Liquid crystals play an important role in biology because the combination of order and mobility is a basic requirement for self-organisation and structure formation in living systems. Cholesteric liquid crystals are omnipresent in living matter under both in vivo and in vitro conditions and address the major types of molecules essential to life. In the animal and plant kingdoms, the cholesteric structure is a recurring design, suggesting a convergent evolution to an optimised left-handed helix. Herein, we review the recent advances in the cholesteric organisation of DNA, chromatin, chitin, cellulose, collagen, viruses, silk and cholesterol ester deposition in atherosclerosis. Cholesteric structures can be found in bacteriophages, archaea, eukaryotes, bacterial nucleoids, chromosomes of unicellular algae, sperm nuclei of many vertebrates, cuticles of crustaceans and insects, bone, tendon, cornea, fish scales and scutes, cuttlebone and squid pens, plant cell walls, virus suspensions, silk produced by spiders and silkworms, and arterial wall lesions. This article specifically aims at describing the consequences of the cholesteric geometry in living matter, which are far from being fully defined and understood, and discusses various perspectives. The roles and functions of biological cholesteric liquid crystals include maximisation of packing efficiency, morphogenesis, mechanical stability, optical information, radiation protection and evolution pressure.

/pdf/cholesteric-liquid-crystals-in-living-matter-2srqjabvxs.pdf

Cholesteric liquid crystals in living matter

This manual is an excellent blending of scientific techniques and knowledge with criminal investigation backgrounds. It works at maintaining the skills and precision needed by the entomologist to translate rather gruesome scenes into worthwhile courtroom information, plus tweaking one's conscience with ethical and objective standards.

A Review of Entomology and Death: A Procedural Guide

Multiwavelength micromirrors in the cuticle of scarab beetle Chrysina gloriosa.

A sympatric assemblage of morphologically similar predators is expected to exhibit fine-scale habitat segregation, or resource partitioning, to reduce the effects of direct competition. This principle has been well studied for predators in terrestrial ecosystems. In the marine environment, the fine-scale spatial segregation of sympatric species of large predators is poorly understood because detailed movement and behavioural data are often not available across multiple species within the same timeframe. The ways in which co-occurring congeneric predators separate spatially is even less well understood. Medium-sized species of skates (genus Raja) co-occur in temperate habitats of the north-east Atlantic Ocean, share similar morphologies and have distributional ranges that overlap significantly in the western English Channel ecosystem. In the present study, detailed depth time series retrieved from 89 electronic data storage tags attached to 4 species of skate were analysed to determine preferred depth ranges. The 4 species were found to segregate spatially into 2 groups, with one group having a significantly shallower core annual depth range than the other. To our knowledge, fine-scale segregation by depth has not been observed previously. Interestingly, the members of each species group appeared complementary, each group comprising species with different dietary preferences and with a larger and smaller body size. An understanding of how core depth ranges differ and how these species utilise vertical habitat could potentially enable geographic ranges around the coast to be predicted, with important implications for how these species interact with fisheries and Marine Protected Areas.

/pdf/two-s-company-three-s-a-crowd-fine-scale-habitat-4g9sxwq7c8.pdf

Two’s company, three’s a crowd: fine-scale habitat partitioning by depth among sympatric species of marine mesopredator

/pdf/food-plants-a-bibliography-1zhsjdjkz7.pdf

Food Plants: A Bibliography

How behavioral patterns are related to niche partitioning is an important question in understanding how closely related species within ecological communities function. Behavioral niche partitioning associated with thermoregulation is well documented in tiger beetles as a group. Co-occurring species of salt flat tiger beetles have adapted many thermoregulatory behaviors to cope with this harsh ecosystem. On first examination these beetles appear to occur in overlapping microhabitats and therefore compete for resources. To determine if behavioral niche partitioning is allowing multiple species to occur within the same harsh salt flat ecosystem we observed Cicindela nevadica lincolniana, Cicindela circumpicta, Cicindela fulgida, and Cicindela togata between 8:00 h and 21:00 h and recorded all behaviors related to thermoregulation using a digital voice recorder. Results of this study strongly indicate that competition among these species for resources has been reduced by the adaptation of different thermoregulatory behaviors such as spending time in shallow water, avoiding the sun during the hottest parts of the day, and by positioning their body against or away from the soil. The endangered C. n. lincolniana appears to rely most heavily on the shallow water of seeps for their diurnal foraging behavior (potentially limiting their foraging habitat), but with the advantage of allowing foraging during the hottest times of the day when potential competitors are less frequent. Ironically, this association also may help explain C. n. lincolniana's susceptibility to extinction: beyond the loss of saline wetlands generally, limited seeps and pools even within remaining saline habitat may represent a further habitat limitation within an already limited habitat.

/pdf/behavioral-niche-partitioning-in-a-sympatric-tiger-beetle-3shc5onmup.pdf

Behavioral niche partitioning in a sympatric tiger beetle assemblage and implications for the endangered Salt Creek tiger beetle

We tested procedures for removing adipocere from insect samples to allow identification. An acceptable procedure was determined: (i) Samples were sorted in petri dishes with 75% alcohol to remove any larvae, adult insects, or other soft-bodied material. (ii) Samples of up to 24 puparia were placed in a vial with 15 mL of 95% acetone, capped, and vortexed for a total of 30–90 sec in 10- to 15-sec bursts. This step removed large masses of adipocere or soil from specimen. (iii) Specimens were removed from acetone and placed in a vial of 15 mL of 2% potassium hydroxide (KOH) and vortexed in 10- to 15-sec bursts until all puparia appeared clean (with our samples this required a total of 60–120 sec). (iv) Specimens were removed from the 2% KOH, placed in 75% ethanol, and examined microscopically. (v) Material was stored in 75% ethanol for identification and long-term preservation.

/pdf/cleaning-puparia-for-forensic-analysis-1cw4m2h3zb.pdf

Cleaning Puparia for Forensic Analysis.

The within-plant distribution of soybean aphid, Aphis glycines Matsumura has been attributed to various causes, yet it is unclear which factor or combination of factors most influence aphid within-plant distribution. Understanding soybean aphid distribution within the soybean canopy is important both in developing sampling programs and in evaluating injury. Because natural enemies have the potential to alter aphid dispersion, we examined how within-plant distribution of soybean aphid was influenced by different natural enemies. Field cages of different mesh diameters were used to exclude different sizes of natural enemies from aphid infested plots. Plots were surveyed and both natural enemy density and soybean aphid density, by strata, were recorded twice weekly. Cages were found to have minimal effect on temperature and soybean plant development. Aphid densities were significantly different each year among dates, treatments, and strata. In 2004 aphid densities were concentrated on the top part of the plant and in 2005 aphid densities were concentrated in the middle of the canopy. Treatments had significant impacts on aphid density in both years of the study. The total exclusion treatment had the highest aphid densities in both years. Treatment also had a significant effect on which stratum aphids were most commonly found. The factor that was found to best explain the differences in aphid distribution was the abundance of natural enemies, primarily Orius insidosus (Say). In treatments left exposed to natural enemies the percentage of the total aphid population was found lower in the canopy. It is clear that aphid densities and distributions are being affected by the presence of natural enemies. Understanding how natural enemies affect the distribution of this economically damaging aphid species is an important component of its management, specifically the development of

/pdf/biotic-and-abiotic-influences-on-within-plant-distribution-54w8iyxgzn.pdf

Biotic and abiotic influences on within-plant distribution of soybean aphid (Hemiptera: Aphididae: Aphis glycines).

/pdf/promoting-the-conservation-of-the-salt-creek-tiger-beetle-4ce8np1zmd.pdf

Promoting the Conservation of the Salt Creek Tiger Beetle Using the Visual Arts

/pdf/covid-19-reflections-from-entomologists-who-rose-to-the-zk251iiv02.pdf

Tierney R. Brosius

Papers

Behavioral niche partitioning in a sympatric tiger beetle assemblage and implications for the endangered Salt Creek tiger beetle

Cleaning Puparia for Forensic Analysis.

Biotic and abiotic influences on within-plant distribution of soybean aphid (Hemiptera: Aphididae: Aphis glycines).

Promoting the Conservation of the Salt Creek Tiger Beetle Using the Visual Arts

COVID-19: Reflections from Entomologists Who Rose to the Occasion