We reviewed the evidence for the effects of fragmentation on insects and plants by conducting a meta-analysis for the effects of artificial forest edge formation on insect herbivore abundance, herbivore richness, and plant herbivory, with data pooled from 31 studies and 159 independent comparisons. Hedge's d was used as the metric to combine all studies. Edge formation exhibited strong effects on plant herbivory rates, as edge plants exhibited 70% more damage than interior plants. Edges also increased herbivore abundance by 14% and herbivore richness by almost 65%, and effects of edge formation were stronger for Lepidoptera (mainly caterpillars) and Orthoptera. Edge effects were also stronger for forested ecosystems compared with open habitats and for temperate regions. Because the studies here evaluated did not simultaneously evaluate bottom-up and top-down factors, the mechanisms responsible for the patterns found cannot be properly addressed, although variation in host plant chemistry, relaxation of pressure exerted by natural enemies, or both, can be suggested as potential factors explaining variation in herbivory between edge and interior habitats. Higher herbivory rates on edge habitats, as shown by our meta-analytical review, have the potential to alter community composition and should be studied in detail to unravel their effects on ecosystem functioning.

Exotic herbivorous insects have drastically and irreversibly altered forest structure and composition of North American forests. For example, emerald ash borer (Agrilus planipennis Fairmaire) from Asia has caused wide-scale mortality of ash trees (Fraxinus spp.) in eastern United States and Canada. We studied the effects of forest changes resulting from emerald ash borer invasion on epigaeic or ground beetles (Coleoptera: Carabidae) along a gradient of ash dieback and gap sizes in southeastern Michigan. Ground beetles were sampled in hydric, mesic, and xeric habitats in which black (Fraxinus nigra Marshall), green (Fraxinus pennsylvanica Marshall), and white (Fraxinus americana L.) ash were the most common species, respectively. During 2006–2007, we trapped 2,545 adult ground beetles comprising 52 species. There was a negative correlation between percent ash tree mortality in 2006 and catches of all beetles. Catches of Agonum melanarium Dejean (in 2006) and Pterostichus mutus (Say) (in 2006–2007) were negatively correlated with tree mortality and gap size, respectively. However, catches of Pterostichus corvinus Dejean were positively correlated with gap size in 2006. As ash mortality and average gap size increased from 2006 to 2007, catches of all beetles as well as P. mutus and Pterostichus stygicus (Say) increased (1.3–3.9 times), while species diversity decreased, especially in mesic and xeric stands. Cluster analysis revealed that beetle assemblages in hydric and mesic stand diverged (25 and 40%, respectively) in their composition from 2006 to 2007, and that hydric stands had the most unique beetle assemblages. Overall, epigaeic beetle assemblages were altered in ash stands impacted by emerald ash borer; however, these impacts may dissipate as canopy gaps close.

Responses of plants to grazing are better understood, and more predictable, than those of consumers in North American grasslands. In 2003, we began a large-scale, replicated experiment that examined the effects of grazing on three important arthropod groups—beetles, spiders, and grasshoppers—in shortgrass steppe of north-central Colorado. We investigated whether modifications of the intensity and seasonality of livestock grazing alter the structure and diversity of macroarthropod communities compared with traditional grazing practices. Treatments represented a gradient of grazing intensity by cattle and native herbivores: long-term grazing exclosures; moderate summer grazing (the traditional regime); intensive spring grazing; intensive summer grazing; and moderately summer-grazed pastures also inhabited by black-tailed prairie dogs (Cynomys ludovicianus Ord). Beetles and spiders were the most common groups captured, comprising 60% and 21%, respectively, of 4,378 total pitfall captures. Grasshopper counts were generally low, with 3,799 individuals observed and densities <4 m^-2. Two years after treatments were applied, vegetation structure differed among grazing treatments, responding not only to long-term grazing conditions, but also to the short-term, more-intensive grazing manipulations. In response, arthropods were, in general, relatively insensitive to these grazing-induced structural changes. However, species-level analyses of one group (Tenebrionidae) revealed both positive and negative effects of grazing treatments on beetle richness and activity-density. Importantly, these responses to grazing were more pronounced in a year when spring-summer rainfall was low, suggesting that both grazing and precipitation—which together may create the greatest heterogeneity in vegetation structure—are drivers of consumer responses in this system.

Studies manipulating predator diversity and measuring the impact on herbivore abundance have found that enhancing predator species richness often increases the strength of prey suppression. This relationship may be due to mechanisms such as complementarity or facilitation, which are considered “true” benefits of diversity because greater prey suppression is an emergent property of the multispecies predator community. Or it may be due to an identity effect, an “apparent” benefit of diversity that results from the greater likelihood of including one particularly voracious predator species as the total number of predator species increases. In separate greenhouse and field experiments, we simultaneously manipulated the species richness and species composition of predators attacking bird cherry-oat aphids (Rhopalosiphum padi) (L.) on wheat (Triticum aestivum L.). We found that on average aphid suppression by species-rich predator assemblages was greater than suppression by single-species monocultures. However, the performance of individual predator species varied and the species-rich assemblages did not outperform all single-species compositions, suggesting an identity effect. In particular, single-species compositions of the lady beetle Coleomegilla maculata (DeGeer) exhibited high performance across experiments, and on average predator assemblages that contained a lady beetle predator had lower overall aphid abundance than compositions where lady beetles were absent. Taken together, these results provide evidence for the dominant role of lady beetles, especially C. maculata, in natural pest suppression and suggest that predator species composition and identity are important factors to consider in efforts to conserve this valuable ecosystem service.

Soybean aphid (Aphis glycines Matsumura) (Hemiptera: Aphididae) is a major pest of soybean in northern production regions of North America, and insecticides have been the primary management approach while alternative methods are developed. Knowledge of arthropod natural enemies and their impact on soybean aphid is critical for developing biological control as a management tool. Soybean is a major field crop in South Dakota, but information about its natural enemies and their impact on soybean aphid is lacking. Thus, this study was conducted in field plots in eastern South Dakota during July and August of 2004 and 2005 to characterize foliar-dwelling, arthropod natural enemies of soybean aphid, and it used exclusion techniques to determine impact of natural enemies and ants (Hymenoptera: Formicidae) on soybean aphid densities. In open field plots, weekly soybean aphid densities reached a plateau of several hundred aphids per plant in 2004, and peaked at roughly 400 aphids per plant in 2005. Despite these densities, a relatively high frequency of aphid-infested plants lacked arthropod natural enemies. Lady beetles (Coleoptera: Coccinellidae) were most abundant, peaking at 90 and 52% of all natural enemies sampled in respective years, and Harmonia axyridis Pallas was the most abundant lady beetle. Green lacewings (Neuroptera: Chrysopidae) were abundant in 2005, due mainly to large numbers of their eggs. Abundances of arachnids and coccinellid larvae correlated with soybean aphid densities each year, and chrysopid egg abundance was correlated with aphid density in 2005. Three-week cage treatments of artificially infested soybean plants in 2004 showed that noncaged plants had fewer soybean aphids than caged plants, but abundance of soybean aphid did not differ among open cages and ones that provided partial or total exclusion of natural enemies. In 2005, plants within open cages had fewer soybean aphids than those within cages that excluded natural enemies, and aphid density on open-cage plants did not differ from that on noncaged plants and those accessible by small predators. In a separate 3-yr experiment, exclusion of ants from soybean plants did not lead to differences in soybean aphid density compared with ant-accessible plants. Overall, these results suggest that the soybean aphid natural enemy guild is unsaturated and could be enhanced to improve biological control of soybean aphid in South Dakota.

Aphids harbor a variety of bacterial endosymbionts, including the obligate symbiont Buchnera aphidicola and diverse facultative symbionts. The former supplies its host with essential amino acids. The latter are not indispensable for insect survival, but often improve their host's fitness. To date, the study of such associations was restricted to aphids of Holarctic origin. The bacterial microbiota of seven Aphis species from Argentina was investigated. The presence of B. aphidicola was assessed by specific PCR. Additional symbionts were identified through PCR with eubacterial universal primers, cloning, and sequencing of nearly complete 16S rRNA gene, intergenic spacer region, and partial 23S rRNA gene and subjected to phylogenetic analysis. Infection with B. aphidicola was confirmed in every species analyzed. The facultative symbiont Serratia symbiotica was detected in Aphis malalhuina Mier Durante, Nieto Nafría & Ortego, 2003, Aphis senecionicoides Blanchard, 1944, and Aphis schinifoliae Blanchard, 1939, while Hamiltonella defensa was identified in Aphis mendocina Mier Durante, Ortego & Nieto Nafría, 2006. Arsenophonus sp. was found infecting Aphis melosae Mier Durante & Ortego, 1999, and a new, undescribed Aphis sp. In Aphis danielae Remaudière, 1994, no facultative symbionts could be recorded. When analyzing the highly conserved 16S rRNA gene, the phylogenetic tree grouped the S. symbiotica, H. defensa, and Arsenophonus isolates into three well-defined clusters showing little variability among clones corresponding to the same aphid host species. This article reports for the first time the endosymbionts associated with aphids native to South America. Despite their geographic origin, the qualitative composition of their microbiota revealed no evident differences from that described for aphids in the Northern Hemisphere.

Insects are associated with a diversity of bacteria that colonize their midguts. The extent to which these communities reflect maternal transmission, environmental acquisition, and subsequent structuring by the extreme conditions within the insect gut are poorly understood in many species. We used gypsy moth (Lymantria dispar L.) as a model to investigate interactions between egg mass and environmental sources of bacteria on larval midgut communities. Egg masses were collected from several wild and laboratory populations, and the effects of diet, initial egg mass community, and internal host environment were evaluated using 454 16S-rRNA gene pyrosequencing. Wild populations were highly diverse, while laboratory-maintained egg masses were associated with few operational taxonomic units. As larvae developed, their midgut bacterial communities became more similar to each other and the consumed diet despite initial differences in egg mass-associated bacteria. Subsequent experiments revealed that while midgut membership was more similar to bacteria associated with diet than with egg mass-associated bacteria, we were unable to detect distinct, persistent differences attributable to specific host plants. The differences between foliar communities and midgut communities of larvae that ingested them were owing to relative changes in populations of several bacteria phylotypes. We conclude that gypsy moth has a relatively characteristic midgut bacterial community that is reflective of, but ultimately distinct from, its foliar diet. This work demonstrates that environmental acquisition of diverse microbes can lead to similar midgut bacterial assemblages, underscoring the importance of host physiological environment in structuring bacterial communities.

Aphids are a group of insects frequently associated with bacterial symbionts. Although Chinese aphids harbor a high level of species diversity, the associations between Chinese aphids and bacterial symbionts are less known. In this study, we uncovered the diversity of bacterial symbionts in a Chinese widespread aphid, Sitobion miscanthi (Takahashi). In this study, we detected the aphid obligate symbiont Buchnera aphidicola, and two secondary symbionts, Hamiltonella defensa and Regiella insecticola, with the diagnostic polymerase chain reaction method in S. miscanthi samples. In addition, symbiotic species of Acinetobacter, Aeromonas, Enterobacter, Pantoea, and Pseudomonas, and the family Enterobacteriaceae were also found. Geographically, sporadic occurrences were detected for H. defensa and R. insecticola. Moreover, the infection rates of them vary widely among the infected populations: H. defensa (5.26–95.2%) and R. insecticola (5.26–46.7%). Phylogenetic analyses indicated that the strain of B. aphidicola mirrored the history and divergence of S. miscanthi; however, the H. defensa and R. insecticola strains were probably experienced horizontal transmission among S. miscanthi and its distantly related species.

The entomopathogen Bacillus thuringiensis is used to control various pest species of scarab beetle but is not particularly effective. Gut bacteria have diverse ecological and evolutionary effects on their hosts, but whether gut bacteria can protect scarabs from B. thuringiensis infection remains poorly understood. To investigate this, we isolated 32 cultivable gut bacteria from Holotrichia oblita Faldermann, Holotrichia parallela Motschulsky, and Anomala corpulenta Motschulsky, and analyzed their effect on B. thuringiensis multiplication and Cry toxin stability. 16S rDNA analysis indicated that these gut bacteria belong to the Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes phyla. A confrontation culture analyses of the 32 isolates against three scarab-specific B. thuringiensis strains showed that the majority of the scarab gut bacteria had antibacterial activity against the B. thuringiensis strains. The Cry toxin stability analysis results showed that while several strains produced proteases capable of processing the scarab-specific toxin Cry8Ea, none were able to completely degrade it. These results suggest that gut bacteria can potentially affect the susceptibility of scarabs to B. thuringiensis and that this should be considered when considering future control measures.

A recent invader of North America, the brown marmorated stink bug (Halyomorpha halys Stål) is a polyphagous pentatomid that harbors a gammaproteobacterial mutualist in the crypts of specialized midgut gastric caeca (region V4). Histological analyses revealed a single rod-shaped morphology abundant in distal V4 midgut caecal crypts. A strong fluorescence signal was detected when thin sections of these tissues were hybridized with a fluorescently-labeled, Enterobacteriaceae-specific oligonucleotide probe. A single operational taxonomic unit (OTU) assigned to the Pantoea genus represented >99% of 3,454 16S rDNA amplicons obtained from midgut V4 tissues and egg samples. Detection of H. halys primary symbiont in DNA extracted from eggs suggested vertical maternal inheritance as the mode of intergenerational transmission. Consistent detection of the bacterial symbiont in geographically distinct H. halys populations strongly supports an intimate association between these two organisms. An inferred phylogeny of gammaproteobacterial symbionts of pentatomids placed the Pantoea-assigned OTU from H. halys within a clade distinct from primary bacterial symbionts of related stink bugs, Nezara viridula (L.) and Eurydema rugosa Motschulsky. Given these data, Candidatus “Pantoea carbekii” is proposed as the name of the primary bacterial symbiont of H. halys.

Silvicultural treatments such as thinning have been suggested as management tools against the spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae). Among other things, parasitoids are also proposed to be influenced by silvicultural procedures, but the effect of thinning on spruce budworm's natural enemies has not been tested yet. In this study, the influence of partial cutting on parasitism of endemic spruce budworm populations has been investigated in mature balsam fir-white birch forests. Two intensities of partial cutting (25 and 40% stand basal area reduced) were conducted in 2009 and parasitism of introduced spruce budworm larvae and pupae was determined during the 3 yr after these treatments. Pupal parasitism was too low for comparison between treatments. However, 2 yr after treatments, parasitism of the fourth- and fifth-instar larvae was significantly reduced in plots with both intensities of partial cutting, which was attributed to the parasitoid Tranosema rostrale (Brischke). Three years after treatments, no significant influence of partial cutting on parasitism of spruce budworm larvae was found. This study suggests that the influence of partial cutting on parasitism of endemic spruce budworm populations is not consistent, but that under certain circumstances parasitism is reduced by partial cutting.

The fungal pathogen Entomophaga maimaiga Humber, Shimazu, and Soper is prevalent in gypsy moth [Lymantria dispar (L.)] populations throughout North America. To understand how weather-related variables influence gypsy moth—E. maimaiga interactions in the field, we measured fungal infection rates at 12 sites in central Pennsylvania over 3 yr, concurrently measuring rainfall, soil moisture, humidity, and temperature. Fungal mortality was assessed using both field-collected larvae and laboratory-reared larvae caged on the forest floor. We found significant positive effects of moisture-related variables (rainfall, soil moisture, and relative humidity) on mortality due to fungal infection in both data sets, and significant negative effects of temperature on the mortality of field-collected larvae. Lack of a clear temperature relationship with the mortality of caged larvae may be attributable to differential initiation of infection by resting spores and conidia or to microclimate effects. These relationships may be helpful in understanding how gypsy moth dynamics vary across space and time, and in forecasting how the gypsy moth and fungus will interact as they move into warmer or drier areas, or new weather conditions occur due to climate change.

When laboratory host specificity tests on weed biological control agents produce ambiguous results or are suspected of producing false-positive findings, field cage or open field tests can be used to help determine the true ecological host range of the agent. The leaf beetle Diorhabda elongata (Brullé) from Crete, imported to the United States for the control of saltcedar (Tamarix spp., Tamaricaceae), showed a low but variable ovipositional response to nontarget Frankenia spp. (Frankeniaceae) in previous laboratory tests conducted in small cages, where up to 11.4% of eggs were laid on these native plants. Results from field tests presented in this article show that no eggs were laid on Frankenia palmeri S. Watson and significantly more eggs were always laid on Tamarix ramosissima Ledebour than Frankenia salina (Molina) I. M. Johnston. Furthermore, the ovipositional response to F. salina was substantially lower than that recorded in laboratory tests. The percent of eggs laid on F. salina in field tests was 3.7 in a paired choice cage test, 4.3 in a multiple choice cage test, and 2.5 in a multiple choice open field test, suggesting that the true acceptance rate of the nontarget by D. elongata in the field will be lower than laboratory tests predicted. However, some damage was caused to F. salina by adult and larval feeding in the field, although this occurred only at the very end of the open field test, when D. elongata densities were extremely high, and all of the surrounding saltcedar had been totally defoliated. Scientific representatives from various stakeholder organizations (state, county, university, and environmental groups) viewed the open field test when in progress and reviewed the final results before advising State regulatory agencies on beetle redistribution. These test results, and the open review process, led regulators to conclude that redistribution of D. elongata in California was warranted owing to its significant ability to defoliate saltcedar, and its low rate of feeding on nontarget Frankenia spp. The introduction of D. elongata provides an interesting case study for risk assessment of a potentially efficacious weed biocontrol agent that may also be capable of using nontarget native plants.

Samples of soils, rice plants, and the adult, long-winged, brown planthoppers, Nilaparvata lugens (Stål) (Homoptera: Delphacidae), were collected from 18 sites of 9 regions in southern China. the concentrations of seven elements (Cu, Zn, As, Mo, Ag, Cd, and Pb) were measured using inductively coupled plasma mass spectrometry. Heavy metal mobility and bioaccumulation were analyzed in the rice plant—N. lugens system. the concentrations of Zn, As, Cd, and Pb in rice plants were positively correlated with their relevant concentrations in soil samples the bioconcentration factors of the seven elements in the rice plant—N. lugens system showed that the order of metal accumulation was Mo>Zn>Ag>Cd>Cu>Pb>As. In particular, Mo and Zn showed signitcantly high accumulation in N. lugens A cluster analysis and factor analysis showed that the bioaccumulation of these seven elements in the rice plant—N. lugens system could be classited into two groups, closely related to their molar mass. the first group consisted of tve elements with relatively light molar masses: Cu, Zn, As, Mo, and Ag. Cu and Zn, which have nearly equal molar masses, showed similar accumulation levels in N. lugens. the second group included two elements with relatively heavy molar masses: Cd and Pb. this study demonstrated that bioaccumulation of seven heavy metals was regular in the rice plant—N. lugens system. N. lugens could be used as bioindicators of the contaminated degree for Zn in rice paddy fields. this information may provide a basis for future ecological research on the bioaccumulation mechanism in N. lugens.

Potato virus Y (PVY) is an economically important and reemerging potato pathogen in North America. PVY infection reduces yield, and some necrotic and recombinant strains render tubers unmarketable. Although PVY^O is the most prevalent strain in the United States, the necrotic and recombinant strains PVY^NTN and PVY^N:O are becoming more widespread. Infection rates in aphidinoculated (Myzus persicae (Sulzer)) and mechanically inoculated plants were compared across two potato genotypes (’Yukon Gold’ and A98345-1), three PVY strains (PVY^O, PVY^N:O, and PVY^NTN), and two growth stages at inoculation (pre- and postflowering). Susceptibility of genotypes was measured as infection rate using a double-antibody sandwich-enzyme-linked immunosorbent assay; virus titer and tuber mass also were recorded from the infected plants. Yukon Gold generally was more susceptible than A98345-1 to all three PVY strains, especially following mechanical inoculation. Within genotypes, Yukon Gold was most susceptible to PVY^O and A98345-1 was most susceptible to PVY^N:O. Plants exhibited age-based resistance, with both genotypes showing higher susceptibility at the prethan postflowering stage. The overall ranking pattern of virus titer in infected plants was PVY^O > PVY^NTN > pvy^N:O; across all three strains, infected Yukon Gold had higher titer than infected A98345-1 plants. Yukon Gold plants had lower tuber mass than A98345-1 when infected, and there were differences between the two inoculation methods in regard to tuber mass for the three stains. The results showed differences in infection response between inoculation methods and as a function of genotype, strain, inoculation stage, and their interactions. These factors should be considered when screening genotypes for resistance.

In the molecular arms race between aphids and plants, both organisms rely on adaptive strategies to outcompete their evolutionary rival. In the current study, we investigated the difference in elicited defense responses of wheat (Triticum aestivum L.) near-isogenic lines with different Dn resistance genes, upon feeding by an avirulent and hypervirulent Diuraphis noxia Kurdjumov biotype. After measuring the activity of a suite of enzymes associated with plant defense, it became apparent that the host does not recognize the invasion by the hypervirulent aphid because none of these were induced, while feeding by the avirulent biotype did result in induction of enzyme activity. Genomic plasticity in D. noxia may be a likely explanation for the observed differences in virulence between D. noxia bio type SA1 and SAM, as demonstrated in the current study.

The cereal aphid Metopolophium festucae subsp. cerealium (Stroyan) is a recent addition to North America, but little is known about this species in its exotic habitat. We surveyed aphid populations for 3 years (2011–2013) to investigate changes in aphid density in the Pacific Northwest United States. We tested aphid host settling preference and fecundity on eight grass species, four native grasses (bluebunch wheatgrass, blue wild rye, Idaho fescue, and rough fescue) and four cereal crops (corn, wheat, barley, and oat), and evaluated the effects of aphid feeding on plant biomass. Four important findings emerged: 1) aphid prevalence in sweep net samples increased from 2011 to 2012, but remained stable from 2012 to 2013; 2) aphids preferentially settled on wheat and avoided corn, but aphids did not discriminate between barley, oat, and native grasses; 3) aphid fecundity was high on wheat and barley, intermediate on oat and blue wild rye, low on Idaho fescue, rough fescue, and bluebunch wheatgrass, and aphids did not reproduce at all on corn; and 4) barley, corn, oats, Idaho fescue, and blue wild rye were not susceptible to aphid feeding damage, but wheat, rough fescue, and bluebunch wheatgrass were susceptible to aphid feeding damage. Our results suggest that wheat and barley are preferred by M. festucae cerealium, and that aphids reproduce most rapidly on these hosts and cause significant reductions in wheat but not barley growth. Also, M. festucae cerealium appears capable of surviving on native grasses, although only bluebunch wheatgrass and rough fescue were susceptible to aphid feeding damage.

Pezothrips kellyanus (Bagnall) (Thysanoptera: Thripidae) has recently become a pest of citrus whose nymphs feed on the surface of young fruitlets. This feeding habit causes patches or rings of tissue scar around the apex as fruit mature. Currently, little is known about the distribution of P. kellyanus nymphs. Further knowledge would allow the development of an appropriate sampling protocol and targeted pesticide application. In our first experiment, the abundance of first- and second-generation P. kellyanus nymphs was surveyed in a citrus orchard at different times of day to characterize their spatial and temporal distributions. The distribution of damaged fruit was also measured at harvest. Our results showed that P. kellyanus nymphs tended to be present in the upper half of the canopy and mainly damaged the fruit located in this area of the canopy. However, P. kellyanus nymphs were uniformly distributed among the four cardinal directions of the canopy and throughout the day. Consequently, cardinal direction and time of the day seem to be less important when developing a sampling plan or in improving targeting or timing of insecticidal spray applications. In our second experiment, we tracked the presence of P. kellyanus nymphs in labeled fruit daily. These data were used to determine how many days the nymphs occupied a fruit and to relate occupancy and premature fruit abscission. The nymphs of P. kellyanus remained on the same fruit for only 1 d. The rate of fruit abscission in June was significantly higher in fruit occupied by first-generation P. kellyanus nymphs than in nonoccupied fruit.

The navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae), is a key pest of almond, pistachio, and walnut tree crops in California. Understanding dispersal of adults between orchards is important to improving management options. Laboratory flight behavior of unmated navel orangeworm of ages 1, 2, 3, 5, and 7 d posteclosion was examined using flight mills. As a group, females flew farther and longer than males, but the differences were not statistically significant. Flight speed did not differ between sexes. Flight duration and distance did not differ with age, except that 7-d-old adults performed worse for these parameters than did 1- and 2-d-old adults. Females began their flights ≈1.5 h after the onset of dusk, and ≈1.5 h earlier in the night than males. Flight capacity and propensity were substantial for both sexes and all age classes tested. At least 20% of adults (except 7-d-old males) made a continuous flight ≥5.5 h, and median total distances flown during the 10.5-h night ranged from 7 to 15 km depending on age class. Thus navel orangeworm flight mill performance was greater than that of most pests tested from the families Pyralidae and Tortricidae. Surface area and length of forewings and hindwings were greater in females than males, but had little effect on flight performance. The results are generally consistent with field observations of navel orangeworm dispersal, but it will be important to characterize the effects of mating on flight, and flight on fecundity.

The Mexican fruit fly, Anastrepha Indens (Loew), is one of the 10 worldwide more important fruit crop pests. Orchards of southeastern Chiapas also shelter the tree-dwelling lizard Norops serranoi (Köhler), which likely prey upon these flies. In standard laboratory conditions, we determined the functional response of four male and four female lizards on mass-reared fruit flies. We used a general logistic analysis of proportion of killed prey versus available prey to determine the shape of the functional response. Male lizards showed a type II functional response, while females showed a type III functional response. For the highest fruit fly densities, female lizards caught significantly more fruit flies than males did. The predator evasion ability and the survival of mass-reared and wild fruit flies were compared. Wild fruit flies evaded more male lizard attacks than mass-reared flies. However, when female lizards attacked, there was no significant difference between strains. Fruit flies survival was higher with male than with female lizards, but it did not depend on fruit fly strains. This is the first report of a vertebrate preying on the Mexican fruit fly, demonstrating that female lizards impose a higher predation pressure and are more efficient at capturing wild fruit flies than males. We discuss the implications of our results on mass-rearing and quality control of sterile flies.

Grape root borer, Vitacea polistiformis (Harris) (Lepidoptera: Sesiidae) is a potentially destructive pest of grape vines, Vitis spp. in the eastern United States. After feeding on grape roots for ≈2 yr in Virginia, larvae pupate beneath the soil surface around the vine base. Adults emerge during July and August, leaving empty pupal exuviae on or protruding from the soil. Weekly collections of pupal exuviae from an ≈1-m-diameter weed-free zone around the base of a grid of sample vines in Virginia vineyards were conducted in July and August, 2008–2012, and their distribution was characterized using both nonspatial (dispersion) and spatial techniques. Taylor's power law showed a significant aggregation of pupal exuviae, based on data from 19 vineyard blocks. Combined use of geostatistical and Spatial Analysis by Distance IndicEs methods indicated evidence of an aggregated pupal exuviae distribution pattern in seven of the nine blocks used for those analyses. Grape root borer pupal exuviae exhibited spatial dependency within a mean distance of 8.8 m, based on the range values of best-fitted variograms. Interpolated and clustering index-based infestation distribution maps were developed to show the spatial pattern of the insect within the vineyard blocks. The temporal distribution of pupal exuviae showed that the majority of moths emerged during the 3-wk period spanning the third week of July and the first week of August. The spatial distribution of grape root borer pupal exuviae was used in combination with temporal moth emergence patterns to develop a quantitative and efficient sampling scheme to assess infestations.

The goldspotted oak borer, Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), is an invasive species that has colonized oak woodlands in southern California. To better define its seasonal flight activity, assist with forest and integrated pest management activities, and define the current distribution in California, an effective monitoring technique for A. auroguttatus is necessary. We assessed the efficacy of two colors of flight-intercept prism traps, the placement of these traps at three heights, and several commercially available lures [Manuka oil, Phoebe oil, and a green leaf volatile, (3Z)-hexenol] for monitoring the flight of adult A. auroguttatus. Landing rates and the densities of D-shaped emergence holes of A. auroguttatus adults were assessed on the lower stems of coast live oak, Quercus agrifolia Née, of varying size and crown health classes. Purple flight-intercept prism traps placed at heights of 3 m and 4.5 m caught significantly more female A. auroguttatus than green prism traps. In one experiment, males also responded at a significantly higher level to purple than to green prism traps placed at 3 m height. The addition of commercially available lures significantly enhanced male, but not female, A. auroguttatus trap catch when compared with unbaited control traps. There were no differences among male flight responses to the three lures. A. auroguttatus landing rates and emergence hole densities were significantly greater on the largest-diameter trees (>76.2 cm diameter at breast height) and on trees with severe crown thinning or complete crown collapse. The annual increment in emergence hole densities was also significantly greater on trees with severe crown thinning or complete crown collapse. In three trapping studies over multiple years in southern California, the adult flight period began as early as mid-May, peaked in mid-June to early July, and ended in early- to mid-September. To demonstrate the efficacy of the detection method for A. auroguttatus (unbaited purple traps at 3 m height), a delimitation survey conducted from 2009 to 2012 confirmed that the species was only present in San Diego Co., but that the distribution was expanding northward.

Spatial distribution of boll injury caused by stink bugs to developing cotton (Gossypium hirsutum L.) bolls was studied in five commercial fields (≈22 ha each) in 2011 and 2012 to understand variability in boll injury dynamics within fields. Cotton bolls and stink bugs were sampled weekly from a georeferenced grid of sampling points (one sample per 0.40 ha) in each field, but no samples were taken within 30 m of field edges. The inverse distance weighted interpolation, variogram analysis, and Moran's 7 were used to describe spatial variability of boll damage within the fields. Boll injury was found to be spatially associated at distances ranging from =75 to 275 m with an average distance ≈150 m. An exponential variogram model was selected as the best fitting model to describe the spatial association in four of the five fields. Moran's 7 indicated that spatial association was significant in three of the five fields. The spread of boll injury from stink bugs was gradual in most fields and always exceeded the treatment threshold during the fourth or fifth week of bloom. Capture of stink bugs using a sweep net was inefficient, strongly suggesting that quantifying boll injury is a better sampling method and predictor of stink bug activity when sampling all but the edges of the field. These data suggest that scouts need to sample boll injury from sample locations separated by at least 150 m to assure independence in the central part of large fields. Second, future researchers who plan to use parametric statistical methods could use a 150-m grid, as opposed to a denser grid that would require greater time and effort.

Plum curculio, Conotrachelus nenuphar (Herbst), one of the most important pests of apple in eastern and central North America, is usually managed in New England apple orchards by multiple full-block insecticide applications. Efforts to reduce insecticide inputs against plum curculio include using an “attract and kill” approach: odor-baited trap trees deployed in the perimeter row of apple orchards. The standard approach is based on baiting apple trees with two olfactory stimuli, the fruit volatile benzaldehyde and the aggregation pheromone of plum curculio, grandisoic acid. We attempted to improve attraction, aggregation, and retention of adult plum curculios within specific baited trap tree canopies within apple orchards using an additional host plant volatile found to be highly stimulating in electroantennogram studies, trans-2-hexenal. We also attempted to increase aggregation using increased release rates of grandisoic acid. We found that trans-2-hexenal did not provide increased aggregation when deployed as an additional attractant within trap trees or when conversely deployed as a “push” component or repellent in perimeter trees lateral to the baited trap tree. Although increasing the release rate of grandisoic acid 5× actually appeared to increase overall aggregation within trap trees, it was not significantly different than that obtained using the standard dose. Therefore, we believe that the standard olfactory stimuli are sufficient to provide aggregation within trap trees, but that other means should be used to manage them after their arrival.

Heartwood samples from Juniperus virginiana L. were extracted with liquid carbon dioxide, and the bioactivity of carbon dioxide-derived cedarwood oil (CWO) toward several species of ants and cedrol toward ticks was determined. Repellency was tested for ants, and toxicity was tested for ticks. Ants in an outdoor bioassay were significantly repelled by the presence of CWO on a pole leading to a sugar—water solution. Similarly, CWO was a significant repellent barrier to red imported fire ants and prevented them from finding a typical food source. Black-legged tick nymphs exhibited dosage-dependent mortality when exposed to cedrol and at the highest dosage (i.e., 6.3 mg/ml) tested, the cedrol killed 100% of the ticks. These repellency and toxicity results together demonstrate a clear potential for the use of CWO as a pest control agent.

Pheromone dose, effective trapping distance, and longevity of the rubber septa loaded with sex pheromone of Cylas formicarius (F.) (Coleoptera: Brentidae) were evaluated for their impact on the efficacy of mass trapping of the insect in sweet potato fields in Guam in 2012–2013. The number of adults caught at different distances (10–100 m) was significantly different. Catches declined with increasing release distance from the trap in both downwind and upwind directions. While the maximum radius of attraction of pheromone-baited trap for C. formicarius in the field was 80 m, the effective distance for recapturing marked adults in the pheromone-baited Unitraps was 60 m. Pheromone lures were able to capture adults of C. formicarius after being stored in the laboratory for up to 98 d. The number of catches per trap per week was highest when lures were 0–14- and 15–28-d-old, and longer storage of septa led to a progressive reduction of catches. Pheromone traps baited with 100-µg lures captured significantly more adults compared with those loaded with 10-µg lures. In addition, effectiveness of pheromone trapping on damage to sweet potato was tested at two locations. Number of trapped adults, damage level at different times after trap installation, and yield production were evaluated. The number of C. formicarius adults collected in traps at both locations fluctuated dramatically among sampling dates and peaked on 13 September 2013, after which time the number of captures noticeably declined. This decrease was correlated to the increasing age and depletion of the pheromone lures. Pheromone traps significantly reduced feeding damage caused by weevils (<1 feeding hole per root in treatment; up to 38 feeding holes per root in the control) at both locations. Being consistent with damage levels, sweet potato yields in fields with traps were higher than those in untreated controls. We conclude that pheromone-baited traps are effective in reducing damage due to C. formicarius.

Popillia quadriguttata (F.) has caused extensive damage to ≈20 families and 25 species of plants in Asia, especially in China and Korea. Adult feeding causes serious damage to soybean leaves, and larvae develop on the roots of soybean, turf, and horticultural crops. As Japanese beetle (Popillia japonica Newman) lures have been used for trapping P. quadriguttata in a previous study, mass trapping this pest with various densities of the Japanese beetle pheromone, Japonilure, and floral lure, alone and in combination, were carried out during 2012–2013 in a northeastern China soybean field. Mass trapping in 2012 with Japonilure gave the best results with 72 and 75% adult and larval reduction, respectively. In 2013, mass trapping (30 traps per hectare) with Japonilure, floral lure, or the combination resulted in a 93, 70, and 74% reduction of adults trapped, and a 90, 77, and 93% reduction of overwintering larvae, respectively. In addition, field tests showed that almost twice as many beetles approached the lure combination compared with the floral lure alone, and the pheromone residual was ≈80% of the initial dosage after 30 d. Because reduction of overwintering larvae is the most critical parameter indicating treatment efficacy, the results here indicate that the lure or lure combinations can be recommended for use by Chinese soybean farmers.

A laboratory experiment was performed to compare fitness parameters of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), populations collected from the Hills and Delta regions of Mississippi. Each population was split into two cohorts to be reared on cotton or artificial diet to make comparisons of food source and region of collection. Each population was maintained separately and allowed to mate. Nymphal survivorship from the F1 generation of each population from each region and food source was compared. Parameters measured included development times to fourth instar, fifth instar and adult, total nymphal survivorship, fecundity, and fertility. Populations collected from the Delta region and reared on cotton developed significantly faster at all life stages than other populations. Tarnished plant bugs from the Hills reared on cotton developed significantly slower than other populations, except those from the Hills reared on artificial diet. Populations reared on diet had significantly higher survivorship than those reared on cotton. Tarnished plant bug populations from the Delta region laid significantly more eggs per female per day than those from the Hills region. Populations reared on cotton also laid significantly more eggs per female per day than those reared on diet. Populations collected in the Delta region laid significantly more viable eggs per female per day than those from the Hills region. Tarnished plant bugs reared on cotton produced significantly more nymphs per female per day than those reared on diet. These data indicate there are differences in several fitness parameters between tarnished plant bug populations from the Hills and Delta regions of Mississippi.

Solar ultraviolet-B (UVB) radiation is deleterious to plant-dwelling mites. Neoseiulus californicus (McGregor) is a predominant predator of agriculturally important pest species of spider mite. However, phytoseiid mites are more vulnerable to UVB radiation than spider mites. Thus, the UVB radiation may influence decision making in foraging phytoseiid mites whether disperse or not. We tested the difference in impact and behavioral response among wavelengths of monochromatic UV radiation using a spectroscopic light source in N. californicus in the laboratory. We also examined whether the behavioral responses of N. californicus females to UV radiation varied based on the presence of prey (Tetranychus urticae Koch) eggs and residues (webs and excreta of T. urticae: foraging cue). The impact of UV radiation on the N. californicus egg hatchability varied drastically between wavelengths of ≤300 nm (0%) and ≥310 nm (100%). The N. californicus females escaped from UV radiation more quickly when they were irradiated with UV at shorter wavelength. Presence of T. urticae eggs had no effects arresting the escape of phytoseiid mites. In contrast, prey residues (including eggs) markedly detained N. californicus females from escaping under UV irradiation at ≥310 nm. However, N. californicus females quickly escaped when irradiated with UV at harmful 300 nm wavelength, regardless of prey cues. This indicates that the eyeless phytoseiid mite is capable of perceiving UV radiation, and whether escape or not is determined on the basis of harmful/harmless UV wavelength and presence/absence of foraging cues.

Age-specific life table parameters, survivorship, and extra molting of the beet armyworm, Spodoptera exigua (Hübner), were determined at eight constant temperatures of 12, 15, 20, 25, 30, 33, 34, and 36°C with a variation of 0.5°C on sugar beet leaves. No development was observed at 12 and 36°C. The survivorship of overall immature stages was higher at 25°C than the other temperatures. The highest (0.276 d^-1) and lowest (0.149 d^-1) value of the intrinsic rate of increase (r) was observed at 30 and 20°C, respectively. Although the highest value of the net reproductive rate was at 25°C (377.7 female offspring at 25°C and 127.4 female offspring at 30°C), the highest value of r was at 30°C, which indicated the importance of shorter development time (16.9 d at 30°C and 27.2 d at 25°C) in enhancing r. The relationship between temperature and r was modeled using the Lactin-2 model. The lower temperature threshold, the upper temperature threshold, and optimal temperature for the r were estimated at 13.1, 32.2, and 34.1°C, respectively. The mean generation time decreased significantly with increasing temperature, with the longest (35.9 d) and shortest (15.1 d) mean generation time was calculated at 20 and 33°C, respectively.

Microsatellite and mitochondrial DNA genetic monitoring of the western corn rootworm, Diabrotica virgifera virgifera LeConte, was undertaken in Croatia and Serbia from 1996 to 2011 and in the United States in 2011. The seven U.S. populations displayed the greatest allelic diversity. In Europe, the highest number of alleles was found in Rugvica, Croatia, and Surčin, Serbia, the two sites closest to international airports. The highest number of mitochondrial (mt) DNA haplotypes was recorded from Croatia in 1996. From 2009 to 2011, haplotype diversity declined, and Croatia and Serbia had a single fixed haplotype. U.S. continuous maize locations had one haplotype, while three haplotypes were found at crop-rotated locations. Minimal temporal genetic differentiation was found within and between populations in Europe and the United States. Bayesian cluster analysis identified two genetic clusters that grouped western corn rootworm from Croatia and Serbia separately from U.S. populations; however, these clusters were not neat, and numerous U.S. individuals had both European and U.S. ancestry, suggesting bidirectional gene flow. Bottlenecks were identified within most Croatian populations sampled in 1996, only two populations in 2009, and in all populations in 2011. Bottlenecks were not identified from Serbia from 1996 to 2011 or from the United States in 2011. As suspected Serbia was identified as the geographic source of western corn rootworm in Croatia. The temporal genetic monitoring undertaken allowed a deeper understanding of the population genetics of western corn rootworm in Croatia, neighboring Serbia, and its geographic source in the United States. The data obtained can be used to inform western corn rootworm pest management strategies in Croatia and Europe.

To assess the potential adverse effects of a Bt rice line (Japonica rice cultivar, Nakdong) expressing a synthetic cry1Ac1 gene, C7-1-9-1-B, which was highly active against all larval stages of Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Crambidae), we investigated the community structure of spiders in Bt and non-Bt rice fields during the rice-growing season in 2007 and 2008 in Chungcheongnam-do, Korea. Spiders were surveyed with a sweep net and suction device. Suction sampling captured more spiders, measured in terms of species level and abundance, than sweeping. Araneidae and Thomisidae were captured more by sweeping, and certain species were captured only by sweeping. These findings show that both suction and sweep sampling methods should be used because these methods are most likely complementary. In total, 29 species in 23 genera and nine families were identified from the 4,937 spiders collected, and both Bt and non-Bt rice fields showed a typical Korean spider assemblage. The temporal patterns of spider species richness and spider abundance were very similar between Bt and non-Bt rice, although significant differences in species richness were observed on a few occasions. Overall, spider community structure, including diversity, the dominant species, and abundance did not differ between Bt and non-Bt rice. The results of the study indicated that the transgenic Cry1Ac rice lines tested in this study had no adverse effects on the spider community structure of the rice fields.

Experimentally manipulated water and insect stresses were applied to field-grown corn with different Bacillus thuringiensis (Bt) transgenes and no Bt transgenes, and different non transgenic hybrid backgrounds (2011 and 2012, Corpus Christi, TX). Differences in leaf injury, ear injury, and yield were detected among experimental factors and their interactions. Under high and low water stress, injury from noctuid larvae (Lepidoptera: Noctuidae) on leaves during vegetative growth (primarily from fall armyworm, Spodoptera frugiperda J.E. Smith) and on developing ears (primarily from corn earworm, Helicoverpa zea [Boddie]) was lowest on more recent releases of Bt hybrids (newer Bt hybrids) expressing Cry1A. 105 Cry2Ab2 and Cry 3Bbl, compared with earlier Bt hybrids (older Bt hybrids) expressing CrylAb and Cry3Bbl and non-Bt hybrids. High water stress led to increased leaf injury under substantial fall armyworm feeding pressure in 2011 (as high as 8.7 on a 1–9 scale of increasing injury). In contrast, ear injury by corn earworm (as high as 20 cm² of surface area of injury) was greater in low water stress conditions. Six hybrid backgrounds did not influence leaf injury, while ear injury differences across hybrid backgrounds were detected for non-Bt and older Bt hybrid versions. While newer Bt hybrids expressing Cry1A.105 Cry2Ab2 and Cry 3Bbl had consistent low leaf injury and high yield and low but less consistent ear injury across six hybrid backgrounds, water stress was a key factor that influenced yield. Bt transgenes played a more variable and lesser role when interacting with water stress to affect yield. These results exemplify the interplay of water and insect stress with plant injury and yield, their interactions with Bt transgenes, and the importance of these interactions in considering strategies for Bt transgene use where water stress is common.

In much of the Corn Belt and parts of Europe, the western corn rootworm, Diabrotica virgifera virgifera LeConte, is the most important insect pest of maize. The need for additional basic knowledge of this pest has been highlighted while developing resistance management plans for insecticidal genetically modified crops. This study evaluated the possibility of tracking feeding habits of western corn rootworm larvae using stable carbon isotope signatures. Plants accumulate different ratios of ¹³C:¹²C isotopes, usually expressed as δ¹³C, according to whether they use the C₃ or C₄ photosynthetic pathway. Herbivore biomass is expected to reflect the δ¹³C of the food they eat. For the current experiment, western corn rootworm larvae were grown on different species of plants exhibiting different δ¹³C values. The δ¹³C values were then measured in elytra of emerged beetles. When beetles were unfed, biomass reflected larval feeding. When beetles were fed for 31 d postemergence, δ¹³C values of elytra almost exclusively reflected adult feeding. These results suggest the use of caution in the interpretation of δ¹³C data aiming to document larval diet history when adult feeding history is unknown. The technique was also used to evaluate western corn rootworm larval choice between alternate hosts and maize with and without genetically modified (Bt) traits aimed at their control. Propensity for feeding on alternate hosts versus maize was biased toward feeding on maize regardless whether the maize had Bt or not, suggesting western corn rootworm larvae were not repelled by Bt. These data will be helpful for regulators in interpreting western corn rootworm feeding data on Bt maize.