@article {113539, title = {An inducible potato (E,E)-farnesol synthase confers tolerance against bacterial pathogens in potato and tobacco.}, journal = {Plant J}, year = {2022}, month = {2022 Jul 02}, abstract = {

Terpene synthases (TPSs) have diverse biological functions in plants. Though the roles of TPSs in herbivore defense are well established in many plant species, their role in bacterial defense has been scarce and is emerging. Through functional genomics, here we report the in planta role of potato (Solanum tuberosum) terpene synthase (StTPS18) in bacterial defense. Expression of StTPS18 was highest in leaves and was induced in response to Pseudomonas syringae and methyl jasmonate treatments. The recombinant StTPS18 exhibited bona fide (E,E)-farnesol synthase activity forming a sesquiterpenoid, (E,E)-farnesol as the sole product, utilising (E,E)-farnesyl diphosphate (FPP). Subcellular localization of GFP fusion protein revealed that StTPS18 is localized to the cytosol. Silencing and overexpression of StTPS18 in potato resulted in reduced and enhanced tolerance, respectively, to bacterial pathogens P. syringae and Ralstonia solanacearum. Bacterial growth assay using medium containing (E,E)-farnesol significantly inhibited P. syringae growth. Moreover, StTPS18 overexpressing transgenic potato and Nicotiana tabacum leaves, and (E,E)-farnesol and P. syringae infiltrated potato leaves exhibited elevated expression of sterol pathway and members of pathogenesis-related genes with enhanced phytosterol accumulation. Interestingly, enhanced phytosterols in C -(E,E)-farnesol infiltrated potato leaves were devoid of any noticeable C labeling, indicating no direct utilization of (E,E)-farnesol in phytosterols formation. Furthermore, leaves of StTPS18 overexpressing transgenic lines had no detectable (E,E)-farnesol similar to the control plant, and emitted lower levels of sesquiterpenes than the control. These findings point towards an indirect involvement of StTPS18 and its product (E,E)-farnesol in bacterial defense through upregulation of phytosterol biosynthesis and defense genes.

}, issn = {1365-313X}, doi = {10.1111/tpj.15890}, author = {Dwivedi, Varun and Kumar, Sarma Rajeev and Shilpashree, H B and Krishna, Ram and Rao, Srinivas and Shasany, Ajit K and Olsson, Shannon B and Nagegowda, Dinesh A} } @article {117963, title = {Rapid brain development and reduced neuromodulator titres correlate with host shifts in .}, journal = {R Soc Open Sci}, volume = {9}, year = {2022}, month = {2022 Sep}, pages = {220962}, abstract = {

Host shifts are considered a key generator of insect biodiversity. For insects, adaptation to new host plants often requires changes in larval/pupal development and adult behavioural preference toward new hosts. Neurochemicals play key roles in both development and behaviour and therefore provide a potential source for such synchronization. Here, we correlated life-history timing, brain development and corresponding levels of 14 neurochemicals in (Diptera: Tephritidae), a species undergoing ecological speciation through an ongoing host shift from hawthorn to apple fruit. These races exhibit differences in pupal diapause timing as well as adult behavioural preference with respect to their hosts. This difference in behavioural preference is coupled with differences in neurophysiological response to host volatiles. We found that apple race pupae exhibited adult brain morphogenesis three weeks faster after an identical simulated winter than the hawthorn race, which correlated with significantly lower titres of several neurochemicals. In some cases, particularly biogenic amines, differences in titres were reflected in the mature adult stage, when host preference is exhibited. In summary, life-history timing, neurochemical titre and brain development can be coupled in this speciating system, providing new hypotheses for the origins of new species through host shifts.

}, issn = {2054-5703}, doi = {10.1098/rsos.220962}, author = {Kharva, Hinal and Feder, Jeffrey L and Hahn, Daniel A and Olsson, Shannon B} } @article {90595, title = {Behavioral Ecology of the Coffee White Stem Borer: Toward Ecology-Based Pest Management of India{\textquoteright}s Coffee Plantations}, journal = {FRONTIERS IN ECOLOGY AND EVOLUTION}, volume = {9}, year = {2021}, month = {02/2021}, abstract = {

India is the seventh largest producer of coffee with 395,000 tons of coffee exports that earn 10 billion US dollars annually. Two varieties of coffee are grown in India, Coffea arabica (arabica) and Coffea canephora (robusta). Xylotrechus quadripes, commonly known as Coffee White Stem Borer (CWSB), is a major pest of arabica, causing yearly crop damage of 17-40 million dollars. Management strategies, over 100 years in development, have provided successful, yet inconsistent solutions due to differences in local climate, elevation, natural enemies, grower diligence, and other factors. In addition, increased pesticide use affects both pests as well as their natural enemies, which has severe negative impacts on the biodiverse regions where coffee is grown. As a result, our goal is to develop an ecology-based solution for long term management of CWSB that reduces the use of pesticides and focuses on the importance of natural enemies and native hosts. In situ behavioral experiments were performed to examine the preferences of CWSB for various local species under field conditions. We found that CWSB beetles were attracted to both healthy arabica and robusta plants, and host plant volatiles played a key role in host selection. In addition, the beetles were attracted to the leaves of these coffee plants and also two species of cut stems from common shade trees; Spathodea campanulata (nandi flame) and Grevillea robusta (silver oak). Beetles were not attracted toward cut stems of Tectona grandis (teak) or Coffea arabica. GC-EAD and EAG experiments were then performed to identify host plant volatiles for these species, and these compounds were tested in field conditions to assess their effectiveness against the known chemical attractant pheromone. We found that the CWSB was attracted to our identified host volatile blend as much as the pheromone lure, although trap catches in general were very low. Having an understanding of the behavioral ecology of this pest can form the basis for new methods that use natural attractant and repellent plants to control the pests, reduce the cost of plantation pest management, and avoid the extensive use of insecticides.

}, doi = {10.3389/fevo.2021.607555}, author = {Rajus, Santosh and Bhagavan, Sriraksha G. and Kharva, Hinal and Rao, Srinivas and Olsson, Shannon B} } @article {82441, title = {Functional characterization of a defense-responsive bulnesol/elemol synthase from potato.}, journal = {Physiol Plant}, volume = {171}, year = {2021}, month = {2020 Sep 03}, pages = {7-21}, abstract = {

Terpene synthases (TPSs) produce a variety of terpenoids that play numerous functional roles in primary and secondary metabolism, as well as in ecological interactions. Here, we report the functional characterization of an inducible potato TPS gene encoding bulnesol/elemol synthase (StBUS/ELS). The expression of StBUS/ELS in potato leaves was significantly induced in response to both bacterial (Pseudomonas syringae) and fungal (Alternaria solani) infection as well as methyl jasmonate treatment, indicating its role in defense. The leaves exhibited the highest StBUS/ELS expression followed by the stem with least and similar expression in tuber, sprout and root. Recombinant StBUS/ELS catalyzed the formation of different sesquiterpenes by utilizing farnesyl diphosphate as substrate, and the monoterpene geraniol from geranyl diphosphate. Among the sesquiterpenes formed by StBUS/ELS, elemol was the predominant product followed by α-bulnesene, bulnesol, and β-elemene. Further GC-MS analysis of StBUS/ELS assay products at different injection temperatures revealed elemol and bulnesol as the major products at 275{\textdegree}C and 200/150{\textdegree}C, respectively, without much change in the levels of minor products. This indicated thermal rearrangement of bulnesol into elemol at higher temperatures. Transient overexpression of StBUS/ELS in potato leaves conferred tolerance against the growth of bacteria P. syringae and Ralstonia solanacearum, and the fungus A. solani. Further, expression analysis of pathogenesis-related (PR) genes in StBUS/ELS overexpressing leaves showed no significant change in comparison to control, indicating a direct involvement of StBUS/ELS enzymatic products against pathogens. Overall, our study suggested that StBUS/ELS is a pathogen-inducible TPS encoding bulnesol/elemol synthase and could provide a direct role in defense against biotic stress in potato.

}, issn = {1399-3054}, doi = {10.1111/ppl.13199}, author = {Dwivedi, Varun and Rao, Srinivas and Bomzan, Dikki Pedenla and Kumar, Sarma Rajeev and Shanmugam, Pragadheesh V and Olsson, Shannon B and Nagegowda, Dinesh A} } @article {83639, title = {Inhibition of plant pathogenic fungi by endophytic Trichoderma spp. through mycoparasitism and volatile organic compounds.}, journal = {Microbiol Res}, volume = {242}, year = {2021}, month = {2020 Sep 17}, pages = {126595}, abstract = {

Antagonism of plant pathogenic fungi by endophytic fungi is a well-known phenomenon. In plate assays, the antagonism could be due to mycoparasitism, competition for space or antibiosis, involving a chemical diffusate, or a volatile organic compound (VOC). In this study, we demonstrate that besides mycoparasitism, VOCs play a major role in antagonism of pathogenic fungi by four endophytic fungi belonging to the genus Trichoderma. Using a double-plate assay, we show that all the four endophytic Trichoderma species significantly inhibited mycelial growth of three of the four pathogens, (Sclerotinia sclerotiorum-TSS, Sclerotium rolfsii-CSR and Fusarium oxysporum-CFO), while that of Macrophomina phaseolina-CMP was not affected. GC-MS analysis of the pure cultures of one of the endophytic fungi studied, namely, Trichoderma longibrachiatum strain 2 (Acc. No. MK751758) and the pathogens, F. oxysporum-CFO and M. phaseolina-CMP revealed the presence of several VOCs including hydrocarbons, alcohols, ketones, aldehydes, esters, acids, ethers and different classes of terpenes. In mixed double plates, where the endophyte was grown along with either of the two plant pathogens, F. oxysporum-CFO or M. phaseolina-CMP, there was an induction of a number of new VOCs that were not detected in the pure cultures of either the endophyte or the pathogens. Several of these new VOCs are reported to possess antifungal and cytotoxic activity. We discuss these results and highlight the importance of such interactions in endophyte-pathogen interactions.

}, issn = {1618-0623}, doi = {10.1016/j.micres.2020.126595}, author = {Rajani, P and Rajasekaran, C and Vasanthakumari, M M and Olsson, Shannon B and Ravikanth, G and Uma Shaanker, R} } @article {91468, title = {A reversal in sensory processing accompanies ongoing ecological divergence and speciation in .}, journal = {Proc Biol Sci}, volume = {288}, year = {2021}, month = {2021 Mar 31}, pages = {20210192}, abstract = {

Changes in behaviour often drive rapid adaptive evolution and speciation. However, the mechanistic basis for behavioural shifts is largely unknown. The tephritid fruit fly is an example of ecological specialization and speciation in action via a recent host plant shift from hawthorn to apple. These flies primarily use specific odours to locate fruit, and because they mate only on or near host fruit, changes in odour preference for apples versus hawthorns translate directly to prezygotic reproductive isolation, initiating speciation. Using a variety of techniques, we found a reversal between apple and hawthorn flies in the sensory processing of key odours associated with host fruit preference at the first olfactory synapse, linking changes in the antennal lobe of the brain with ongoing ecological divergence. Indeed, changes to specific neural pathways of any sensory modality may be a broad mechanism for changes in animal behaviour, catalysing the genesis of new biodiversity.

}, issn = {1471-2954}, doi = {10.1098/rspb.2021.0192}, author = {Tait, Cheyenne and Kharva, Hinal and Schubert, Marco and Kritsch, Daniel and Sombke, Andy and Rybak, J{\"u}rgen and Feder, Jeffrey L and Olsson, Shannon B} } @article {90237, title = {Securing biodiversity, securing our future: A national mission on biodiversity and human well-being for India}, journal = {BIOLOGICAL CONSERVATION}, volume = {253}, year = {2021}, month = {01/2021}, abstract = {

Highly populated tropical countries face tremendous pressures in reconciling the needs for improved economic security and the protection of declining biodiversity. India is no exception and its biodiversity is under severe pressure due to complex interactions among land use change, other human economic activities, and climate change. Preservation and restoration of biodiversity is perhaps the cheapest and least risky way to mitigate the impacts of threats such as climate change, diminishing food and nutritional security, declining economy, absence of affordable healthcare, rising zoonotic diseases and lack of capacity to address these issues. Here we describe a framework for biodiversity conservation - the National Mission on Biodiversity and Human Well-Being (NMBHWB) for India - which integrates biodiversity, ecosystem services, climate change, agriculture, health, bio-economy and capacity building in the realm of biodiversity science. We provide an overview of the seven Programs of the Mission which make it interdisciplinary, integrative, and comprehensive in its approach. The Mission explicitly links research with policy-making and implementation for effective management of biodiversity with sustainable development. With its emphasis on convergence and synergies among various goals, themes and project sites, the Mission will further develop new models for stakeholder consultations and co-production of knowledge. We posit that the NMBHWB will enable India to realize the United Nations Sustainable Development Goals and Targets while advancing India{\textquoteright}s commitments to the Paris Agreement on climate change and other international environmental conventions and treaties.

}, doi = {10.1016/j.biocon.2020.108867}, author = {Bawa, Kamaljit S and Sengupta, Asmita and Chavan, Vishwas and Chellam, Ravi and Ganesan, R. and Krishnaswamy, Jagdish and Mathur, Vinod B. and Nawn, Nandan and Olsson, Shannon B and Pandit, Nitin and Quader, Suhel and Rajagopal, Prabhakar and Ramakrishnan, Uma and Ravikanth, G. and Sankaran, Mahesh and Shankar, Darshan and Seidler, Reinmar and Shaanker, R. Uma and Vanak, Abi Tamim} } @article {78003, title = {Characterizing long-range search behavior in Diptera using complex 3D virtual environments.}, journal = {Proc Natl Acad Sci U S A}, volume = {117}, year = {2020}, month = {2020 Jun 02}, pages = {12201-12207}, abstract = {

The exemplary search capabilities of flying insects have established them as one of the most diverse taxa on Earth. However, we still lack the fundamental ability to quantify, represent, and predict trajectories under natural contexts to understand search and its applications. For example, flying insects have evolved in complex multimodal three-dimensional (3D) environments, but we do not yet understand which features of the natural world are used to locate distant objects. Here, we independently and dynamically manipulate 3D objects, airflow fields, and odor plumes in virtual reality over large spatial and temporal scales. We demonstrate that flies make use of features such as foreground segmentation, perspective, motion parallax, and integration of multiple modalities to navigate to objects in a complex 3D landscape while in flight. We first show that tethered flying insects of multiple species navigate to virtual 3D objects. Using the apple fly , we then measure their reactive distance to objects and show that these flies use perspective and local parallax cues to distinguish and navigate to virtual objects of different sizes and distances. We also show that apple flies can orient in the absence of optic flow by using only directional airflow cues, and require simultaneous odor and directional airflow input for plume following to a host volatile blend. The elucidation of these features unlocks the opportunity to quantify parameters underlying insect behavior such as reactive space, optimal foraging, and dispersal, as well as develop strategies for pest management, pollination, robotics, and search algorithms.

}, issn = {1091-6490}, doi = {10.1073/pnas.1912124117}, author = {Kaushik, Pavan Kumar and Renz, Marian and Olsson, Shannon B} } @article {80780, title = {A field-based quantitative analysis of sublethal effects of air pollution on pollinators.}, journal = {Proc Natl Acad Sci U S A}, year = {2020}, month = {2020 Aug 10}, abstract = {

While the impact of air pollution on human health is well studied, mechanistic impacts of air pollution on wild systems, including those providing essential ecosystem services, are largely unknown, but directly impact our health and well-being. India is the world{\textquoteright}s largest fruit producer, second most populous country, and contains 9 of the world{\textquoteright}s 10 most polluted cities. Here, we sampled Giant Asian honey bees, , at locations with varying air pollution levels in Bangalore, India. We observed significant correlations between increased respirable suspended particulate matter (RSPM) deposition and changes in bee survival, flower visitation, heart rate, hemocyte levels, and expression of genes related to lipid metabolism, stress, and immunity. Lab-reared exposed to these same sites also exhibited similar molecular and physiological differences. Our study offers a quantitative analysis on the current impacts of air pollution on insects, and indicates the urgency for more nonhuman studies to accurately assess the effects of pollution on our natural world.

}, issn = {1091-6490}, doi = {10.1073/pnas.2009074117}, author = {Thimmegowda, Geetha G and Mullen, Susan and Sottilare, Katie and Sharma, Ankit and Mohanta, Saptashi Soham and Brockmann, Axel and Dhandapany, Perundurai S and Olsson, Shannon B} } @article {78164, title = {More than smell - COVID-19 is associated with severe impairment of smell, taste, and chemesthesis.}, journal = {Chem Senses}, year = {2020}, month = {2020 Jun 20}, abstract = {

Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, and generally lacked quantitative measurements. Here, we report the development, implementation and initial results of a multi-lingual, international questionnaire to assess self-reported quantity and quality of perception in three distinct chemosensory modalities (smell, taste, and chemesthesis) before and during COVID-19. In the first 11 days after questionnaire launch, 4039 participants (2913 women, 1118 men, 8 other, ages 19-79) reported a COVID-19 diagnosis either via laboratory tests or clinical assessment. Importantly, smell, taste and chemesthetic function were each significantly reduced compared to their status before the disease. Difference scores (maximum possible change {\textpm}100) revealed a mean reduction of smell (-79.7 {\textpm} 28.7, mean {\textpm} SD), taste (-69.0 {\textpm} 32.6), and chemesthetic (-37.3 {\textpm} 36.2) function during COVID-19. Qualitative changes in olfactory ability (parosmia and phantosmia) were relatively rare and correlated with smell loss. Importantly, perceived nasal obstruction did not account for smell loss. Furthermore, chemosensory impairments were similar between participants in the laboratory test and clinical assessment groups. These results show that COVID-19-associated chemosensory impairment is not limited to smell, but also affects taste and chemesthesis. The multimodal impact of COVID-19 and lack of perceived nasal obstruction suggest that SARS-CoV-2 infection may disrupt sensory-neural mechanisms.

}, issn = {1464-3553}, doi = {10.1093/chemse/bjaa041}, author = {Parma, Valentina and Ohla, Kathrin and Veldhuizen, Maria G and Niv, Masha Y and Kelly, Christine E and Bakke, Alyssa J and Cooper, Keiland W and Bouysset, C{\'e}dric and Pirastu, Nicola and Dibattista, Michele and Kaur, Rishemjit and Liuzza, Marco Tullio and Pepino, Marta Y and Sch{\"o}pf, Veronika and Pereda-Loth, Veronica and Olsson, Shannon B and Gerkin, Richard C and Rohlfs Dom{\'\i}nguez, Paloma and Albayay, Javier and Farruggia, Michael C and Bhutani, Surabhi and Fjaeldstad, Alexander W and Kumar, Ritesh and Menini, Anna and Bensafi, Moustafa and Sandell, Mari and Konstantinidis, Iordanis and Di Pizio, Antonella and Genovese, Federica and {\"O}zt{\"u}rk, Lina and Thomas-Danguin, Thierry and Frasnelli, Johannes and Boesveldt, Sanne and Saatci, {\"O}zlem and Saraiva, Luis R and Lin, Cailu and Golebiowski, J{\'e}r{\^o}me and Dar Hwang, Liang- and Ozdener, Mehmet Hakan and Gu{\`a}rdia, Maria Dolors and Laudamiel, Christophe and Ritchie, Marina and Havl{\'\i}cek, Jan and Pierron, Denis and Roura, Eugeni and Navarro, Marta and Nolden, Alissa A and Lim, Juyun and Whitcroft, K L and Colquitt, Lauren R and Ferdenzi, Camille and Brindha, Evelyn V and Altundag, Aytug and Macchi, Alberto and Nunez-Parra, Alexia and Patel, Zara M and Fiorucci, S{\'e}bastien and Philpott, Carl M and Smith, Barry C and Lundstr{\"o}m, Johan N and Mucignat, Carla and Parker, Jane K and van den Brink, Mirjam and Schmuker, Michael and Fischmeister, Florian Ph S and Heinbockel, Thomas and Shields, Vonnie D C and Faraji, Farhoud and Santamar{\'\i}a, Enrique and Fredborg, William E A and Morini, Gabriella and Olofsson, Jonas K and Jalessi, Maryam and Karni, Noam and D{\textquoteright}Errico, Anna and Alizadeh, Rafieh and Pellegrino, Robert and Meyer, Pablo and Huart, Caroline and Chen, Ben and Soler, Graciela M and Alwashahi, Mohammed K and Welge-L{\"u}ssen, Antje and Freiherr, Jessica and de Groot, Jasper H B and Klein, Hadar and Okamoto, Masako and Singh, Preet Bano and Hsieh, Julien W and Reed, Danielle R and Hummel, Thomas and Munger, Steven D and Hayes, John E} } @article {83636, title = {Opinion: Envisioning a biodiversity science for sustaining human well-being.}, journal = {Proc Natl Acad Sci U S A}, year = {2020}, month = {2020 Sep 30}, issn = {1091-6490}, doi = {10.1073/pnas.2018436117}, author = {Bawa, Kamaljit S and Nawn, Nandan and Chellam, Ravi and Krishnaswamy, Jagdish and Mathur, Vinod and Olsson, Shannon B and Pandit, Nitin and Rajagopal, Prabhakar and Sankaran, Mahesh and Shaanker, R Uma and Shankar, Darshan and Ramakrishnan, Uma and Vanak, Abi Tamim and Quader, Suhel} } @article {83637, title = {Using virtual worlds to understand insect navigation for bio-inspired systems.}, journal = {Curr Opin Insect Sci}, year = {2020}, month = {2020 Sep 30}, abstract = {

Insects perform a wide array of intricate behaviors over large spatial and temporal scales in complex natural environments. A mechanistic understanding of insect cognition has direct implications on how brains integrate multimodal information and can inspire bio-based solutions for autonomous robots. Virtual Reality (VR) offers an opportunity assess insect neuroethology while presenting complex, yet controlled, stimuli. Here, we discuss the use of insects as inspiration for artificial systems, recent advances in different VR technologies, current knowledge gaps, and the potential for application of insect VR research to bio-inspired robots. Finally, we advocate the need to diversify our model organisms, behavioral paradigms and embrace the complexity of the natural world. This will help in uncovering the proximate and ultimate basis of brain and behavior and extract general principles for common challenging problems.

}, issn = {2214-5753}, doi = {10.1016/j.cois.2020.09.010}, author = {Kaushik, Pavan Kumar and Olsson, Shannon B} } @article {59715, title = {A Functional Agonist of Insect Olfactory Receptors: Behavior, Physiology and Structure.}, journal = {Front Cell Neurosci}, volume = {13}, year = {2019}, month = {2019}, pages = {134}, abstract = {

Chemical signaling is ubiquitous and employs a variety of receptor types to detect the cacophony of molecules relevant for each living organism. Insects, our most diverse taxon, have evolved unique olfactory receptors with as little as 10\% sequence identity between receptor types. We have identified a promiscuous volatile, 2-methyltetrahydro-3-furanone (coffee furanone), that elicits chemosensory and behavioral activity across multiple insect orders and receptors. and physiology showed that coffee furanone was detected by roughly 80\% of the recorded neurons expressing the insect-specific olfactory receptor complex in the antenna of , at concentrations similar to other known, and less promiscuous, ligands. Neurons expressing specialized receptors, other chemoreceptor types, or mutants lacking the complex entirely did not respond to this compound. This indicates that coffee furanone is a promiscuous ligand for the insect olfactory receptor complex itself and did not induce non-specific cellular responses. In addition, we present homology modeling and docking studies with selected olfactory receptors that suggest conserved interaction regions for both coffee furanone and known ligands. Apart from its physiological activity, this known food additive elicits a behavioral response for several insects, including mosquitoes, flies, and cockroaches. A broad-scale behaviorally active molecule non-toxic to humans thus has significant implications for health and agriculture. Coffee furanone serves as a unique tool to unlock molecular, physiological, and behavioral relationships across this diverse receptor family and animal taxa.

}, issn = {1662-5102}, doi = {10.3389/fncel.2019.00134}, author = {Batra, Srishti and Corcoran, Jacob and Zhang, Dan-Dan and Pal, Pramit and K P, Umesh and Kulkarni, Renuka and L{\"o}fstedt, Christer and Sowdhamini, Ramanathan and Olsson, Shannon B} } @article {45449, title = {An optimized protocol for large-scale in situ sampling and analysis of volatile organic compounds}, journal = {Ecology and Evolution}, volume = {8}, year = {2018}, month = {06/2018}, pages = {59242-5935}, abstract = {

Chemical ecology is an ever-expanding field with a growing interest in population- and community-level studies. Many such studies are hindered due to lack of an efficient and accelerated protocol for large-scale sampling and analysis of chemical compounds. Here, we present an optimized protocol for such large-scale study of volatiles. A large-scale in situ study to understand role of semiochemicals in variation in mating success of lekking blackbuck was conducted. Suitable methods for sampling and statistical analysis were identified by testing and comparing the efficiencies of available techniques to reduce analysis time while retaining sensitivity and comprehensiveness. Solid-phase extraction using polydimethylsiloxane, analysis using a semiautomated detection of retention time and base peak, and statistical analysis using random forest algorithm were identified as the most efficient methods for large-scale in situ sampling and analysis of volatiles. The protocol for large-scale volatile analysis can facilitate evolutionary and metaecological studies of volatiles in situ from all types of biological samples. The protocol has potential for wider application with the analysis and interpretation methods being suitable for all kinds of semiochemicals, including nonvolatile chemicals.

}, doi = {10.1002/ece3.4138}, author = {Nair, Jyothi and Sanmugam, PV and Karpe, Snehal D and Ramakrishnan, Uma and Olsson, Shannon B} } @article {12202, title = {Identification of Host Fruit Volatiles from Snowberry (Symphoricarpos albus), Attractive to Rhagoletis zephyria Flies from the Western United States.}, journal = {J Chem Ecol}, year = {2017}, month = {2017 Jan 11}, abstract = {

A mixture of behaviorally active volatiles was identified from the fruit of snowberry, Symphoricarpos albus laevigatus, for Rhagoletis zephyria flies reared from snowberry fruit. A nine-component blend containing 3-methylbutan-1-ol (3\%), dimethyl trisulfide (1\%), 1-octen-3-ol (40\%), myrcene (8\%), nonanal (9\%), linalool (13\%), (3E)-4,8-dimethyl-1,3,7-nonatriene (DMNT, 6\%), decanal (15\%), and β-caryophyllene (5\%) was identified that gave consistent electroantennogram activity and was behaviorally active in flight tunnel tests. In other flight tunnel assays, snowberry flies from two sites in Washington state, USA, displayed significantly greater levels of upwind oriented flight to sources with the snowberry volatile blend compared with previously identified volatile blends from domestic apple (Malus domestica) and downy hawthorn (Crataegus mollis) fruit from the eastern USA, and domestic apple, black hawthorn (C. douglasii) and ornamental hawthorn (C. monogyna) from Washington state. Selected subtraction assays showed that whereas removal of DMNT or 1-octen-3-ol significantly reduced the level of upwind flight, removal of myrcene and β-caryophyllene, or dimethyl trisulfide alone did not significantly affect the proportion of upwind flights. Our findings add to previous studies showing that populations of Rhagoletis flies infesting different host fruit are attracted to unique mixtures of volatile compounds specific to their respective host plants. Taken together, the results support the hypothesis that differences among flies in their behavioral responses to host fruit odors represent key adaptations involved in sympatric host plant shifts, contributing to host specific mating and generating prezygotic reproductive isolation among members of the R. pomonella sibling species complex.

}, issn = {1573-1561}, doi = {10.1007/s10886-016-0814-8}, author = {Cha, Dong H and Olsson, Shannon B and Yee, Wee L and Goughnour, Robert B and Hood, Glen R and Mattsson, Monte and Schwarz, Dietmar and Feder, Jeffrey L and Linn, Charles E} } @article {26570, title = {In situ modeling of multimodal floral cues attracting wild pollinators across environments.}, journal = {Proc Natl Acad Sci U S A}, year = {2017}, month = {2017 Nov 27}, abstract = {

With more than 80\% of flowering plant species specialized for animal pollination, understanding how wild pollinators utilize resources across environments can encourage efficient planting and maintenance strategies to maximize pollination and establish resilience in the face of environmental change. A fundamental question is how generalist pollinators recognize "flower objects" in vastly different ecologies and environments. On one hand, pollinators could employ a specific set of floral cues regardless of environment. Alternatively, wild pollinators could recognize an exclusive signature of cues unique to each environment or flower species. Hoverflies, which are found across the globe, are one of the most ecologically important alternative pollinators after bees and bumblebees. Here, we have exploited their cosmopolitan status to understand how wild pollinator preferences change across different continents. Without employing any a priori assumptions concerning the floral cues, we measured, predicted, and finally artificially recreated multimodal cues from individual flowers visited by hoverflies in three different environments (hemiboreal, alpine, and tropical) using a field-based methodology. We found that although "flower signatures" were unique for each environment, some multimodal lures were ubiquitously attractive, despite not carrying any reward, or resembling real flowers. While it was unexpected that cue combinations found in real flowers were not necessary, the robustness of our lures across insect species and ecologies could reflect a general strategy of resource identification for generalist pollinators. Our results provide insights into how cosmopolitan pollinators such as hoverflies identify flowers and offer specific ecologically based cues and strategies for attracting pollinators across diverse environments.

}, issn = {1091-6490}, doi = {10.1073/pnas.1714414114}, author = {Nordstr{\"o}m, Karin and Dahlbom, Josefin and Pragadheesh, V S and Ghosh, Suhrid and Olsson, Amadeus and Dyakova, Olga and Suresh, Shravanti Krishna and Olsson, Shannon B} } @article {17526, title = {New Frontiers for Chemical Ecology: Reaffirming a Commitment to the G{\"o}teborg Resolution : Guest Editorial: *The Bengaluru Consortium.}, journal = {J Chem Ecol}, volume = {43}, year = {2017}, month = {2017 Jan}, pages = {2-3}, issn = {1573-1561}, doi = {10.1007/s10886-016-0813-9}, author = {Olsson, Shannon B} } @article {11619, title = {Intracellular regulation of the insect chemoreceptor complex impacts odour localization in flying insects.}, journal = {J Exp Biol}, volume = {219}, year = {2016}, month = {2016 Nov 01}, pages = {3428-3438}, abstract = {

Flying insects are well known for airborne odour tracking and have evolved diverse chemoreceptors. While ionotropic receptors (IRs) are found across protostomes, insect odorant receptors (ORs) have only been identified in winged insects. We therefore hypothesized that the unique signal transduction of ORs offers an advantage for odour localization in flight. Using Drosophila, we found expression and increased activity of the intracellular signalling protein PKC in antennal sensilla following odour stimulation. Odour stimulation also enhanced phosphorylation of the OR co-receptor Orco in vitro, while site-directed mutation of Orco or mutations in PKC subtypes reduced the sensitivity and dynamic range of OR-expressing neurons in vivo, but not IR-expressing neurons. We ultimately show that these mutations reduce competence for odour localization of flies in flight. We conclude that intracellular regulation of OR sensitivity is necessary for efficient odour localization, which suggests a mechanistic advantage for the evolution of the OR complex in flying insects.

}, issn = {1477-9145}, doi = {10.1242/jeb.143396}, author = {Getahun, Merid N and Thoma, Michael and Lavista-Llanos, Sofia and Keesey, Ian and Fandino, Richard A and Knaden, Markus and Wicher, Dieter and Olsson, Shannon B and Hansson, Bill S} } @article {11586, title = {Sensory specificity and speciation: a potential neuronal pathway for host fruit odour discrimination in Rhagoletis pomonella.}, journal = {Proc Biol Sci}, volume = {283}, year = {2016}, month = {2016 Dec 28}, abstract = {

Behavioural changes in habitat or mate choice can trigger population divergence, leading to speciation. However, little is known about the neurological bases for such changes. Rhagoletis pomonella (Diptera: Tephritidae) is a model for ecological speciation via host plant shifts. Within the past 180 years, Rhagoletis flies infesting hawthorn (Crataegus spp.) shifted to attack domesticated apple (Malus pumila). The two populations differ in their olfactory preferences for apple versus hawthorn fruit. Here, we looked for patterns of sensory organization that may have contributed to this shift by characterizing the morphology, specificity and distribution of olfactory sensory neurons (OSNs) on the antennae of Rhagoletis responding to host fruit and non-host volatiles. Of 28 OSN classes identified, two colocalized OSN pairs were found that specifically responded to the major behavioural attractant and antagonist volatiles for each fly population. A reversal in the response of these OSNs to fruit volatiles, either through a switch in receptor expression between these paired neurons or changes in neuronal projections in the brain, could therefore account for the behavioural difference between apple and hawthorn flies. The finding supports the hypothesis that relatively minor changes in olfactory sensory pathways may contribute to rapid host shifting and divergence in Rhagoletis.

}, issn = {1471-2954}, doi = {10.1098/rspb.2016.2101}, author = {Tait, Cheyenne and Batra, Srishti and Ramaswamy, Sree Subha and Feder, Jeffrey L and Olsson, Shannon B} }