Nutritional and Defensive Chemistry of Three North American Ash Species: Possible Roles in Host Performance and Preference by Emerald Ash Borer Adults

Black ash (Fraxinus nigra), green ash (F. pennsylvanica), and white ash (F. americana) are the three most abundant ash species in the northeastern USA. We compared emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), adult performance and preference among seedlings of the three ash species, and then related performance and preference to foli- age nutritional quality and defensive compounds. Longevity of EAB adults reared on green and white ash was found to be greater than on black ash. EAB adult females also seemed to show feeding preference among the three species of ash trees because the total foliage area consumption was greater on green ash and white ash compared to black ash in dual-choice tests; however, the total mass of foliage consumed did not differ. The foliage of all ash species was high in nitrogen and in most macro- and micro-nutrients studied. The patterns of EAB performance and preference did not correspond to any of the individual chemical compounds tested (nitrogen, proteins, most macro- and micro-nutrients, or putative defensive compounds of ash seedlings). Never- theless, greater longevity of EAB adults on green and white ash compared to black ash was probably related to unbalanced nutrients (total nitrogen/total non-structural carbohydrate ratio) of black ash. Putative defensive compounds (i.e., phenolics and protease inhibitors) did not contribute to EAB longevity in this study, probably because (1) EAB adults were able to excrete most of these compounds and (2) their effects were alleviated by high nitrogen levels. More research is needed to elucidate the interactions of nitrogen and carbohydrate levels, and the interactions of nutrient balance and defensive plant allelochemicals on EAB performance and preference

Nutritional and Defensive Chemistry of Three North American Ash Species: Possible Roles in Host Performance and Preference by Emerald Ash Borer Adults

Black ash (Fraxinus nigra), green ash (F. pennsylvanica), and white ash (F. americana) are the three most abundant ash species in the northeastern USA. We compared emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), adult performance and preference among seedlings of the three ash species, and then related performance and preference to foli- age nutritional quality and defensive compounds. Longevity of EAB adults reared on green and white ash was found to be greater than on black ash. EAB adult females also seemed to show feeding preference among the three species of ash trees because the total foliage area consumption was greater on green ash and white ash compared to black ash in dual-choice tests; however, the total mass of foliage consumed did not differ. The foliage of all ash species was high in nitrogen and in most macro- and micro-nutrients studied. The patterns of EAB performance and preference did not correspond to any of the individual chemical compounds tested (nitrogen, proteins, most macro- and micro-nutrients, or putative defensive compounds of ash seedlings). Never- theless, greater longevity of EAB adults on green and white ash compared to black ash was probably related to unbalanced nutrients (total nitrogen/total non-structural carbohydrate ratio) of black ash. Putative defensive compounds (i.e., phenolics and protease inhibitors) did not contribute to EAB longevity in this study, probably because (1) EAB adults were able to excrete most of these compounds and (2) their effects were alleviated by high nitrogen levels. More research is needed to elucidate the interactions of nitrogen and carbohydrate levels, and the interactions of nutrient balance and defensive plant allelochemicals on EAB performance and preference

Influence of host plant nitrogen fertilization on haemolymph protein profiles of herbivore Spodoptera exigua and development of its endoparasitoid Cotesia marginiventris

Citation: Chen, Y., Ruberson, J. R., & Ni, X. (2014). Influence of host plant nitrogen fertilization on haemolymph protein profiles of herbivore Spodoptera exigua and development of its endoparasitoid Cotesia marginiventris. Retrieved from http://krex.ksu.eduNitrogen has complex effects on plant-herbivore-parasitoid tri-trophic interactions. The negative effects of host plant low nitrogen fertilization on insect herbivores in many cases can be amplified to the higher trophic levels. In the present study, we examined the impact of varying nitrogen fertilization (42, 112, 196, and 280 ppm) on cotton plants (Gossypium hirsutum L.) on the interactions between the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), and the hymenopteran endoparasitoid Cotesia marginiventris (Cresson) (Hymenoptera: Braconidae). We predicted that the development and fitness of C. marginiventris would be adversely affected by low host plant nitrogen fertilization through the herbivore S. exigua. The percentage of C. marginiventris offspring developing to emerge and spin a cocoon, and total mortality of parasitized S. exigua larvae were unaffected by nitrogen level. The developmental time of C. marginiventris larvae in S. exigua larvae feeding on low (42 ppm) nitrogen cotton plants was approximately 30% longer than that of those feeding on high (112, 196, and 280 ppm) nitrogen plants. Parasitoid size (length of right metathoracic tibia), a proxy for fitness, of C. marginiventris males was positively affected by nitrogen level. Total amounts of S. exigua haemolymph proteins were not affected by nitrogen level, but were reduced by parasitism by C. marginiventris. Two proteins with molecular weights of ca. 84 and 170 kDa dominated the S. exigua larval haemolymph proteins. Concentrations of the 170 kDa haemolymph protein were unaffected by nitrogen treatment, but parasitism reduced concentrations of the the 170 kDa protein. Concentrations of the 84 kDa protein, on the other hand, were interactively affected by parasitism and nitrogen treatment: higher nitrogen fertilization (112, 196, and 280 ppm) increased protein concentrations relative to the 42 ppm treatment for unparasitized S. exigua larvae, whereas nitrogen treatment had no effects on parasitized larvae. For S. exigua larvae feeding on 42 ppm nitrogen plants, parasitism increased concentration of the 84 kDa protein, while for those feeding on 112, 196, and 280 ppm nitrogen plants, parasitism decreased concentrations of the protein. Possible mechanisms and ecological consequences for the extended development of C. marginiventris on S. exigua hosts grown on low-nitrogen plants are discussed

Real-Time online target tracking based on compressed sensing

We randomly extracted the feature of local binary patterns(LBP) with different sizes within both positive samples and negative samples.The high-dimensional feature information was projected onto the low rank compression domain based on which the characterization model was established.Then,it compressed samples of foreground and the background targets by using the same random sparse measurement matrix.Finally,the tracking task was formulated as a binary classification via a Naive Bayes classifier.The experiment showed that the proposed method could track the target quickly and constantly.Furthermore,it could also solve the problem of multi-scale change and occlusion issue at the same time

Parameter (<i>β</i>s) estimation of the best set of models predicting flight of <i>Pityophthorus juglandis</i> in response to ambient temperature (T), light intensity (L), wind speed (W), and barometric pressure (P) and some of their interactions.

<p>See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105945#pone.0105945.s002" target="_blank">Appendix S2</a> for detailed model components.</p><p>Parameter (<i>β</i>s) estimation of the best set of models predicting flight of <i>Pityophthorus juglandis</i> in response to ambient temperature (T), light intensity (L), wind speed (W), and barometric pressure (P) and some of their interactions.</p

Daily <i>Pityophthorus juglandis</i> catches from 8 May to 17 September, 2012.

<p>(A) 0600–1000 h; (B) 1200–1600 h; (C) 1800–2200 h. Time intervals: 0600 h (2200 h of the previous day–0600 h the current day); 0800 h (0600–0800 h); 1000 h (0800–1000 h); 1200 h (1000–1200 h); 1400 h (1200–1400 h); 1600 h (1400–1600 h); 1800 (1600–1800 h); 2000 h (1800–2000 h); and 2200 h (2000–2200 h). Green arrow points to 3 September, 2012 when <i>P. juglandis</i> flight activity stopped between 2000 and 2200 h for the season. <i>N</i> = 133 days.</p

Sum of <i>w_i</i> (an indicator of relative importance in the model) for variables (terms) from selection of models predicting flight of <i>Pityophthorus juglandis</i> in response to ambient temperature (T), light intensity (L), wind speed (W), and barometric pressure (P) and their interactions.

<p>A total of 94 models (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105945#pone.0105945.s002" target="_blank">Appendix S2</a>) were tested. <i>w_i</i> indicates the relative likelihood of the model <i>i</i> being the best model given the data. Computation and interpretation of statistics followed <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105945#pone.0105945-Burnham1" target="_blank">[29]</a>. Superscripted numbers in parentheses denote ranks of the sum of <i>w_i</i> across terms appeared the same number of times in the models. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105945#pone.0105945.s003" target="_blank">Appendix S3</a> (Female) and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105945#pone.0105945.s004" target="_blank">S4</a> (Male) for detailed statistics.</p><p>Sum of <i>w_i</i> (an indicator of relative importance in the model) for variables (terms) from selection of models predicting flight of <i>Pityophthorus juglandis</i> in response to ambient temperature (T), light intensity (L), wind speed (W), and barometric pressure (P) and their interactions.</p

Crepuscular Flight Activity of an Invasive Insect Governed by Interacting Abiotic Factors

<div><p>Seasonal and diurnal flight patterns of the invasive walnut twig beetle, <i>Pityophthorus juglandis</i>, were assessed between 2011 and 2014 in northern California, USA in the context of the effects of ambient temperature, light intensity, wind speed, and barometric pressure. <i>Pityophthorus juglandis</i> generally initiated flight in late January and continued until late November. This seasonal flight could be divided approximately into three phases (emergence: January–March; primary flight: May–July; and secondary flight: September–October). The seasonal flight response to the male-produced aggregation pheromone was consistently female-biased (mean of 58.9% females). Diurnal flight followed a bimodal pattern with a minor peak in mid-morning and a major peak at dusk (76.4% caught between 1800 and 2200 h). The primarily crepuscular flight activity had a Gaussian relationship with ambient temperature and barometric pressure but a negative exponential relationship with increasing light intensity and wind speed. A model selection procedure indicated that the four abiotic factors collectively and interactively governed <i>P. juglandis</i> diurnal flight. For both sexes, flight peaked under the following second-order interactions among the factors when: 1) temperature between was 25 and 30°C and light intensity was less than 2000 lux; 2) temperature was between 25 and 35°C and barometric pressure was between 752 and 762 mba (and declined otherwise); 3) barometric pressure was between 755 and 761 mba and light intensity was less than 2000 lux (and declined otherwise); and 4) temperature was ca. 30°C and wind speed was ca. 2 km/h. Thus, crepuscular flight activity of this insect can be best explained by the coincidence of moderately high temperature, low light intensity, moderate wind speed, and low to moderate barometric pressure. The new knowledge provides physical and temporal guidelines for the application of semiochemical-based control techniques as part of an IPM program for this invasive pest.</p></div

Effects of time interval of the day and <i>Pityophthorus juglandis</i> sex on <i>P. juglandis</i> catches (mean + SE).

<p>(A) Effect of time interval; (B) Effect of <i>P. juglandis</i> sex. Time intervals: 0600 h: 2200 h the previous day–0600 h the current day; 0800 h: 0600–0800 h; 1000 h: 0800–1000 h; 1200 h: 1000–1200 h; 1400 h: 1200–1400 h; 1600 h: 1400–1600 h; 1800: 1600–1800 h; 2000 h: 1800–2000 h; and 2200 h: 2000–2200 h. Different lower-case letters above bars denote significant difference between time intervals (A) or between <i>P. juglandis</i> sexes (B) at <i>α</i> = 0.05. <i>N</i>_{time interval} = 268 except the time interval 0800 when <i>N</i> = 266. <i>N</i>_sex = 1205 for both sexes. Means plotted in (B) represent catches per 2 h interval.</p

Weekly <i>Pityophthorus juglandis</i> total trap catches (A) and percentage of males in selected catches (B) from 29 August, 2011 to 2 June, 2014 in five Lindgren funnel traps.

<p>Hash marks along the x-axis denote the first day of each week. Percentages of males are presented for weeks when more than 50 <i>P. juglandis</i> were trapped. Inset in (A): rescaling of weekly <i>P. juglandis</i> catches from 29 August, 2011 to 31 December, 2012 to facilitate comparison of seasonal flight pattern with 2013 and 2014 when flight responses were higher.</p