Drone Laying Honey Bee Workers in Queen Monitoring Cages

Techniques to monitor honey bee (Apis mellifera) egg production in cages allow researchers to study how different environmental factors contribute to reproduction. However, although the conditions required to facilitate queen egg production in a laboratory setting have been established, limited work has addressed the requirements for stimulating and monitoring worker egg laying. Here, we documented that drone laying workers will lay eggs in Queen Monitoring Cages (QMC), specialized cages designed to facilitate queen egg laying under controlled conditions. Egg production and worker mortality were compared between QMCs containing queens and those containing drone laying workers. High-definition images of the last abdominal segments of living first-instar larvae hatched from worker laid eggs and those putatively laid by queens were qualitatively compared to identify candidate characteristics to determine their sex.     

Reproductive and Morphological Quality of Commercial Honey Bee (Hymenoptera: Apidae) Drones in the United States

Exploration into reproductive quality in honey bees (Apis mellifera Linneaus (Hymenoptera: Apidae) largely focuses on factors that affect queens, with drones primarily being considered insofar as they pass on effects of environmental stressors to the queen and subsequent offspring. In those studies that consider drone quality explicitly, a primary focus has been on the dimorphic nature of drones laid in worker cells (either through rare queen error or worker reproduction) as compared to drones laid by the queen in the slightly larger drone cells. The implication from these studies is that that there exists a bimodality of drone morphological quality that is related to reproductive quality and competitive ability during mating. Our study quantifies the presence of such small drones in commercial populations, finding that rates of ‘low-quality’ drones are far higher than theoretically predicted under optimum conditions. Observations from commercial colonies also show significant inter-colony variation among the size and fecundity of drones produced, prompting speculation as to the mechanisms inducing such variation and the potential use of drone-quality variation for the colony- or apiary-level exposure to nutrition, agrichemical, or parasitic stressors.     

Pollen Treated with a Combination of Agrochemicals Commonly Applied During Almond Bloom Reduces the Emergence Rate and Longevity of Honey Bee (Hymenoptera: Apidae) Queens

Honey bee (Apis mellifera L.) colonies that pollinate California’s almond orchards are often exposed to mixtures of agrochemicals. Although agrochemicals applied during almond bloom are typically considered bee-safe when applied alone, their combined effects to honey bees are largely untested. In recent years, beekeepers providing pollination services to California’s almond orchards have reported reductions in queen quality during and immediately after bloom, raising concerns that pesticide exposure may be involved. Previous research identified a synergistic effect between the insecticide active ingredient chlorantraniliprole and the fungicide active ingredient propiconazole to lab-reared worker brood, but their effects to developing queens are unknown. To test the individual and combined effects of these pesticides on the survival and emergence of developing queens, we fed worker honey bees in closed queen rearing boxes with pollen artificially contaminated with formulated pesticides containing these active ingredients as well as the spray adjuvant Dyne-Amic, which contains both organosilicone and alkyphenol ethoxylate. The translocation of pesticides from pesticide-treated pollen into the royal jelly secretions of nurse bees was also measured. Despite consistently low levels of all pesticide active ingredients in royal jelly, the survival of queens from pupation to 7 d post-emergence were reduced in queens reared by worker bees fed pollen containing a combination of formulated chlorantraniliprole (Altacor), propiconazole (Tilt), and Dyne-Amic, as well as the toxic standard, diflubenzuron (Dimilin 2L), applied in isolation. These results support recommendations to protect honey bee health by avoiding application of pesticide tank-mixes containing insecticides and adjuvants during almond bloom.     

Demographic consequences of reproductive interference in multi-species communities

Background

Reproductive interference can mediate interference competition between species through sexual interactions that reduce the fitness of one species by another. Theory shows that the positive frequency-dependent effects of such costly errors in mate recognition can dictate species coexistence or exclusion even with countervailing resource competition differences between species. While usually framed in terms of pre-mating or post-zygotic costs, reproductive interference manifests between individual Caenorhabditis nematodes from negative interspecies gametic interactions: sperm cells from interspecies matings can migrate ectopically to induce female sterility and premature death. The potential for reproductive interference to exert population level effects on Caenorhabditis trait evolution and community structure, however, remains unknown.

Results

Here we test whether a species that is superior in individual-level reproductive interference (C. nigoni) can exact negative demographic effects on competitor species that are superior in resource competition (C. briggsae and C. elegans). We observe coexistence over six generations and find evidence of demographic reproductive interference even under conditions unfavorable to its influence. C. briggsae and C. elegans show distinct patterns of reproductive interference in competitive interactions with C. nigoni.

Conclusions

These results affirm that individual level negative effects of reproductive interference mediated by gamete interactions can ramify to population demography, with the potential to influence patterns of species coexistence separately from the effects of direct resource competition.

     

Characterization and Developmental Expression Patterns of Four Hexamerin Genes in the Bumble Bee,Bombus terrestris (Hymenoptera: Apidae)

Hexamerins are members of the hemocyanin superfamily and play essential roles in providing amino acids and energy for the nonfeeding stages of insects. In this study, we cloned and analyzed the expression patterns of four hexamerin genes (hex 70a, hex 70b, hex 70c, and hex 110) at different worker development stages and queen diapause statuses in the bumble bee, Bombus terrestris. The results of this study showed that hex 110 has the longest open reading frame (ORF; 3,297 bp) compared to the ORFs of hex 70a (2,034 bp), hex 70b (2,067 bp), and hex 70c (2,055 bp). The putative translation product of Hex 70a, Hex 70b, Hex70c, and Hex 110 has 677, 688, 684, and 1,098aa with predicted molecular mass of 81.13, 79.69, 81.58, and 119 kDa. In the development stages of workers, the expression levels of hex 70a, hex 70b, and hex 70c increased gradually from the larval stage and exhibited high expression levels at the pink eyed and brown eyed pupae stage, whereas hex 110 exhibited the highest expression level at the larval period. Four hexamerin genes were highly expressed at the prediapause status of queen (P < 0.05), and compared to the eclosion queen, the lowest upregulation was 3.7-fold, and the highest upregulation was 1,742-fold. The expression levels of hex 70b, hex 70c, and hex 110 at diapause were significantly higher than those at postdiapause (P < 0.05). In conclusion, hexamerins may play important roles in queen diapause and metamorphosis of larval and pupal stages.     

Relationships between reproductive output, morpho-physiological traits and life span in Lesquerella (Brassicaceae)

The development of perennial industrial crops could contribute to increase agriculture sustainability and yield stability in arid environments. Since perennial plants allocate resources preferentially to perpetuation and to structural and functional characters that provide drought tolerance, they tend to have lower reproductive output (yield) than their congeneric annuals. Four species of Lesquerella native to arid regions were evaluated to understand the relationships between reproduction, drought tolerance, and their association with the plant's life span. We assessed the following set of characters (defined as plant strategies): phenology, gas exchange, specific leaf area, leaf area ratio, total biomass and biomass allocation. Annual (Lesquerella gracilis and Lesquerella angustifolia) and perennial (Lesquerella mendocina and Lesquerella pinetorum) species were compared under water limiting conditions. Within this set of species differences in structural and functional characters were observed. The annual, L. gracilis showed a plant strategy characterized by high reproductive output, harvest index (HI) and specific leaf area (SLA). L. mendocina (perennial), produced more total biomass, but had a low reproductive output, and also showed characters that provide drought tolerance (high allocation to roots-root mass ratio (RMR), and storage-total non structural carbohydrates (TNC) and low SLA). The annual L. angustifolia and the perennial L. pinetorum had intermediate plant strategies (i.e. intermediate values of traits typically related with annual or perennial life span). In the case of L. pinetorum we found some traits common to L. mendocina: long vegetative period, high biomass, CO₂ assimilation rate (A), and water use efficiency (WUE), and low SLA. The high reproductive output in L. pinetorum was a result of both, higher total biomass and longer growing season compared to the annuals, and of higher HI in relation to the other perennial. These differences in plant strategies among perennial Lesquerella show that there are different combinations of traits that could be used as criteria for the selection of a perennial crop in programs of domestication for Patagonia and others arid lands.     

Mating Systems of the Tree-Killing Bark Beetle Polygraphus proximus (Coleoptera: Curculionidae: Scolytinae)

Polygraphus proximus Blandford (Coleoptera: Curculionidae: Scolytinae) has caused mass mortality of fir (Abies spp. (Pinaceae)) forests across large areas of Russia in the past decade. More recently, mass mortality of A. veitchii  Lindl. due to P. proximus infestation has been reported in Japan. This bark beetle species traditionally has been considered to be polygynous because their galleries have multiple gallery arms, and because harem-polygyny is common in the tribe Polygraphini. Although the mating system(s) potentially could have a marked effect on their reproductive success and population dynamics, the reproductive behavior of the tree-killing bark beetle P. proximus has not been investigated in detail in a natural setting in Japan. We, therefore, investigated the number of males and females in a gallery and the number of gallery arms in Abies species in Japan. None of the galleries examined contained more than one male, and 57.2% of the galleries had multiple gallery arms, even though only 2.8% of the galleries contained two females. The findings showed that the typical mating system employed by P. proximus is monogyny and that this species constructs multiple gallery arms in each gallery. In addition, 70.4% of galleries in which the sex of adult beetles could be determined contained no males, and 26.6% contained no females, suggesting that P. proximus males and females re-emerge.     

Behavioural and chemical evidence for multiple colonisation of the Argentine ant, Linepithema humile, in the Western Cape, South Africa

Background

The Argentine ant, Linepithema humile, is a widespread invasive ant species that has successfully established in nearly all continents across the globe. Argentine ants are characterised by a social structure known as unicoloniality, where territorial boundaries between nests are absent and intraspecific aggression is rare. This is particularly pronounced in introduced populations and results in the formation of large and spatially expansive supercolonies. Although it is amongst the most well studied of invasive ants, very little work has been done on this ant in South Africa. In this first study, we investigate the population structure of Argentine ants in South Africa. We use behavioural (aggression tests) and chemical (CHC) approaches to investigate the population structure of Argentine ants within the Western Cape, identify the number of supercolonies and infer number of introductions.

Results

Both the aggression assays and chemical data revealed that the Western Cape Argentine ant population can be divided into two behaviourally and chemically distinct supercolonies. Intraspecific aggression was evident between the two supercolonies of Argentine ants with ants able to discriminate among conspecific non-nestmates. This discrimination is linked to the divergence in cuticular hydrocarbon profiles of ants originating from the two supercolonies.

Conclusions

The presence of these two distinct supercolonies is suggestive of at least two independent introductions of this ant within the Western Cape. Moreover, the pattern of colonisation observed in this study, with the two colonies interspersed, is in agreement with global patterns of Argentine ant invasions. Our findings are of interest because recent studies show that Argentine ants from South Africa are different from those identified in other introduced ranges and therefore provide an opportunity to further understand factors that determine the distributional and spread patterns of Argentine ant supercolonies.     

Species-specific interference exerted by the shrub <Emphasis Type="Italic">Cistus clusii</Emphasis> Dunal in a semi-arid Mediterranean gypsum plant community

Background

The gypsovag shrub Cistus clusii is locally dominant in semi-arid gypsum plant communities of North-Eastern Spain. This species commonly grows in species-poor patches even though it has nurse potential, suggesting interference on neighbouring species. Other Cistus species exert a chemically mediated interference on plant communities, suggesting that it might be a common phenomenon in this genus. This study aimed investigating whether C. clusii exerts chemically mediated interference on neighbouring species in gypsum plant communities. We tested in a greenhouse whether aqueous extracts from C. clusii leaves (L), roots (R) and a mixture of both (RL) affected germination, seedling survival, and growth of nine native species of gypsum communities, including C. clusii itself. We further assessed in the field richness and abundance of plants under the canopy of C. clusii compared to Gypsophila struthium (shrub with a similar architecture having a nurse role) and in open patches. Finally, we specifically assessed in the field the influence of C. clusii on the presence of the species tested in the greenhouse experiment.

Results

Aqueous extracts from C. clusii (R and RL) negatively affected either germination or survival in four of nine species. In the field, richness and abundance of plants were lower under the canopy of C. clusii than under G. struthium, but higher than in open patches. Specifically, five of nine species were less frequent than expected under the canopy of C. clusii.

Conclusions

Cistus clusii shows species-specific interference with neighbouring species in the community, which may be at least partially attributable to its phytotoxic activity. To our knowledge, this is the first report of species-specific interference by C. clusii.

     

Seasonality and synchrony of reproduction in three species of nectarivorous Philippines bats

Background  

Differences among species and among years in reproductive seasonality (the tendency for clusters of events to fall at approximately the same point in each year) and synchrony (amount of clustering of events within a year) have been intensively studied in bats, but are difficult to assess. Here, we use randomization methods with circular statistics to test for synchrony and seasonality of reproduction in three species of nectarivorous megachiropteran bats on Negros Island in the central Philippines.     

Metabolomics-Based Study of Logarithmic and Stationary Phases of Promastigotes in Leishmania major by 1H NMR Spectroscopy

Background:

Cutaneous leishmaniasis is one of the most important parasitic diseases in humans. In this disease, one of the responsible organisms is Leishmania major, which is transmitted by sandfly vector. There are specific differences in biochemical profiles and metabolite pathways in logarithmic and stationary phases of Leishmania parasites. In the present study, ¹H NMR spectroscopy was used to examine the metabolites outliers in the logarithmic and stationary phases of promastigotes in L. major to enlighten more about the transmission mechanism in metacyclogenesis of L. major.

Methods:

Promastigote was cultured, logarithmic and stationary phases were separated by the peanut agglutinin, and cell metabolites were extracted. ¹H NMR spectroscopy was applied, and outliers were analyzed using principal component analysis.

Results:

The most altered metabolites in stationary and logarithmic phases were limited to citraconic acid, isopropylmalic acid, L-leucine, ornithine, caprylic acid, capric acid, and acetic acid.

Conclusion:

¹H NMR spectroscopy could play an important role in the characterization of metabolites in biochemical pathways during a metacyclogenesis process. These metabolites and their pathways can help in exploiting a transmission mechanism in metacyclogenesis, and outcoming data might be used in the metabolic network reconstruction of L. major modeling. Key Words: Leishmania major, Metabolomics, Principal component analysis     

Different Morphologies of Leishmania major Amastigotes with No Molecular Diversity in a Neglected Endemic Area of Zoonotic Cutaneous Leishmaniasis in Iran

Background:

Molecular diversity of Leishmania major and its morphological changes have become a controversial issue among researchers. Some aspects of polymorphic shapes of amastigotes in clinical manifestations along with molecular variation were evaluated among suspected patients of some exceptional zoonotic cutaneous leishmaniasis locations in Northern Khuzestan, Southwestern Iran.

Methods:

Suspected patients (n = 165) were sampled in zoonotic cutaneous leishmaniasis foci over two consecutive years during 2012-2014. Prepared smears were stained, scaled and measured by ocular micrometer. DNA was extracted from smears; ITS-rDNA and Cytochrome b (Cyt b) markers were amplified, and PCR products were digested by BsuR1 restriction enzyme. Then the RFLP and sequencing were employed.

Results:

Only L. major was identified in patients containing regular amastigotes'' shapes (oval or round) with a size of 2-4 µm in each of classical wet, dry, mixed lesions. Meanwhile, irregular shapes (spindle, pear, or cigarette) were observed separately in non-classical wet lesions with more than 4 µm. Interestingly, a few amastigotes with an external flagellum were observed in some lesions. All sequenced ITS-rDNA and Cyt b genes of L. major did not show any molecular variation (χ ² P > 0.05), including only one common haplotype (GenBank access no. {"type":"entrez-nucleotide","attrs":{"text":"EF413075","term_id":"151936076","term_text":"EF413075"}}EF413075).

Conclusion:

Findings proved that unlike other endemic foci, there is not a meaningful correlation between phenotypic and genotypic features of L. major isolates. This study is considered as the first comprehensive report to incriminate morphometric shapes of L. major amastigotes, which enhances our knowledge concerning their relevance with various clinical appearances and genotypic traits. Key Words: Leishmania major, Nuclear gene, Mitochondrial gene, Amastigote shapes, Iran