Catalase (CAT), glutathione reductase (GR), glutathione S-transferase (GST), and thiobarbituric acid reactive substances (TBARS) were measured together with cadmium (Cd) toxicity and accumulation in newly molted adults of Oncopeltus fasciatus (Dallas) exposed to the metal in drinking water. Insects were provided with either 200 or 20 mg Cd/liter (96-h LC₃₀ and LC₁₀, respectively) or with tap water for 1, 3, 5, and 7 d. Insects exposed to either concentration accumulated Cd in a time-dependent manner. Peroxilipids measured as TBARS were significantly elevated (1.7- to 1.9-fold) from day 3 in insects exposed to 200 mg Cd/liter, whereas TBARS levels of insects exposed to 20 mg Cd/liter were unaffected. Significant 2.3- and 1.9-fold inductions were observed in GR activity of insects treated with 200 mg Cd/liter for 5 and 7 d, respectively, while CAT and GST levels were not affected by Cd exposure. These findings indicate that 200 mg Cd/liter causes oxidative stress to O. fasciatus and induces GR activity, suggesting that glutathione may be involved in protection against Cd oxidative damage in this species.

We measured winter survival, emergence time following incubation at 20°C, and postemergence longevity in males of the orchard pollinator Osmia lignaria Say exposed to 25 artificial wintering treatments differing in duration (30, 90, 150, 210, and 270 d) and temperature (0, 4, 7, 10, and 13°C). For all temperatures, survival was highest at 90 d of wintering. Temperatures ≥10°C were unsuitable for wintering O. lignaria populations even for short periods. At 7°C, bees showed increased mortality, signs of excessive fat body depletion, and decreased longevity when wintered for >150 d. Wintering durations ≥210 d required temperatures ≤4°C for acceptable survival. Time to emerge following incubation at 20°C decreased with increasing wintering duration and wintering temperature. Many bees emerged before incubation when wintered for long periods at the warmest temperatures. Postemergence longevity was highest when bees were wintered at 0°C for 210 d. Managing the activity of O. lignaria to coincide with fruit tree bloom initiation is much more easily accomplished with the use of populations exhibiting short emergence times. Several wintering treatments that resulted in acceptable survival and longevity (150 d at 0, 4 and 7°C, and 210–270 d at 0 and 4°C), produced mean emergence times ≤5 d. Our results can be used to establish appropriate wintering regimes for O. lignaria populations managed to pollinate orchard crops differing in bloom time (from almonds in February to apples in May), and therefore, allowing for shorter or longer wintering durations.

Urolepis rufipes (Hymenoptera: Pteromalidae) is a newly recorded species in Denmark. It occurs in connection with livestock facilities, is a parasitoid on houseflies, and may therefore have potential as a biological fly control agent. The effects of five temperatures (15, 20, 25, 30, and 35°C) on sex ratio, development time, survivorship, age-specific fecundity, net reproductive rate, intrinsic rate of natural increase (r_m) and generation time of U. rufipes were investigated. Sex ratio was female-biased at all temperatures. Successful development occurred at all temperatures, with a minimum development time near 34°C. Development time of males was significantly shorter than that of females. Immature survivorship was highest at 25°C and 30°C and lowest at 35°C. An inverse relationship was found between longevity of adult females and temperature. The net reproductive rate (R₀) was highest at 25°C and 30°C and lowest at 35°C. The maximum r_m-value was 0.346 d⁻¹ at 30°C, and the minimum was 0.038 d⁻¹ at 15°C. r_m-values of the Danish strain were higher than those previously reported in a New York strain of U. rufipes. Generally, r_m was higher than in most other fly pupal pteromalid parasitoids investigated, and hence U. rufipes appears to be a promising control agent for houseflies.

In laboratory experiments, western cherry fruit flies, Rhagoletis indifferens Curran, were exposed to sweet cherries, aphid honeydew, and bird feces to determine fly longevity and fecundity. Longevity was not sustained in females and males exposed to intact unripe cherries or no food, whereas it was in females exposed to intact, fully-ripe cherries, and in females and males exposed to opened unripe or ripe cherries. Females exposed to intact fully-ripe cherries alone usually survived as long as females exposed to sucrose-yeast diets, but fecundity of flies exposed to cherries (79.5–110.8 eggs/female) was lower than that of flies exposed continuously to sucrose-yeast diets (277.5–326.2 eggs/female). Longevity of flies exposed to aphid honeydew was sustained and was similar to that of flies exposed to intact ripe cherries, sucrose-yeast, and sucrose diets. However, exposure to aphid honeydew or bird feces in the absence of ripe cherries did not result in high fecundity (4.6–32.2 eggs/female). Despite the inability of flies to extract nutrients from unripe cherries and the moderate fecundity of flies that were exposed to intact ripe cherries alone, R. indifferens was clearly capable of using its principal host fruit for both sustained longevity and egg production. Results suggest cherries damaged by birds throughout the season and intact fully-ripe cherries later in the season can contribute about the same nutrition as honeydew to female longevity, but that cherries contribute significantly more than either honeydew or bird feces to fecundity in nature.

Selection imposed by mating disruption could lead to changes in the pest insect’s chemical communication system if there is genetically based variation in signal and/or response characteristics. Ultimately, this evolution, in the absence of courteracting selection, could lead to resistance to this control tactic. For this reason, the effects of mating disruption on the reproductive success of two pheromone strains of the cabbage looper, Trichoplusia ni (Hübner), were examined in field-cage experiments in which we could monitor mating success. The first experiment evaluated mating disruption using the major component of the cabbage looper pheromone [(Z)-7-dodecenyl acetate: Z7–12:Ac], and the complete pheromone blend emitted by females. The second experiment focused on disruption with the compound that is often most abundant in the pheromone blend of mutant females [(Z)-9-tetradecenyl acetate: Z9-14:Ac], and the complete pheromone blend emitted by mutant females. In the first experiment, mutant males tended to have greater mating success than normal males in the presence of the full normal blend, as they do in the absence of disruptants. By itself, this result would indicate that the mutant alleles would spread through a population. However, normal females had greater mating success than mutant females in the presence of the normal blend disruptant (and Z7-12:Ac). This directional selection on females would tend to counter the selection on males, and dampen or eliminate any change in allelic frequency in the next generation. In the second experiment, the full mutant blend decreased male and female mating frequency relative to control, but did not influence the relative mating success of the two strains. Results of these experiments demonstrate for the first time that the effects of a mating disruptant on mating success of T. ni can be complex, with the pheromone blend having sometimes counteracting effects on pheromone strains and sexes.

Synthetic, angiosperm bark-derived volatiles, which elicit antennal responses in a number of coniferophagous bark beetles (Coleoptera: Scolytidae), were tested in groups for their ability to disrupt the pheromone-positive response of the spruce beetle (SB), Dendroctonus rufipennis (Kirby), the western balsam bark beetle (WBBB), Dryocoetes confusus Swaine, and the mountain pine beetle (MPB), Dendroctonus ponderosae Hopkins, to attractant-baited traps. One complex mixture disrupted WBBB response to pheromone-baited multiple-funnel traps to a level not significantly different than that in unbaited control traps. No group of compounds, including a group of green leaf volatiles, was active in disrupting SB response, a result that contrasts other published findings and that is different from the behavioral responses that are elicited by nonhost volatiles in other species of coniferophagous bark beetles. For the MPB, the two green leaf alcohols, 1-hexanol and (Z)-3-hexen-1-ol, were highly disruptive. In addition, combinations of compounds from the group consisting of salicylaldehyde, benzaldehyde, nonanal, guaiacol, benzyl alcohol, and conophthorin acted to augment the disruptive activity of the green leaf alcohols.

The casuarina moth, Lymantria xylina Swinhoe, is a serious defoliator of hardwood and fruit trees in Taiwan. Currently, overwintering egg mass density is the primary criterion used to monitor the population size of the casuarina moth. We assessed the relationship between casuarina moth egg mass size and the number of eggs per egg mass from two heavily infested sites in central Taiwan. Size parameters (length, width, area, and weight) were measured for each egg mass, and the egg number in each egg mass was counted. Results indicated substantial geographic variation in egg mass size. Regression analyses revealed a positive relationship between mass size (length, width, area, and weight) and the number of eggs per mass, and that weight explains ≈98% of the variation in the number of eggs per egg mass. The use of weight and other egg mass density measurements may provide forest and orchard managers with increased accuracy in estimating casuarina moth population size.

Field studies have demonstrated mixed success in trap cropping to manage Crocidolomia pavonana (=binotalis) [F.], a major pest of cruciferous crops in Asia. A possible explanation for this is an influence of host plant phenology on oviposition preference. We tested this in simultaneous two-choice oviposition bioassays under laboratory conditions. In cylindrical cardboard experimental arenas, with 5-cm² leaf windows, individual C. pavonana females were offered eight sequential phenological stages of cabbage (Brassica oleracea L., Capitata group, cultivar Gloria) with a constant stage of preflowering Indian mustard (Brassica juncea, variety rugosa, cultivar Green Wave). Results showed a significant effect of cabbage developmental stage on oviposition preference. We continued with two-choice bioassays, using whole leaves, in screen cage experimental arenas. Females were offered the three most preferred phenological stages of cabbage and differing stages of four potential trap crop alternatives: preflowering Indian mustard; preflowering Chinese cabbage (B. rapa L., variety pekinensis [Lour.] Olsson); preflowering, flowering, and “with silique” sawi manis (B. rapa, variety parachinensis [Bailey] Tsen and Lee); and preflowering and flowering sayur pahit (B. rapa, variety parachinensis [Bailey] Tsen and Lee). Results indicated that the phenological stages of both plants had a significant effect on relative oviposition preference. However, patterns of preference changed in the context of the different plant species combinations. In addition, implicit hierarchical preference order was frequently contradicted. These results have implications for the improvement of trap cropping strategies to manage C. pavonana and for the potential success of biological control of Plutella xylostella [L.], where these pests occur in complex.

Crocidolomia pavonana (=binotalis) [F.] demonstrates oviposition peaks in the field that we believe to be correlated with host plant phenology. In previous two-choice laboratory experiments, we found the highest relative proportion of oviposition on cabbage to correspond either to plant growth stages ≈7–8 wk or ≈9–11 wk old, depending on the alternate host plant with which it was presented. In cabbage-only trials, leaves from 7- to 8-wk-old plants were preferred. Inconsistency in preference led to the question of whether oviposition on either cabbage growth stage would confer adaptive advantages in offspring performance. We simulated oviposition on four phenological stages of cabbage in two ways. In a study of complete immature development, growth rate, pupal weight, and survivorship were measured. We also compared food utilization efficiency during the fourth larval instar by analyzing growth rate, efficiency of biomass accumulation, and frass production by analysis of covariance (ANCOVA). For both experiments, cabbage plants of defined phenological stages were designated at the time of oviposition, and larvae were fed from these as plants continued to grow throughout larval development. Our data indicate adaptive advantages in larval growth rate and food conversion efficiency to oviposition on cabbage at ≈7–8 wk from planting. Oviposition on later cabbage growth stages resulted in comparatively poor larval performance. Possible explanations for C. pavonana oviposition behavior in light of these results are discussed.

A spatially replicated study of Argentine stem weevil Listronotus bonariensis (Kuschel) population dynamics was carried out in six dryland Canterbury, South Island ryegrass Lolium perenne L./white clover Trifolium repens L. pastures over three seasons between 1994 and 1997. The aims were to provide information on the weevil’s population dynamics in dryland environments and to determine population regulatory mechanisms. In dryland Canterbury pastures, L. bonariensis adults and larvae exhibit phenology similar to that reported elsewhere in New Zealand. Population density was generally low, probably reflecting the loss of endophyte-free ryegrass tillers as the pasture aged. Density-dependence relationships were found in both halves of the life cycle: 1) between densities of overwintered adults in spring and those of the next generation in summer; and 2) densities of adults over winter, from the summer peak to those remaining the following spring. Endophyte-free tiller density also played a part in determining summer adult abundance. Partitioning the first relationship into two components, spring (overwintered) adults to first generation summer larvae, and from those larvae to peak summer adults, showed density dependence in both, but an endophyte-free tiller effect only in the first. In all cases, endophyte-free tiller densities provided more significant contributions to predictive relationships for weevil densities than did total tiller densities, suggesting that weevil abundance is partly determined by the endophyte-free tiller resource in dryland habitats.

We conducted timed visual observations of the peach canopy to monitor beneficial fauna diversity and abundance in orchards with reduced risk and conventional arthropod management programs. In addition, we placed sentinel Grapholita molesta (Busck) (Lepidoptera: Tortricidae) eggs in the peach canopy and determined egg parasitism, predation, and the total impact of natural enemies. Reduced risk orchards used minimal insecticide, G. molesta mating disruption, and managed sod ground cover to suppress Lygus lineolaris (Palisot de Beauvois) (Heteroptera: Miridae). Conventional orchards used organophosphorus and carbamate insecticides to control G. molesta, L. lineolaris, and other pests. Chrysoperla rufilabris (Burmeister) and C. plorabunda (Fitch) (Neuroptera: Chrysopidae), Coccinella septempunctata L. and Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), Orius insidiosus (Say) (Heteroptera: Anthocoridae), and Trichogramma minutum Riley (Hymenoptera: Trichogrammatidae) were the most frequently observed natural enemies in southern New Jersey peach orchards. Hippodamia convergens (Guerin-Meneville), Adalia bipunctata L., Coleomegilla maculata De Geer (Coleoptera: Coccinellidae), and T. exiguum Pinto et Platner (Hymenoptera: Trichogrammatidae) were observed less frequently. Beneficial fauna was more abundant in orchards with the reduced risk program compared with conventionally farmed orchards. The rate of G. molesta sentinel egg parasitism and predation was significantly higher in reduced risk orchards compared with conventional orchards. Overall, predators destroyed more sentinel eggs than did egg parasitoids.

In quasi-gregarious egg parasitoids, the effects of host age on patch use can be significant because host quality declines with host age; this occurs simultaneously in all hosts in a patch (i.e., egg mass). We assessed such effects in the laboratory using Gryon obesum Masner, an egg parasitoid of Euschistus conspersus Uhler. Host eggs hatched ≈6 d after oviposition; therefore, individual parasitoid females were allowed to oviposit on egg masses (14 eggs/mass) of 0-, 1-, 2-, 3-, 4-, and 5-d-old hosts. We measured body size and developmental time of parasitoid progeny from these hosts. On egg masses of 0-, 2-, 4-, and 5-d-old hosts, we observed ovipositional behavior of parasitoid wasps, and estimated rates of host acceptance, progeny survival, and patch residence time. There was a general decline in host quality with host age. Exposure of wasps to 5-d-old hosts resulted in reduced percentage parasitism, lowered acceptance and ovipositional success per patch, increased patch time, reduced survival and body size of parasitoid progeny, and lengthened developmental time of parasitoid progeny. In many of these hosts, however, wasps left the patch after a short time without any successful oviposition. These results confirm earlier studies showing that successful parasitism of eggs declines with host age, and suggest that such age effects should be incorporated into models of patch use by egg parasitoids. The relevance of host-age effects to augmentative biological control is discussed.

The endemic-rich Afromontane grassland on the Drakensberg in Southern Africa is subjected to intensive afforestation. We describe fine-scale variation in the assemblages of the Coleoptera within the context of a grassland fragmentation experiment. The study site supports a speciose coleopteran fauna of >131 morphospecies. Variation in beetle assemblage corresponds to fine-scale variation within the plant community of which the 10 most dominant plant species are shared across all plant associations. Because these variants of the grassland community are localized, this suggests a high degree of endemicity for the grassland Coleoptera. The correlation between ordinations of beetle assemblages and those reflecting botanical composition is remarkable. Spatial autocorrelation analysis reveals that several species have geographically clumped distributions among sites. There was a correlation between, on the one hand, seasonal differences between beetle assemblages within each treatment (due to the fact that some insects are closely associated with particular plant assemblages), and, on the other hand, seasons in which correlations in beetle-habitat ordinations were high. However, within the context of the fragmentation experiment, the grassland fragments and control sites are statistically comparable because similar plant-beetle associations existed in both treatments. Thirteen beetle taxa are identified which collectively comprise an efficient tool for monitoring the effects of habitat fragmentation on the montane grassland.

Ecological analysis was used to evaluate over 2 yr of adult mosquito surveillance data from Citrus County, Florida. The analysis was intended to demonstrate a systematic approach to make better use of the abundance of surveillance data as a prerequisite to predict future mosquito population trends. Twenty-eight mosquito species (157,600 individuals) were collected using a modified New Jersey light trap. Analysis of species dominance index revealed that the seven most dominant species comprised 84% of the total individuals captured. Three culicine mosquitoes, Culex quinquefasciatus, Cx. nigripalpus, and Cx. erraticus, showed recurring seasonal abundance peaks in July and August, while two anopheline species, Anopheles crucians and An. atropos, showed interannual abundance variability. The population of the salt-marsh mosquito, Ochlerotatus taeniorhynchus, consistently peaked in June and July, while that of Oc. infirmatus peaked in September and July of 1999 and 2000, respectively. With 66% Oc. taeniorhynchus, the Ozello site had the highest aggregation index (0.4975) of all the trap sites in the county. Adult mosquitoes exhibited the highest diversity (index = 2.3476) at a mixed salt-marsh and freshwater site (Homosassa). A cluster analysis provided a systematic way to gauge both similarities and dissimilarities of sites and divided the 14 trap sites into 7 basic groups. For districts that have a large number of trap sites, results of cluster analysis might be used to streamline the adult mosquito surveillance program by combining or relocating traps with very similar mosquito collections.

Banana plantations are treated with herbicides, nematocides, fungicides, and insecticides to control weeds, nematodes, fungal pathogens, and insect pests. The impact of these pesticides on the organisms within plantations, however, is largely unknown. Because they are integral to terrestrial ecosystems, ants have been widely used as biological indicators in invertebrate biodiversity assessments and studies of habitat rehabilitation. Hence, to evaluate the effects of pesticides on banana plantation invertebrates, ants were surveyed in six conventional plantations treated with the pesticides described above and in two low-input plantations that received reduced applications of herbicides, nematocides, and insecticides. To put banana into perspective relative to other tropical monocultures, ants in banana were also compared with those in four other crops: citrus (Citrus sinensis L. Osbeck), heart of palm (Bactris gasipaes Kunth), macadamia (Macadamia integrifolia Maiden and Betche), and Gmelina arborea (L.) Roxb. A total of 23,364 ants comprising 107 species, 48 genera, and 6 subfamilies was collected at the 12 study sites. Species richness was highest in the other crops, being lower in both low-input and conventional banana, which did not differ significantly. Ant species richness correlated with the richness of parasitoids collected concurrently from the same sites, but differences among low-input banana, conventional banana, and the other four monocultures were more pronounced for parasitoids. Species richness in conventional banana, low input banana, and the four other crops was independent of species origin (native or exotic), habitat preference, nest type, diet, or ant functional groups sensu Andersen.

Four West Virginia apple orchards under different management (unmanaged; horticultural management only; horticultural management with apple, peach, and cherry trees interplanted; and standard commercial management) were sampled for spider abundance. Sampling was done with limb jarring at four times during the season; samples were taken hourly over a 24-h period. A total of 1,926 spiders from 15 families was collected, and 44% of all spiders were Salticidae. More spiders were collected in August (37%) than earlier months, but the highest diversity of spider families was in July. Older, unsprayed apple trees had the greatest diversity of spiders. The family Oxyopidae was most abundant in the commercially managed orchard. Spiders in the families Anyphaenidae, Philodromidae, and Thomisidae were significantly more abundant during night samples than during the day. Philodromids were also significantly more abundant on peach and cherry trees than on apple, possibly being attracted to extrafloral nectaries. Comparisons with other published data sets found that regional differences were more important determinants of spider community structure in apple than insecticide use. Northwest European, sprayed Quebec, and sprayed Washington apple orchards were found to be dominated by web-building spiders; the other North American and Israeli orchards were dominated by hunting spiders. Abundance and diversity of the spider community in orchards suggests that spiders could be major contributors to biological control of many insect pests.

Predatory mite releases can be an effective means of managing spider mites in many perennial cropping systems, yet little research has been performed in annual cropping systems. Herein we evaluate the compatibility of predaceous mite releases with the conservation of resident natural enemies in an annual agroecosystem. We quantify the impact of naturally occurring generalist predators, Geocoris spp. and Orius tristicolor White, and the omnivore Frankliniella occidentalis (Pergande), on the establishment of the western predatory mite Galendromus occidentalis (Nesbitt) and how these predator-predator interactions influence spider mite control. Field experiments showed that in the absence of generalist predators, released predatory mites can establish populations on cotton, increase in abundance through reproductive recruitment, and suppress spider mite populations. Hemipteran predators had a negative impact on predatory mite populations but generally improved spider mite suppression. The presence of F. occidentalis had no impact on predatory mite performance.

The parasitic nematode Thripinema nicklewoodi is a potential inoculative biological control agent of the western flower thrips, Frankliniella occidentalis. Laboratory studies were undertaken to assess the effect of T. nicklewoodi infection on: 1) host feeding, 2) host fecundity, and 3) viral competency of F. occidentalis coinfected with a tospovirus. Individual thrips infected with nematodes as larvae and maintained on leaf discs in microcentrifuge vials showed a reduced feeding throughout the adult life span. This per capita reduction in feeding by parasitized individuals contributed to a total reduction in feeding of 87% on chrysanthemum petals and 91% on bean foliage relative to uninfected thrips. Parasitism also reduced the longevity of adult thrips by 3–5 d, although the preadult developmental time was unaffected. In a separate study, thrips infected with nematodes as larvae became reproductively sterile and appeared to have a reduced vector competency for tomato spotted wilt virus (TSWV). Thrips larvae were inoculated with both TSWV and nematodes in a factorial design, and adults were subsequently exposed to a petunia leaf disc assay to test for fecundity and virus transmission using enzyme-linked immunosorbent assay (ELISA). No eggs were recovered from thrips infected with nematodes, and dissections revealed that their embryos remained fully degenerate, which was not observed among healthy thrips. Although the proportion of thrips testing positive to a TSWV nonstructural protein (indicating systemic virus acquisition) was statistically similar between treatments, fewer viruliferous F. occidentalis coinfected with T. nicklewoodi became virus transmitters. Moreover, the per capita frequency of virus transmission among nematode-infected thrips was reduced by ≈50% relative to nematode-free thrips. Our results suggest that T. nicklewoodi may help prevent thrips outbreaks and reduce direct feeding damage and secondary virus spread during the prelethal period of infection.

The western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a major pest of corn in Kansas. Planting Bt corn hybrids resistant to this pest is being tested as a method to control the larval stage of corn rootworms. These hybrids express Cry3Bb1 toxin and are expected to only directly impact chrysomelids and possibly related taxa. Soil samples were examined to evaluate the effect of Bt corn for corn rootworm control on soil microarthropods and nematodes in Kansas in 2000 and 2001. Soil samples from soil close to Bt corn and to its isoline were taken on three occasions (early, mid, and late season) from eight locations in 2000 and three locations in 2001. Soil mites and Collembola were extracted using a modified Tullgren high-gradient extractor. Nematodes were extracted using a centrifugal-flotation procedure. In general, numbers of soil mites (Prostigmata, Mesostigmata, and Oribatei), Collembola, and nematodes were similar in soil planted with Bt corn and soil planted with its isoline.

Parallorhogas pyralophagus (Marsh) is the principal parasitoid of Mexican rice borer, Eoreuma loftini (Dyar), the primary pest of sugarcane in south Texas. Insect resistant transgenic sugarcane producing Galanthus nivalis agglutinin (GNA) was developed to improve control of E. loftini. The present laboratory study addressed whether transgenic sugarcane adversely affects parasitism of E. loftini by P. pyralophagus. Females of P. pyralophagus preferentially probed, drilled, and parasitized E. loftini larvae fed artificial diet based on conventional sugarcane versus larvae fed diet based on transgenic sugarcane. Activity levels of E. loftini were reduced when fed diet based on transgenic sugarcane, but no differences were evident in frass volatile profiles. Overall, the results suggested a positive association between larval activity level and likelihood of parasitism, which may render E. loftini larvae feeding on transgenic sugarcane less susceptible to parasitism by P. pyralophagus. However, it was concluded that this may not significantly affect control of E. loftini because (1) while E. loftini larvae that are most susceptible to transgenic sugarcane may be less prone to parasitism by P. pyralophagus, they are less likely to cause severe crop damage and reproduce successfully; and (2) those E. loftini larvae least susceptible to transgenic sugarcane, and therefore more active and damaging to plants, may be more prone to parasitism by P. pyralophagus.

The Japanese beetle (Popillia japonica Newman), a polyphagous scarab, feeds on certain palatable plants that are toxic, or reputedly toxic. Paralysis of the beetle after consumption of flowers of zonal geranium (Pelargonium × hortorum L. H. Bailey) has been documented, but factors affecting expression and range of this phenomenon are poorly known. Published anecdotes regarding toxicity of two other hosts, larkspur (Delphinium sp.) and bottlebrush buckeye (Aesculus parviflora Walt.), have not been empirically tested. For zonal geraniums, we compared toxicity with P. japonica of flowers versus leaves, sun-grown and shaded plants, and different-colored flowers. The progression of paralysis and recovery, as well as survival of paralyzed beetles under laboratory and field conditions, also were evaluated. Beetles became paralyzed after feeding on flowers of zonal geranium, but not by consuming leaves, suggesting the active compound is unique to flowers. Shaded or sun-grown flowers, and red-, white-, or salmon-colored flowers, were equally active. Beetles generally became paralyzed within 3 h of the onset of feeding. Most of them recovered when held in the laboratory, but paralyzed beetles placed in the field for 3 h did not recover. Flowers of Pelargonium inquinins (L.) L’Héritier, and Pelargonium zonale (L.) L’Héritier, which are the parental species of P. × hortorum, as well as ivy geranium (Pelargonium peltatum [L.] L’Héritier), another member of the type section Ciconium, all were active. Pelargonium × scarborovia, which belongs to the type section Pelargonium, was the only geranium species that did not cause paralysis. Although the active compounds have not been identified, our results suggest that light-activated flavonoids or anacardic acids probably are not responsible for geranium-induced paralysis. Contrary to published anecdotes, neither flowers nor foliage or larkspur and bottlebrush buckeye were toxic to Japanese beetles.

Although the importance of omnivory in food webs has been established, the community niche of generalist arthropod predators such as praying mantids is usually assumed to be at most bitrophic, feeding on herbivores and other carnivores. As with most predators, mantids often are food limited in nature. Flowering plants in their environment offer mantids an opportunity to obtain high-protein pollen, a potential vegetarian alternative to their normal arthropod prey. Although some arthropod predators have been shown to feed occasionally on pollen, the extent to which they gain fitness from this behavior is unclear, and often assumed to be minor. In replicated laboratory tests, Chinese mantids, Tenodera aridifolia sinensis (Saussure), actively fed on pollen just after hatching, and on pollen-laden insects as adults. Pollen feeding enhanced fitness of these mantids by: 1) preventing starvation of nymphs at egg hatch in the absence of normal insect prey; 2) increasing body mass of nymphs fed pollen in addition to normal prey; and 3) allowing adults that were fed both pollen and insects to maintain the same fecundity on fewer insect prey than those fed insects alone. These predators are therefore tritrophic because the extent of their omnivory includes a fitness-enhancing plant product in addition to herbivore and carnivore prey. Pollen feeding may explain higher fecundity of females located on flowers, and also may enable these and other generalist predators to maintain high population densities when animal prey are scarce, which has potential consequences for the rest of the community.

The ovipositional preferences of two stemboring pests, Eoreuma loftini Dyar and Diatraea saccharalis (F.) (Lepidoptera: Pyralidae), were evaluated in choice tests on transgenic sugarcane expressing Galanthus nivalis agglutinin (GNA) and the corresponding conventional near-isogenic sugarcane. Differences in various host-selection indices indicated that both D. saccharalis and E. loftini preferentially laid eggs on conventional sugarcane versus the transgenic cultivar. A significantly higher proportion of leaves per plant were allocated eggs on conventional relative to transgenic sugarcane plants by both D. saccharalis and E. loftini. In addition, larger proportions of both total eggs and egg masses laid by females were allocated to conventional (66–71%) relative to transgenic (29–34%) sugarcane, but the size of egg masses of both stemborer species did not vary with plant type. An oviposition preference index, computed as the ratio of the difference in egg loads (eggs or egg masses) allocated to transgenic or conventional plants and the total number of eggs laid, indicated that transgenic sugarcane plants were refractory to ovipositing E. loftini and D. saccharalis. However, differences in host-selection indices for transgenic and conventional sugarcane plants in D. saccharalis were associated largely with the presence of the transgene (i.e., plant type), while differences in E. loftini were associated largely with plant morphological characteristics related with plant type. The unintended antixenotic effects of transgenic sugarcane observed in this study are important because they highlight the validity of concerns over unanticipated consequences of releasing transgenic plants before intensive evaluation.

Previous observations on the effect of endophyte infection in turfgrass on white grub development and natural incidence have been variable and contradictory. We reexamined these white grub-endophyte interactions and expanded them to the previously not studied oriental beetle (Exomala [= Anomala] orientalis Waterhouse). Endophyte infection in strong creeping red fescue (Festuca rubra L. rubra) had no effect on survival and weight gain of neonate Japanese beetle (P. japonica Newman) and E. orientalis larvae in greenhouse pot experiments. In tall fescue (Festuca arundinacea Schreber) in greenhouse pot and in microplot field experiments, endophyte infection had no significant effect on survival and a weak negative effect on weight gain of P. japonica, but reduced E. orientalis survival without affecting its weight gain. In samples taken from tall fescue fields in October, the natural incidence of third instars was higher in endophytic than in nonendophytic turf in 3 of 4 yr. The effect was strongest in oriental beetle and Asiatic garden beetle (Maladera castanea [Arrow]), but generally not significant for Japanese beetle and European chafer (Rhizotrogus majalis [Razoumowsky]). The effect was also more pronounced in samples taken in August 2000 and 2001 among first and second instars (not identified to species) compared with the October samples. Pitfall trap catches in 2002 provided little evidence of endophyte effects on generalist predator activity, suggesting that elevated white grub populations did not result from reduced predation. We hypothesize that ovipositional preferences of adult scarabs could contribute to the higher populations of some white grub species in endophytic versus nonendophytic tall fescue, and that increased efficiency of predation may have contributed to the observed reduction of this difference between August and October. Additional experiments will be required to determine the validity of these hypotheses.

Interactions between host plant resistance and biological control may be advantageous or disadvantageous for pest management. Turfgrass cultivars have rarely been tested for extrinsic resistance characteristics such as occurrence and performance of beneficial arthropods on plants with resistance to known turf pests. Among six turfgrass cultivars tested, the bigeyed bug, Geocoris uliginosus (Say) nymphs varied in ability to reduce numbers of fall armyworm, Spodoptera frugiperda (J. E. Smith), larvae. The six grasses tested (Sea Isle 1 and 561-79 seashore paspalum, Paspalum vaginatum Swartz; TifSport and TifEagle bermudagrass, Cynodon dactylon [L.] x C. transvaalensis [Burtt-Davy]; and Cavalier and Palisades zoysiagrass Zoysia japonica von Steudel and Z. matrella [L.] Merrill) represented a range in resistance to S. frugiperda. In the laboratory, the greatest reduction in S. frugiperda larvae by a low density of G. uliginosus occurred on the resistant Cavalier zoysiagrass. A 7-fold difference in weight of 10-d-old larvae between those feeding on susceptible versus resistant grasses suggested that on the resistant grass larvae remained for a longer period in a size range susceptible to predation. Results of laboratory studies were not directly translated to the field, in which a diverse predatory arthropod community varied in composition depending on turfgras cultivar. In the field, the greatest reduction in S. frugiperda larvae by a low density of G. uliginosus occurred on Sea Isle 1 and 561-79 seashore paspalum grass. In the field, vacuum samples indicated that predaceous Heteroptera were most abundant in paspalum grasses and bermudagrasses, while Carabidae, Staphylinidae, and Araneae were more common in zoysiagrasses. In contrast, pitfall traps indicated that carabids were more common in bermudagrasses, Araneae and Staphylinids were similar among grass taxa, and Cicindellidae were most common in paspalum grasses and bermudagrasses. Predation was never significantly decreased on resistant turfgrass cultivars in any of the experiments described in this work, indicating no negative tritrophic interactions.