Impact of waste dump on surface water quality and aquatic insect diversity of Deepor Beel (Ramsar site), Assam, North-east India

Water and aquatic insects were collected seasonally from site 1, the low-lying area of the dump near Deepor Beel, and from sites 2 and 3 of the main wetland and analysed. While dissolved oxygen (DO) increased from site 1 to site 3 in each season, electrical conductivity (EC), total dissolved solid (TDS), total alkalinity (TA) and free CO₂ (F-CO₂) decreased. Pb and Cd were found to exceed the limits set for drinking water in all the sites and seasons. Species richness (SpR) was found highest (23) at site 2 and lowest (14) at site 1. Sensitive species was absent. The Shannon (H') values at site 1 were < 1 while at sites 2 and 3 were > 1 in most of the seasons. Biological monitoring scores (Biological Monitoring Working Party and Stream Invertebrate Grade Number-Average Level) in different sites and seasons inferred severely poor to moderate water quality. At site 1, significant negative correlations were seen for Pb and Cr with SpR while Ni and Cu with insect density (ID). At site 2, TA had highly significant positive correlations with SpR and ID while Cu showed negative correlation with SpR. At site 3, ID had significant negative relationships with air temperature, water temperature, depth, TA, F-CO₂, PO₄^3- and Cr. Canonical correspondence analysis triplot has clearly separated site 1 associated with tolerant species and highly influenced by TA, TDS, EC, F-CO_2, Cr, Ni, Cd and Zn confirming high anthropogenic activities on that site. Tolerant and semitolerant species were present at site 2 (influenced by depth and transparency) and site 3 (influenced by Pb and WT) both. Results of this study discerned that the dump site is the point source of pollution.

Comprehensive characterization of the acute and chronic toxicity of the neonicotinoid insecticide thiamethoxam to a suite of aquatic primary producers, invertebrates, and fish

Thiamethoxam is a neonicotinoid insecticide used widely in agriculture to control a broad spectrum of chewing and sucking insect pests. Recent detection of thiamethoxam in surface waters has raised interest in characterizing the potential impacts of this insecticide to aquatic organisms. We report the results of toxicity testing (acute and chronic) conducted under good laboratory practices for more than 30 freshwater species (insects, molluscs, crustaceans, algae, macrophytes, and fish) and 4 marine species (an alga, a mollusc, a crustacean, and a fish). As would be anticipated for a neonicotinoid, aquatic primary producers and fish were the least sensitive organisms tested, with acute median lethal and effect concentrations (LC50/EC50) observed to be ≥80 mg/L in all cases, which far exceeds surface water exposure concentrations. Tested molluscs, worms, and rotifers were similarly insensitive (EC50 ≥ 100 mg/L), except for Lumbriculus sp., with an EC50 of 7.7 mg/L. In general, insects were the most sensitive group in the study, with most acute EC50 values < 1 mg/L. However, the crustaceans Asellus aquaticus and Ostracoda exhibited a sensitivity similar to that of insects (acute EC50 < 1 mg/L), and the midge larvae Chaoborus sp. were relatively insensitive compared with other insects (EC50 > 5.5 mg/L). The most sensitive chronic response was for Chironomus riparius, with a 30-d no-observed-effect concentration (NOEC; emergence) of 0.01 mg/L. Observed toxicity to the tested marine organisms was comparable to that of freshwater species. We used the reported data to construct species sensitivity distributions for thiamethoxam, to calculate 5% hazard concentrations (HC5s) for acute data (freshwater invertebrates), and compared these with measured concentrations from relevant North American surface waters. Overall, based on acute toxicity endpoints, the potential acute risk to freshwater organisms was found to be minimal (likelihood of exceeding HC5s < 1%). Environ Toxicol Chem 2017;36:2838-2848. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Rearing of Mallada basalis (Neuroptera: Chrysopidae) on modified artificial diets

Mallada basalis (Walker) has the potential to be a valuable biological control agent because of its predatory abilities, strong reproductive capacity, and broad prey range. This study aimed to improve on a previously used artificial diet for M. basalis, to achieve a longer oviposition period and greater survival rate and fecundity. We analyzed the development, survival, longevity, and reproduction of M. basalis (F1 and F2 generations) fed two artificial diets (AD1 and AD2). Both diets contained chicken egg yolk, beer yeast powder, honey, trehalose, seawater spirulina, and potassium sorbate. AD1 also contained sucrose and vitamin C. The duration of F1 1st larvae, F1 2nd larvae, F1 pupae, F2 egg, and F2 2nd larvae reared on AD1 were significantly shorter than those reared on AD2. F1 adult longevity and F2 oviposition period for AD1 (45.40 d and 31.00 d) were significantly longer than for AD2 (30.74 d and 20.80 d). All the following were significantly greater for AD1 compared with AD2: F1 female proportion, F1 daily oviposition, F1 female oviposition, F2 daily oviposition, F2 female oviposition, F1 emergence rate, F2 pupation rate, and F3 egg hatching rate. Moreover, for M. basalis fed AD2, the duration of F2 2nd and 3rd larvae (9.00 d and 8.64 d) were significantly longer than for F1 (4.70 d and 4.92 d). The F1 oviposition period (31.57 d) was significantly longer than F2 (20.80 d). The F2 female oviposition (189.20 egg/female) was significantly less than F1 (307.14 egg/female). We found that the oviposition period and female longevity of F1 reared on AD1 was longer than that reared on the artificial diet in a previous study. The daily oviposition and female oviposition of F1 from AD1 was larger, while the F2 egg hatching rate was greater compared with that from the previous diet. However, the offspring of M. basalis fed AD2 were less thrifty. We found diet AD1 supported development and reproduction better than AD2 and the diets in our previous study. These findings may contribute to the mass rearing of this economically important predatory green lacewing.

Effect of oil palm on the Plecoptera and Trichoptera (Insecta) assemblages in streams of eastern Amazon

The production of oil palm is expected to increase in the Amazon region. However, expansion of oil palm plantation leads to significant changes in the physical structure of aquatic ecosystems, mainly through the reduction of riparian vegetation that is essential for aquatic biodiversity. Here, we evaluated the effects of oil palm on the physical habitat structure of Amazonian stream environments and assemblages of Plecoptera and Trichoptera (PT), ​both found in these streams. We compared streams sampled in oil palm plantations (n = 13) with natural forest areas ("reference" streams, n = 8), located in the eastern Amazon, Brazil. Our results showed that oil palm streams were more likely to be in close proximity to roads, had higher pH values, and higher amounts of fine substrate deposited in the channel than reference streams. Further, these environmental changes had important effects on the aquatic invertebrate assemblages, reducing the abundance and richness of PT. Nevertheless, the genera composition of the assemblages did not differ between reference and oil palm (PERMANOVA, pseudo-F _(1,19) = 1.891; p = 0.111). We conclude that oil palm production has clear negative impacts on aquatic environments and PT assemblages in Amazonian streams. We recommend that oil palm producers invest more in planning of road networks to avoid the construction of roads near to the riparian vegetation. This planning can minimize impacts of oil palm production on aquatic systems in the Amazon.

Survival and Locomotory Behavior of Earwigs After Exposure to Reduced-Risk Insecticides

The conservation of natural enemies is an important tactic to promote biological control of arthropod pests. The earwig Doru luteipes (Sccuder) is the most important predator of the fall armyworm Spodoptera frugiperda (J.E. Smith) in corn fields. One way of conserving these predators in the field is by using only selective insecticides when the pest population reaches the economic threshold. Some recent insecticides such as azadirachtin, chlorantraniliprole, and novaluron have been claimed to pose reduced risk for natural enemies. Nevertheless, there is a dearth of information regarding the selectivity of these insecticides upon earwigs in specific. In this study, we carried out a series of laboratory assays to examine the survivorship and locomotory behavior of D. luteipes after exposure to fresh dry residue of azadirachtin, chlorantraniliprole, and novaluron. Our results show a significant survival reduction for D. luteipes nymphs exposed to fresh residues of chlorantraniliprole and novaluron. In the behavioral studies, adults of D. luteipes stopped more often, spent more time resting (inactive), and moved more slowly immediately after exposure to chlorantraniliprole residue. These results suggest that chlorantraniliprole may mediate an impaired movement and a behavior arrestment of earwigs after contact with this insecticide fresh residue. This could translate into reduced foraging efficiency, and increase exposure and insecticide uptake. Although chlorantraniliprole and novaluron showed a potential to undermine the biological control provided by earwigs, it is yet essential to conduct field trials in order to confirm our laboratory results.

Nutritional and reproductive signaling revealed by comparative gene expression analysis in Chrysopa pallens (Rambur) at different nutritional statuses

Background

The green lacewing, Chrysopa pallens Rambur, is one of the most important natural predators because of its extensive spectrum of prey and wide distribution. However, what we know about the nutritional and reproductive physiology of this species is very scarce.

Results

By cDNA amplification and Illumina short-read sequencing, we analyzed transcriptomes of C. pallens female adult under starved and fed conditions. In total, 71236 unigenes were obtained with an average length of 833 bp. Four vitellogenins, three insulin-like peptides and two insulin receptors were annotated. Comparison of gene expression profiles suggested that totally 1501 genes were differentially expressed between the two nutritional statuses. KEGG orthology classification showed that these differentially expression genes (DEGs) were mapped to 241 pathways. In turn, the top 4 are ribosome, protein processing in endoplasmic reticulum, biosynthesis of amino acids and carbon metabolism, indicating a distinct difference in nutritional and reproductive signaling between the two feeding conditions.

Conclusions

Our study yielded large-scale molecular information relevant to C. pallens nutritional and reproductive signaling, which will contribute to mass rearing and commercial use of this predaceous insect species.

Integrative taxonomy by molecular species delimitation: multi-locus data corroborate a new species of Balkan Drusinae micro-endemics

BACKGROUND

Taxonomy offers precise species identification and delimitation and thus provides basic information for biological research, e.g. through assessment of species richness. The importance of molecular taxonomy, i.e., the identification and delimitation of taxa based on molecular markers, has increased in the past decade. Recently developed exploratory tools now allow estimating species-level diversity in multi-locus molecular datasets.

RESULTS

Here we use molecular species delimitation tools that either quantify differences in intra- and interspecific variability of loci, or divergence times within and between species, or perform coalescent species tree inference to estimate species-level entities in molecular genetic datasets. We benchmark results from these methods against 14 morphologically readily differentiable species of a well-defined subgroup of the diverse Drusinae subfamily (Trichoptera, Limnephilidae). Using a 3798 bp (6 loci) molecular data set we aim to corroborate a geographically isolated new species by integrating comparative morphological studies and molecular taxonomy.

CONCLUSIONS

Our results indicate that only multi-locus species delimitation provides taxonomically relevant information. The data further corroborate the new species Drusus zivici sp. nov. We provide differential diagnostic characters and describe the male, female and larva of this new species and discuss diversity patterns of Drusinae in the Balkans. We further discuss potential and significance of molecular species delimitation. Finally we argue that enhancing collaborative integrative taxonomy will accelerate assessment of global diversity and completion of reference libraries for applied fields, e.g., conservation and biomonitoring.

The Potential Effect of Bt Maize on Chrysoperla pudica (Neuroptera: Chrysopidae)

Previous studies into third trophic level exposure of Chrysoperla spp. (Neuroptera: Chrysopidae) to Cry1Ab proteins produced by Bt crops yielded contradicting results. These contradictions were largely ascribed to differences in prey quality and exposure methods. In this study, we used healthy prey to expose lacewing larvae to Cry1Ab protein produced by Bt maize, and also determined the concentration of this protein at different trophic levels. Experiments were conducted in which Chrysoperla pudica (Navás) larvae were fed different diets which included aphids and healthy Bt-resistant Busseola fusca (Fuller) (Lepidoptera: Noctuidae) larvae feeding on Bt maize tissue. Lacewing larval and pupal development times as well as overall mortality were determined. The concentration of Cry1Ab protein in B. fusca larvae were fourfold reduced compared with that in leaf tissue and was below detection level in lacewing larvae. Survival to the pupal stage was higher than 96% in all treatments. Larval and pupal development periods did not differ significantly between treatments in which prey fed on Bt or non-Bt maize. This study showed feeding on healthy prey that consumed Cry1Ab protein has no adverse effect on the biology of C. pudica.

Cuticular microstructures turn specular black into matt black in a stick insect

The stick insect Peruphasma schultei stands out from other insects by its deep matt black cuticle. We tested whether the appearance of P. schultei is due to microstructures of the cuticle, a phenomenon that has recently been described for the velvet black scales of the Gaboon viper. The shiny black stick insect Anisomorpha paromalus served as a control. We found that the P. schultei cuticle is characterised by two different types of microstructures, tall elevations with a maximum size of 18 μm and small structures with a height of 4 μm. Other than in the snake, P. schultei microstructures do not bear nanostructures. The microstructures scatter light independently of the viewing angle. This causes the matt appearance of the cuticle, whereas pigments are responsible for the black colouration, resulting in a maximum reflectance of 2.8% percent. The microstructures also cause the hydrophobic properties of the cuticle with contact angles near 130°. Resin replicas and bleaching of the cuticle strongly support these results. Moreover, the matt black cuticle has a higher heat absorption compared to the control. We discuss the selective benefit of the matt black appearance of P. schultei in the context of behaviour, ecology and phylogeny.

Germ cell proliferation and cluster behavior in ovarioles of Sialis flavilatera (Megaloptera: Sialidae) during larval growth

Telotrophic meroistic insect ovaries are assigned to four different types. The Sialis type is found in Sialidae (Megaloptera), Raphidioptera and a coleopteran subgroup (Myxophaga: Hydroscaphidae). King and Büning (1985) proposed a hypothetical model for the development of this ovariole type; however, a detailed description of ovarian development in Sialis was missing so far. Using light and electron microscopy, we investigated developing ovaries of Sialis flavilatera starting in the 10th month of the biennial larval phase until adulthood. At least from the 10th month onwards, a Sialis ovariole anlage contains a single germ cell syncytium, whose growth is promoted by a mitotic cell population maintained in its anterior compartment. The stem-like, dividing germ cells form synchronous sub-clusters consisting of 2-16 cystocytes, which are spatially arranged in bigger rosettes that stay connected to each other via cytoplasmic tubes. Within individual rosettes, cells communicate by centrally gathering intercellular bridges. Following each round of cystocyte division and subsequent rosette formation, plasma membrane wrinkles sprout near newborn bridges, elongate, and interdigitate with the preexisting membrane tubes. In this way the membrane labyrinth emerges and grows. Germ cells leaving the proliferation zone posteriorly enter meiotic prophase. Hypotheses on the phylogenetic origin of this ovary type are discussed in the light of our results.

Larval aquatic insect responses to cadmium and zinc in experimental streams

To evaluate the risks of metal mixture effects to natural stream communities under ecologically relevant conditions, the authors conducted 30-d tests with benthic macroinvertebrates exposed to cadmium (Cd) and zinc (Zn) in experimental streams. The simultaneous exposures were with Cd and Zn singly and with Cd+Zn mixtures at environmentally relevant ratios. The tests produced concentration-response patterns that for individual taxa were interpreted in the same manner as classic single-species toxicity tests and for community metrics such as taxa richness and mayfly (Ephemeroptera) abundance were interpreted in the same manner as with stream survey data. Effect concentrations from the experimental stream exposures were usually 2 to 3 orders of magnitude lower than those from classic single-species tests. Relative to a response addition model, which assumes that the joint toxicity of the mixtures can be predicted from the product of their responses to individual toxicants, the Cd+Zn mixtures generally showed slightly less than additive toxicity. The authors applied a modeling approach called Tox to explore the mixture toxicity results and to relate the experimental stream results to field data. The approach predicts the accumulation of toxicants (hydrogen, Cd, and Zn) on organisms using a 2-pK_a bidentate model that defines interactions between dissolved cations and biological receptors (biotic ligands) and relates that accumulation through a logistic equation to biological response. The Tox modeling was able to predict Cd+Zn mixture responses from the single-metal exposures as well as responses from field data. The similarity of response patterns between the 30-d experimental stream tests and field data supports the environmental relevance of testing aquatic insects in experimental streams. Environ Toxicol Chem 2017;36:749-762. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Cuticle itself as a central and dynamic player in shaping cuticle

The wide variety of external morphologies has underlain the evolutionary success of insects. The insect exoskeleton, or cuticle, which covers the entire body and constitutes the external morphology, is extracellular matrix produced by the epidermis. How is cuticle shaped during development? Past studies have mainly focused on patterning, differentiation and morphogenesis of the epidermis. Recently, however, it is becoming clear that cuticle itself plays important and active roles in regulation of cuticle shape. Studies in the past several years show that pre-existing cuticle can influence shaping of new cuticle, and cuticle can sculpt its own shape through its material property. In this review, I summarize recent advances and discuss future prospects.

Developmental mechanism of the tarsus in insect legs

Insects show a tremendous morphological variety and have been a subject of studying morphological evolution. In legs, the tarsus is especially variable in the number of subsegments (tarsal segments) and their proportion unlike other leg segments. Recent studies in Drosophila melanogaster have revealed details of the tarsal development: regionalization of the tarsal region through integration of regulatory network and its growth, determination of the joint-forming region in each segment through strict regulation of Notch activity, changes in tissue morphology through regulation of RhoGTPases regulators and localized cell death, and finally, the morphogenetic mechanism of the ball-and-socket joint between tarsal segments. The substantial knowledge of the tarsal development makes it a suitable model for studying mechanisms of morphological evolution and diversification.

Susceptibility of Ceraeochrysa cubana larvae and adults to six insect growth-regulator insecticides

The impacts of six insect growth-regulators were assessed on the predator Ceraeochrysa cubana (Hagen) larvae and adults. Our results showed that diflubenzuron, lufenuron and pyriproxyfen caused 100% larva mortality, whereas buprofezin, methoxyfenozide and tebufenozide were similar to control treatment. In comparison to the control, buprofezin prolonged the duration of larval stage, while methoxyfenozide and tebufenozide reduced the predator larva development time. Buprofezin, methoxyfenozide and tebufenozide did not affect the C. cubana duration and survival of pupal stage, fecundity and fertility. However, methoxyfenozide and tebufenozide reduced predator female and male longevities. Based on a reduction coefficient, diflubenzuron, lufenuron and pyriproxyfen were highly harmful to first instar larvae, while buprofezin, methoxyfenozide and tebufenozide were considered slightly harmful to the predator. Estimating the life table parameters, our results showed that buprofezin, methoxyfenozide and tebufenozide reduced the C. cubana R_o, r and λ. In comparison to the control, buprofezin prolonged the T and methoxyfenozide and tebufenozide shortened the predator T. In adults, our results showed that the insecticides did not cause significant mortality, but diflubenzuron, lufenuron and pyriproxyfen reduced the C. cubana fecundity and longevity. Diflubenzuron and lufenuron also reduced the C. cubana fertility. Based on a reduction coefficient, diflubenzuron and lufenuron were highly harmful to C. cubana adults, while pyriproxyfen was slightly harmful and buprofezin, methoxyfenozide and tebufenozide were considered harmless to the predator. Therefore, insect growth-regulators affect the C. cubana biological or populational parameters, and they can harm the integrated pest management programs that aim the predator conservation and/or augmentation in agroecosystems.

Molecular Evolution of Insect Sociality: An Eco-Evo-Devo Perspective

The evolution of eusociality is a perennial issue in evolutionary biology, and genomic advances have fueled steadily growing interest in the genetic changes underlying social evolution. Along with a recent flurry of research on comparative and evolutionary genomics in different eusocial insect groups (bees, ants, wasps, and termites), several mechanistic explanations have emerged to describe the molecular evolution of eusociality from solitary behavior. These include solitary physiological ground plans, genetic toolkits of deeply conserved genes, evolutionary changes in protein-coding genes, cis regulation, and the structure of gene networks, epigenetics, and novel genes. Despite this proliferation of ideas, there has been little synthesis, even though these ideas are not mutually exclusive and may in fact be complementary. We review available data on molecular evolution of insect sociality and highlight key biotic and abiotic factors influencing social insect genomes. We then suggest both phylogenetic and ecological evolutionary developmental biology (eco-evo-devo) perspectives for a more synthetic view of molecular evolution in insect societies.

MicroRNAs and the Evolution of Insect Metamorphosis

MicroRNAs (miRNAs) are involved in the regulation of a number of processes associated with metamorphosis, either in the less modified hemimetabolan mode or in the more modified holometabolan mode. The miR-100/let-7/miR-125 cluster has been studied extensively, especially in relation to wing morphogenesis in both hemimetabolan and holometabolan species. Other miRNAs also participate in wing morphogenesis, as well as in programmed cell and tissue death, neuromaturation, neuromuscular junction formation, and neuron cell fate determination, typically during the pupal stage of holometabolan species. A special case is the control of miR-2 over Kr-h1 transcripts, which determines adult morphogenesis in the hemimetabolan metamorphosis. This is an elegant example of how a single miRNA can control an entire process by acting on a crucial mediator; however, this is a quite exceptional mechanism that was apparently lost during the transition from hemimetaboly to holometaboly.

Neuropeptides as Regulators of Behavior in Insects

Neuropeptides are by far the largest and most diverse group of signaling molecules in multicellular organisms. They are ancient molecules important in regulating a multitude of processes. Their small proteinaceous character allowed them to evolve and radiate quickly into numerous different molecules. On average, hundreds of distinct neuropeptides are present in animals, sometimes with unique classes that do not occur in distantly related species. Acting as neurotransmitters, neuromodulators, hormones, or growth factors, they are extremely diverse and are involved in controlling growth, development, ecdysis, digestion, diuresis, and many more physiological processes. Neuropeptides are also crucial in regulating myriad behavioral actions associated with feeding, courtship, sleep, learning and memory, stress, addiction, and social interactions. In general, behavior ensures that an organism can survive in its environment and is defined as any action that can change an organism's relationship to its surroundings. Even though the mode of action of neuropeptides in insects has been vigorously studied, relatively little is known about most neuropeptides and only a few model insects have been investigated. Here, we provide an overview of the roles neuropeptides play in insect behavior. We conclude that multiple neuropeptides need to work in concert to coordinate certain behaviors. Additionally, most neuropeptides studied to date have more than a single function.

Conserving herbivorous and predatory insects in urban green spaces

Insects are key components of urban ecological networks and are greatly impacted by anthropogenic activities. Yet, few studies have examined how insect functional groups respond to changes to urban vegetation associated with different management actions. We investigated the response of herbivorous and predatory heteropteran bugs to differences in vegetation structure and diversity in golf courses, gardens and parks. We assessed how the species richness of these groups varied amongst green space types, and the effect of vegetation volume and plant diversity on trophic- and species-specific occupancy. We found that golf courses sustain higher species richness of herbivores and predators than parks and gardens. At the trophic- and species-specific levels, herbivores and predators show strong positive responses to vegetation volume. The effect of plant diversity, however, is distinctly species-specific, with species showing both positive and negative responses. Our findings further suggest that high occupancy of bugs is obtained in green spaces with specific combinations of vegetation structure and diversity. The challenge for managers is to boost green space conservation value through actions promoting synergistic combinations of vegetation structure and diversity. Tackling this conservation challenge could provide enormous benefits for other elements of urban ecological networks and people that live in cities.

Paleozoic Nymphal Wing Pads Support Dual Model of Insect Wing Origins

The appearance of wings in insects, early in their evolution [1], has been one of the more critical innovations contributing to their extraordinary diversity. Despite the conspicuousness and importance of wings, the origin of these structures has been difficult to resolve and represented one of the "abominable mysteries" in evolutionary biology [2]. More than a century of debate has boiled the matter down to two competing alternatives-one of wings representing an extension of the thoracic notum, the other stating that they are appendicular derivations from the lateral body wall. Recently, a dual model has been supported by genomic and developmental data [3-6], representing an amalgamation of elements from both the notal and pleural hypotheses. Here, we reveal crucial information from the wing pad joints of Carboniferous palaeodictyopteran insect nymphs using classical and high-tech techniques. These nymphs had three pairs of wing pads that were medially articulated to the thorax but also broadly contiguous with the notum anteriorly and posteriorly (details unobservable in modern insects), supporting their overall origin from the thoracic notum as well as the expected medial, pleural series of axillary sclerites. Our study provides support for the formation of the insect wing from the thoracic notum as well as the already known pleural elements of the arthropodan leg. These results support the unique, dual model for insect wing origins and the convergent reduction of notal fusion in more derived clades, presumably due to wing rotation during development, and they help to bring resolution to this long-standing debate.

Recent Advances in the Chemistry and Biology of Podophyllotoxins

Podophyllotoxin and its related aryltetralin cyclolignans belong to a family of important products that exhibit various biological properties (e.g., cytotoxic, insecticidal, antifungal, antiviral, anti-inflammatory, neurotoxic, immunosuppressive, antirheumatic, antioxidative, antispasmogenic, and hypolipidemic activities). This Review provides a survey of podophyllotoxin and its analogues isolated from plants. In particular, recent developments in the elegant total chemical synthesis, structural modifications, biosynthesis, and biotransformation of podophyllotoxin and its analogues are summarized. Moreover, a deoxypodophyllotoxin-based chemosensor for selective detection of mercury ion is described. In addition to the most active podophyllotoxin derivatives in each series against human cancer cell lines and insect pests listed in the tables, the structure-activity relationships of podophyllotoxin derivatives as cytotoxic and insecticidal agents are also outlined. Future prospects and further developments in this area are covered at the end of the Review. We believe that this Review will provide necessary information for synthetic, medicinal, and pesticidal chemistry researchers who are interested in the chemistry and biology of podophyllotoxins.

Response of Chrysoperla nipponensis (Okamoto) (Neuroptera: Chrysopidae) Under Long and Short Photoperiods

Photoperiod is an important factor influencing many biological processes including population dynamics of many insect species in temperate zones. To determine the population response of Chrysoperla nipponensis under altered conditions (high temperature and short photoperiod) and to test whether the short photoperiod was suitable for artificial storage, the life table data of were collected at 25 °C under a long photoperiod, 15:9 h (L:D), and a short photoperiod, 9:15 h (L:D) and analyzed using the age-stage, two-sex life table approach. We found that developed faster under long photoperiod than under the short photoperiod. The shorter developmental time, higher fecundity, and higher proportion of females found during the long photoperiod resulted in higher intrinsic and net reproductive rates, but a shorter mean generation time and life expectancy compared to those reared during the short photoperiod. Individuals reared under the short photoperiod also had a high reproductive value. Population projection demonstrated that reared at long photoperiod would complete four generations in 150 d, while reared under short photoperiod would just be entering the second generation. Our results demonstrated that the different fitness values obtained for individuals by varying photoperiod lengths, were readily distinguishable when using the age-stage, two-sex life table.

Resource allocation and compensation during development in holometabolous insects

We provide an extensive review on current knowledge and future research paths on the topic of resource allocation and compensation during development in holometabolous insects, emphasizing the role of resource management during development, and how compensatory mechanisms may be acting to remediate nutritional deficiencies carried over from earlier stages of development. We first review resource allocation in "open" and "closed" developmental stages and then move on to the topic of modelling resource allocation and its trade-offs. In doing so, we review novel methodological developments such as response-surface methods and mixture experiments as well as nutritional geometry. We also dwell on the fascinating topic of compensatory physiology and behavior. We finish by discussing future research paths, among them the emerging field of nutrigenomics and gut microbiome, which will shed light into the yet poorly understood role of the symbiotic microbiota in nutrient compensation or assimilation.

Extending the "Ecology of Fear" Beyond Prey: Reciprocal Nonconsumptive Effects Among Competing Aphid Predators

Nonconsumptive effects of predators on prey are well known, but similar effects among competing predators are not. Aphidophagous insect larvae are notorious for cannibalism and intraguild predation, as they compete for aggregated but ephemeral prey. We tested for indirect effects of competitors on the development of Coleomegilla maculata DeGeer and Hippodamia convergens Guerin-Meneville (Coleoptera: Coccinellidae), and a green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), with all larvae reared on eggs of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). Control larvae were reared singly, while treatment larvae were reared pairwise, with either a conspecific or heterospecific, in partitioned Petri dishes that allowed the passage of chemical cues. Larvae of C. maculata, a dietary generalist, appeared stressed by the presence of competing larvae, whether con- or heterospecific, and suffered fitness costs (longer pupation times, lower male adult mass). In contrast, H. convergens and C. carnea, both aphid specialists, responded to competing larvae with accelerated development, and without any apparent costs in terms of adult size or reproductive performance. Adult C. carnea in some treatments were heavier than solitary controls, suggesting a higher consumption rate by the induced phenotype, and those exposed to H. convergens began oviposition earlier. Thus, the phenotypes induced in the specialized aphid predators were adaptive for development in aphid colonies, whereas that induced in the generalist was not. These results indicate that nonconsumptive effects are not simply a vertical force acting on prey, but can also impact conspecific and heterospecific competitors on the same trophic level.

Molecular mechanisms of secondary sexual trait development in insects

Secondary sexual traits are those traits other than the primary gametes that distinguish the sexes of a species. The development of secondary sexual traits occurs when sexually dimorphic factors, that is, molecules differentially produced by primary sex determination systems in males and females, are integrated into the gene regulatory networks responsible for sexual trait development. In insects, these molecular asymmetric factors were always considered to originate inside the trait-building cells, but recent work points to external factors, such as hormones, as potential candidates mediating secondary sexual trait development. Here, we review examples of the different molecular mechanisms producing sexually dimorphic traits in insects, and suggest a need to revise our understanding of secondary sexual trait development within the insect lineage.