Transcriptome profiling reveals the developmental regulation of NaCl-treated Forcipomyia taiwana eggs

Background The biting midge, Forcipomyia taiwana, is one of the most annoying blood-sucking pests in Taiwan. Current chemical control methods only target the adult, not the immature stages (egg to pupa), of F. taiwana. Discovering new or alternative tactics to enhance or replace existing methods are urgently needed to improve the effectiveness of F. taiwana control. The egg is the least understood life stage in this pest species but may offer a novel point of control as addition of NaCl to the egg environment inhibits development. Thus, the objective of this study was to use RNA profiling to better understand the developmental differences between wild-type melanized (black) and NaCl-induced un-melanized (pink), infertile F. taiwana eggs. Results After de novo assembly with Trinity, 87,415 non-redundant transcripts (Ft-nr) with an N50 of 1099 were obtained. Of these, 26,247 (30%) transcripts were predicted to have long open reading frames (ORFs, defined here as ≥300 nt) and 15,270 (17.5%) transcripts have at least one predicted functional domain. A comparison between two biological replicates each of black and pink egg samples, although limited in sample size, revealed 5898 differentially expressed genes (DEGs; 40.9% of the transcripts with long ORFs) with ≥2-fold difference. Of these, 2030 were annotated to a Gene Ontology biological process and along with gene expression patterns can be separated into 5 clusters. KEGG pathway analysis revealed that 1589 transcripts could be assigned to 18 significantly enriched pathways in 2 main categories (metabolism and environmental information processing). As expected, most (88.32%) of these DEGs were down-regulated in the pink eggs. Surprisingly, the majority of genes associated with the pigmentation GO term were up-regulated in the pink egg samples. However, the two key terminal genes of the melanin synthesis pathway, laccase2 and DCE/yellow, were significantly down-regulated, and further verified by qRT-PCR. Conclusion We have assembled and annotated the first egg transcriptome for F. taiwana, a biting midge. Our results suggest that down-regulation of the laccase2 and DCE/yellow genes might be the mechanism responsible for the NaCl-induced inhibition of melanization of F. taiwana eggs.

Lethal Effects of Commercial Kaolin Dust and Silica Aerogel Dust With and Without Botanical Compounds on Horn Fly Eggs, Larvae, Pupae, and Adults in the Laboratory

The horn fly, Haematobia irritans irritans (L.) (Diptera: Muscidae), is an important bloodsucking ectoparasite of cattle throughout much of the world. The fly is mostly controlled using conventional synthetic insecticides but as concerns about resistance increase, alternative tactics have come under heightened scrutiny. Four desiccant dust products: Surround WP, a kaolin clay-based wettable powder; CimeXa, comprised of silica aerogel; Drione, silica aerogel + pyrethrins; and EcoVia, silica aerogel + thyme oil, were assessed for their lethal effects against horn fly eggs, larvae, pupae, and adults, under laboratory conditions. Although Surround WP and CimeXa did not prevent egg hatching and (when mixed with manure substrate) pupal development, the two products were associated with moderate reductions of emerged adults, and with complete adult contact mortality within 6 hr and 24 hr, respectively. Drione and EcoVia eliminated egg hatching, pupal development, and adults within 15 min to 1 hr, respectively, whether the flies were exposed to treated filter paper substrate or exposed by immersion in the dusts. Implications for horn fly control and advantages of inert desiccant dust formulations are discussed.

A Review of Alternative Management Tactics Employed for the Control of Various Cockroach Species (Order: Blattodea) in the USA

Effective control of domestic and peridomestic cockroaches requires integrated approaches that emphasize concurrent use of chemicals with alternative control tactics. An integrated pest management (IPM) approach is particularly justified in environments where satisfactory cockroach control cannot be achieved due to multiple factors including development of insecticide aversion and resistance in some cockroach species, and poor sanitation or structural issues that foster infestations. While a flurry of research effort has been devoted to study alternative tactics for cockroach control, only a few of them have been evaluated in the context of IPM programs. This review focuses on examining studies on alternative tactics that are proven efficacious, economical, and logistically feasible for their inclusion in IPM programs for important domestic and peridomestic cockroaches in the USA. Management programs that educate the public on cockroach biology, behavior, and the importance of sanitation; use of traps to monitor infestation levels; apply targeted low impact insecticides such as baits, have demonstrated a greater success for effective and sustainable control of cockroaches when compared to an insecticide-only approach. Incorporation of other alternative control methods to IPM programs will require more applied research that validates their use in real-world scenarios and demonstrates their cost-effectiveness.

Morph-specific investment in testes mass in a trimorphic beetle, Proagoderus watanabei

When competition between males for mates is intense it is common to find that some males will adopt alternative tactics for acquiring fertilisations, often involving the use of sneak tactics whereby males avoid contests. These alternative tactics are sometimes associated with discrete differences in male morphology, with sneak males investing less in weaponry but more in traits such as testes which will give an advantage in sperm competition. In some cases it appears that males develop into more than two morphs, with a number of examples of tri- and even tetramorphic arthropod species being described. Here we analyse the scaling relations of the dung beetle species Proagoderus watanabei, which expresses two distinct weapon traits: paired head horns and a pronotal horn. We find that males of this species are trimorphic, with alpha males expressing long head horns and a pronotal horn, beta males with long head horns but no pronotal horn, and gamma males with short head horns only. We also find that alpha males invest less in testes than do beta or gamma males, indicating that beta and gamma males in this species probably experience higher risks of sperm competition than do alphas.

Transcriptome Profiling Reveals The Developmental Regulation of NaCl-Treated Forcipomyia Taiwana Eggs

Background: The biting midge, Forcipomyia taiwana, is one of the most annoying blood-sucking pests in Taiwan. Current chemical control only targets the adult, not the immature stages (egg to pupa) of F. taiwana. Discovering new or alternative tactics to enhance or replace existing methods are urgently needed to improve the effectiveness of F. taiwana control. The egg is the least understood life stage in this pest species but may offer a novel point of control as addition of NaCl to the egg environment inhibits development. Thus, the objective of this study was to use RNA profiling to better understand the developmental differences of wild-type melanized and NaCl-induced un-melanized and infertile F. taiwana eggs. Results: After de novo assembly with Trinity, 112,959 non-redundant transcripts (Ft-nr) with an N50 of 1,044 were obtained. Of these, 28,455 (24.8%) transcripts were predicted to have long open reading frames (ORFs, defined here as ≥300 nt) and 17,791 (15.8%) transcripts have at least one predicted functional domain. A comparison between the melanized (control) and un-melanized eggs revealed 15,996 differentially expressed genes (DEGs; 56.2% of the transcripts with long ORFs) with ≥2-fold difference. Of these, 8,865 were annotated to a Gene Ontology biological process and along with gene expression patterns can be separated into 5 clusters. KEGG pathway analysis revealed that 6,888 transcripts could be assigned to 102 significantly enriched pathways in 3 main categories (metabolism, genetic information processing, environmental information processing). As expected, most (78.24%) of these DEGs were down-regulated in un-melanized eggs. Surprisingly, the majority of genes associated with the pigmentation GO term were up-regulated in the pink egg samples; however, two key terminal genes, laccase2 and DCE/Yellow, were significantly down-regulated, and further verified by qPCR. Conclusion: We have assembled and annotated the first egg transcriptome for F. taiwana, a biting midge. We found that down-regulation of laccase2 and DCE/Yellow genes might be the mechanism responsible for the NaCl-induced inhibition of melanization of F. taiwana eggs.

Lethal Effects of a Silica Gel + Pyrethrins (Drione) on Amblyomma americanum (Ixodida: Ixodidae) Larvae and Nymphs

Ixodids (hard ticks) ingest blood from host animals, and they can transmit pathogenic organisms that induce medical and veterinary diseases. As resistance to synthetic conventional acaricides becomes more common, alternative tactics are coming under heightened scrutiny. Laboratory bioassays were used to assess the efficacy of CimeXa, a commercially available silica gel desiccant dust product, and Drione, a commercial product containing silica gel + pyrethrins and a synergist, piperonyl butoxide, against lone star tick, Amblyomma americanum (L.) (Ixodida: Ixodidae), larvae and nymphs. Both life stages were completely killed by CimeXa by 24 h, and Drione caused total larval mortality within 1 h when they were briefly immersed in the dusts and when they crawled across dust-treated substrate; nymphs were completely killed by 4 h after the same kinds of exposure. Mortality of A. americanum larvae and nymphs occurred after the pests crawled across dried aqueous suspensions of the products, but this was not as efficient and fast-acting as when the immature life stages were exposed to dry dusts. Further, dried aqueous suspensions of Drione were not substantially more lethal than dried aqueous suspensions of CimeXa. CimeXa and Drione will provide prophylactic control on vegetation and animals for as long as the silica gel remains without being physically removed. Both of the dust-based products will likely also be effective against other problematic ixodid species. Advantages and disadvantages, and potential uses, of desiccant dust-based acaricides are discussed.

Lethal Effects of a Silica Gel + Thyme Oil (EcoVia) Dust and Aqueous Suspensions on Amblyomma americanum (Ixodida: Ixodidae) Larvae and Nymphs

Ixodids suck blood from host animals and transmit pathogens that cause important medical and veterinary diseases. As synthetic conventional acaricide resistance becomes increasingly common, alternative tactics are likely to enhance control efforts. Laboratory bioassays assessed the lethality of CimeXa, a commercial silica gel desiccant dust, and EcoVia, a commercial product containing silica gel + thyme oil, against lone star tick, Amblyomma americanum (L.), larvae and nymphs. Both life stages were completely killed by CimeXa by 24 h, and EcoVia achieved total larval mortality within 1 h when they were initially immersed in the dusts and when they crawled across treated substrate. Larvae were killed faster than nymphs. Temporary immersion of A. americanum larvae and nymphs in aqueous suspensions of the dusts were less effective than exposure to the dusts applied dry. Larval and nymphal mortality associated with crawling on dried aqueous suspensions of the products was also not as strong as when the immature life stages crawled across substrate treated with dry dusts, and EcoVia was not more efficient than CimeXa. CimeXa and EcoVia can likely be used to protect cattle in a prophylactic context because silica gel does not degrade, and EcoVia might be effective at eliminating ticks that are feeding on cattle as well. We suggest that the two dust products be assessed for efficacy against other ixodid species, such as the southern cattle fever tick, Rhipicephalus microplus (Canestrini), which transmits the causal agents of babesiosis to cattle.

Global existence theory for fractional differential equations: New advances via continuation methods for contractive maps

The aim of this article is to form new existence theory for global solutions to nonlinear fractional differential equations. Traditional approaches to existence, uniqueness and approximation of global solutions for initial value problems involving fractional differential equations have been unwieldy or intractable due to the limitations of previously used methods. This includes, for example, certain invariance conditions of the underlying local fixed point strategies. Herein we draw on an alternative tactics, applying the more modern ideas of continuation methods for contractive maps to fractional differential equations. In doing so, we shed new light on the situation, producing these new perspectives through a range of novel theorems that involve sufficient conditions under which global existence, uniqueness, approximation and location of solutions are ensured.

Direct Action and the Search for “Freedom of Movement”

Chapter 4 examines Wheeler’s activism during the direct-action phase of the civil rights movement. It pushes us to consider how a black businessman in Wheeler’s position could serve not as an obstacle to but as a steadfast advocate of alternative tactics during the 1960s. Despite the emergence of student-centered leadership with the 1960 sit-in movement, Wheeler did not take a sidelines position. Instead, he continued to operate behind the scenes while publicly and privately lending his support to student activists. Wheeler had a reputation for always being ahead of his time, and white leaders considered him to be a radical. His acceptance of young activists and his integrationist views represented a unique departure from many of his black business contemporaries. I argue that while direct action represented a shift away from strict reliance on legal tactics, as well as a generational shift in leadership, Wheeler recognized that ongoing civil disobedience meant that he was in a much better position than ever before to fulfill the ideals of New South prosperity through increased involvement in reform and policymaking at the local, state, and national levels.

Recent Investigations on the Functionalizations of C(sp3)-H Bonds Adjacent to a Heteroatom

The selective functionalization of unactivated C(sp3)-H bonds has been regarded as an efficient and atom-economical approach for the formation of carbon-carbon or carbon-heteroatom bonds in modern organic synthesis. Especially, the oxidative activation of C(sp3)–H bonds adjacent to a heteroatom exhibits quite significant features in synthetic chemistry. For example, the direct functionalizations of amines, amides and ethers present important alternative tactics for the synthesis of various novel and useful molecules from simple starting materials. Many remarkable achievements in the area had continuously been made in the past decades. Here we reviewed recent investigations on the transformations of C(sp3)-H bond adjacent to a heteroatom.