations in North America by C. albicans supports the hypothesis that natural enemies that are rare in their native habitat will be effective control agents when released into exotic habitats without competitors or their own natural enemies.

Host-plant resistance can play an important part of an integrated pest management system. Potato is generally consider susceptible to the main insect pests of the crop, the Colorado potato beetle ( Leptinotarsa decemlineata L.), potato tuber moths ( Phthorimaea operculella [Zell.], Tecia solanivora Polovny, Symmetrischema tangolias [Gyen]), and aphids (the potato aphid, Macrosiphum euphorbiae [Thomas], and the green peach aphid, Myzus persicae [Sulzer]). Two approaches have been used for the development of potato cultivars resistant to those pests; traditional breeding and the transgenic approach. Wild Solanum species are the main source of resistance for breeding insect-resistant potato. Glycoalkaloids, trichomes, and other undefined factors are responsible for the resistance of wild Solanum species to insects. The transgenic approach uses gene from different sources such as the endotoxin of Bacillus thuringiensis , protease inhibitors, avidin, and lectins.

{null=Meloidogyne minor is a serious threat to turfgrass in north-west Europe, and has a broad host range that includes other economically important plants. The species was described only recently and little is known about its biology. This study examines the effect of temperature on hatch and motility of second-stage juveniles (J2), and records hatching from egg masses collected from golf greens in different seasons. Eggs were present throughout the year and a high percentage hatch (46-88%) was recorded when they were incubated at 20°C. When egg masses were incubated at constant temperatures, J2 hatched between 15 and 25°C, with limited hatch ( Meloidogyne minor is a serious threat to turfgrass in north-west Europe, and has a broad host range that includes other economically important plants. The species was described only recently and little is known about its biology. This study examines the effect of temperature on hatch and motility of second-stage juveniles (J2), and records hatching from egg masses collected from golf greens in different seasons. Eggs were present throughout the year and a high percentage hatch (46-88%) was recorded when they were incubated at 20°C. When egg masses were incubated at constant temperatures, J2 hatched between 15 and 25°C, with limited hatch (

Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species' threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project - and avert - future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups - including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems - www.predicts.org.uk). We make site-level summary data available alongside this article. The full database will be publicly available in 2015. The collation of biodiversity datasets with broad taxonomic and biogeographic extents is necessary to understand historical declines and to project - and hopefully avert - future declines. We describe a newly collated database of more than 1.6 million biodiversity measurements from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. © 2014 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.