Pesticides and reduced‐risk insecticides,native bees and pantropical stingless bees: pitfalls and perspectives

Although invertebrates generally have a low public profile, the honey bee, Apis mellifera L., is a flagship species whose popularity likely derives from the products it provides and its perceived ecological services. Therefore, the raging debate regarding honey bee decline has surpassed the realm of beekeepers, academia, industry and regulatory agencies and now also encompasses non‐governmental agencies, media, fiction writers and the general public. The early interest and concern about honey bee colony collapse disorder (CCD) soon shifted to the bigger issue of pollinator decline, with a focus on the potential involvement of pesticides in such a phenomenon. Pesticides were previously recognised as the potential culprits of the reported declines, particularly the neonicotinoid insecticides owing to their widespread and peculiar use in agriculture. However, the evidence for the potential pivotal role of these neonicotinoids in honey bee decline remains a matter of debate, with an increased recognition of the multifactorial nature of the problem and the lack of a direct association between the noted decline and neonicotinoid use. The focus on the decline of honey bee populations subsequently spread to other species, and bumblebees became another matter of concern, particularly in Europe and the United States. Other bee species, ones that are particularly important in other regions of the world, remain the object of little concern (unjustifiably so). Furthermore, the continuous focus on neonicotinoids is also in need of revision, as the current evidence suggests that a broad spectrum of compounds deserve attention. Here we address both shortcomings. © 2015 Society of Chemical Industry     

Fundamental considerations about design and sample size in strain comparisons and their implications

Well‐known formulae for the calculation of the necessary number of animals in strain comparisons are presented. Their use is illustrated with an example with fish. Use of the formulae in the planning and design of strain comparisons is recommended. When the necessary number cannot be attained and the experiment is conducted with fewer animals than what the formulae indicate, or the animals originate from a low and thus most likely non‐random sample of parents, no inferences should be drawn about any observed between strain differences.     

Larval cannibalism and fitness in the stored grain weevils <Emphasis Type="Italic">Sitophilus granarius</Emphasis> and <Emphasis Type="Italic">Sitophilus zeamais</Emphasis>

Resource limitation is an important determinant of life history and behavior while mediating competition and reproduction among organisms. Discreet and closed systems such as grain kernels and seeds impose drastic restrictions to grain beetles that spend their immature stages within a single kernel selected by their mother. This is the case of internally feeding stored grain beetles, such as the grain weevils. Female egg-laying decisions and larval competition largely determine resource limitation for such insects where clustered egg distribution and contest competition with larval interference and cannibalism take place. As the clustered eggs within a grain lead to larval competition and conspecific weevil larvae face each other off during development allowing the emergence of one or two larvae per kernel, we hypothesized that such competition and consequent cannibalism will have fitness consequences for the competing individuals and their offspring. Thus, larvae of the granary weevil (Sitophilus granarius L.) and the maize weevil (Sitophilus zeamais Motsch.) were subjected to larval competition with cannibalism, and lack of it, to assess the potential fitness consequence of cannibalism on these non-carnivorous pest species of stored grains. Larval cannibalism reduced developmental time of maize weevil, but not of granary weevil. However, such condition led to heavier adult weevils of both species exhibiting higher reproductive output generating more and better quality progeny than non-cannibal weevils. These findings indicate direct nutritional benefits of cannibalism to grain weevils favoring their status of key pest species of stored cereal grains.     

Tryptophan hydroxylase-2 controls brain serotonin synthesis

Dysregulation of brain serotonin contributes to many psychiatric disorders. Tryptophan hydroxylase-2 (Tph2), rather than Tph1, is preferentially expressed in the brain. We report a functional (C1473G) single-nucleotide polymorphism in mouse Tph2 that results in the substitution of Pro447 with Arg447 and leads to decreased serotonin levels in PC12 cells. Moreover, in BALB/cJ and DBA/2 mice that are homozygous for the 1473G allele, brain serotonin tissue content and synthesis are reduced in comparison to C57Bl/6 and 129X1/SvJ mice that are homozygous for the 1473C allele. Our data provide direct evidence for a fundamental role of Tph2 in brain serotonin synthesis.     

Protein digestibility, protease activity, and post-embryonic development of the velvetbean caterpillar (Anticarsia gemmatalis) exposed to the trypsin-inhibitor benzamidine

Protein digestibility, proteolytic activity, and post-embryonic development of Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae) were assessed in larvae reared on artificial diet containing 0.00, 0.25, 0.50, and 0.75% (w/w) of the synthetic trypsin inhibitor benzamidine. Diet consumption was affected by the inhibitor when the insects were exposed to 0.50% benzamidine showing a 4-day delay and a 70%-higher peak of consumption. Larva weight gain was also affected by benzamidine and again the results of 0.50% benzamidine were unexpected due to the worst performance of the insects at this inhibitor concentration and not at 0.75% benzamidine. These patterns of consumption and weight gain were however consistent with the results of protein digestibility, which affects larvae mortality and adult emergence. The insect proteolytic activity was also affected by benzamidine, particularly at 0.50%. These results indicate that the insects are able to circumvent the potentially harmful effects of the inhibitor since at the highest concentration the negative impact is mitigated.     

Calculation of pH in fresh and sea water aquaculture systems

A procedure for the calculation of pH in fresh and salt waters has been developed. The method is based on a fourth-order polynomial relationship between hydrogen ion concentration and other (conservative) water quality parameters. The method avoids trial and error estimations and results in a direct calculation procedure that can be implemented in models developed in various modeling environments, such as spreadsheets, conventional programming languages (BASIC, C, FORTRAN, PASCAL, etc.) or specialized modeling languages (Extend^™, Stella^™).

The method developed is based on the solution of the full alkalinity-pH equation. Because of the need for simplification of the equations to yield explicitly solvable polynomial equations, the accuracy of the solutions depends on the simplification made and varies with water properties. Three simplifications are tested based on a second-, a third-and a fourth-order polynomial equation for hydrogen ion concentrations. the equations have been tested for salinities ranging from 0 to 35‰ (fresh to sea water), for temperatures ranging from 0 to 35°C, for total carbonate carbon concentrations of 0·1 and 5·0 mmol/liter, and for total ammonia nitrogen concentrations of 0 and 10 mg/liter. Approximations are most accurate in waters of high total carbonate carbon and low ammonia concentrations, where the fourth-order approximation yields results that are within 0.05 pH units for the full range of pH values tested (5–10).     

Seasonal Divergence of Landscape Use by Heritage and Conventional Cattle on Desert Rangeland

Adopting livestock with heritage genetics may help to improve the sustainability of agriculture on rangelands with harsh, challenging conditions. In the Chihuahuan Desert, preliminary evidence suggests that heritage Raramuri Criollo exploit a greater variety of range resources than do conventional cattle. Accordingly, the use of Raramuri Criollo may help sustain vegetation and soils, as well as agricultural production. To explore these possibilities, we used Global Positioning System collars to track Angus × Hereford and Raramuri Criollo cows in a 1 535-ha pasture in southern New Mexico in June–December 2008. As predicted on the basis of past research, home range sizes of Raramuri Criollo exceeded those of Angus × Hereford during seasons with low forage availability—by 31.4 ± 6.5 ha during Pregreenup and 17.2 ± 6.5 ha during Drydown—but sizes converged during more productive seasons (Greenup 1, Greenup 2). Angus × Hereford allotted more daily time to resting, with the difference most pronounced during Drydown (71.1 ± 21.1 min day^{? 1}). Angus × Hereford had twice as many hotspots of use (locations with multiple visits of long duration), with seasonal timing and location corresponding with distribution patterns known to impact desirable natural resources. Raramuri Criollo more strongly preferred the Bare/Forbs ecological state with seasonal timing that possibly signals an ability to use nutritious forbs on open ground despite summer heat. Results are consistent with conjectures that compared with conventional cattle, Raramuri Criollo have greater daily mobility and wider spatial distribution during dry seasons. Although not directly measured, results also suggest that the heritage breed has superior heat tolerance and lower impact on desirable natural resources. These findings provide evidence that Raramuri Criollo can support sustainable livestock production in the Chihuahuan Desert, but direct measurements of profitability and environmental effects are needed before adoption can be recommended widely.     

Epidemiological and diagnostic findings during a 16-year-long trichinellosis surveillance in Timis County,Romania

The main source of trichinellosis in Romania is insufficiently cooked pork infected with Trichinella spiralis. Timis, the largest Romanian county, is located in the western part of the country where pork and traditional food prepared from pork are extensively consumed. The objective of the present study was to conduct a retrospective investigation of the incidence of human trichinellosis in Timis County over a period of 16 years (1990–2005). The medical records of 521 patients were used as the source of data. Patients were hospitalized at “Victor Babes” Hospital of Infectious Diseases from Timisoara during the period 1990–2005. The highest number of cases was recorded in 1994 (16.90%) and most of the patients were in the age group of 20–29 (23.22%). Males and females were almost equally affected by trichinellosis. The clinical pattern was mainly characterised by myalgia (72.55%) and edema (54.12%). Laboratory investigations included mainly elevated eosinophil and leucocyte values. In 52.02% of the patients, the hospitalization period ranged between 8 and 14 days. Most of the patients were from urban areas, but often the source of infection was found in rural areas. Hospitalization of the affected patients required considerable health care resources. The decreasing incidence of trichinellosis in Romania over the last decade has been due to sanitary education programmes for both swine breeders and consumers.