Simplification traps

When experiments are analyzed with simple functions, one gets simple results. A trap springs when experiments show deviations from the expected simplicity. When kinetic experiments do not follow exponential curves, they simply are not of the first or pseudofirst order. They can and have to be calculated on the base of plausible reaction schemes. When dose–response curves are analyzed with logistic functions (“4-parameter fit”) and give Hill coefficients different from one, this is an experimental result stating that more than one molecule is involved in eliciting the response. If one ignores that result, one usually finds forgiving referees, but one will loose real money when one tries to develop such an unspecific compound into a drug.

Electronic supplementary material

The online version of this article (doi:10.1007/s12154-011-0069-3) contains supplementary material, which is available to authorized users.     

A comparison of water traps, cylindrical sticky traps and suction traps for sampling thysanopteran populations at different levels

Thysanoptera drifting over and around a wheat field were trapped using black, green and white water traps, black cylindrical sticky traps and suction traps. Certain Taeniothrips spp., Thrips spp., and Aeolothrips spp. were strongly attracted to white but not to green or black; Limothrips cerealium Hal., Chirothrips manicatus Hal., and Stenothrips gramium Uzel were not markedly attracted to any of these colours. At crop level suction traps gave more consistent catches² than either sticky or water traps; at higher levels, catches from sticky traps were more consistent than those from water traps. Up to 48 ft the aerial density of all species decreased with height but the rapidity of the decrease differed between species.

---

Sommaire Les Thysanoptères qui flottaient autour et au-dessus d'un champ de blé étaient attrapés par le moyen de pièges à l'eau noirs, verts ou blancs, de pièges cylindriques qui étaient visqueuz et noirs et d'aspirateurs. De certaines espèces des genres Taeniothrips, Thrips et Aeolothrips étaient très attirées par le blanc mais pas par le vert ni le noir: les espèces Limothrips cerealium Hal., Chirothrips manicatus Hal., et Stenothrips gramium Uzel n'étaient pas notablement attirées par chacune de ces couleurs. Au niveau des épis les données obtenues avec les aspirateurs étaient plus justes que ne l'étaient celles obtenues avec les pièges à glu ou les pièges à eau: plus haut les pièges à glu indiquaient des données plus justes que les pièges à eau. Jusqu'à quinze mètres environ de hauteur la densité aérienne de toutes les espèces diminuaient progressivement, mais la rapidité de la diminution était différente entre les espèces.

     

Ecologically seIective coIoured traps

Abstract. 1. This paper analyses catches of flower thrips, grass thrips and predatory flies in water-traps of seven colours.
2. A correlation is demonstrated between type of host-plant of thrips and the relative numbers caught by traps of different colours.
3. The literature is reviewed and some general relationships with the effectiveness of different trap colours are hypothesized for: non-grass foliage insects and their predators and parasites; grass foliage insects; flower-dwelling insects; predators and parasites not associated with foliage; biting insects; and wood-borers.
4. This may permit trap colours to be chosen, in particular circumstances, that are ecologically selective for different types of insect.     

Odour-baited traps influence thrips capture in proximal unbaited traps in the field

Two field experiments examined the distance over which an attractant odour of a volatile chemical could influence thrips capture in proximal traps that were without the odour. In each experiment a star‐shaped array of water traps consisted of a centre trap with or without an odour surrounded by odourless traps at 0.5, 1, 2, 5, and 10 m in eight equally spaced radial arms 45° apart. Experiments ran for 47 h (centre trap: ethyl nicotinate) or 7 h (centre trap: ethyl isonicotinate). Each had four replicates. With ethyl nicotinate, more thrips were trapped in the centre‐baited traps than in the unbaited centre traps (63×, 7×, 98× and 200× for total thrips, Thrips tabaci Lindeman ♀, and Thrips obscuratus Crawford ♀and ♂, respectively) (Thysanoptera: Thripidae). More total thrips and T. tabaci♀ were trapped in the centre traps baited with ethyl isonicotinate than in unbaited centre traps (21× for both). For ethyl nicotinate, numbers of T. obscuratus in unbaited traps downwind from the baited centre trap declined by 50% within 0.4 m (♀) and 2 m (♂) and by 95% within 3 m (both ♀ and ♂) based on model predictions. For ethyl isonicotinate, numbers of T. tabaci in unbaited traps downwind from the baited centre trap declined by 50% within 1.3 m and by 95% within 10 m based on model predictions. Wind direction was an important factor in the degree and direction of thrips capture with the highest thrips capture downwind from the centre trap with odour. There was no increase in numbers of T. tabaci in any traps without odour in the ethyl nicotinate‐centred array. Differences in trapping patterns between thrips species and odours indicated that there were thrips species–odour specific interactions. Experiments examining differences between traps with and without a thrips attractant odour need to be designed very carefully to ensure meaningful results especially in enclosed and/or low‐wind indoor situations.     

Ultra-fast underwater suction traps

Carnivorous aquatic Utricularia species catch small prey animals using millimetre-sized underwater suction traps, which have fascinated scientists since Darwin's early work on carnivorous plants. Suction takes place after mechanical triggering and is owing to a release of stored elastic energy in the trap body accompanied by a very fast opening and closing of a trapdoor, which otherwise closes the trap entrance watertight. The exceptional trapping speed--far above human visual perception--impeded profound investigations until now. Using high-speed video imaging and special microscopy techniques, we obtained fully time-resolved recordings of the door movement. We found that this unique trapping mechanism conducts suction in less than a millisecond and therefore ranks among the fastest plant movements known. Fluid acceleration reaches very high values, leaving little chance for prey animals to escape. We discovered that the door deformation is morphologically predetermined, and actually performs a buckling/unbuckling process, including a complete trapdoor curvature inversion. This process, which we predict using dynamical simulations and simple theoretical models, is highly reproducible: the traps are autonomously repetitive as they fire spontaneously after 5-20 h and reset actively to their ready-to-catch condition.     

Simple traps for invertebrates

Four simple traps for dendrobiontic invertebrates and two light traps that attract nonflying (wingless and larval) forms of invertebrates are described. Along with data on phenology, population dynamics, and other aspects of invertebrate biology and ecology, the new traps provide the possibility of revealing migrations of entomophages and economically dangerous species in a timely manner, thereby improving the efficiency of pest population monitoring.     

Efficiency of subaquatic light traps

Subaquatic light traps are often used for sampling of the aquatic insects; however, their efficiency has not been tested yet. Here, we describe the use of such traps, illustrate the design of a simple trap allowing standardised sampling, and present results of assessment of the light trap efficiency according to the different turbidity levels, as well as model insects’ escape rates. The effect of turbidity on the capture efficiency was not significant for Sigara lateralis (Leach, 1817), Notonecta glauca Linnaeus, 1758 and Corixa punctata (Illiger, 1807) and was marginally significant for Chaoborus sp. Escape rates were affected by the entrance size and daylight exposure time. Although subaquatic light traps are helpful for standardised sampling, their entrance should be adequate for the target species, and the traps should be removed soon after the dawn or the resulting specimen counts should be corrected for the daylight exposure time before the trap removal.     

Neutrophil extracellular traps impair regeneration

Fibrosis is a major health burden across diseases and organs. To remedy this, we study wound-induced hair follicle neogenesis (WIHN) as a model of non-fibrotic healing that recapitulates embryogenesis for de novo hair follicle morphogenesis after wounding. We previously demonstrated that TLR3 promotes WIHN through binding wound-associated dsRNA, the source of which is still unclear. Here, we find that multiple distinct contexts of high WIHN all show a strong neutrophil signature. Given the correlation between neutrophil infiltration and endogenous dsRNA release, we hypothesized that neutrophil extracellular traps (NETs) likely release nuclear spliceosomal U1 dsRNA and modulate WIHN. However, rather than enhance regeneration, we find mature neutrophils inhibit WIHN such that mice with mature neutrophil depletion exhibit higher WIHN. Similarly, Pad4 null mice, which are defective in NET production, show augmented WIHN. Finally, using single-cell RNA sequencing, we identify a dramatic increase in mature and activated neutrophils in the wound beds of low regenerating Tlr3−/− mice. Taken together, these results demonstrate that although mature neutrophils are stimulated by a common pro-regenerative cue, their presence and NETs hinder regeneration.     

A comparison of pitfall traps with bait traps for studying leaf litter ant communities.

A comparison of pitfall traps with bait traps for sampling leaf litter ants was studied in oak-dominated mixed forests during 1995-1997. A total of 31,732 ants were collected from pitfall traps and 54,694 ants were collected from bait traps. They belonged to four subfamilies, 17 genera, and 32 species. Bait traps caught 29 species, whereas pitfall traps caught 31 species. Bait traps attracted one species not found in pitfall traps, but missed three of the species collected with pitfall traps. Collections from the two sampling methods showed differences in species richness, relative abundance, diversity, and species accumulation curves. Pitfall traps caught significantly more ant species per plot than did bait traps. The ant species diversity obtained from pitfall traps was higher than that from bait traps. Bait traps took a much longer time to complete an estimate of species richness than did pitfall traps. Little information was added to pitfall trapping results by the bait trapping method. The results suggested that the pitfall trapping method is superior to the bait trapping method for leaf litter ant studies. Species accumulation curves showed that sampling of 2,192+/-532 ants from six plots by pitfall traps provided a good estimation of ant species richness under the conditions of this study.     

Chemical meat bait traps versus basic meat bait traps in collection of adult flies

The aim of the present study is to compare the effectiveness of chemical meat bait traps and basic meat bait traps for collecting adult flies. Bait traps used to collect these species can be damaged by anthropogenic or environmental effects. In this study, chemical meat bait traps and basic meat bait traps were hung from trees in the garden of the Ankara University Forensic Sciences Institute. This activity was carried out on the first Monday of each month for nine months. During the study, 1894 specimens were collected. Of all these species, 1787 (94.35%) were obtained from chemical meat bait traps (CMBTs), while 107 (5.65%) were obtained from basic meat bait traps (BMBTs). To determine the diversity of species in CMBT and BMBT sample groups in our study, Shannon Wiener and Simpson diversity and dominance indices were used. Shannon Evenness Index was calculated to determine the relationship between species community‐density. Cluster analysis provided a summary of the similarity in species composition of different regions. The CMBT and BMBT trap groups similarity/dissimilarity feature was checked using Bray–Curtis cluster analysis. The number of species collected from CMBTs was considerably higher than in BMBTs. The results of this study will help researchers to save time. In addition, it should be kept in mind that thiamethoxam is harmful to the environment when it contaminates sources of water.     

Dielectrophoretic traps for single-particle patterning

We present a novel microfabricated dielectrophoretic trap designed to pattern large arrays of single cells. Because flowing away untrapped cells is often the rate-limiting step during cell patterning, we designed the trap to be strong enough to hold particles against practical flow rates. We experimentally validated the trap strength by measuring the maximum flow rate that polystyrene beads could withstand while remaining trapped. These bead experiments have shown excellent agreement with our model predictions, without the use of fitting parameters. The model was able to provide us with a fundamental understanding of how the traps work, and additionally allowed us to establish a set of design rules for optimizing the traps for a wide range of cell sizes. We provide the foundations for an enabling technology that can be used to pattern cells in unique ways, allowing us to do novel cell biology experiments at the microscale.     

Introduced species as evolutionary traps

Invasive species can alter environments in such a way that normal behavioural decision‐making rules of native species are no longer adaptive. The evolutionary trap concept provides a useful framework for predicting and managing the impact of harmful invasive species. We discuss how native species can respond to changes in their selective regime via evolution or learning. We also propose novel management strategies to promote the long‐term co‐existence of native and introduced species in cases where the eradication of the latter is either economically or biologically unrealistic.     

Sonochemistry of nitrone spin traps in aqueous solutions. Evidence for pyrolysis radicals from spin traps

When argon-saturated aqueous solutions of alpha-phenyl-N-tert-butylnitrone (PBN) were sonicated, the spin adducts PBN-Phenyl (Ph), PBN-X, and PBN-H were observed. It can be inferred that PBN-Ph and -X arise from spin adducts of thermal decomposition products of PBN induced by the high temperature due to ultrasonic cavitation. The ESR signal of PBN-H was observed at a lower PBN concentration than those of PBN-Ph and PBN-X. The ratios of ESR intensity of PBN-H to those of PBN-Ph and PBN-X increased with the final temperatures of the cavitation bubbles created by different rare gases. The spin adducts of methyl and tert-butyl radicals from the pyrolysis of PBN, induced by the high temperatures due to cavitation, were found from spin trapping experiments in which 3,5-dibromo-2,6-dideuterio-4-nitrosobenzene sulfonate was used as a spin trap. Similar spin adducts induced by pyrolysis were also observed in sonicated aqueous solutions of other nitrone spin traps, such as alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone, and alpha-(4-nitrophenol) N-tert-butylnitrone. The greater the hydrophobicity of the spin traps, as measured by the 2-octanol/water partition coefficients, the lower the concentration of spin trap at which methyl radicals generated by thermal decomposition of the spin trap can be observed. The present results indicate that the nonvolatile, highly hydrophobic spin traps accumulate preferentially in the interfacial region of cavitation bubbles where they undergo thermal decomposition during cavitation to produce the radicals.     

Virus population extinction via ecological traps

Populations are at risk of extinction when unsuitable or when sink habitat exceeds a threshold frequency in the environment. Sinks that present cues associated with high-quality habitats, termed ecological traps, have especially detrimental effects on net population growth at metapopulation scales. Ecological traps for viruses arise naturally, or can be engineered, via the expression of viral-binding sites on cells that preclude viral reproduction. We present a model for virus population growth in a heterogeneous host community, parameterized with data from populations of the RNA bacteriophage Φ6 presented with mixtures of suitable host bacteria and either neutral or trap cells. We demonstrate that viruses can sustain high rates of population growth in the presence of neutral non-hosts as long as some host cells are present, whereas trap cells dramatically reduce viral fitness. In addition, we demonstrate that the efficacy of traps for viral elimination is frequency dependent in spatially structured environments such that population viability is a nonlinear function of habitat loss in dispersal-limited virus populations. We conclude that the ecological concepts applied to species conservation in altered landscapes can also contribute to the development of trap cell therapies for infectious human viruses.