Medium molecular weight polar substances of the cuticle as tools in the study of the taxonomy, systematics and chemical ecology of tropical hover wasps (Hymenoptera: Stenogastrinae)

The Stenogastrinae wasps have been proposed as a key group for an understanding of social evolution in insects, but the phylogeny of the group is still under discussion. The use of chemical characters, in particular cuticular hydrocarbons, for insect taxonomy is relatively recent and only a few studies have been conducted on the cuticular polar substances. In this work, we ascertain, by the matrix-assisted laser desorption ionization-time of flight mass spectrometry technique, that different species of primitively eusocial hover wasps have different compositions of the epicuticular polar compounds ranging from 900 to 3600 Da. General linear model analysis and discriminant analysis showed that the average spectral profiles of this fraction can be diagnostic for identification of the species. Moreover, for the first time we show population diversification in the medium MW polar cuticular mixtures in insects. In conclusion, the results demonstrate that the chemical characters are consistent with the physical characters and the study support the importance of medium MW polar substances as powerful tools for systematics (chemosystematics) and chemical ecology (fertility signal and population characterization) in a primitively social insect taxon. Riassunto Le vespe primitivamente eusociali della sottofamiglia delle Stenogastrinae sono state proposte come gruppo chiave per lo studio dell'evoluzione della socialita negli insetti. Ancora oggi, pero, la filogenesi del gruppo rimane incerta e discussa. Sebbene l'uso dei caratteri chimici, e in particolare degli idrocarburi cuticolari, negli studi tassonomici sugli insetti sia ben noto, seppur di recente applicazione, sono ancora pochi gli studi condotti sulle sostanze cuticolari di natura polare. In questo lavoro abbiamo saggiato, mediante tecniche di spettrometria di massa (MALDI-TOF MS), la presenza di composti polari cuticolari di massa compresa tra i 900 e i 3600 (probabilmente provenienti dal veleno) sulla cuticola di alcune specie di vespe stenogastrine. Analisi statistiche multivariate hanno dimostrato che lo spettro medio dei profili chimici nel range da noi indagato puo essere utilizzato per l'identificazione delle specie e la nostra ricerca propone questo metodo come un potente strumento non solo per studi di tassonomia (chemotassonomia) ma anche per studi di sistematica e di ecologia chimica (es. segnali di fertilita e differenze intra-popolazioni) nei taxon di insetti primitivamente eusociali

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Microbial associates and social behavior in ants

Current research in life sciences provides advances on how animal-associated microbes affect behavior and its underlying neurophysiology. However, studies in this field are often limited to individuals outside of their social context and neglect social dynamics. Contrarily, animals and humans develop and live in complex societies where they constantly adjust physiology and behavior to social interactions. To improve our understanding of how microbes and hosts interact and produce phenotypes at social and group levels, we need to broaden our experimental approaches to a group-level dimension. Here, we point out that eusocial insects, and ants in particular, are ideal models for this purpose. We first examine the most common types of microorganismal associations that ants engage in, and then briefly summarize what is known about the role of symbiotic microbes in ant social behavior. Finally, we propose future directions in the field, in the light of recent technical advances in behavior measuring techniques.Accepted versio

Reduced foraging investment as an adaptation to patchy food sources: A phasic army ant simulation

International audienceColonies of several ant species within the subfamily Dorylinae alternate stereotypical discrete phases of foraging and reproduction. Such phasic cycles are thought to be adaptive because they minimize the amount of foraging and the related costs, and at the same time enhance the colony-level ability to rely on patchily distributed food sources. In order to investigate these hypotheses, we use here a simple computational approach to study the population dynamics of two species of virtual ant colonies that differ quantitatively in their foraging investment. One species, which we refer to as “phasic”, forages only half of the time, mirroring the phasic activity of some army ants; the other “non-phasic” species forages instead all the time. We show that, when foraging costs are relatively high, populations of phasic colonies grow on average faster than non-phasic populations, outcompeting them in mixed populations. Interestingly, such tendency becomes more consistent as food becomes more difficult to find but locally abundant. According to our results, reducing the foraging investment, for example by adopting a phasic lifestyle, can result in a reproductive advantage, but only in specific conditions. We thus suggest phasic colony cycles to have emerged together with the doryline specialization in feeding on the brood of other eusocial insects, a resource that is hard to obtain but highly abundant if available

Why behavioral neuroscience still needs diversity? : A curious case of a persistent need

In the past few decades, a substantial portion of neuroscience research has moved from studies conducted across a spectrum of animals to reliance on a few species. While this undoubtedly promotes consistency, in-depth analysis, and a better claim to unraveling molecular mechanisms, investing heavily in a subset of species also restricts the type of questions that can be asked, and impacts the generalizability of findings. A conspicuous body of literature has long advocated the need to expand the diversity of animal systems used in neuroscience research. Part of this need is utilitarian with respect to translation, but the remaining is the knowledge that historically, a diverse set of species were instrumental in obtaining transformative understanding. We argue that diversifying matters also because the current approach limits the scope of what can be discovered. Technological advancements are already bridging several practical gaps separating these two worlds. What remains is a wholehearted embrace by the community that has benefitted from past history. We suggest the time for it is now.Ministry of Education (MOE)Accepted versionASM was supported via Yale-NUS College grants R-607-265-225-121, FL via the United States-Israel Binational Sciences Foundation(2015161), AV via Human Frontier Science Program (RGP0062/2018) and by the Ministry of Education, Singapore, under its MOE AcRF Tier 3Award MOE2017-T3-1-002. and ST via a Presidential Postdoctoral Fellowship from Nanyang Technological University (NTU) M408080000

G. sinense and P. notoginseng extracts improve healthspan of aging flies and provide protection in a Huntington disease model

In the last decades, the strong increase in the proportion of older people worldwide, and the increased prevalence of age associated degenerative diseases, have put a stronger focus on aging biology. In spite of important progresses in our understanding of the aging process, an integrative view is still lacking and there is still need for efficient anti-aging interventions that could improve healthspan, reduce incidence of age-related disease and, eventually, increase the lifespan. Interestingly, some compounds from traditional medicine have been found to possess anti-oxidative and anti-inflammatory properties, suggesting that they could play a role as anti-aging compounds, although in depth in vivo investigations are still scarce. In this study we used one the major aging model organisms, Drosophila melanogaster, to investigate the ability of four herb extracts (HEs: Dendrobium candidum, Ophiopogon japonicum, Ganoderma sinense and Panax notoginseng) widely used in traditional Chinese medicine (TCM). to slow down aging and improve healthspan of aged animals. Combining multiple approaches (stress resistance assays, lifespan and metabolic measurements, functional heart characterizations and behavioral assays), we show, that these four HEs provide in vivo protection from various insults, albeit with significant compound-specific differences. Importantly, extracts of P. notoginseng and G. sinense increase the healthspan of aging animals, as shown by increased activity during aging and improved heart function. In addition, these two compounds also provide protection in a Drosophila model of Huntington’s disease (HD), suggesting that, besides their anti-aging properties in normal individuals, they could be also efficient in the protection against age-related diseases.Published versionThis work was supported by a grant from Infinitus Ltd Guangzhou (China)

Integrating real-time data analysis into automatic tracking of social insects

Automatic video tracking has become a standard tool for investigating the social behaviour of insects. The recent integration of computer vision in tracking technologies will probably lead to fully automated behavioural pattern classification within the next few years. However, many current systems rely on offline data analysis and use computationally expensive techniques to track pre-recorded videos. To address this gap, we developed BACH (Behaviour Analysis maCHine), a software that performs video tracking of insect groups in real time. BACH uses object recognition via convolutional neural networks and identifies individually tagged insects via an existing matrix code recognition algorithm. We compared the tracking performances of BACH and a human observer (HO) across a series of short videos of ants moving in a two-dimensional arena. We found that BACH detected ant shapes only slightly worse than the HO. However, its matrix code-mediated identification of individual ants only attained human-comparable levels when ants moved relatively slowly, and fell when ants walked relatively fast. This happened because BACH had a relatively low efficiency in detecting matrix codes in blurry images of ants walking at high speeds. BACH needs to undergo hardware and software adjustments to overcome its present limits. Nevertheless, our study emphasizes the possibility of, and the need for, further integrating real-time data analysis into the study of animal behaviour. This will accelerate data generation, visualization and sharing, opening possibilities for conducting fully remote collaborative experiments.Nanyang Technological UniversityPublished versionThis work was supported by a Presidential Postdoctoral Fellowship (grant no. M408080000) from NanyangTechnological University (NTU) to S.T

2-other experiments

This is a 3-sheet excel file containing the data of the other three experiments included in the study: 1) the egg-laying test under different sexual harassment conditions; 2) the experiment testing how many female flies were on the correct oviposition medium during the sexual harassment assay; 3) the occurrence of sexual harassment during the assa