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1.
J Econ Entomol ; 117(2): 508-515, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38428947

RESUMO

Popillia japonica Newman (Coleoptera: Scarabaeidae) feeding negatively impacts many plant species, including grapes, potentially reducing fruit quality and yield. Chemical control, representing the current grower standard, relies on frequent broadcast applications of broad-spectrum insecticides, with alternative management strategies mostly lacking. Attract-and-kill (A&K) is a behavioral management strategy that combines semiochemical attractants and a killing agent on a substrate. This study assessed the impact of A&K on (i) the number of P. japonica adults and (ii) the percent of P. japonica feeding injury on grape foliage compared to the grower standard in commercial vineyards. This 2-year study was conducted at 3 commercial vineyards with 4 paired plots consisting of a grower standard control and an A&K treatment. The A&K treatment consisted of commercial lures, each placed on outside-edge grapevines, and weekly applications of carbaryl on the plants holding lures. The grower standard received broadcast insecticide applications at the grower's discretion. The A&K treatment experienced similar numbers of P. japonica adults and similar proportions of leaf injury compared to the grower standard. The use of A&K reduced by 96% the crop area treated with insecticides compared to the grower standard. The area treated by A&K was at the edge of the vineyards, where more leaf injury occurred regardless of treatment. A&K is a targeted approach that was effective at managing P. japonica and reducing chemical inputs on a small scale. It has the potential to be scaled up and refined to provide growers with a new management strategy.


Assuntos
Besouros , Inseticidas , Vitis , Animais , Inseticidas/farmacologia , Fazendas , Carbaril , Plantas , Folhas de Planta
2.
bioRxiv ; 2023 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-37461625

RESUMO

Biological invasions carry substantial practical and scientific importance, and represent natural evolutionary experiments on contemporary timescales. Here, we investigated genomic diversity and environmental adaptation of the crop pest Drosophila suzukii using whole-genome sequencing data and environmental metadata for 29 population samples from its native and invasive range. Through a multifaceted analysis of this population genomic data, we increase our understanding of the D. suzukii genome, its diversity and its evolution, and we identify an appropriate genotype-environment association pipeline for our data set. Using this approach, we detect genetic signals of local adaptation associated with nine distinct environmental factors related to altitude, wind speed, precipitation, temperature, and human land use. We uncover unique functional signatures for each environmental variable, such as a prevalence of cuticular genes associated with annual precipitation. We also infer biological commonalities in the adaptation to diverse selective pressures, particularly in terms of the apparent contribution of nervous system evolution to enriched processes (ranging from neuron development to circadian behavior) and to top genes associated with all nine environmental variables. Our findings therefore depict a finer-scale adaptive landscape underlying the rapid invasion success of this agronomically important species.

3.
Front Insect Sci ; 2: 961437, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-38468765

RESUMO

Landscapes surrounding agroecosystems can provide resources that may benefit insect pests. This project examined the influence of the surrounding landscape on the abundance and spatial pattern of Popillia japonica (Coleoptera: Scarabaeidae) in vineyards. Twenty vineyards across Southern Wisconsin, spanning a gradient of 5-80% cropland in a 1.5km radius surrounding landscape, were sampled in 2017 and 2018 for P. japonica adults and leaf injury. The distribution of P. japonica and leaf injury was assessed by sampling along a transect at the edge, halfway from the edge to the center, and at the center of each vineyard. The proportion of cropland and pasture in the surrounding landscape along with abiotic factors of temperature, precipitation, longitude, and pesticide use (determined using Environmental Impact Quotient) were included in models to explain the variation of P. japonica abundance and leaf injury. No significant relationship was observed between proportion cropland in the surrounding landscape and P. japonica abundance or leaf injury. Combined effects of pasture, longitude, and temperature best explained variation in the abundance of P. japonica adults while longitude, temperature and EIQ best explained variability in leaf injury. Vineyards with more pastures in the surrounding landscape, located further east, and with higher temperatures, generally had more P. japonica adults and vineyards further east with higher temperature and lower EIQ pesticide use generally had higher levels of leaf injury. Additionally, variability in weekly temperature and precipitation influenced weekly abundance, with higher temperatures and less precipitation resulting in greater weekly abundance of P. japonica adults. Significantly more adult P. japonica and greater leaf injury were found at the edges than in the center of vineyards. Our results suggest beetles from the surrounding landscape likely contribute to populations of P. japonica adults found feeding on vines on vineyard edges, and P. japonica abundance and associated leaf injury are influenced by geographical location, local weather conditions, and pesticide use.

4.
J Econ Entomol ; 114(3): 1401-1405, 2021 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-33760914

RESUMO

The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a well-documented pest of agricultural crops across the globe. However, not all crops are suitable hosts for H. halys, and it is necessary to proactively document the susceptibility of economically important specialty crops, such as cranberry (Vaccinium macrocarpon; Ericaceae), a native fruit crop that contributes millions of dollars to the North American economy. In this study, we tested whether cranberry is a suitable host for H. halys by measuring the development and feeding injury inflicted by H. halys on cranberry fruit and foliage. We found that H. halys nymphs cannot successfully develop on cranberry fruit or foliage alone, but that the fruit are susceptible to adult feeding. On the basis of these findings, cranberry does not seem to be a suitable host to support nymph development, but adult feeding could negatively impact fruit quality. Future research should consider the impacts of adult feeding on fruit quality and how adult abundance in and near agricultural crops might change the risk profile of this pest.


Assuntos
Heterópteros , Vaccinium macrocarpon , Animais , Produtos Agrícolas , Frutas , Ninfa
5.
J Insect Sci ; 21(1)2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33560361

RESUMO

Pest management of emerging pests can be challenging because very little fundamental knowledge is available to inform management strategies. One such pest, the red-headed flea beetle Systena frontalis (Fabricius) (Coleoptera: Chrysomelidae), is increasingly being identified as a pest of concern in cranberries Vaccinium macrocarpon Aiton (Ericales: Ericaceae). To improve our understanding of this pest and to develop more targeted management programs, we conducted field and laboratory studies to characterize the development, seasonal emergence patterns, and density-dependent plant injury. We found that significantly more flea beetle eggs hatched when exposed to sustained cold treatment between 0 and 5°C for 15 wk than at warmer temperatures, and for shorter and longer cold-period durations. The adults emerged sporadically over the summer, were patchily distributed, fed on both fruit and foliage, and preferentially fed on new plant growth. Using soil cores, we found eggs and larvae located relatively deep (>30 cm) in the soil. These patterns indicate that S. frontalis likely overwinters as eggs, and that targeting the larval stage may be the most effective management approach. Despite the cryptic nature of the larvae, continuing to improve our understanding of this life stage will be critical to optimizing control strategies.


Assuntos
Besouros/fisiologia , Herbivoria , Controle de Insetos , Características de História de Vida , Vaccinium macrocarpon , Animais , Besouros/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Óvulo/crescimento & desenvolvimento , Densidade Demográfica , Vaccinium macrocarpon/crescimento & desenvolvimento , Wisconsin
6.
Ecol Evol ; 10(14): 7669-7685, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32760556

RESUMO

Overwintering Drosophila often display adaptive phenotypic differences beneficial for survival at low temperatures. However, it is unclear which morphological traits are the best estimators of abiotic conditions, how those traits are correlated with functional outcomes in cold tolerance, and whether there are regional differences in trait expression.We used a combination of controlled laboratory assays, and collaborative field collections of invasive Drosophila suzukii in different areas of the United States, to study the factors affecting phenotype variability of this temperate fruit pest now found globally.Laboratory studies demonstrated that winter morph (WM) trait expression is continuous within the developmental temperature niche of this species (10-25°C) and that wing length and abdominal melanization are the best predictors of the larval abiotic environment.However, the duration and timing of cold exposure also produced significant variation in development time, morphology, and survival at cold temperatures. During a stress test assay conducted at -5°C, although cold tolerance was greater among WM flies, long-term exposure to cold temperatures as adults significantly improved summer morph (SM) survival, indicating that these traits are not controlled by a single mechanism.Among wild D. suzukii populations, we found that regional variation in abiotic conditions differentially affects the expression of morphological traits, although further research is needed to determine whether these differences are genetic or environmental in origin and whether thermal susceptibility thresholds differ among populations within its invaded range.

7.
PLoS One ; 15(4): e0227726, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32330137

RESUMO

Spotted-wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is an invasive economic pest of soft-skinned and stone fruit across the globe. Our study establishes both a predictive generalized linear mixed model (GLMM), and a generalized additive mixed model (GAMM) of the dynamic seasonal phenology of D. suzukii based on four years of adult monitoring trap data in Wisconsin tart cherry orchards collected throughout the growing season. The models incorporate year, field site, relative humidity, and degree days (DD); and relate these factors to trap catch. The GLMM estimated a coefficient of 2.21 for DD/1000, meaning for every increment of 1000 DD, trap catch increases by roughly 9 flies. The GAMM generated a curve based on a cubic regression smoothing function of DD which approximates critical DD points of first adult D. suzukii detection at 1276 DD, above average field populations beginning at 2019 DD, and peak activity at 3180 DD. By incorporating four years of comprehensive seasonal phenology data from the same locations, we introduce robust models capable of using DD to forecast changing adult D. suzukii populations in the field leading to the application of more timely and effective management strategies.


Assuntos
Drosophila/fisiologia , Frutas/parasitologia , Modelos Biológicos , Prunus avium/parasitologia , Estações do Ano , Animais , Monitorização de Parâmetros Ecológicos/estatística & dados numéricos , Previsões/métodos , Jardins/estatística & dados numéricos , Umidade , Controle de Insetos , Espécies Introduzidas/estatística & dados numéricos , Estágios do Ciclo de Vida/fisiologia , Modelos Lineares , Temperatura , Wisconsin
8.
Mol Biol Evol ; 37(8): 2369-2385, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32302396

RESUMO

Evidence is accumulating that evolutionary changes are not only common during biological invasions but may also contribute directly to invasion success. The genomic basis of such changes is still largely unexplored. Yet, understanding the genomic response to invasion may help to predict the conditions under which invasiveness can be enhanced or suppressed. Here, we characterized the genome response of the spotted wing drosophila Drosophila suzukii during the worldwide invasion of this pest insect species, by conducting a genome-wide association study to identify genes involved in adaptive processes during invasion. Genomic data from 22 population samples were analyzed to detect genetic variants associated with the status (invasive versus native) of the sampled populations based on a newly developed statistic, we called C2, that contrasts allele frequencies corrected for population structure. We evaluated this new statistical framework using simulated data sets and implemented it in an upgraded version of the program BayPass. We identified a relatively small set of single-nucleotide polymorphisms that show a highly significant association with the invasive status of D. suzukii populations. In particular, two genes, RhoGEF64C and cpo, contained single-nucleotide polymorphisms significantly associated with the invasive status in the two separate main invasion routes of D. suzukii. Our methodological approaches can be applied to any other invasive species, and more generally to any evolutionary model for species characterized by nonequilibrium demographic conditions for which binary covariables of interest can be defined at the population level.


Assuntos
Adaptação Biológica , Drosophila/genética , Genoma de Inseto , Espécies Introduzidas , Modelos Genéticos , Animais , Frequência do Gene
9.
J Econ Entomol ; 113(1): 159-171, 2020 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-31502635

RESUMO

Reliable monitoring of the invasive Halyomorpha halys abundance, phenology and geographic distribution is critical for its management. Halyomorpha halys adult and nymphal captures on clear sticky traps and in black pyramid traps were compared in 18 states across the Great Lakes, Mid-Atlantic, Southeast, Pacific Northwest and Western regions of the United States. Traps were baited with commercial lures containing the H. halys pheromone and synergist, and deployed at field sites bordering agricultural or urban locations with H. halys host plants. Nymphal and adult captures in pyramid traps were greater than those on sticky traps, but captures were positively correlated between the two trap types within each region and during the early-, mid- and late season across all sites. Sites were further classified as having a low, moderate or high relative H. halys density and again showed positive correlations between captures for the two trap types for nymphs and adults. Among regions, the greatest adult captures were recorded in the Southeast and Mid-Atlantic on pyramid and sticky traps, respectively, with lowest captures recorded in the West. Nymphal captures, while lower than adult captures, were greatest in the Southeast and lowest in the West. Nymphal and adult captures were, generally, greatest during July-August and September-October, respectively. Trapping data were compared with available phenological models showing comparable population peaks at most locations. Results demonstrated that sticky traps offer a simpler alternative to pyramid traps, but both can be reliable tools to monitor H. halys in different geographical locations with varying population densities throughout the season.


Assuntos
Heterópteros , Animais , Ninfa , Feromônios , Densidade Demográfica , Estações do Ano , Estados Unidos
10.
J Econ Entomol ; 112(4): 1789-1797, 2019 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-31329912

RESUMO

Drosophila suzukii (Matsumura) is an invasive species of vinegar fly that infests soft-skinned and stone fruits. Since its first detection in the United States, D. suzukii has become a prominent economic threat in fruit crop industries, particularly affecting caneberry and sweet cherry growers. This study examined the susceptibility of tart cherries (Prunus cerasus) to D. suzukii and sampled for larvae and adult D. suzukii during the tart cherry growing season. Four tart cherry cultivars (Montmorency, Balaton, Carmine Jewel, and Kántorjánosi) were tested at three different ripeness stages (unripe, ripening, and ripe), in no-choice laboratory bio-assays. Field monitoring and sampling revealed that first adult D. suzukii detection occurred on 16 June, and first field larval D. suzukii detection occurred on 28 July. Adult D. suzukii populations increased through late August, and high numbers of adults overlapped with the tart cherry harvest. Lab assays indicated that tart cherry cultivars generally became more susceptible to D. suzukii as they ripened. As the fruit developed, °Brix (sugar content) increased and firmness generally decreased. Tart cherry °Brix and firmness were not correlated with the number of D. suzukii eggs per gram of fruit, but showed a significant interaction effect with the number of larvae and adults per gram of fruit. This study shows that tart cherries are largely not susceptible to D. suzukii when unripe and become susceptible as soon as the fruits change color, suggesting that fruits should be protected as soon as they begin to ripen and D. suzukii populations begin to rise.


Assuntos
Prunus avium , Rosaceae , Rosales , Animais , Drosophila , Frutas
11.
Pest Manag Sci ; 75(8): 2188-2194, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30663241

RESUMO

BACKGROUND: Drosophila suzukii (Diptera: Drosophilidae) is the most prominent arthropod pest of caneberries. Current management practices rely on chemical control, which has raised concerns over the sustainability of this approach. We currently understand little about D. suzukii activity, and whether activity patterns can be exploited to improve management. In this study, we investigated the vertical and temporal distribution of D. suzukii, as well as pollinators, in cultivated raspberries. RESULTS: D. suzukii were generally crepuscular, and most active in the morning within the bottom half of the crop, and in the evening within the top half of the crop. Pollinators were most active during the day and within the top half of the canopy. Humidity and temperature were correlated with insect activity. CONCLUSION: Pesticides applied during twilight that ensure coverage in the bottom half of the crop, or if applied in the late afternoon cover the entire crop, should improve the pesticide efficacy. However, previous studies suggest that specific D. suzukii (e.g. sex, mating status, age) may exploit different areas in the crop at different times, and more work needs to be done to understand how these aspects before a specific management program can be recommended. © 2019 Society of Chemical Industry.


Assuntos
Distribuição Animal , Drosophila/fisiologia , Rubus/fisiologia , Animais , Feminino , Cadeia Alimentar , Frutas , Masculino , Polinização , Densidade Demográfica , Fatores de Tempo , Wisconsin
12.
Bioscience ; 68(12): 990-995, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30524133

RESUMO

We develop a transdisciplinary deliberative model that moves beyond traditional scientific collaborations to include nonscientists in designing complexity-oriented research. We use the case of declining honey bee health as an exemplar of complex real-world problems requiring cross-disciplinary intervention. Honey bees are important pollinators of the fruits and vegetables we eat. In recent years, these insects have been dying at alarming rates. To prompt the reorientation of research toward the complex reality in which bees face multiple challenges, we came together as a group, including beekeepers, farmers, and scientists. Over a 2-year period, we deliberated about how to study the problem of honey bee deaths and conducted field experiments with bee colonies. We show trust and authority to be crucial factors shaping such collaborative research, and we offer a model for structuring collaboration that brings scientists and nonscientists together with the key objects and places of their shared concerns across time.

13.
Environ Entomol ; 47(6): 1365-1375, 2018 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-30395182

RESUMO

Drosophila suzukii (Matsumura) is an invasive pest of soft-skinned fruits that has caused significant economic damage worldwide. In this study, we focused on the seasonal abundance of D. suzukii during the early years of establishment in Wisconsin. We explored the seasonal patterns of summer and winter morphs, their reproductive output, and the effect temperature and humidity may have on their seasonal phenology. The seasonal abundance of D. suzukii during 2 yr (2014-2015) revealed that flies were detected in Wisconsin from early July to late December, with winter morphs being trapped from August through December. The adult populations trapped spanned 1 mo longer in 2015 than in 2014. The peak proportional abundance of D. suzukii in 2015 was recorded in August which was about 2 mo earlier than that in 2014. The combined factor [maximum temperature and maximum humidity] explained the most amount of variation in D. suzukii abundance consistently across the 2 yr in Wisconsin. We did not find significant differences in the fat content, number of mature eggs, proportion of females with immature eggs, or proportion of mated females between summer morph females at the beginning, summer and winter morph females during the middle, or winter morph females at the end of the collecting season in 2015. Our results build on the body of work providing a better understanding of the D. suzukii-overwintering abilities and strengthen the importance of early crop risk assessment and targeted control strategies.


Assuntos
Drosophila/fisiologia , Estações do Ano , Animais , Drosophila/anatomia & histologia , Feminino , Umidade , Masculino , Reprodução , Temperatura
14.
Insects ; 9(2)2018 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-29857557

RESUMO

Social wasps can be serious pests in fruit growing plantings and are becoming increasingly problematic for grape growers. In this study, we conducted two experiments to assess the species composition and seasonal phenology of social wasps in Wisconsin vineyards in 2015 and 2017. In 2015, three attractants were used: (1) wine; (2) heptyl butyrate (HB); and (3) acetic acid and isobutanol (AAIB) and in 2017, two attractants were used: HB and AAIB. In both years, the same eight species were trapped from the genera Vespula, Dolichovespula, and Polistes. The predominant wasp species trapped were Vespula maculifrons, Vespula vidua, Vespula flavopilosa, and Vespula germanica in 2015 and V. maculifrons, V. flavopilosa, V. germanica, and Dolichovespula maculata in 2017, in order of total abundance. The populations of V. vidua decreased in 2017 compared to 2015, indicating large inter-annual variation. In both years, AAIB lures trapped significantly more V. flavopilosa, V. maculifrons, and V. germanica, the three most prevalent species during grape harvest, than HB, whereas HB lures trapped more V. vidua than AAIB. Wine was generally attractive to all species in 2015. This study identifies for the first time the wasp species present in Wisconsin commercial vineyards using chemical attractants. This knowledge, along with the seasonal phenology of these pest species, will help facilitate the development of management strategies for social wasps in commercial vineyards.

15.
J Econ Entomol ; 111(4): 1983-1986, 2018 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-29668962

RESUMO

Codling moth Cydia pomonella L. (Lepidoptera: Tortricidae) is a major pest of pome fruits worldwide. Fruit is damaged by larval feeding, and numbers of larvae are directly related to the numbers of females in the preceding generation. In Pacific Northwest, apple orchards, C. pomonella are generally managed with insecticides and mating disruption. However, additional control methods are needed when these treatments fail or are undesirable. Using a three-component kairomone lure that attracts both sexes, we mass-trapped C. pomonella in 4-acre plots located within commercial apple orchards. In all cases, there were smaller increases in fruit infestation in the mass-trapped plots than in the corresponding control plots. This relative decrease in fruit infestation in the mass-trapped plots corresponded with the removal of more male and female C. pomonella. Mass-trapping using this lure has potential to be a novel and promising addition to integrated pest management of C. pomonella.


Assuntos
Malus , Mariposas , Animais , Feminino , Frutas , Larva , Masculino , Feromônios
16.
Environ Entomol ; 47(4): 935-945, 2018 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-29668869

RESUMO

Spotted-wing drosophila, Drosophila suzukii Matsumura (Diptera: Drosophilidae), is an invasive pest of soft-skinned fruits across the globe. Effective monitoring is necessary to manage this pest, but suitable attractants are still being identified. In this study, we combined lures with fermenting liquid baits to improve D. suzukii trapping specificity and attractiveness. We also measured the efficiency and specificity of baits/lures during different times of the season; the reproductive status of females among baits/lures; and the effects of locations and crop type on these response variables. We developed a metric that combined mating status and fat content to determine differences in types of females attracted. Lures utilizing yeast and sugar-based volatiles trapped the most D. suzukii. The addition of a commercial lure to yeast and sugar-based lures increased catches in most locations, but was also the least specific to D. suzukii. Apple juice-based chemical lures tended to be most specific to D. suzukii, while lures comprised of a singular attractant tended to trap more D. suzukii with a higher reproductive potential than combinations of attractants. Trap catch and lure specificity was lower during fruit development than fruit ripening. While catch amounts varied by geographic location and crop type, attractants performed similarly relative to each other in each location and crop. Based on the metrics in this study, the yeast and sugar-based attractants were the most effective lures. However, further work is needed to improve early season monitoring, elucidate the effects of physiological status on bait attraction, and understand how abiotic factors influence bait attraction.


Assuntos
Mirtilos Azuis (Planta)/crescimento & desenvolvimento , Quimiotaxia , Drosophila/fisiologia , Controle de Insetos/métodos , Feromônios/farmacologia , Rubus/crescimento & desenvolvimento , Animais , Feminino , Frutas/crescimento & desenvolvimento , Geografia , Masculino , Estados Unidos
17.
Insects ; 9(1)2018 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-29301287

RESUMO

Sparganothis fruitworm (Sparganothis sulfureana Clemens) (Lepidoptera: Tortricidae) is a serious pest of cranberry (Vaccinium macrocarpon Aiton), a native North American fruit cultivated in northern regions of the United States and southeastern Canada. This study assessed antibiosis in several cranberry cultivars commonly grown in Wisconsin. Five cultivars previously shown to host different levels of populations of S. sulfureana in commercial cranberry were assessed in this study to evaluate the performance of S. sulfureana amongst these cultivars. We measured growth and time to developmental stages of newly emerged larvae to adulthood on selected cranberry cultivars in the laboratory. There was no difference in the rates of survival to pupation and to adult emergence among any of the cultivars tested. Mid-instar larvae that fed on the cultivar 'Ben Lear' were heavier than those feeding on 'GH-1', 'Stevens', or 'HyRed', and larvae that fed on 'Mullica Queen' were heavier than those feeding on 'HyRed'. However, there were no significant differences in pupal weights or in the number of days from neonate to adult emergence among varieties. Therefore, this study did not provide evidence of antibiosis among the cultivars tested, and found that larval weight was not correlated with other measurements of performance.

18.
Ecol Evol ; 7(10): 3532-3541, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28515888

RESUMO

Detritivory is the dominant trophic paradigm in most terrestrial, aquatic, and marine ecosystems, yet accurate measurement of consumer trophic position within detrital (="brown") food webs has remained unresolved. Measurement of detritivore trophic position is complicated by the fact that detritus is suffused with microbes, creating a detrital complex of living and nonliving biomass. Given that microbes and metazoans are trophic analogues of each other, animals feeding on detrital complexes are ingesting other detritivores (microbes), which should elevate metazoan trophic position and should be rampant within brown food webs. We tested these hypotheses using isotopic (15N) analyses of amino acids extracted from wild and laboratory-cultured consumers. Vertebrate (fish) and invertebrate detritivores (beetles and moths) were reared on detritus, with and without microbial colonization. In the field, detritivorous animal specimens were collected and analyzed to compare trophic identities among laboratory-reared and free-roaming detritivores. When colonized by bacteria or fungi, the trophic positions of detrital complexes increased significantly over time. The magnitude of trophic inflation was mediated by the extent of microbial consumption of detrital substrates. When detrital complexes were fed to vertebrate and invertebrate animals, the consumers registered similar degrees of trophic inflation, albeit one trophic level higher than their diets. The wild-collected detritivore fauna in our study exhibited significantly elevated trophic positions. Our findings suggest that the trophic positions of detrital complexes rise predictably as microbes convert nonliving organic matter into living microbial biomass. Animals consuming such detrital complexes exhibit similar trophic inflation, directly attributable to the assimilation of microbe-derived amino acids. Our data demonstrate that detritivorous microbes elevate metazoan trophic position, suggesting that detritivory among animals is, functionally, omnivory. By quantifying the impacts of microbivory on the trophic positions of detritivorous animals and then tracking how these effects propagate "up" food chains, we reveal the degree to which microbes influence consumer groups within trophic hierarchies. The trophic inflation observed among our field-collected fauna further suggests that microbial proteins represent an immense contribution to metazoan biomass. Collectively, these findings provide an empirical basis to interpret detritivore trophic identity, and further illuminate the magnitude of microbial contributions to food webs.

19.
Insects ; 8(1)2017 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-28245642

RESUMO

The cranberry fruitworm (Acrobasis vaccinii Riley), sparganothis fruitworm (Sparganothis sulfureana Clemens), and blackheaded fireworm (Rhopobota naevana Hübner) are historically significant pests of cranberries (Vaccinium macrocarpon Aiton) in the Upper Midwest (Wisconsin), USA. Their respective natural histories are well documented but correlations between developmental benchmarks (e.g., larval eclosion) and degree-day accruals are not yet known. Treatment timings are critical to the optimization of any given control tactic, and degree-day accrual facilitates optimization by quantifying the developmental status of pest populations. When key developmental benchmarks in the pest life cycle are linked to degree-days, real-time weather data can be used to predict precise treatment timings. Here, we provide the degree-day accumulations associated with discrete biological events (i.e., initiation of flight and peak flight) for the three most consistent moth pests of cranberries in Wisconsin. Moths were trapped each spring and summer from 2003 to 2011. To characterize flight dynamics and average timing of flight initiation, pheromone-baited trap-catch data were tallied for all three pest species within each of seven growing seasons. These flight dynamics were then associated with the corresponding degree-day accumulations generated using the cranberry plant's developmental thresholds. Finally, models were fit to the data in order to determine the peak flight of each species. The initiation of the spring flight among all three moth species was highly synchronous, aiding in the timing of control tactics; however, there were substantial differences in the timing of peak flight among the moth species. Characterization of the relationship between temperature and pest development allows pest management professionals to target specific life stages, improving the efficacy of any given pest control tactic.

20.
Insects ; 8(1)2017 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-28287438

RESUMO

The spotted wing drosophila, Drosophila suzukii (Diptera: Drosophilidae), is an emerging invasive pest, which attacks a wide variety of fruits and berries. Although previous studies have focused on different aspects of D. suzukii reproductive biology, there are no protocols available for determining the mating status of D. suzukii females and drosophilids in general. In this study, a step-by-step protocol for tissue dissection, isolating spermathecae, and determining the mating status of females was developed specifically for D. suzukii. This protocol is an effective and relatively quick method for determining female mating status. It has important applications from exploring reproductive output of D. suzukii females to understanding the biology of D. suzukii winter morph, which presumably plays the main role in the overwintering of this invasive species. We demonstrated applicability of this protocol for both field collected flies and flies reared in the lab, including fly specimens stored on a long-term basis.

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