Ephemeral Resources Research Articles

Spatial memory obviates following behaviour in an information centre of wild fruit bats.

According to the information centre hypothesis (ICH), colonial species use social information in roosts to locate ephemeral resources. Validating the ICH necessitates showing that uninformed individuals follow informed ones to the new resource. However, following behaviour may not be essential when individuals have a good memory of the resources' locations. For instance, Egyptian fruit bats forage on spatially predictable trees, but some bear fruit at unpredictable times. These circumstances suggest an alternative ICH pathway in which bats learn when fruits emerge from social cues in the roost but then use spatial memory to locate them without following conspecifics. Here, using an unique field manipulation and high-frequency tracking data, we test for this alternative pathway: we introduced bats smeared with the fruit odour of the unpredictably fruiting Ficus sycomorus trees to the roost, when they bore no fruits, and then tracked the movement of conspecifics exposed to the manipulated social cue. As predicted, bats visited the F. sycomorus trees with significantly higher probabilities than during routine foraging trips (of >200 bats). Our results show how the integration of spatial memory and social cues leads to efficient resource tracking and highlight the value of using large movement datasets and field experiments in behavioural ecology. This article is part of the theme issue 'The spatial-social interface: a theoretical and empirical integration'.

A statistical approach to assess interspecific consumptive competition and functional redundancy in ephemeral resource uses using camera traps.

Camera traps have been widely used in wildlife research, offering significant potential for monitoring species interactions at ephemeral resources. However, raw data obtained from camera traps often face limitations due to observation censoring, where resource consumption by dominant animals may obscure potential resource use by less dominant animals. We extended time-to-detection occupancy modeling to quantify interspecific consumptive competition and redundancy of ecosystem functions through consumption between two species, while accounting for observation censoring. By treating resource use by rival species as censored data, we estimated the proportion of resources potentially used in the absence of rival species and calculated the loss caused by the rival species, which is defined as "Competition Intensity Index." We also defined the Unique Functional Contribution, which represents the net functional loss when a species is removed, calculated by excluding the contribution potentially substituted by the other species. We also considered resource degradation and computed the quantity of resources acquired by each species. This established framework was applied to predation data on bird nests by alien squirrels and other predators (Case 1) as well as scavenging on mammalian carcasses by two carnivores (Case 2). In Case 1, the introduction of squirrels significantly affected the breeding success of birds. Although nests were being preyed upon by native crows also, our model estimated that Unique Functional Contribution by the squirrels was 0.47. This means that, by eradicating the squirrels, the reproductive success of the birds could potentially increase by as much as 47%. In Case 2, the Competition Intensity Index for foxes was 0.17, whereas that for raccoon dogs was 0.46, suggesting an asymmetric effect of resource competition between the two species. The frequency distribution of wet mass available to the two species differed significantly. This approach will enable a more robust construction of resource-consumer interaction networks.

Lion lords and sharing hyaenas: Carnivore guild dynamics around elephant carcasses.

Megaherbivore carcasses represent sporadic but energetically rewarding resources for carnivores, offering a unique opportunity to study coexistence dynamics between facultative scavengers. South African fenced protected areas, such as Madikwe Game Reserve (Madikwe hereafter), host viable populations of large carnivores and high densities of elephants, Loxodonta africana. However, high carnivore densities can lead to potentially fatal interspecific encounters and increased competition, particularly around high-quality trophic resources. This study explores the temporal partitioning and co-detection strategies of carnivores at six elephant carcasses in Madikwe, aiming to understand how the increased carrion biomass available at elephant carcasses influences coexistence dynamics. Camera traps were deployed to monitor carcasses during two periods (2019 and 2020), revealing occurrences of six carnivore species. Carnivores, particularly black-backed jackals, Lupulella mesomelas, (hereafter jackal), lions, Panthera leo, and spotted hyaenas, Crocuta crocuta, comprised 56.7% of carcass observations, highlighting their pivotal roles in scavenging dynamics. Pairwise co-detection analysis demonstrated consistent association and shared peak activity periods between jackals and spotted hyaenas, indicating potential resource sharing. However, the minimal co-detection rates between lions and other carnivores highlight their resource domination. There was some evidence of temporal partitioning between carnivores, with most species exhibiting earlier peaks in nocturnal activity to avoid temporal overlap with lions. This study emphasises the importance of elephant carcasses in the diet of multiple species and coexistence techniques utilised to exploit this ephemeral resource. As fenced protected areas become crucial for conserving intact carnivore guilds globally, further research into carnivore behavioural adaptations at carcasses is recommended to shed light on their coexistence strategies.

Remote cameras capture dung burial by burrowing cricket

Animal dung holds an important role in the nutrient cycle of nearly every ecosystem on Earth. It also acts as an ephemeral resource for invertebrate communities and has facilitated the specialization of many life history strategies. Most ecosystem functions associated with dung are linked to burial - a process most often attributed to dung beetles. However, identifying other organisms that contribute to dung burial is important to understand how communities provide this ecosystem service. During a trail camera experiment intended to monitor dung beetle behavior, we observed an unidentified species of cricket burying dung pellets underground. We were unable to find previous documentation of dung-burying behavior for this animal group, raising questions of how common or extensive this behavior is. Particularly under the threat of global insect declines, understanding which species are responsible for key processes may be crucial to maintaining ecosystem function and resilience. Additionally, this experiment exemplifies how camera traps can be used in nontraditional applications to observe and monitor unique events, behaviors, and processes, such as the decay of ephemeral resource patches and insect behavior.

Coursing the mottled mosaic: Generalist predators track pulses in availability of neonatal ungulates.

The density and distribution of resources shape animal movement and behavior and have direct implications for population dynamics. Resource availability often is "pulsed" in space and time, and individuals should cue in on resource pulses when the energetic gain of doing so exceeds that of stable resources. Birth pulses of prey represent a profitable but ephemeral resource and should thereby result in shifting functional responses by predators. We evaluated movements and resource selection of coyotes (Canis latrans) across a gradient of reproductive stages ranging from late gestation to peak lactation of female mule deer (Odocoileus hemionus) in southwest Wyoming, USA, to test whether coyotes exhibited shifts in selection and movement behavior relative to the availability and vulnerability of neonatal mule deer. We expected coyotes to track pulses in availability of neonatal mule deer, and such behavior would be represented by shifts in resource selection and search behavior of coyotes that would be strongest during peak parturition of mule deer. Coyotes selected areas of high relative probability of use by female mule deer and did so most strongly during peak parturition. Furthermore, searching behavior of coyotes intensified during pulses of availability of deer neonates. Our findings support the notion that coyotes exploit pulses of neonatal deer, presumably as an attempt to capitalize on a vulnerable, energy-rich resource. Our work quantifies the behavioral mechanisms by which coyotes consume ungulate neonates and provides one of the first examples of a mammalian predator-prey system centered on a pulsed resource.

Sarcosaprophagous dipterans associated with differentially-decomposed substrates in Atlantic Forest environments

Sarcosaprophagous flies may show temporal variations in terms of their location and colonization in ephemeral resources, in addition to their richness and abundance changing according to the substrate age. The present study examined the influence of decomposition time on the: (i) composition of the sarcosaprophagous dipterofauna; (ii) sexual proportion of the collected specimens; and (iii) the stage of sexual maturity of female flies (Calliphoridae and Sarcophagidae). For this, we used chicken liver with different decomposition times (0h, 24h, 48h, and 76h) for the collection of adult flies. The results showed that: i) the assemblages were most diverse and abundant in more decomposed baits; ii) Calliphoridae was the most abundant taxa in all treatments; iii) the reproductive stage varied according to the age of the substrate, with high rates of mature or pregnant females in the older substrates; and iv) the number of males blowflies was higher in older baits, but it did not vary for flesh flies. Thus, this work demonstrates experimentally that the substrate age is an influencing factor in the composition of sarcosaprophagous flies’ assemblage, and it indication of the dipterans potential as primary or secondary colonizers throughout colonization of ephemeral resources.

Rapid but narrow - Evolutionary adaptation and transcriptional response of Drosophila melanogaster to toxic mould.

Insects have adapted to a multitude of environmental conditions, including the presence of xenobiotic noxious substances. Environmental microorganisms, particularly rich on ephemeral resources, employ these noxious chemicals in a chemical warfare against predators and competitors, driving co-evolutionary adaptations. In order to analyse how environmental microbes may be driving such evolutionary adaptations, we experimentally evolved Drosophila melanogaster populations by exposing larvae to the toxin-producing mould Aspergillus nidulans that infests the flies' breeding substrate. To disentangle the effects of the mycotoxin Sterigmatocystin from other substrate modifications inflicted by the mould, we used the following four selection regimes: (i) control without fungus, (ii) A. nidulans wild type, (iii) a mutant of A. nidulans ΔlaeA with impaired toxin production, (iv) synthetic Sterigmatocystin. Experimental evolution was carried out in five independent D. melanogaster populations each, for a total of 11 generations. We further combined our evolution experiment with transcriptome analysis to identify evolutionary shifts in gene expression due to the selection regimes and mould confrontation. Populations that evolved in presence of the toxin-producing mould or the pure mycotoxin rapidly adapted to the respective conditions and showed higher viability in subsequent confrontations. Yet, mycotoxin-selected populations had no advantage in A. nidulans wild type confrontation. Moreover, distinctive changes in gene expression related to the selection-regime contrast were only associated with the toxin-producing-fungus regime and comprised a narrow set of genes. Thus, it needs the specific conditions of the selection agent to enable adaptation to the fungus.

Differential colonization of ephemeral resources by sarcosaprophagous Diptera in the Brazilian Caatinga and its implications for forensic entomology in arid environments

Surveys of forensically important insects usually rely on sampling adults on baits – which may not represent the colonizing assemblage on a carcass or cadaver. We investigated the diversity of dipterans (Calliphoridae, Sarcophagidae, Muscidae, Fanniidae) in the Brazilian dry forest, an area exposed to high rates of homicide, under an integrated approach of ecology and forensic entomology. Specifically, we compared the species’ ability to colonize different substrates, related to their potential as early carrion colonizers. We used suspended traps baited with fish, feces and bovine spleen to collect adults (visitors) and eggs/larvae on baits (colonizers) and reared immatures in the laboratory until the emergence of adults. Over 30,000 adult flies belonging to at least 30 species were collected on baits, but only 10 species successfully colonized the substrates. Our data corroborate the high diversity of species in the area, especially those with previous record as cadaver colonizers – such as Chrysomya albiceps, Synthesiomyia nudiseta and Tricharaea (Sarcophagula) occidua. Minimum developmental time of the species varied from 9 to 23 days post bait colonization in the field. Blaesoxipha (Gigantotheca) stallengi (Sarcophagidae) was the most efficient colonizer of ephemeral resources in dry forests, and we discuss its potential in forensic entomology.

Forest conversion into pasture selects dung beetle traits at different biological scales depending on species pool composition.

The conversion of forests into open areas has large effects on the diversity and structure of native communities. The intensity of these effects may vary between regions, depending on the existence of native species adapted to open habitats in the regional pool or the time since habitat change.We assess the differences in species richness and functional diversity of dung beetle communities (Coleoptera: Scarabaeinae) between native forests and novel pasturelands of the Atlantic Forest and the Cerrado, two biomes with contrasting histories of human occupation in Brazil. We conducted standardized surveys in seven forest fragments and adjacent pastures in each region and measured 14 traits in individuals collected in each type of habitat at each particular site. We calculated functional richness, functional evenness, functional divergence, and community-weighted mean of traits for each area, and analyzed individual variation through nested variance decomposition and Trait Statistics.Communities were richer and more numerous at the Cerrado. We did not find any consistent relationship between functional diversity and forest conversion beyond the changes in species diversity. Although landscape changes were more recent at the Cerrado, the colonization of the new habitat by native species already adapted to open habitats lessens the functional loss in this biome. This indicates that habitat change's effects on trait diversity depend on the regional species pool rather than on time since land conversion.Forest conversion effects were primarily due to internal filtering. The effects of external filtering only appear at the intraspecific variance level, with contrasting differences between the Cerrado, where traits related to relocation behavior and size are selected, and the Atlantic Forest, where selection operates for traits related to relocation behavior and flight. These results evidence the importance of considering individual variance to address the responses of dung beetle communities to forest conversion.

The ephemeral resource patch concept.

Ephemeral resource patches (ERPs) - short lived resources including dung, carrion, temporary pools, rotting vegetation, decaying wood, and fungi - are found throughout every ecosystem. Their short-lived dynamics greatly enhance ecosystem heterogeneity and have shaped the evolutionary trajectories of a wide range of organisms - from bacteria to insects and amphibians. Despite this, there has been no attempt to distinguish ERPs clearly from other resource types, to identify their shared spatiotemporal characteristics, or to articulate their broad ecological and evolutionary influences on biotic communities. Here, we define ERPs as any distinct consumable resources which (i) are homogeneous (genetically, chemically, or structurally) relative to the surrounding matrix, (ii) host a discrete multitrophic community consisting of species that cannot replicate solely in any of the surrounding matrix, and (iii) cannot maintain a balance between depletion and renewal, which in turn, prevents multiple generations of consumers/users or reaching a community equilibrium. We outline the wide range of ERPs that fit these criteria, propose 12 spatiotemporal characteristics along which ERPs can vary, and synthesise a large body of literature that relates ERP dynamics to ecological and evolutionary theory. We draw this knowledge together and present a new unifying conceptual framework that incorporates how ERPs have shaped the adaptive trajectories of organisms, the structure of ecosystems, and how they can be integrated into biodiversity management and conservation. Future research should focus on how inter- and intra-resource variation occurs in nature - with a particular focus on resource×environment×genotype interactions. This will likely reveal novel adaptive strategies, aid the development of new eco-evolutionary theory, and greatly improve our understanding of the form and function of organisms and ecosystems.

Accessing the ephemeral using multiscale 3D microscopy of bone microwear

Ancient people used perishable resources much as people do today. Such materials do not preserve well in the archaeological record, and so there are types of items that would have been made from animal skins or vegetal matter like clothing, footwear, and containers that are not present in many assemblages. Direct evidence for such items is often lacking, but indirect evidence in the form of microwear traces can be found on more durable materials, such as bone tools, that interacted with these less permanent items prior to deposition. In this study, 3D microscopic methods are applied to quantitatively evaluate traces from three perishable materials (semi-fresh animal skin, processed split leather, and dry bark) on experimental bone tools. Bones were scanned on two objectives (20x and 100x) with a confocal disc-scanning microscope and evaluated using 3D surface texture parameters. Quantitative measurements of the bone surfaces varied at the different scales, but material wear patterns were evident and indicative of the differences in properties of the three materials. This study indicates that the use of 3D microscopic methods on bone tools at multiple scales is useful for understanding how contact with perishable materials affects bone surfaces. This method has the potential to indirectly evaluate ephemeral resources that once came into contact with ancient bone artifacts and reconstruct some of the less tangible aspects of ancient human behavior.

Insectivorous bats form mobile sensory networks to optimize prey localization: The case of the common noctule bat

Animals that depend on ephemeral, patchily distributed prey often use public information to locate resource patches. The use of public information can lead to the aggregation of foragers at prey patches, a mechanism known as local enhancement. However, when ephemeral resources are distributed over large areas, foragers may also need to increase search efficiency, and thus apply social strategies when sampling the landscape. While sensory networks of visually oriented animals have already been confirmed, we lack an understanding of how acoustic eavesdropping adds to the formation of sensory networks. Here we radio-tracked a total of 81 aerial-hawking bats at very high spatiotemporal resolution during five sessions over 3 y, recording up to 19 individuals simultaneously. Analyses of interactive flight behavior provide conclusive evidence that bats form temporary mobile sensory networks by adjusting their movements to neighboring conspecifics while probing the airspace for prey. Complementary agent-based simulations confirmed that the observed movement patterns can lead to the formation of mobile sensory networks, and that bats located prey faster when networking than when relying only on local enhancement or searching solitarily. However, the benefit of networking diminished with decreasing group size. The combination of empirical analyses and simulations elucidates how animal groups use acoustic information to efficiently locate unpredictable and ephemeral food patches. Our results highlight that declining local populations of social foragers may thus suffer from Allee effects that increase the risk of collapses under global change scenarios, like insect decline and habitat degradation.

Short- and long-term modulation of forager motivation by colony state in bumble bees

The question of how animals make decisions has been intensely studied by ethologists, behavioural ecologists, psychologists and neuroscientists alike. Foraging bumble bees are an excellent system to study decision making because, as eusocial insects, foragers are solely focused on the task of collecting food for the colony. Bumble bees are generalist foragers of ephemeral resources that do not store food long term and are thus expected to show flexible adjustments in foraging motivation in response to stored food. However, their feeding behaviour at resources as a function of stored food has not been explored. Here, we present results demonstrating that bumble bees ( Bombus impatiens ) show flexible adjustments in foraging motivation in response to colony food stores across different timescales. First, bumble bees showed decreased foraging motivation as the colony accumulated food over the course of a day. Second, bees that developed in colonies with full food stores showed persistently lower motivation than bees developing in colonies with impoverished food stores even days after those food stores were removed. We further demonstrate that this persistent low motivation may be explained by the lower amount of abdominal lipids in nutrient-depleted colonies. Our results provide evidence for a mechanism that may mediate the social control of individual foraging motivation, an important step in the evolution of eusociality. • We examined bumble bee feeding behaviour at resources as a function of stored food. • We tested bees from provisioned and unprovisioned colonies. • Bees showed flexible foraging based on colony food stores across timescales. • Bees from provisioned colonies showed lower foraging motivation. • This low foraging motivation may be explained by lower abdominal lipid levels.

Mayflies as resource pulses in Jurassic lacustrine ecosystems

Abstract Resource pulses, occasional events of ephemeral resource superabundance, represent a fundamental mechanism by which energy, nutrients, and biomass are transported across ecotones. They are widespread in extant ecosystems; however, little is known about their deep-time record. We report the earliest-known mayfly swarm from the Early Jurassic Xiwan biota of southern China. Our taphonomic and sedimentological analyses show that these mayflies were buried on the bottom of a calm lake after post-mating death. Our suite of analyses suggests that the complex mating-swarm behavior was already well established in mayflies by the Early Jurassic. More importantly, our find represents the earliest-known resource pulse of insects, a mechanism that can play a substantial role in nutrient transport from aquatic ecosystems to surrounding terrestrial ecosystems. Such an aquatic-terrestrial ecosystem linkage may be a key novelty in Mesozoic lacustrine ecosystems. Our results high-light the underappreciated ecological significance of insects in deep-time terrestrial ecology.

Priority effects and density promote coexistence between the facultative predator Chrysomya rufifacies and its competitor Calliphora stygia

Highly competitive ephemeral resources like carrion tend to support much greater diversity relative to longer-lived resources. The coexistence of diverse communities on short-lived carrion is a delicate balance, maintained by several processes including competition. Despite this balance, few studies have investigated the effect of competition on carrion, limiting our understanding of how competition drives coexistence. We investigated how priority effects and larval density influence coexistence between two blowfly species, the facultative predator Chrysomya rufifacies and its competitor Calliphora stygia, which occupy broadly similar niches but differ in their ecological strategies for exploiting carrion. We examined how adult oviposition, larval survival, developmental duration, and adult fitness were affected by the presence of differently aged heterospecific larval masses, and how these measures varied under three larval densities. We found C. rufifacies larval survival was lowest in conspecific masses with low larval densities. In heterospecific masses, survival increased, particularly at high larval density, with priority effects having minimal effect, suggesting a dependency on collective exodigestion. For C. stygia, we found survival to be constant across larval densities in a conspecific mass. In heterospecific masses, survival decreased drastically when C. rufifacies arrived first, regardless of larval density, suggesting C. stygia is temporally constrained to avoid competition with C. rufifacies. Neither species appeared to completely outcompete the other, as they were either constrained by density requirements (C. rufifacies) or priority effects (C. stygia). Our results provide new mechanistic insights into the ecological processes allowing for coexistence on a competitively intense, ephemeral resource such as carrion.

Evaluating the Existence of Vertebrate Deadfall Communities from the Early Jurassic Posidonienschiefer Formation

Large vertebrate carcasses contain significant amounts of nutrients that upon death are transferred from the water column to the benthos, enriching the immediate environment. The organisms exploiting these ephemeral resources vary as the carcass decays, creating an ecological succession: mobile scavengers arrive first, followed by enrichment opportunists, sulfophilic taxa, and lastly reef species encrusting the exposed bones. Such communities have been postulated to subsist on the carcasses of Mesozoic marine vertebrates, but are rarely documented in the Jurassic. In particular, these communities are virtually unknown from the Early Jurassic, despite the occurrence of several productive fossil Lagerstätte that have produced thousands of vertebrate bones and skeletons. We review published occurrences and present new findings related to the development of deadfall communities in the Toarcian Posidonienschiefer Formation of southwestern Germany, focusing on the classic locality of Holzmaden. We report the presence of the mobile scavenger, enrichment opportunist, and reef stages, and found potential evidence for the poorly documented sulfophilic stage. Although rare in the Posidonienschiefer Formation, such communities do occur in association with exceptionally preserved vertebrate specimens, complementing a growing body of evidence that a temporarily oxygenated benthic environment does not preclude exceptional vertebrate fossil preservation.

Diet quality and conspecific larval density predict functional trait variation and performance in a polyphagous frugivorous fly

AbstractDiet quality and the presence and abundance of conspecifics feeding on the same food resource are critical factors that affect functional traits of many animal species and influence ecological processes.We hypothesized that in insects whose larvae live in groups of varying sizes in ephemeral and nutritionally variable environments, extreme macronutrient content in the feeding substrate is a barrier for optimal performance that can be overcome by the collective feeding behaviour of large numbers of larvae.We experimentally examined how multiple immature and adult traits of the polyphagous tephritid fruit fly,Anastrepha ludens, vary as a function of the quality of its larval diet (protein + carbohydrate [P + C] content of 8.0%–12.6% w/w, and protein‐to‐carbohydrate [P/C] ratio of 1.8–0.11) across extreme levels of conspecific larval densities (60–600 larvae/60 g of diet).Overall, we found positive effects on survival of immature and adult stages, the duration of the larval stage, pupal weight and adult emergence of flies, as dietary P + C content increased, followed by negative effects when the diet had extremely high carbohydrate‐biased macronutrient content. Larval density had positive, negative and curvilinear effects depending on the macronutrient composition of the food, resulting in a range of fly responses through a continuous scale of macronutrient content and larval density combinations. Optimal performance ofA.ludens, in terms of larval development time, body weight and survival to adulthood, was found when the diet consisted of low P + C content and high P/C ratios, and low larval densities.Our findings point to a diet‐mediated relationship between density and survival to the adult stage, suggesting that large numbers (up to a point) of larvae can balance negative effects of conspecific competition when food is characterised by high macronutrient content and low P/C ratios. We conclude that diet quality and conspecific density interact in complex ways to shape trait expression and performance in a frugivorous fly. Addressing this interaction is key to advance the understanding of the mechanisms behind changes in population dynamics in insect species living in groups confined in isolated and ephemeral resources.Read the freePlain Language Summaryfor this article on the Journal blog.

Ant body size mediates functional performance and species interactions in carrion decomposer communities

Abstract Growing concern over rapid species declines and extinctions has led to considerable interest in the role of biodiversity for maintaining ecological processes. However, the loss of particular species has more pronounced effects on ecosystem services than others, highlighting the importance of key functional species traits and their relationships to ecosystem functioning. Human‐induced disturbances, such as species invasions, land use changes, or abiotic changes, appear to disproportionally impact larger species rather than smaller ones. The loss of large‐bodied species in the community diminishes key ecosystem services like seed dispersal, pest control, pollination and decomposition. Here, we use carrion, a nutrient‐rich ephemeral resource, to test the hypotheses that ants positively affect decomposition rates and that their role in the necrophilous community—as predator or decomposer—is mediated by body size. We further investigate the relative contribution of maggots versus ants to biomass decomposition. Our results show that ants contributed positively to the decomposition process. Moreover, decomposition was shaped by an intricate interplay between competition and predation among the guild of decomposer insects. As predicted, larger ants show a double action in increasing decomposition rate and predating on maggots, while small ants are rather inefficient decomposers and did not act as predators on other decomposer species. Our study shows that differentiating key taxonomic groups in function of their body size is key to untangle the diversity and directions of the various roles they play within complex ecological processes. Read the free Plain Language Summary for this article on the Journal blog.

Size variation, allometry and mating success in Aotearoa|New Zealand kelp flies (Coelopidae)

The need to respond quickly to the presence of an ephemeral resource required for breeding is often a feature of scramble competition mating systems. Scramble competition mating systems can feature extreme levels of sexual conflict and coercive mating by males. As a result, sexual selection can act on various traits used by males to overcome female resistance behaviours. Selection on these traits may result in significant intra and intersexual size variation and sexual dimorphism. Additionally, traits that influence mating success in males often show positive static allometry. Kelp flies (Coelopidae) are a small family of Diptera which specialise on wrack (beach cast marine macroalgae), a highly ephemeral resource. The mating system of these flies involves high levels of sexual conflict, with females rejecting all male mating attempts. In this study we describe intra and intersexual size variation and static allometry of traits in two of Aotearoa|New Zealand’s species, Coelopella curvipes and Chaetocoelopa littoralis. In addition, we investigate the mating behaviour of C. littoralis under ecologically relevant mating conditions. We found high levels of variation in both species with significant evidence of sexual dimorphism across all traits measured in C. littoralis, and in mid tibia length in C. curvipes. Furthermore, mid tibia length in both species exhibits positive static allometry and is disproportionally larger in larger males, suggesting that this trait in particular may be under strong sexual selection. We found that larger male C. littoralis which attempt to mate are significantly more likely to mate successfully demonstrating a large-size advantage in this species similar to findings across the Coelopidae. However, we only found a non-significant trend towards a mating advantage for males with longer mid-tibiae. We discuss these findings with reference to the population dynamics and ecology of these species.

Directed endozoochorous dispersal by scavengers facilitate sexual reproduction in otherwise clonal plants at cadaver sites.

The regeneration niche of many plant species involves spatially and temporally unpredictable disturbances, called recruitment windows of opportunity. However, even species with clear dispersal adaptations such as fleshy berries may not successfully reach such elusive regeneration microsites. Ericaceous, berry‐producing species in the northern hemisphere demonstrate this dispersal limitation. They are said to display a reproductive paradox owing to their lack of regeneration in apparently suitable microsites despite considerable investment in producing large quantities of berries.Cadavers generate vegetation‐denuded and nutrient‐rich disturbances termed cadaver decomposition islands (CDIs). Cadavers attract facultative scavengers with considerable capacity for endozoochorous seed dispersal. We hypothesize that CDIs facilitate recruitment in berry‐producing ericaceous species due to endozoochorous dispersal directed toward favorable microsites with low competition.We examined seedling establishment within a permanent, semi‐regular 10 × 10 m grid across an ungulate mass die‐off on the Hardangervidda plateau in southeastern Norway. Competing models regarding the relative importance of factors governing recruitment were evaluated, specifically cadaver location (elevated seed rain) and microsite conditions (competition).We found that CDIs did facilitate seedling establishment, as cadaver density was the best predictor of seedling distribution. Other important factors governing seedling establishment such as percentage cover of soil and vascular plants alone were inadequate to explain seedling establishment. Synthesis: This study provides a novel understanding of sexual reproduction in species with cryptic generative reproduction. The directed nature of endozoochorous dispersal combined with long‐distance dispersal abilities of medium to large vertebrate scavengers toward cadavers allows plants to exploit the advantageous but ephemeral resource provided by CDIs.