Scholarly Works - Zoology
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- ItemOpen AccessWHAT CAN WE DO FOR URBAN INSECT BIODIVERSITY? APPLYING LESSONS FROM ECOLOGICAL RESEARCH(Magnolia Press, 2018) Helden, Alvin J; Morley, Geoffrey J; Davidson, Gabrielle L; Turner, Edgar C; Davidson, Gabrielle [0000-0001-5663-2662]; Turner, Edgar [0000-0003-2715-2234]Urban ecosystems are not unique, as the ecological processes and anthropological effects they encapsulate can equally be found in a range of human dominated environments. Applying ecological lessons from both within and outside urban areas is important for insect conservation within our expanding towns and cities. The management of urban grasslands, which in many cases is controlled by private individual and corporate landowners, has the potential to make a large difference to the biodiversity they support. Here we report on an investigation of invertebrate biodiversity within a series of small urban grasslands with contrasting frequency of management by mowing. Seven gardens and five other grassland areas were suction sampled for grassland invertebrates in July 2016. Samples were taken in patches that were regularly cut on a 7-14 day cycle (very short), those cut every six weeks (short) and those than had not been cut since the previous year (long). Invertebrates were mostly identified to order level, with the Hemiptera to species or morphospecies. Invertebrate abundance was significantly inversely related to mowing frequency but overall species richness did not differ between short and very short grasslands. Community structure also was most distinct in the long grasslands. The pattern of abundance varied between different taxonomic groups, with the Hemiptera particularly benefiting from very low levels of management. The value to invertebrates, especially Hemiptera, of reduced grassland management is discussed, with reference to how the owners of gardens and other urban grassy areas can make simple changes to benefit biodiversity on their land
- ItemOpen AccessA collaboratively derived environmental research agenda for Galapagos(CSIRO Publishing, 2018) Izurieta, Arturo; Delgado, Byron; Moity, Nicolas; Calvopina, Monica; Cedeno, Ivan; Banda-Cruz, Gonzalo; Cruz, Eliecer; Aguas, Milton; Arroba, Francisco; Astudillo, Ivan; Bazurto, Diana; Soria, Monica; Banks, Stuart; Bayas, Steve; Belli, Simone; Bermudez, Rafael; Boelling, Nicolai; Bolanos, Jimmy; Borbor, Mercy; Brito, Ma Lorena; Bucheli, Leopoldo; Campbell, Karl; Carranza, David; Carrion, Jorge; Casafont, Maria; Castro, Xavier; Chamorro, Sandra; Chavez, Juan; Chicaiza, David; Chumbi, Rene; Couenberg, Paulina; Cousseau, David; Cruz, Marilyn; D'Ozouville, Noemi; de la Guia, Cristina; de la Torre, Giorgio; Molina Diaz, Carla; Duchicela, Jessica; Endara, Daniel; Garcia, Vanessa; Gellibert, Cynthia; Gibbs, James; Carlos Guzman, Juan; Heylings, Pippa; Iglesias, Andres; Carlos Izurieta, Juan; Jaramillo, Patricia; Klingman, Asleigh; Laurie, Andrew; Leon, Patricia; Medina, Jaime; Mendieta, Edison; Merlen, Godfrey; Montalvo, Carla; Naula, Edwin; Paez-Rosas, Diego; Peralta, Manuel; Peralvo, Marcos; Piu, Mario; Poma, Jose; Ponton, Jose; Pozo, Mireya; Proano, Daniel; Ramos, Monica; Rousseaud, Ana; Rueda, Danny; Salinas, Pelayo; Salmoral, Gloria; Saraguro, Silvia; Simon-Baile, Debora; Tapia, Washington; Teran, Byron; Valverde, Marilu; Vargas, Andrea; Vega, Josue; Velasquez, Wilson; Velez, Alberto; Verdesoto, Santiago; Villarraga, Hernan G; Vissioli, Fernando; Viteri-Mejia, Cesar; Norris-Crespo, Lucia; Cooke, Sophia C; Toral-Granda, M Veronica; Sutherland, William J; Cooke, Sophia [0000-0001-5179-4435]; Sutherland, William [0000-0002-6498-0437]Galápagos is one of the most pristine archipelagos in the world and its conservation relies upon research and sensible management. In recent decades both the interest in, and the needs of, the islands have increased, yet the funds and capacity for necessary research have remained limited. It has become, therefore, increasingly important to identify areas of priority research to assist decision-making in Galápagos conservation. This study identified 50 questions considered priorities for future research and management. The exercise involved the collaboration of policy makers, practitioners and researchers from more than 30 different organisations. Initially, 360 people were consulted to generate 781 questions. An established process of preworkshop voting and three rounds to reduce and reword the questions, followed by a two-day workshop, was used to produce the final 50 questions. The most common issues raised by this list of questions were human population growth, climate change and the impact of invasive alien species. These results have already been used by a range of organisations and politicians and are expected to provide the basis for future research on the islands so that its sustainability may be enhanced.
- ItemOpen AccessEvidence for the temporal regulation of insect segmentation by a conserved sequence of transcription factors(The Company of Biologists, 2018-05-03) Clark, EA; Peel, Andrew; Clark, Erik [0000-0002-5588-796X]Long-germ insects, such as the fruit fly Drosophila melanogaster, pattern their segments simultaneously, whereas short-germ insects, such as the beetle Tribolium castaneum, pattern their segments sequentially, from anterior to posterior. While the two modes of segmentation at first appear quite distinct, much of this difference might simply reflect developmental heterochrony. We now show here that, in both Drosophila and Tribolium, segment patterning occurs within a common framework of sequential Caudal, Dichaete, and Odd-paired expression. In Drosophila these transcription factors are expressed like simple timers within the blastoderm, while in Tribolium they form wavefronts that sweep from anterior to posterior across the germband. In Drosophila, all three are known to regulate pair-rule gene expression and influence the temporal progression of segmentation. We propose that these regulatory roles are conserved in short-germ embryos, and that therefore the changing expression profiles of these genes across insects provide a mechanistic explanation for observed differences in the timing of segmentation. In support of this hypothesis we demonstrate that Odd-paired is essential for segmentation in Tribolium, contrary to previous reports.
- ItemOpen AccessResponse-Ivory crisis.(American Association for the Advancement of Science (AAAS), 2018-04-20) Biggs, Duan; Smith, Robert J; Adams, Vanessa M; Brink, Henry; Cook, Carly N; Cooney, Rosie; Holden, Matthew H; Maron, Martine; Phelps, Jacob; Possingham, Hugh P; Redford, Kent H; Scholes, Robert J; Sutherland, William J; Underwood, Fiona M; Milner-Gulland, EJ; Sutherland, William [0000-0002-6498-0437]Sekar et al. argue that there is unequivocal evidence that ivory trade bans are necessary for conserving elephants, and that a growing consensus removes the need to consider or incorporate alternative values in this debate. In doing so, they overlook relevant literature [e.g., (1–3)] and do not account for marginalized voices from key range states (4). Their response illustrates why the current impasse is unlikely to be resolved without a new structured process, underpinned by recognition that interpretation of scientific information on both sides of any contentious debate is influenced by values (5, 6).
- ItemOpen AccessAuthor Correction: An earlier revolution: genetic and genomic analyses reveal pre-existing cultural differences leading to Neolithization.(Springer Science and Business Media LLC, 2018-01-09) Leonardi, Michela; Barbujani, Guido; Manica, Andrea; Leonardi, Michela [0000-0001-8933-9374]; Manica, Andrea [0000-0003-1895-450X]A correction to this article has been published and is linked from the HTML version of this paper. The error has not been fixed in the paper.
- ItemOpen AccessEnergy efficiency drives the global seasonal distribution of birds.(Springer Science and Business Media LLC, 2018-06) Somveille, Marius; Rodrigues, Ana SL; Manica, Andrea; Somveille, Marius [0000-0002-6868-5080]; Manica, Andrea [0000-0003-1895-450X]The uneven distribution of biodiversity on Earth is one of the most general and puzzling patterns in ecology. Many hypotheses have been proposed to explain it, based on evolutionary processes or on constraints related to geography and energy. However, previous studies investigating these hypotheses have been largely descriptive due to the logistical difficulties of conducting controlled experiments on such large geographical scales. Here, we use bird migration-the seasonal redistribution of approximately 15% of bird species across the world-as a natural experiment for testing the species-energy relationship, the hypothesis that animal diversity is driven by energetic constraints. We develop a mechanistic model of bird distributions across the world, and across seasons, based on simple ecological and energetic principles. Using this model, we show that bird species distributions optimize the balance between energy acquisition and energy expenditure while taking into account competition with other species. These findings support, and provide a mechanistic explanation for, the species-energy relationship. The findings also provide a general explanation of migration as a mechanism that allows birds to optimize their energy budget in the face of seasonality and competition. Finally, our mechanistic model provides a tool for predicting how ecosystems will respond to global anthropogenic change.
- ItemOpen AccessResults from on-the-ground efforts to promote sustainable cattle ranching in the Brazilian Amazon(MDPI AG, 2018) zu Ermgassen, EKHJ; de Alcântara, MP; Balmford, A; Barioni, L; Neto, FB; Bettarello, MMF; de Brito, G; Carrero, GC; Florence, EDAS; Garcia, E; Gonçalves, ET; da Luz, CT; Mallman, GM; Strassburg, BBN; Valentim, JF; Latawiec, A; zu Ermgassen, Erasmus [0000-0002-9168-6057]; Balmford, Andrew [0000-0002-0144-3589]Agriculture in Brazil is booming. Brazil has the world’s second largest cattle herd and is the second largest producer of soybeans, with the production of beef, soybeans, and bioethanol forecast to increase further. Questions remain, however, about how Brazil can reconcile increases in agricultural production with protection of its remaining natural vegetation. While high hopes have been placed on the potential for intensification of low-productivity cattle ranching to spare land for other agricultural uses, cattle productivity in the Amazon biome (29% of the Brazilian cattle herd) remains stubbornly low, and it is not clear how to realize theoretical productivity gains in practice. We provide results from six initiatives in the Brazilian Amazon, which are successfully improving cattle productivity in beef and dairy production on more than 500,000 hectares of pastureland, while supporting compliance with the Brazilian Forest Code. Spread across diverse geographies, and using a wide range of technologies, participating farms have improved productivity by 30-490%. High-productivity cattle ranching requires some initial investment (R$1300-6900/ha or US$410-2180/ha), with average pay-back times of 2.5-8.5 years. We conclude by reflecting on the challenges that must be overcome to scale up these young initiatives, avoid rebound increases in deforestation, and mainstream sustainable cattle ranching in the Amazon.
- ItemOpen AccessInvolving stakeholders in agricultural decision support systems: Improving user-centred design(2018-01-01) Rose, DC; Parker, C; Fodey, J; Park, C; Sutherland, WJ; Dicks, LV; Sutherland, William [0000-0002-6498-0437]; Dicks, Lynn [0000-0002-8304-4468]© 2017 International Farm Management Association and Institute of Agricultural Management. Decision Support Systems (DSS) can improve farm management decisions and offer the opportunity to improve productivity and limit environmental degradation, both key tenets of the sustainable intensification of agriculture. While DSS are becoming increasingly useful for agriculture, the uptake of computer-based support systems by farmers has remained disappointingly low as evidenced by studies spanning at least two decades. This paper explores the reasons behind this continued lack of interest. Is it, as previous researchers have proposed, the lack of user involvement in the design and development of these systems? If so why should this be the case given decades of evidence underlining the value in user centred design (UCD)? The paper reviews literature on the desirable characteristics of DSS, and then uses 78 interviews and five focus groups to explore a case study of system use. The paper suggests that without changes to how systems are developed, particularly in how users are consulted, use of this technology will continue to be low. Practical suggestions are proposed to encourage more effective user-centred design. Chief amongst these, the need for designers to undertake a 'decision support context assessment' before building and launching a product is highlighted. Better knowledge of user-centred design practices, a clear understanding of advice systems, and greater collaboration with human-computer interaction researchers are also required.
- ItemOpen AccessSubstrate texture affects female cricket walking response to male calling song(The Royal Society, ) Hedwig, Berthold; Sarmiento-Ponce, Edith; Sutcliffe, Michael; Hedwig, Berthold [0000-0002-1132-0056]; Sutcliffe, Michael [0000-0001-9729-4460]Field crickets are extensively used as a model organism to study female phonotactic walking behaviour, i.e. their attraction to the male calling song. Laboratory-based phonotaxis experiments generally rely on arena or trackball-based settings; however, no attention has been paid to the effect of substrate texture on the response. Here, we tested phonotaxis in female Gryllus bimaculatus, walking on trackballs machined from methyl-methacrylate foam with different cell sizes. Surface height variations of the trackballs, due to the cellular composition of the material, were measured with profilometry and characterized as smooth, medium or rough, with roughness amplitudes of 7.3, 16 and 180 µm. Female phonotaxis was best on a rough and medium trackball surface, a smooth surface resulted in a significant lower phonotactic response. Claws of the cricket foot were crucial for effective walking. Females insert their claws into the surface pores to allow mechanical interlocking with the substrate texture and a high degree of attachment, which cannot be established on smooth surfaces. These findings provide insight to the biomechanical basis of insect walking and may inform behavioural studies that the surface texture on which walking insects are tested is crucial for the resulting behavioural response.
- ItemOpen AccessAge-related variation in non-breeding foraging behaviour and carry-over effects on fitness in an extremely long-lived bird(Wiley, 2018) Clay, TA; Pearmain, EJ; McGill, RAR; Manica, A; Phillips, RA; Clay, TA [0000-0002-0644-6105]Senescence has been widely documented in wild vertebrate populations, yet the proximate drivers of age‐related declines in breeding success, including allocation trade‐offs and links with foraging performance, are poorly understood. For long‐lived, migratory species, the non‐breeding period represents a critical time for investment in self‐maintenance and restoration of body condition, which in many species is linked to fitness. However, the relationships between age, non‐breeding foraging behaviour and fitness remain largely unexplored. We performed a cross‐sectional study, investigating age‐related variation in the foraging activity, distribution and diet of an extremely long‐lived seabird, the wandering albatross Diomedea exulans, during the non‐breeding period. Eighty‐two adults aged 8–33 years were tracked with geolocator‐immersion loggers, and body feathers were sampled for stable isotope analysis. We tested for variation in metrics of foraging behaviour and linked age‐related trends to subsequent reproductive performance. There was an age‐related decline in the number of landings (a proxy of foraging effort) during daylight hours, and a decrease in body feather δ¹³C values in older males but not females, yet this did not accompany an age‐related shift in distributions. Males conducted fewer landings than females, and the sexes showed some spatial segregation, with males foraging further south, likely due to their differential utilization of winds. Although younger (<20 years) birds had higher foraging effort, they all went on to breed successfully the following season. In contrast, among older (20+ years) birds, individuals that landed more often were more likely to defer breeding or fail during incubation, suggesting they have lower foraging success. As far as we are aware, this is the first demonstration of an age‐specific carry‐over effect of foraging behaviour in the non‐breeding period on subsequent reproductive performance. This link between foraging behaviour and fitness in late but not early adulthood indicates that the ability of individuals to forage efficiently outside the breeding period may be an important driver of fitness differences in old age. A plain language summary is available for this article.
- ItemOpen AccessNo evidence of a cleaning mutualism between burying beetles and their phoretic mites.(Springer Science and Business Media LLC, 2017-10-23) Duarte, Ana; Cotter, Sheena C; De Gasperin, Ornela; Houslay, Thomas M; Boncoraglio, Giuseppe; Welch, Martin; Kilner, Rebecca M; Duarte, Ana [0000-0002-1215-0458]; Cotter, Sheena C [0000-0002-3801-8316]Burying beetles (Nicrophorus vespilloides) breed on small vertebrate carcasses, which they shave and smear with antimicrobial exudates. Producing antimicrobials imposes a fitness cost on burying beetles, which rises with the potency of the antimicrobial defence. Burying beetles also carry phoretic mites (Poecilochirus carabi complex), which breed alongside them on the carcass. Here we test the novel hypothesis that P. carabi mites assist burying beetles in clearing the carcass of bacteria as a side-effect of grazing on the carrion. We manipulated the bacterial environment on carcasses and measured the effect on the beetle in the presence and absence of mites. With next-generation sequencing, we investigated how mites influence the bacterial communities on the carcass. We show that mites: 1) cause beetles to reduce the antibacterial activity of their exudates but 2) there are no consistent fitness benefits of breeding alongside mites. We also find that mites increase bacterial diversity and richness on the carcass, but do not reduce bacterial abundance. The current evidence does not support a cleaning mutualism between burying beetles and P. carabi mites, but more work is needed to understand the functional significance and fitness consequences for the beetle of mite-associated changes to the bacterial community on the carcass.
- ItemOpen AccessComparison of techniques for eliciting views and judgements in decision-making(Wiley, 2018) Mukherjee, N; Zabala, A; Huge, J; Nyumba, TO; Adem Esmail, B; Sutherland, WJ; Mukherjee, Nibedita [0000-0002-2970-1498]; Zabala, Aiora [0000-0001-8534-3325]; Nyumba, Tobias [0000-0002-7821-5197]; Sutherland, William [0000-0002-6498-0437]1. Decision‐making is a complex process that typically includes a series of stages: identifying the issue, considering possible options, making judgements and then making a decision by combining information and values. The current status quo relies heavily on the informational aspect of decision‐making with little or no emphasis on the value positions that affect decisions. 2. There is increasing realization of the importance of adopting rigorous methods for each stage such that the information, views and judgements of stakeholders and experts are used in a systematic and repeatable manner. Though there are several methodological textbooks which discuss a plethora of social science techniques, it is hard to judge the suitability of any given technique for a given decision problem. 3. In decision‐making, the three critical aspects are “what” decision is to be made, “who” makes the decisions and “how” the decisions are made. The methods covered in this paper focus on “how” decisions can be made. We compare six techniques: Focus Group Discussion (FGD), Interviews, Q methodology, Multi‐criteria Decision Analysis (MCDA), Nominal Group Technique and the Delphi technique specifically in the context of biodiversity conservation. All of these techniques (with the exception of MCDA) help in understanding human values and the underlying perspectives which shape decisions. 4. Based on structured reviews of 423 papers covering all six methods, we compare the conceptual and logistical characteristics of the methods, and map their suitability for the different stages of the decision‐making process. While interviews and FGD are well‐known, techniques such the Nominal Group technique and Q methodology are relatively under‐used. In situations where conflict is high, we recommend using the Q methodology and Delphi technique to elicit judgements. Where conflict is low, and a consensus is needed urgently, the Nominal Group technique may be more suitable. 5. We present a nuanced synthesis of methods aimed at users. The comparison of the different techniques might be useful for project managers, academics or practitioners in the planning phases of their projects and help in making better informed methodological choices.
- ItemOpen AccessDiverse and durophagous: early Carboniferous chondrichthyans from the Scottish Borders(Cambridge University Press, 2018) Richards, Kelly R; Sherwin, Janet E; Smithson, Timothy R; Bennion, Rebecca F; Davies, Sarah J; Marshall, John EA; Clack, Jennifer A; Smithson, Timothy [0000-0002-6546-1145]; Clack, Jennifer [0000-0003-0017-5831]Chondrichthyan teeth from a new locality in the Scottish Borders supply additional evidence of early Carboniferous chondrichthyans in the UK. The interbedded dolostones and siltstones of the Ballagan Formation exposed along Whitrope Burn are interpreted as representing a restricted lagoonal environment that received significant amounts of land-derived sediment. This site is palynologically dated to the latest Tournaisian – early Viséan. The diverse dental fauna documented here is dominated by large crushing holocephalan toothplates, with very few, small non-crushing chondrichthyan teeth. Two new taxa are named and described. Our samples are consistent with worldwide evidence that chondrichthyan crushing faunas are common following the Hangenberg extinction event. The lagoonal habitat represented by Whitrope Burn may represent a temporary refugium that was host to a near-relict fauna dominated by large holocephalan chondrichthyans with crushing dentitions. Many of these had already become scarce in other localities by the Viséan and become extinct later in the Carboniferous. This fauna provides evidence of early endemism or niche separation within European chondrichthyan faunas at this time. This evidence points to a complex picture in which the diversity of durophagous chondrichthyans is controlled by narrow spatial shifts in niche availability over time.
- ItemOpen AccessMoving from frugivory to seed dispersal: incorporating the functional outcomes of interactions in plant-frugivore networks(Wiley, 2018-07) Simmons, Benno I; Sutherland, William J; Dicks, Lynn V; Albrecht, Jörg; Farwig, Nina; García, Daniel; Jordano, Pedro; González-Varo, Juan P; Simmons, Benno [0000-0002-2751-9430]; Sutherland, William [0000-0002-6498-0437]; Dicks, Lynn [0000-0002-8304-4468]1. There is growing interest in understanding the functional outcomes of species interactions in ecological networks. For many mutualistic networks, including pollination and seed dispersal networks, interactions are generally sampled by recording animal foraging visits to plants. However, these visits may not reflect actual pollination or seed dispersal events, despite these typically being the ecological processes of interest. 2. Frugivorous animals can act as seed dispersers, by swallowing entire fruits and dispersing their seeds, or as pulp peckers or seed predators, by pecking fruits to consume pieces of pulp or seeds. These processes have opposing consequences for plant reproductive success. Therefore, equating visitation with seed dispersal could lead to biased inferences about the ecology, evolution and conservation of seed dispersal mutualisms. 3. Here we use natural history information on the functional outcomes of pairwise bird-plant interactions to examine changes in the structure of seven European plant-frugivore visitation networks after non-mutualistic interactions (pulp-pecking and seed predation) have been removed. Following existing knowledge of the contrasting structures of mutualistic and antagonistic networks, we hypothesised a number of changes following interaction removal, such as increased nestedness and lower specialisation. 4. Non-mutualistic interactions with pulp peckers and seed predators occurred in all seven networks, accounting for 21–48% of all interactions and 6–24% of total interaction frequency. When non-mutualistic interactions were removed, there were significant increases in network-level metrics such as connectance and nestedness, while robustness decreased. These changes were generally small, homogenous and driven by decreases in network size. Conversely, changes in species-level metrics were more variable and sometimes large, with significant decreases in plant degree, interaction frequency, specialisation and resilience to animal extinctions, and significant increases in frugivore species strength. 5. Visitation data can overestimate the actual frequency of seed dispersal services in plant-frugivore networks. We show here that incorporating natural history information on the functions of species interactions can bring us closer to understanding the processes and functions operating in ecological communities. Our categorical approach lays the foundation for future work quantifying functional interaction outcomes along a mutualism–antagonism continuum, as documented in other frugivore faunas.
- ItemOpen AccessGlobal importance of vertebrate pollinators for plant reproductive success: a meta-analysis(Wiley, 2018) Ratto, F; Simmons, BI; Spake, R; Zamora-Gutierrez, V; MacDonald, MA; Merriman, JC; Tremlett, CJ; Poppy, GM; Peh, KSH; Dicks, LV; Simmons, Benno [0000-0002-2751-9430]; Dicks, Lynn [0000-0002-8304-4468]Vertebrate pollinators are increasingly threatened worldwide, but little is known about the potential consequences of their declines for plants and wider ecosystems. We present the first global assessment of the importance of vertebrate pollinators for zoophilous plant reproduction. Our meta-analysis of 126 experiments on plants revealed that excluding vertebrate pollinators reduced fruit and/or seed production by 63% on average. We found bat-pollinated plants to be more dependent on pollinators than bird-pollinated plants (an average 84% reduction in fruit/seed production when bats were being excluded, compared to 46% when birds were excluded). Dependence on vertebrate pollinators for fruit/seed production was greater in the tropics than at higher latitudes. With such a large potential impact of vertebrate pollinator loss, there is a clear need for prompt, effective conservation action for threatened flower-visiting vertebrate species. More research is needed on how such changes might affect wider ecosystems.
- ItemOpen AccessHoneybees Tolerate Cyanogenic Glucosides from Clover Nectar and Flowers.(MDPI AG, 2018-03-13) Lecocq, Antoine; Green, Amelia A; Pinheiro De Castro, Érika Cristina; Olsen, Carl Erik; Jensen, Annette B; Zagrobelny, Mika; Lecocq, Antoine [0000-0002-8013-0221]; Zagrobelny, Mika [0000-0001-5574-2894]Honeybees (Apis mellifera) pollinate flowers and collect nectar from many important crops. White clover (Trifolium repens) is widely grown as a temperate forage crop, and requires honeybee pollination for seed set. In this study, using a quantitative LC-MS (Liquid Chromatography-Mass Spectrometry) assay, we show that the cyanogenic glucosides linamarin and lotaustralin are present in the leaves, sepals, petals, anthers, and nectar of T. repens. Cyanogenic glucosides are generally thought to be defense compounds, releasing toxic hydrogen cyanide upon degradation. However, increasing evidence indicates that plant secondary metabolites found in nectar may protect pollinators from disease or predators. In a laboratory survival study with chronic feeding of secondary metabolites, we show that honeybees can ingest the cyanogenic glucosides linamarin and amygdalin at naturally occurring concentrations with no ill effects, even though they have enzyme activity towards degradation of cyanogenic glucosides. This suggests that honeybees can ingest and tolerate cyanogenic glucosides from flower nectar. Honeybees retain only a portion of ingested cyanogenic glucosides. Whether they detoxify the rest using rhodanese or deposit them in the hive should be the focus of further research.
- ItemOpen AccessResponse to Akcali et al.: What keeps them from mingling.(Wiley, 2017-11) Van Belleghem, Steven M; Hendrickx, Frederik; Van Belleghem, Steven [0000-0001-9399-1007]The salt marsh beetle Pogonus chalceus has diverged into short- and long-winged populations, which can be found in hundreds of interlaced habitat patches that sharply differ in their hydrological regime. In a recent study, we investigated how a behavioral adaptation to these contrasting hydrological regimes might drive the neat spatial sorting of the ecotypes and facilitate divergence. Simulated inundation experiments revealed that the ecotypes differ in dispersal response toward the hydrological regime and that this is a plastic behavior imprinted during the nondispersive immature stages. In their comment, Akcali and Porter (2017) question if the observed plastic response would effectively reduce gene-flow in this system. Based on the natural history of this species we demonstrate why this is plausible and we propose future avenues that may further strengthen this conclusion. In addition, Akcali and Porter (2017) illustrate some current inconsistencies in the use of terminology of the different habitat choice mechanisms. We agree that proper classification of the existing theories is indispensable in advancing the field of habitat choice mechanisms and their effect on gene flow, but the unique attributes of any given biological system may thwart this exercise.
- ItemOpen AccessPatterns of Z chromosome divergence among Heliconius species highlight the importance of historical demography.(Wiley, 2018-10) Van Belleghem, Steven M; Baquero, Margarita; Papa, Riccardo; Salazar, Camilo; McMillan, W Owen; Counterman, Brian A; Jiggins, Chris D; Martin, Simon H; Van Belleghem, Steven M [0000-0001-9399-1007]; Salazar, Camilo [0000-0001-9217-6588]; McMillan, W Owen [0000-0003-2805-2745]; Counterman, Brian A [0000-0003-2724-071X]; Jiggins, Chris D [0000-0002-7809-062X]; Martin, Simon H [0000-0002-0747-7456]Sex chromosomes are disproportionately involved in reproductive isolation and adaptation. In support of such a "large-X" effect, genome scans between recently diverged populations and species pairs often identify distinct patterns of divergence on the sex chromosome compared to autosomes. When measures of divergence between populations are higher on the sex chromosome compared to autosomes, such patterns could be interpreted as evidence for faster divergence on the sex chromosome, that is "faster-X", barriers to gene flow on the sex chromosome. However, demographic changes can strongly skew divergence estimates and are not always taken into consideration. We used 224 whole-genome sequences representing 36 populations from two Heliconius butterfly clades (H. erato and H. melpomene) to explore patterns of Z chromosome divergence. We show that increased divergence compared to equilibrium expectations can in many cases be explained by demographic change. Among Heliconius erato populations, for instance, population size increase in the ancestral population can explain increased absolute divergence measures on the Z chromosome compared to the autosomes, as a result of increased ancestral Z chromosome genetic diversity. Nonetheless, we do identify increased divergence on the Z chromosome relative to the autosomes in parapatric or sympatric species comparisons that imply postzygotic reproductive barriers. Using simulations, we show that this is consistent with reduced gene flow on the Z chromosome, perhaps due to greater accumulation of incompatibilities. Our work demonstrates the importance of taking demography into account to interpret patterns of divergence on the Z chromosome, but nonetheless provides evidence to support the Z chromosome as a strong barrier to gene flow in incipient Heliconius butterfly species.
- ItemOpen AccessNudging pro-environmental behavior: evidence and opportunities(Wiley, 2018) Byerly, Hilary; Balmford, Andrew; Ferraro, Paul J; Wagner, Courtney Hammond; Palchak, Elizabeth; Polasky, Stephen; Ricketts, Taylor H; Schwartz, Aaron J; Fisher, Brendan; Balmford, Andrew [0000-0002-0144-3589]Human actions are responsible for many of our greatest environmental challenges. Studies from the human behavioral sciences show that minor features of decision settings can have major effects on people’s choices. While such behavioral insights have positively influenced individual health and financial decisions, less is known about whether and how these insights can encourage choices that are better for the environment. We review 160 experimental interventions that attempt to alter behavior in six domains where decisions have large environmental impacts: family planning, land management, meat consumption, transportation choices, waste production, and water use. Claims that social influence (norms) and simple adjustments to automatic settings (defaults) can influence pro-environmental decisions are supported by the evidence. Yet for other interventions, knowledge gaps preclude clear conclusions and policy applications. To address these gaps, we identify four opportunities for future research and encourage collaboration between scholars and practitioners to embed tests of behavioral interventions within environmental programs.
- ItemOpen AccessTrait evolution, resource specialization and vulnerability to plant extinctions among Antillean hummingbirds(Royal Society Publishing, 2018-03-28) Dalsgaard, Bo; Kennedy, Jonathan; Simmons, BI; Baquero, Andrea C; Martín González, Ana M; Timmermann, Allan; Maruyama, Pietro K; McGuire, Jimmy A; Ollerton, Jeff; Sutherland, William J; Rahbek, Carsten; Simmons, Benno [0000-0002-2751-9430]; Sutherland, William [0000-0002-6498-0437]Species traits are thought to predict feeding specialization and the vulnerability of a species to extinctions of interaction partners, but the context in which a species evolved and currently inhabits may also matter. Notably, the predictive power of traits may require that traits evolved to fit interaction partners. Furthermore, local abiotic and biotic conditions may be important. On islands, for instance, specialized and vulnerable species are predicted to be found mainly in mountains, whereas species in lowlands should be generalized and less vulnerable. We evaluated these predictions for hummingbirds and their nectar-food plants on Antillean islands. Our results suggest that the rates of hummingbird trait divergence were higher among ancestral mainland forms before the colonization of the Antilles. In correspondence with the limited trait evolution that occurred within the Antilles, local abiotic and biotic conditions—not species traits—correlate with hummingbird resource specialization and the vulnerability of hummingbirds to extinctions of their floral resources. Specifically, hummingbirds were more specialized and vulnerable in conditions with high topographical complexity, high rainfall, low temperatures and high floral resource richness, which characterize the Antillean Mountains. These findings show that resource specialization and species vulnerability to extinctions of interaction partners are highly context-dependent.