γ-TuRCs and the augmin complex are required for the development of highly branched dendritic arbors in Drosophila.

Microtubules are nucleated by γ-tubulin ring complexes (γ-TuRCs) and are essential for neuronal development. Nevertheless, γ-TuRC depletion has been reported to perturb only higher-order branching in elaborated Drosophila larval class IV dendritic arborization (da) neurons. This relatively mild phenotype has been attributed to defects in microtubule nucleation from Golgi outposts, yet most Golgi outposts lack associated γ-TuRCs. By analyzing dendritic arbor regrowth in pupae, we show that γ-TuRCs are also required for the growth and branching of primary and secondary dendrites, as well as for higher-order branching. Moreover, we identify the augmin complex (hereafter augmin), which recruits γ-TuRCs to the sides of pre-existing microtubules, as being required predominantly for higher-order branching. Augmin strongly promotes the anterograde growth of microtubules in terminal dendrites and thus terminal dendrite stability. Consistent with a specific role in higher-order branching, we find that augmin is expressed less strongly and is largely dispensable in larval class I da neurons, which exhibit few higher-order dendrites. Thus, γ-TuRCs are essential for various aspects of complex dendritic arbor development, and they appear to function in higher-order branching via the augmin pathway, which promotes the elaboration of dendritic arbors to help define neuronal morphology.

Complexity-functioning relationships differ across different environmental conditions.

Habitat complexity is widely considered an important determinant of biodiversity, and enhancing complexity can play a key role in restoring degraded habitats. However, the effects of habitat complexity on ecosystem functioning - as opposed to biodiversity and community structure - are relatively poorly understood for artificial habitats, which dominate many coastlines. With Greening of Grey Infrastructure (GGI) approaches, or eco-engineering, increasingly being applied around the globe, it is important to understand the effects that modifying habitat complexity has on both biodiversity and ecological functioning in these highly modified habitats. We assessed how manipulating physical (primary substrate) and/or biogenic habitat (bivalves) complexity on intertidal artificial substrata affected filtration rates, net and gross primary productivity (NPP and GPP, respectively) and community respiration (CR) - as well as abundance of filter feeders and macro-algae and habitat use by cryptobenthic fish across six locations in three continents. We manipulated both physical and biogenic complexity using 1) flat or ridged (2.5 cm or 5 cm) settlement tiles that were either 2) unseeded or seeded with oysters or mussels. Across all locations, increasing physical and biogenic complexity (5 cm seeded tiles) had a significant effect on most ecological functioning variables, increasing overall filtration rates and community respiration of the assemblages on tiles but decreasing productivity (both GPP and NPP) across all locations. There were no overall effects of increasing either type of habitat complexity on cryptobenthic fish MaxN, total time in frame or macro-algal cover. Within each location, there were marked differences in the effects of habitat complexity. In Hobart, we found higher filtration, filter feeder biomass and community respiration on 5 cm tiles compared to flat tiles. However, at this location, both macro-algae cover and GPP decreased with increasing physical complexity. Similarly in Dublin, filtration, filter feeder biomass and community respiration were higher on 5 cm tiles compared to less complex tiles. In Sydney, filtration and filter feeder biomass were higher on seeded than unseeded tiles, and fish MaxN was higher on 5 cm tiles compared to flat tiles. On unseeded tiles in Sydney, filter feeder biomass also increased with increasing physical complexity. Our findings suggest that GGI solutions via increased habitat complexity are likely to have trade-offs among potentially desired functions, such as productivity and filtration rates, and variable effects on cryptobenthic fish communities. Importantly, our results show that the effects of GGI practices can vary markedly according to the environmental context and therefore should not be blindly and uniformly applied across the globe.

Material type influences the abundance but not richness of colonising organisms on marine structures.

Urbanisation of coastal areas and growth in the blue economy drive the proliferation of artificial structures in marine environments. These structures support distinct ecological communities compared to natural hard substrates, potentially reflecting differences in the materials from which they are constructed. We undertook a meta-analysis of 46 studies to compare the effects of different material types (natural or eco-friendly vs. artificial) on the colonising biota on built structures. Neither the abundance nor richness of colonists displayed consistent patterns of difference between artificial and natural substrates or between eco-friendly and standard concrete. Instead, there were differences in the abundance of organisms (but not richness) between artificial and natural materials, that varied according to material type and by functional group. When compared to biogenic materials and rock, polymer and metal supported significantly lower abundances of total benthic species (in studies assessing sessile and mobile species together), sessile invertebrates and corals (in studies assessing these groups individually). In contrast, non-indigenous species were significantly more abundant on wood than metal. Concrete supported greater abundances of the general community, including habitat-forming species, compared to wood. Our results suggest that the ecological requirements of the biological community, alongside economic, logistic and engineering factors should be considered in material selection for multifunctional marine structures that deliver both engineering and ecological (enhanced abundance and diversity) benefits.

Artificial shorelines lack natural structural complexity across scales.

From microbes to humans, habitat structural complexity plays a direct role in the provision of physical living space, and increased complexity supports higher biodiversity and ecosystem functioning across biomes. Coastal development and the construction of artificial shorelines are altering natural landscapes as humans seek socio-economic benefits and protection from coastal storms, flooding and erosion. In this study, we evaluate how much structural complexity is missing on artificial coastal structures compared to natural rocky shorelines, across a range of spatial scales from 1 mm to 10 s of m, using three remote sensing platforms (handheld camera, terrestrial laser scanner and uncrewed aerial vehicles). Natural shorelines were typically more structurally complex than artificial ones and offered greater variation between locations. However, our results varied depending on the type of artificial structure and the scale at which complexity was measured. Seawalls were deficient at all scales (approx. 20-40% less complex than natural shores), whereas rock armour was deficient at the smallest and largest scales (approx. 20-50%). Our findings reinforce concerns that hardening shorelines with artificial structures simplifies coastlines at organism-relevant scales. Furthermore, we offer much-needed insight into how structures might be modified to more closely capture the complexity of natural rocky shores that support biodiversity.

Humidity determines snowpack ablation under a warming climate.

Climate change is altering historical patterns of snow accumulation and melt, threatening societal frameworks for water supply. However, decreases in spring snow water equivalent (SWE) and changes in snowmelt are not ubiquitous despite widespread warming in the western United States, highlighting the importance of latent and radiant energy fluxes in snow ablation. Here we demonstrate how atmospheric humidity and solar radiation interact with warming temperature to control snowpack ablation at 462 sites spanning a gradient in mean winter temperature from -8.9 to +2.9 °C. The most widespread response to warming was an increase in episodic, midwinter ablation events. Under humid conditions these ablation events were dominated by melt, averaging 21% (202 mm/year) of SWE. Winter ablation under dry atmospheric conditions at similar temperatures was smaller, averaging 12% (58 mm/year) of SWE and likely dominated by sublimation fluxes. These contrasting patterns result from the critical role that atmospheric humidity plays in local energy balance, with latent and longwave radiant fluxes cooling the snowpack under dry conditions and warming it under humid conditions. Similarly, spring melt rates were faster under humid conditions, yet the second most common trend was a reduction in spring melt rates associated with earlier initiation when solar radiation inputs are smaller. Our analyses demonstrate that regional differences in atmospheric humidity are a major cause of the spatial variability in snowpack response to warming. Better constraints on humidity will be critical to predicting both the amount and timing of surface water supplies under climate change.

Plant hydraulics improves and topography mediates prediction of aspen mortality in southwestern USA.

Elevated forest mortality has been attributed to climate change-induced droughts, but prediction of spatial mortality patterns remains challenging. We evaluated whether introducing plant hydraulics and topographic convergence-induced soil moisture variation to land surface models (LSM) can help explain spatial patterns of mortality. A scheme predicting plant hydraulic safety loss from soil moisture was developed using field measurements and a plant physiology-hydraulics model, TREES. The scheme was upscaled to Populus tremuloides forests across Colorado, USA, using LSM-modeled and topography-mediated soil moisture, respectively. The spatial patterns of hydraulic safety loss were compared against aerial surveyed mortality. Incorporating hydraulic safety loss raised the explanatory power of mortality by 40% compared to LSM-modeled soil moisture. Topographic convergence was mostly influential in suppressing mortality in low and concave areas, explaining an additional 10% of the variations in mortality for those regions. Plant hydraulics integrated water stress along the soil-plant continuum and was more closely tied to plant physiological response to drought. In addition to the well-recognized topo-climate influence due to elevation and aspect, we found evidence that topographic convergence mediates tree mortality in certain parts of the landscape that are low and convergent, likely through influences on plant-available water.

Persistent Urban Influence on Surface Water Quality via Impacted Groundwater.

Growing urban environments stress hydrologic systems and impact downstream water quality. We examined a third-order catchment that transitions from an undisturbed mountain environment into urban Salt Lake City, Utah. We performed synoptic surveys during a range of seasonal baseflow conditions and utilized multiple lines of evidence to identify mechanisms by which urbanization impacts water quality. Surface water chemistry did not change appreciably until several kilometers into the urban environment, where concentrations of solutes such as chloride and nitrate increase quickly in a gaining reach. Groundwater springs discharging in this gaining system demonstrate the role of contaminated baseflow from an aquifer in driving stream chemistry. Hydrometric and hydrochemical observations were used to estimate that the aquifer contains approximately 18% water sourced from the urban area. The carbon and nitrogen dynamics indicated the urban aquifer also serves as a biogeochemical reactor. The evidence of surface water-groundwater exchange on a spatial scale of kilometers and time scale of months to years suggests a need to evolve the hydrologic model of anthropogenic impacts to urban water quality to include exchange with the subsurface. This has implications on the space and time scales of water quality mitigation efforts.

High-throughput method for simultaneous quantification of N, C and S stable isotopes and contents in organics and soils.

RATIONALE: Information about the sulfur stable isotope composition (δ(34) S value) of organic materials and sediments, in addition to their nitrogen (δ(15) N value) and carbon (δ(13) C value) stable isotope compositions, can provide insights into mechanisms and processes in different areas of biological and geological research. The quantification of δ(34) S values has traditionally required an additional and often more difficult analytical procedure than NC dual analysis. Here, we report on the development of a high-throughput method that simultaneously measures the elemental and isotopic compositions of N, C and S in a single sample, and over a wide range of sample sizes and C/N and C/S ratios. METHODS: We tested a commercially available CHNOS elemental analyzer in line with an isotope ratio mass spectrometer for the simultaneous quantification of N, C and S stable isotope ratios and contents, and modified the elemental analyzer in order to overcome the interference of (18) O in δ(34) S values, to minimize any water condensation that could also influence S memory, and to achieve the complete reduction of nitrogen oxides to N2 gas for accurate measurement of δ(15) N values. A selection of organic materials and soils was analyzed with a ratio of 1:1.4 standards to unknowns per run. RESULTS: The modifications allowed high quality measurements for N, C and S isotope ratios simultaneously (1 SD of ±0.13‰ for δ(15) N value, ±0.12‰ for δ(13) C value, and ±0.4‰ for δ(34) S value), with high throughput (>75 unknowns per run) and over a wide range of element amount per capsule (25 to 500 µg N, 200-4000 µg C, and 8-120 µg S). CONCLUSIONS: This method is suitable for widespread use and can significantly enhance the application of δ(34) S measurements in a broad range of soils and organic samples in ecological and biogeochemical research. Copyright © 2016 John Wiley & Sons, Ltd.

Stream Nitrogen Inputs Reflect Groundwater Across a Snowmelt-Dominated Montane to Urban Watershed.

Snowmelt dominates the hydrograph of many temperate montane streams, yet little work has characterized how streamwater sources and nitrogen (N) dynamics vary across wildland to urban land use gradients in these watersheds. Across a third-order catchment in Salt Lake City, Utah, we asked where and when groundwater vs shallow surface water inputs controlled stream discharge and N dynamics. Stream water isotopes (δ(2)H and δ(18)O) reflected a consistent snowmelt water source during baseflow. Near-chemostatic relationships between conservative ions and discharge implied that groundwater dominated discharge year-round across the montane and urban sites, challenging the conceptual emphasis on direct stormwater inputs to urban streams. Stream and groundwater NO3(-) concentrations remained consistently low during snowmelt and baseflow in most montane and urban stream reaches, indicating effective subsurface N retention or denitrification and minimal impact of fertilizer or deposition N sources. Rather, NO3(-) concentrations increased 50-fold following urban groundwater inputs, showing that subsurface flow paths potentially impact nutrient loading more than surficial land use. Isotopic composition of H2O and NO3(-) suggested that snowmelt-derived urban groundwater intercepted NO3(-) from leaking sewers. Sewer maintenance could potentially mitigate hotspots of stream N inputs at mountain/valley transitions, which have been largely overlooked in semiarid urban ecosystems.

The influence of environmental context on community composition in artificial rockpools associated with seawalls.

Artificial structures have become widespread features of coastal marine environments, and will likely proliferate further over the coming decades. These constitute new hard substrata in the marine environment which provide a fundamentally different habitat than natural shores. Eco-engineering solutions aim to ameliorate these differences by combining ecological knowledge and engineering criteria in the construction and modification of artificial substrata. Vertipools™ are artificial bolt-on rockpools intended for deployment on seawalls, where they have been shown to provide biodiversity benefits. In this study, a total of 32 Vertipools were retrofitted on eight seawalls in different environmental contexts (estuarine vs marine and urban vs rural) along the Irish Sea coastline, and were exposed to the environment for a period of two years. After two years, there were no differences in species richness, species-abundance distributions, diversity, or community composition between the specific environmental contexts examined here. Site-level variation was significant, and communities on Vertipools deployed in marine contexts were more variable in general than those in estuarine contexts. Community composition differed significantly between structural sections of the Vertipools, indicating that different sections provide specific microhabitats for colonisation. This study indicates that Vertipools provide biodiversity benefits in a variety of environmental contexts, and therefore are broadly viable as an eco-engineering solution.

Incidence, Healthcare Resource Use and Costs Associated With Incisional Hernia Repair.

Background: Incisional hernia (IH) is a common complication of abdominal surgery affecting between 12.8% and 30% of patients. In spite of this, rates of IH repair remain low, at around 5% in the literature. We aimed to assess the rate of IH repair in the UK across surgical specialties and the cost burden associated with IH repair. Methods: This is a retrospective observational study of patients undergoing abdominal surgery in England between 2012 and 2022 using the Hospital Episode Statistics (HES) database. Index abdominal surgery was identified between March 2014 and March 2017. Diagnostic and surgical procedure codes were used to identify pre-operative risk factors, index surgeries, IH repair and healthcare contact. Healthcare resource use (HCRU) costs were derived for index surgery and all post-index, non-elective inpatient admissions and outpatient visits using Healthcare Resource Group (HRG) codes within HES. Results: Of 297,134 patients undergoing abdominal surgery, 5.1% (n = 15,138) subsequently underwent incisional hernia repair. By specialty, rates were higher in Colorectal (10.0%), followed by Hepatobiliary (8.2%), Transplant (6.8%), Urological (4.0%), Bariatric (3.5%), Vascular (3.2%) and Gynaecological (2.6%) surgery. Patients undergoing IH repair had more healthcare contacts, longer length of inpatient stays and more A+E visits vs. those with no IH repair post index surgery (83% ≥ 1 A+E visit vs. 69%), as well as higher rates of referral to mental health services (19.8% vs. 11.5%). IH repair was associated with an average HCRU cost of £23,148 compared to £12,321 in patients with no IH repair. Conclusion: Patients undergoing IH repair have a greater morbidity than those not undergoing repair, shown by higher HCRU and more healthcare contacts. Despite this, rates of surgery for IH are low, suggesting that most patients with hernias are not undergoing repair. Emphasis must be placed squarely on primary prevention, rather than cure.

Comparative connectomics of the descending and ascending neurons of the Drosophila nervous system: stereotypy and sexual dimorphism.

In most complex nervous systems there is a clear anatomical separation between the nerve cord, which contains most of the final motor outputs necessary for behaviour, and the brain. In insects, the neck connective is both a physical and information bottleneck connecting the brain and the ventral nerve cord (VNC, spinal cord analogue) and comprises diverse populations of descending (DN), ascending (AN) and sensory ascending neurons, which are crucial for sensorimotor signalling and control. Integrating three separate EM datasets, we now provide a complete connectomic description of the ascending and descending neurons of the female nervous system of Drosophila and compare them with neurons of the male nerve cord. Proofread neuronal reconstructions have been matched across hemispheres, datasets and sexes. Crucially, we have also matched 51% of DN cell types to light level data defining specific driver lines as well as classifying all ascending populations. We use these results to reveal the general architecture, tracts, neuropil innervation and connectivity of neck connective neurons. We observe connected chains of descending and ascending neurons spanning the neck, which may subserve motor sequences. We provide a complete description of sexually dimorphic DN and AN populations, with detailed analysis of circuits implicated in sex-related behaviours, including female ovipositor extrusion (DNp13), male courtship (DNa12/aSP22) and song production (AN hemilineage 08B). Our work represents the first EM-level circuit analyses spanning the entire central nervous system of an adult animal.

Colonisation after disturbance on artificial structures: The influence of timing and grazing.

Artificial structures are poor surrogates of natural rocky shores, meaning they generally support depauperate assemblages. These differences may result from a combination of recruitment processes, biotic interactions, and structuring by environmental factors. In this study, plots were cleared on two seawalls and two natural shores at two separate timepoints - in August 2020 (summer) and February 2021 (winter) - and monitored over one year to determine the influence of timing of disturbance on recruitment and succession. Additional plots were cleared at one of the seawalls at a single timepoint in August 2020, and exclusion cages were installed to determine the influence of grazing pressure on colonisation; these were monitored for 18 months. Disturbance during winter resulted in higher concentrations of all biofilm components up to 3 months, but did not impact benthic community composition beyond this point. Grazer exclusion on artificial structures increased biofilm concentrations and influenced community composition in comparison to plots on artificial structures without exclusion, while communities on natural surfaces differed in terms of species composition to those on artificial plots at 12 months. We conclude that the timing of routine maintenance works on artificial structures may impact initial biofilm abundances. Furthermore, while grazing pressure does influence community structure on artificial structures, this alone is not sufficient to explain biological differences between artificial structures and natural shores.

Using valve gape analysis to compare sensitivity of native Mytilus edulis to invasive Magallana gigas when exposed to heavy metal contamination.

Coastal ecosystems are ecologically and economically important but are under increasing pressure from numerous anthropogenic sources of stress. Both heavy metal pollution and invasive species pose major environmental concerns that can have significant impacts on marine organisms. It is likely that many stresses will occur simultaneously, resulting in potential cumulative ecological effects. The aim of this study was to compare the relative resilience of an invasive oyster Magallana gigas and a native mussel Mytilus edulis to heavy metal pollution, utilising their valve gape response as an indicator. The gape activity of bivalves has been utilised to monitor a range of potential impacts, including for example oil spills, increased turbidity, eutrophication, heavy metal contamination etc. In this study, Hall effect sensors were used on both the native blue mussel (M. edulis) and the pacific oyster (M. gigas), invasive to Ireland. Mussels were shown to be more responsive to pollution events than oysters, where all heavy metals tested (copper, cadmium, zinc, lead) had an effect on transition frequency though significant differences were only observed for lead and cadmium (Control; > Copper, p = 0.0003; >lead, p = 0.0002; >Cadmium, p = 0.0001). Cadmium had an apparent effect on mussels with specimens from this treatment remaining closed for an average of 45.3% of the time. Similarly, significant effects on the duration of time mussels spent fully open was observed when treated with lead and cadmium (Control; > lead, p = 0.03, > cadmium, p = 0.02). In contrast, oysters displayed no significant difference for any treatment for number of gapes, or duration spent open or closed. Though there was an effect of both zinc and copper on the amount of time spent closed, with averages of 63.2 and 68.7% respectively. This indicates oysters may be potentially more resilient to such pollution events; further boosting their competitive advantage. Future mesocosm or field studies are required to quantify this relative resilience.

The population structure, sex ratio and reproductive potential of limpets (Patella spp.) on natural shores and artificial structures in the Irish Sea.

Artificial structures often support depauperate communities compared to natural rocky shores. Understanding variation in ecological success across shore types, particularly regarding habitat-forming species or those with structuring roles, is important to determine how artificial structure proliferation may influence ecosystem functioning and services. We investigated the population structure, sex ratio and reproductive potential of limpets on natural shores and artificial structures on Irish Sea coasts. Limpets were generally less abundant and Patella vulgata populations were often male dominated on artificial structures compared to natural shores, suggesting that shore type may influence these factors. P. vulgata length varied across sites within the Irish Sea (nested in coast and shore type) in autumn/winter, as well as temporally across sites along the Welsh coast. There was no difference in the proportion of P. vulgata in advanced stages of gonad development across shore types. The results suggest that rip-rap artificial structures may provide a habitat comparable to natural shores, however, the addition of ecological engineering interventions on artificial structures may allow limpet populations to better approximate those on natural shores.

Population structure and reproductive states of the dogwhelk Nucella lapillus differ between artificial structures and natural rocky shores.

Artificial structures are an increasingly common feature of coastal marine environments. These structures are poor surrogates of natural rocky shores, and generally support less diverse communities and reduced population sizes. Little is known about sub-lethal effects of such structures in terms of demographic properties and reproductive potential, both of which may influence the dynamics and long-term viability of populations. This study examines the population structure, reproductive states and embryo production of Nucella lapillus populations on artificial structures and natural shores in Ireland and Wales. Population density was measured twice at six natural shores and six artificial structures: once in winter and once in spring. At each sampling, the shell height of 100 individuals from each site was measured. Monthly collections of adult specimens and egg capsules were made at each site from November-January and from March-May, in order to determine sex ratios, reproductive states, and embryo abundances. Artificial structures supported larger individuals and very few juveniles compared to natural shores. Between December and January, natural shores experienced a distinctive pulse in spawning activity followed by a decline in the proportion of females in a reproductive state, whereas on artificial structures the proportion of reproductive females remained relatively stable. Differences observed may be due to a lack of microhabitats on artificial structures, along with subtle variations in structure slope. Eco-engineering interventions, including the addition of refugia such as cracks and crevices, may allow N. lapillus populations on artificial structures to approximate those on natural shores.

Artificial rockpools: Seaweed colonisation and productivity vary between sites but are consistent across environmental contexts.

Artificial structures are widespread features of coastal environments, but are poor surrogates of natural rocky shores because they generally support depauperate assemblages with reduced population sizes. This has generated significant interest in eco-engineering solutions, including retrofitting seawalls with artificial rockpools to increase water retention and provide microhabitats. Although these have proven effective at individual sites, widespread uptake is contingent on evidence of consistent benefits across a range of contexts. In this study, Vertipools™ were retrofitted on eight seawalls in different environmental contexts (urban v rural and estuarine v marine) along the Irish Sea coastline and were monitored regularly for two years. Seaweed colonisation proceeded in a manner similar to patterns described for natural and artificial intertidal systems in general, consisting of early dominance by ephemeral species followed by the appearance and eventual establishment of perennial habitat-formers. After 24 months, species richness did not differ between contexts, but differed between sites. The units supported populations of large habitat-forming seaweeds at all sites. Productivity and community respiration of the colonising communities differed between sites by up to 0.5 mg O2 L-1 min-1, but not across environmental contexts. This study demonstrates that bolt-on rockpools attract similar levels of biotic colonisation and functioning in a variety of temperate environmental contexts, and could be considered for widespread implementation as an eco-engineering solution.

Whole-brain annotation and multi-connectome cell typing quantifies circuit stereotypy in Drosophila.

The fruit fly Drosophila melanogaster combines surprisingly sophisticated behaviour with a highly tractable nervous system. A large part of the fly's success as a model organism in modern neuroscience stems from the concentration of collaboratively generated molecular genetic and digital resources. As presented in our FlyWire companion paper 1 , this now includes the first full brain connectome of an adult animal. Here we report the systematic and hierarchical annotation of this ~130,000-neuron connectome including neuronal classes, cell types and developmental units (hemilineages). This enables any researcher to navigate this huge dataset and find systems and neurons of interest, linked to the literature through the Virtual Fly Brain database 2 . Crucially, this resource includes 4,552 cell types. 3,094 are rigorous consensus validations of cell types previously proposed in the hemibrain connectome 3 . In addition, we propose 1,458 new cell types, arising mostly from the fact that the FlyWire connectome spans the whole brain, whereas the hemibrain derives from a subvolume. Comparison of FlyWire and the hemibrain showed that cell type counts and strong connections were largely stable, but connection weights were surprisingly variable within and across animals. Further analysis defined simple heuristics for connectome interpretation: connections stronger than 10 unitary synapses or providing >1% of the input to a target cell are highly conserved. Some cell types showed increased variability across connectomes: the most common cell type in the mushroom body, required for learning and memory, is almost twice as numerous in FlyWire as the hemibrain. We find evidence for functional homeostasis through adjustments of the absolute amount of excitatory input while maintaining the excitation-inhibition ratio. Finally, and surprisingly, about one third of the cell types proposed in the hemibrain connectome could not yet be reliably identified in the FlyWire connectome. We therefore suggest that cell types should be defined to be robust to inter-individual variation, namely as groups of cells that are quantitatively more similar to cells in a different brain than to any other cell in the same brain. Joint analysis of the FlyWire and hemibrain connectomes demonstrates the viability and utility of this new definition. Our work defines a consensus cell type atlas for the fly brain and provides both an intellectual framework and open source toolchain for brain-scale comparative connectomics.

Fucus vesiculosus populations on artificial structures have potentially reduced fecundity and are dislodged at greater rates than on natural shores.

Artificial structures are widespread features of coastal marine environments. These structures, however, are poor surrogates of natural rocky shores, meaning they generally support depauperate assemblages with reduced population sizes. Little is known about sub-lethal effects of such structures, for example, in terms of demographic properties and reproductive potential that may affect the dynamics and long-term viability of populations. Such understanding is particularly important for ecosystem engineer species, such as the intertidal seaweed Fucus vesiculosus. In this study, F. vesiculosus was sampled on eight artificial structures and eight natural shores along the east coast of Ireland and the west coast of Wales. Algal percentage cover, biomass, density of individuals, and growth rate did not differ between artificial and natural shores. Growth and reproductive cycles were consistent with previous studies for this species. While there was considerable variation from site to site, on average, populations on natural shores produced a higher number of mature receptacles during the peak reproductive period in April, and lower rates of dislodgement than on artificial structures. As F. vesiculosus reach peak reproductive output after 24 months, this suggests that individuals may be removed from populations on artificial structures before reaching their full reproductive potential. In this case, this did not influence density, percentage cover, or biomass, which suggests that F. vesiculosus populations on artificial structures may function similarly to those on natural shores if supported by suitable source populations, but potentially may not persist otherwise.