Colonization of Coquillettidia linealis (Skuse) with reference to other Coquillettidia and Mansonia species

The immature stages of Coquillettidia and Mansonia mosquitoes are cryptic and spend the duration of their development attached to the tissues of subsurface aquatic plants. This obligatory association makes them difficult to collect and has precluded detailed investigation of the biology of Coquillettidia linealis, a species of significant pest and vector status in Australia, as well as other species in the genus Coquillettidia in Australia and elsewhere. This paper describes the first successful establishment and maintenance of a colony of Cq. linealis. Blood‐seeking wild adults were collected and induced to oviposit under laboratory conditions, where methods were developed to rear larval populations to adult maturity in a colony that was maintained through eight successive generations. Colonies of Coquillettidia xanthogaster and Coquillettidia sp. nr crassipes were also established and reared through at least six generations and five generations, respectively, while two species of Mansonia, Mansonia uniformis and Mansonia septempunctata, were also reared successfully for six and two generations, respectively.     

Compatibility of flonicamid and a formulated mixture of pyrethrins and azadirachtin with predators for soybean aphid (Hemiptera: Aphididae) management

The invasive soybean aphid, Aphis glycines Matsumura, is an important pest in North American soybean production. Predators can play an important role in suppressing A. glycines. However, current A. glycines management practices rely primarily on broad-spectrum insecticides, which can adversely affect natural enemy populations. An alternative is the use of selective insecticides that control the targeted pest species, while having a reduced impact on natural enemies. In greenhouse and laboratory assays, we tested the effects of lambda-cyhalothrin, two rates of flonicamid, which is currently not registered for use in soybean, and a formulated mixture of pyrthrins and azadirachtin on A. glycines and its natural enemies, Chrysoperla rufilabris (Burmeister), Orius insidiosus (Say) and Hippodamia convergens (Guerin-Meneville). All insecticides significantly reduced A. glycines populations. Lambda-cyhalothrin was highly toxic to the natural enemies tested. Flonicamid showed the lowest toxicity to natural enemies, but the high rate did decrease survival of O. insidiosus. The mixture of pyrethrins and azadirachtin was toxic to larvae of C. rufilabris and adult O. insidiosus. Moreover, the mixture of pyrethrins and azadirachtin increased the developmental time of C. rufilabris. These results indicate potential for flonicamid and the mixture of pyrethrins and azadirachtin to increase compatibility between chemical and biological controls.     

Bombinins, antimicrobial peptides from Bombina species

The skin secretions of Bombina species contain peptides and small proteins with interesting biological properties. These include bombesin, thyrotropin releasing hormone, BSTI and Bv8. In this review, the biosynthesis and antimicrobial activity of two groups of peptides, bombinins and bombinins H, are described. To date, these have only been found in Bombina skin. They are derived from common precursors containing one or two bombinin copies at the amino and a single bombinin H at the carboxyl end. Bombinins are active against Gram-positive and Gram-negative bacteria and fungi but virtually inactive in haemolysis assays. Conversely, bombinins H have lower bactericidal activities but lyse erythrocytes. In the skin secretions, bombinins H are present in two sizes with either 20 or 17 amino acids. Moreover, they occur as epimers with either an l- or a d-amino acid at position 2. An enzyme catalyzing this inversion of chirality of an amino acid in peptide linkage has been isolated from Bombina skin secretions. In different tests, also with different stages of the life cycle of Leishmania parasites, the d-forms were found to be more active. Biophysical studies have yielded some insight into the different behaviours of the epimers in model membranes.     

Potential cotton aphid,Aphis gossypii,population suppression by arthropod predators in upland cotton

The cotton aphid, Aphis gossypii Glover, predation rate of convergent lady beetle, Hippodamia convergens Guerin‐Meneville, was determined by assigning a single predator randomly to each of four prey density treatments in the laboratory. Prey densities included 25, 50, 100, and 200 aphids per Petri dish arena. Predation response was recorded at 1, 4, 8, 16, 24, and 48 h after assigning predators to their prey treatments. Rate of consumption increased through time, with all 25 aphids consumed during the first 4 h of the experiment. At the highest density, adult lady beetle consumed on average 49, 99, 131, 163, 183, and 200 aphids within 1, 4, 8, 16, 24 and 48 h, respectively. Predators showed a curvilinear feeding response in relation to total available time, indicating that convergent lady beetles have the potential to suppress larger populations of aphids through continuous feeding by regulating their predation efficiency during feeding. The analysis of age‐specific mortality in absence of prey revealed that lady beetles could survive for an extended period of time (more than 2 weeks) without prey. The ability of a predator to survive without prey delays or prevents the rebound of pest populations that is a significant factor in natural biological control. A two‐year field sampling of 10 cotton arthropod predator species showed that spiders (27%) were the most dominant foliage dwelling predators in the Texas High Plains cotton followed by convergent lady beetles (23.5%), hooded beetles (13.5%), minute pirate bugs (11%), green lacewings (9.5%), bigeyed bugs (7.5%), scymnus beetles (3%), soft‐winged flower beetles (2%), damsel bugs (1.5%), and assassin bugs (1.5%). A field cage study showed that one H. convergens adult per plant released at prey density of one aphid per leaf kept the aphid population below economic threshold for the entire growing season.     

Inhibitory Potency of Erythrina variegata Proteinase Inhibitors toward Serine Proteinases in the Blood Coagulation and Fibrinolytic Systems

The Erythrina variegata Kunitz family trypsin inhibitors, ETIa and ETIb, prolonged the activated partial thromboplastin time (APTT) and also the prothrombin time (PT) of human plasma, but the Kunitz family chymotrypsin inhibitor, ECI, and Bowman–Birk family inhibitor, EBI, from E. variegata hardly prolonged these times. Trypsin inhibitors ETIa and ETIb inhibited the amidolytic activity of factor Xa, and ETIb but not ETIa inhibited plasma kallikrein. Neither ETIa nor ETIb exhibited any inhibitory activity toward β-factor XIIa and thrombin. Furthermore, trypsin inhibitors ETIa and ETIb inhibited plasmin, a serine proteinase in the fibrinolytic system, whereas ECI and EBI did not. These results indicate that Erythrina Kunitz proteinase inhibitors possess different potency toward serine proteinases in the blood coagulation and fibrinolytic systems, in spite of their high similarity in amino acid sequence.     

A barcode analysis of the genus Lobophora (Dictyotales,Phaeophyceae) in the western Atlantic Ocean with four novel species and the epitypification of L. variegata (J.V. Lamouroux) E.C. Oliveira

In the western Atlantic Ocean, the brown algal genus Lobophora is currently represented by a single species, L. variegata, with a type locality designated by Lamouroux as ‘Antilles’. In this study, we used molecular-assisted alpha taxonomy (MAAT) to assess species diversity of Lobophora in Bermuda, the Florida Keys, St. Croix and Guadeloupe (Lesser Antilles). Using cox1 and cox3 sequences as barcode markers, five species of Lobophora, four of them novel, were delineated, all previously having been identified in the area as L. variegata. Our morphological and habitat studies, made possible by abundant sampling, have revealed unique characters for each of these western Atlantic species, including distinct cellular arrangements, as well as different depth ranges for certain species. Observations made from Lamouroux’s holotype of Dictyota variegata (= Lobophora variegata) allowed us to assess the anatomy of this species, which enabled us to easily align this early taxon to one of our genetic species from the western Atlantic. As the type was unavailable for genetic analysis, we selected a recent St. Croix (Virgin Is., Antilles) specimen as the epitype to support it with molecular sequence data.     

镉胁迫对秋华柳根系活力及其Ca、Mg、Mn、Zn、Fe积累的影响

以秋华柳为试验材料,采用水培试验方式,设置CK(0 mg·L^-1 Cd²⁺)、T₁(2 mg·L^-1 Cd²⁺)、T₂(10 mg·L^-1Cd²⁺)、T₃(20 mg·L^-1Cd²⁺)、T₄(50 mg·L^-1Cd²⁺)5种镉处理浓度,通过对秋华柳根系活力,叶、韧皮部、木质部和根部的镉含量,以及Ca、Mg、Mn、Zn、Fe 5种常规金属元素含量的测定,研究了不同浓度镉胁迫下秋华柳根系活力及Ca、Mg、Mn、Zn、Fe 等金属元素含量的变化.结果表明:1)秋华柳根系活力随着镉处理浓度的增加而逐渐下降,当镉浓度≥10 mg·L^-1时,根系活力与对照相比显著下降.2)随着镉处理浓度的增加,秋华柳叶中Fe的积累受到显著抑制;韧皮部Mg、Mn、Fe的积累受到显著抑制;木质部Ca、Mg、Mn、Zn、Fe 等5种常规金属元素的积累无显著性差异;根部5种常规金属元素的吸收和积累受到显著抑制,表现出镉对其他金属元素积累的拮抗作用.其中,50 mg·L^-1的镉胁迫下,根部Zn的积累量降幅最大,受Cd的抑制最明显.3)各处理组Fe的转移系数与对照相比均无显著性差异;Ca、Mg、Mn、Zn的转移系数均高于对照,且在一定的镉处理水平上差异显著.4)镉胁迫下,秋华柳根部镉的积累量与Ca的积累量呈显著负相关,与其他4种常规金属元素的积累量呈极显著负相关,说明根部常规金属元素的变化可作为秋华柳受镉毒害程度的指示之一.     

A false‐positive food chain error associated with a generic predator gut content ELISA

Conventional prey‐specific gut content ELISA (enzyme‐linked immunosorbent assay) and PCR (polymerase chain reaction) assays are useful for identifying predators of insect pests in nature. However, these assays are prone to yielding certain types of food chain errors. For instance, it is possible that prey remains can pass through the food chain as the result of a secondary predator (hyperpredator) consuming a primary predator that had previously consumed the pest. If so, the pest‐specific assay will falsely identify the secondary predator as the organism providing the biological control services to the ecosystem. Recently, a generic gut content ELISA was designed to detect protein‐marked prey remains. That assay proved to be less costly, more versatile, and more reliable at detecting primary predation events than a prey‐specific PCR assay. This study examines the chances of obtaining a ‘false positive’ food chain error with the generic ELISA. Data revealed that the ELISA was 100% accurate at detecting protein‐marked Lygus hesperus Knight (Hemiptera: Miridae) remains in the guts of two (true) primary predators, Hippodamia convergens Guérin‐Méneville (Coleoptera: Coccinellidae) and Collops vittatus (Say) (Coleoptera: Melyridae). However, there was also a high frequency (70%) false positives associated with hyperpredators, Zelus renardii Kolenati (Hemiptera: Reduviidae), that consumed a primary predator that possessed protein‐marked L. hesperus in its gut. These findings serve to alert researchers that the generic ELISA, like the PCR assay, is susceptible to food chain errors.