Temporal Dispersal Research Articles

An experimental study to assess resistance and resilience strategies of freshwater diatoms to cope with drying in Mediterranean temporary rivers

Temporary rivers are aquatic ecosystems that alternate periods of water flow with dry periods. Diatoms are a group of unicellular microalgae with a high colonizing ability, but little is known about their responses to drying. We carried out different resistance and resilience experiments to evaluate temporal and spatial dispersal capacity of diatoms during the dry period. The resistance was tested experimentally by rehydrating dried biofilms and sediments from temporary rivers, whereas resilience was tested by installing artificial mesocosms along a dry river section. Disconnected pools were also sampled to evaluate their propagule emission capacity. In turn, dogs from the area were sampled to test potential zoochory dispersal capacity. In the resistance experiment, we found living diatoms in all the rehydrated sediments but not in biofilms. Diatoms with mobility traits, high ecological plasticity, and resistance spores presented high, along with typical soil diatoms. In the resilience experiment, all mesocosms hosted living diatoms, which were low-profile, pioneering, and small species. Diatoms found in the mesocosms were also common in the disconnected pools, underscoring the potential role of the latter as a propagule emission zone. Dogs' paws also had living diatoms, which evidences that wild fauna could potentially act as passive diatom vectors.

Temporal Dynamics and Dispersal Patterns of the Primary Inoculum of Coniella diplodiella, the Causal Agent of Grape White Rot.

Grape white rot can cause considerable yield losses in viticulture areas worldwide and is principally caused by Coniella diplodiella. The fungus overwinters in berry mummies on the soil surface or on the trellis and produces pycnidia and conidia that serve as primary inoculum. However, little is known about the temporal dynamics and dispersal pattern of C. diplodiella conidia. In this study, we investigated the production and dispersal of C. diplodiella conidia from a primary inoculum source, namely, affected mummified berries that overwintered in two vineyards in northern Italy in 2021 and 2022. Conidia of C. diplodiella were repeatedly produced in berry mummies from the budburst of vines to harvesting, with approximately 50 and 75% of the total conidia in a season being produced before fruit set and véraison, respectively. The production dynamics of C. diplodiella conidia over time were described by a Weibull equation in which the thermal time is the independent variable, with a concordance correlation coefficient of ≥0.964. A rainfall cutoff of ≥0.2 mm provided an overall accuracy of ≥0.86 in predicting conidial dispersal through rain splashes from berry mummies on the soil surface, with the number of dispersed conidia increasing with the amount of rainfall. The dispersal of conidia from mummies on the trellis by washing with rain required at least 6.1 mm of rain. The proposed mathematical equations and rain cutoffs can be used to predict periods with a high dispersal risk of C. diplodiella.

Host and parasite identity interact in scale-dependent fashion to determine parasite community structure.

Understanding the ecological assembly of parasite communities is critical to characterise how changing host and environmental landscapes will alter infection dynamics and outcomes. However, studies frequently assume that (a) closely related parasite species or those with identical life-history strategies are functionally equivalent, and (b) the same factors will drive infection dynamics for a single parasite across multiple host species, oversimplifying community assembly patterns. Here, we challenge these two assumptions using a naturally occurring host-parasite system, with the mussel Anodonta anatina infected by the digenean trematode Echinoparyphium recurvatum, and the snail Viviparus viviparus infected by both E. recurvatum and Echinostoma sp. By analysing the impact of temporal parasite dispersal, host species and size, and the impact of coinfection (moving from broader environmental factors to within-host dynamics), we show that neither assumption holds true, but at different ecological scales. The assumption that closely related parasites can be functionally grouped is challenged when considering dispersal to the host (i.e. larger scales), while the assumption that the same factors will drive infection dynamics for a single parasite across multiple host species is challenged when considering within-host interspecific competition (i.e. smaller scales). Our results demonstrate that host identity, parasite identity and ecological scale require simultaneous consideration in studies of parasite community composition and transmission.

First ultrastructural description of an apomictic opsiblastic egg in freshwater Gastrotricha.

Freshwater gastrotrichs have a biphasic lifecycle that reputedly involves the production of three types of eggs: apomictic and fast hatching (tachyblastic ova), apomictic and delayed hatching (opsiblastic ova), and plaque-bearing eggs (potentially derived from mixis). While some details of oogenesis and eggshell structure are known for tachyblastic ova, there are few details on other egg types. Here, we provide the first ultrastructural description of the oviposited opsiblastic eggs of the freshwater gastrotrich, Lepidodermella squamata. Scanning electron microscopy revealed the eggshell surface to be ornamented with long flattened pillar-like structures centered on polygonal plates that are pitted along their periphery. Transmission electron microscopy showed the pits to lead to a vast labyrinth of tubular spaces and larger cavities throughout the thick apical layer of the shell. The basal layer of the shell is amorphous and connected to a network of fine fibers that traverse an extra-oocyte space and forms a protective sheet around the uncleaved oocyte. The uncleaved oocyte has a dense layer of peripheral ooplasm surrounding a core of organelles including mitochondria, membrane-bound secretion granules, endoplasmic reticulum, and a single nucleus in a granular, ribosome-rich cytoplasm. Secretion granules are the most abundant organelles and presumably contain lipid-rich yolk that will be used as energy for delayed cleavage, thus functioning in temporal dispersal. These data are compared to the fine structure of invertebrate resting eggs across the phylogenetic spectrum to determine the novelty of opsiblastic egg structure in L. squamata.

Monitoring Spore Dispersal and Early Infections of Diplocarpon coronariae Causing Apple Blotch Using Spore Traps and a New qPCR Method.

Apple blotch (AB) is a major disease of apple in Asia and recently emerged in Europe and the United States. It is caused by the fungus Diplocarpon coronariae (formerly Marssonina coronaria; teleomorph: Diplocarpon mali) and leads to severe defoliation of apple trees in late summer, resulting in reduced yield and fruit quality. To develop effective disease management strategies, a sound knowledge of the pathogen's biology is crucial. Data on the early phase of disease development are scarce: No data on spore dispersal in Europe are available. We developed a highly sensitive TaqMan qPCR method to quantify D. coronariae conidia in spore trap samples. We monitored temporal and spatial dispersal of conidia of D. coronariae and the progress of AB in spring and early summer in an extensively managed apple orchard in Switzerland in 2019 and 2020. Our results show that D. coronariae overwinters in leaf litter, and spore dispersal and primary infections occur in late April and early May. We provide the first results describing early-season dispersal ofconidia of D. coronariae, which, combined with the observed disease progress, helps to understand the disease dynamics and will be a basis for improved disease forecast models. Using the new qPCR method, we detected D. coronariae in buds, on bark, and on fruit mummies, suggesting that several apple tissues might serve as overwintering habitats for the fungus, in addition to fallen leaves. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

IMPACTS OF PHYSICO-CHEMICAL PARAMETERS ON COPEPOD’S HYDRODYNAMICS AT JALLO LAKE, LAHORE, PUNJAB, PAKISTAN

The Temporal and Spatial dispersal of copepods were studied from October 2012 to August 2013 at Jallo lake wildlife park, Lahore. Water samples were collected in the last week of every month. A total of ten species belonging to seven orders, including nauplius larvae, were identified. The physicochemical parameters were observed, i.e., water and air temperature, oxygen saturation, pH, transparency, dissolved oxygen and conductivity. ANOVA was applied to all the physicochemical parameters. It and was found to be highly significant for all parameters (P= 0.000, α = 0.05) except for the transparency. Copepod diversity and density was at its peak in June. Pearson correlation was applied between the physicochemical parameters and copepods. Air temperature (0.835), water temperature (0.729), and conductivity (0.840) were positively correlated, whereas dissolved oxygen (-0.759), oxygen saturation (-0.725), transparency (-0.401), and pH (-0.471) were negatively correlated. The quantity of the Shannon Weaver index and Simpson index was studied and calculated every month, showing fluctuations during the study period.

The influence of landscape structure on the dispersal pattern of yellow fever virus in the state of São Paulo

Man-made changes to the landscape play a crucial role in altering the epidemiologic patterns of infectious diseases, mainly as a result of pathogen spillover. Sylvatic yellow fever is ideally suited to modeling of this phenomenon as the risk of transmission of the disease as well as its circulation and dispersal are associated with forest fragmentation. In this study we investigated the temporal dispersal pattern of yellow fever virus (YFV) by means of confirmed cases of epizootics in non-human primates in municipalities in the state of São Paulo where there was no recommendation for vaccination in 2017. We analyzed the resistance to dispersal associated with different classes of land use and the geographic distances between the different locations where epizootics were recorded. The model that best explained the temporal dispersal pattern of YFV in the study area indicated that this was influenced by the geographic distance between collection locations and by the permeability of the forest edges (150 m) at the interface with the following core areas: Water, Agricultural, Non-Forest Formation and Forestry. Water, Agricultural, Urban and Forest core areas and the interfaces between the latter two formed important barriers to circulation of the virus. These findings indicate that fragmentation of vegetation tends to decrease the time taken for pathogens to spread, while conservation of forest areas has the opposite effect.

How to assess the temporal dynamics of landscape connectivity in ever-changing landscapes: a literature review

Landscape connectivity plays a key role in determining the persistence of species inhabiting fragmented habitat patches. In dynamic landscapes, most studies measure connectivity at multiple time steps, but pay less attention to explicitly quantifying its temporal dynamics to gain insights into its role in biodiversity patterns, thereby enabling more effective operational outcomes. This article aimed at making an overview of the existing methods for the assessment of the temporal dynamics of connectivity. By analysing their differences and possible applications, we aimed to highlight knowledge gap and future research directions. We conducted a systematic review of literature dealing with the assessment of the temporal dynamics of connectivity and obtained 32 studies. We presented two main approaches based on graph theory and compared them from conceptual and operational perspectives. The first widely used approach, accounting only for the spatial dispersal of organisms, quantifies temporal changes in spatial connectivity. Based on two or multiple time steps in the time series, this approach enables assessment of the sense and magnitude of the temporal changes in spatial connectivity. The second recently developed approach quantifies spatio-temporal connectivity, thus accounting for both spatial and temporal dispersal. So far, this holistic assessment of spatio-temporal connectivity only covers two time steps. Existing methods for the assessment of the temporal dynamics of connectivity provide indicators to advance our understanding of biodiversity patterns, and to be able to implement measures to conserve and restore connectivity. We propose future directions to develop these methods.

Differences in seed dormancy and germination in amphicarpic legumes: manifold bet-hedging in space and time

Abstract Aims Dispersal through space or time via dormancy is one of the primary processes whereby organisms can influence the environment they experience. In plants, strong evolutionary correlations are expected between the two kinds of dispersal because both are performed by the seeds and play comparable adaptive roles. In this paper, we investigated these evolutionary correlations using amphicarpic plants, which simultaneously produce aerial seeds with high spatial dispersal propensity and subterranean seeds that do not disperse. Methods We investigated the variation in dormancy and germination in aerial and subterranean seeds of two amphicarpic legumes (Vicia amphicarpa L. and Lathyrus amphicarpos L.) and two closely related homocarpic taxa (Vicia sativa L. and Lathyrus cicera L.) by estimating germination percentages following different combinations of dormancy breaking treatments (i.e. dry after-ripening, cold stratification and physical scarification). Important Findings Our results showed complex interactions between spatial and temporal dispersal. Right after dispersal, aerial seeds were more dormant than their subterranean counterparts, but this trend reversed with after-ripening, as seeds developed physical dormancy. Seeds of homocarpic plants germinated at higher percentages than those of their amphicarpic congeners and lost dormancy homogeneously with after-ripening. Conversely, amphicarpic seeds exhibited varied dormancy strategies modulated by both physiological and physical dormancy. These are expected to increase variation in emergence timing, providing multiple levels of diversifying bet-hedging. This strategy might be adaptive under highly unpredictable conditions by enabling plants to rely on historically favorable sites in good seasons without preventing spatial and temporal migration.

New optical soliton solutions for Fokas–Lenells dynamical equation via two various methods

In this paper, we examine the Fokas–Lenells equation (FLE) that depicts the promulgation of ultra-short pulsation in visual fibers while confirming the terms of the following asymptotic arrangement beyond those indispensable for the nonlinear Schrödinger equation. In addition the model includes both spatio–temporal dispersal and self-steepening terms. Then, we discuss deep visual solutions of the FLE via taking the modified Kudryashov method and the extended tanh expansion method.

Dormancy and germination of the trimorphic achenes of a cold desert annual: spreading the risk over time.

Many studies have been done on the relationship between variation in morphology, dispersal ability and degree of dormancy of heterocarpic species with dimorphic diaspores. However, there are far fewer such studies on species that produce trimorphic diaspores. Our aim was to compare dormancy and germination of achenes from peripheral, intermediate and central positions in the capitulum of the diaspore-trimorphic cold desert annual Asteraceae species Heteracia szovitsii, an important component of plant communities in the cold deserts of NW China. Dormancy breaking/germination responses of the three achene morphs and of seeds isolated from the pericarp were tested in the laboratory using standard procedures, and seedling emergence phenology of the achene morphs was monitored under natural cold desert temperature conditions in an experimental garden with and without supplemental watering. Depth of dormancy of the three achene morphs was peripheral > intermediate > central. Seedlings from the three morphs emerged in spring and in autumn. Cumulative seedling emergence percentage from achenes during 47 months of burial was central > intermediate > peripheral. Central achene morphs emerged over a period of ~12 months after sowing, while intermediate and peripheral achene morphs did so for ~40 and 47 months, respectively. Thus, H. szovitsii exhibits a temporal dispersal strategy. No viable central or intermediate achene morphs were present after 16 and 40 months, respectively, but ~60 % of the non-emerged peripheral achenes morphs were viable after 47 months. Based on our results on diaspore dormancy and those of a previous study of diaspore spatial dispersal of H. szovitsii, we conclude that this species has a high–intermediate–low risk diaspore dispersal/dormancy strategy that likely increases the chances for population persistence over time and space.

Grazing livestock increases both vegetation and seed bank diversity in remnant and restored grasslands

AbstractQuestionsRestoring grasslands is of great importance to biodiversity conservation to counteract widespread, ongoing losses of plant species diversity. Using source populations in remnant habitats and increasing functional connectivity mediated by grazing animals within and between habitats can benefit grassland restoration efforts. Here we investigate how grazing contributes to vegetation and seed bank diversity and composition in remnant and restored grassland communities in fragmented landscapes.LocationStockholm archipelago, Sweden.MethodsWe investigated the effects of the presence or absence of grazing animals as potential elements of functional connectivity on grassland species composition in both the vegetation layer and in the seed bank. Species inventory and seed bank sampling were carried out in 2 m × 2 m plots in remnant grassland habitats and adjacent restored grasslands on former arable fields.ResultsSpecies composition varied between remnant and restored grasslands, with management‐dependent species more common in remnant grasslands. Remnant habitats with active grazing management contained a higher number of species in both the vegetation and seed bank compared to restored grasslands, but grazing reduced dispersal limitation from higher distance to source populations for specialist species. Where grazing was absent fewer plant species occurred in both the vegetation and in the seed bank.ConclusionOur results show that grazing livestock play a key role in facilitating both spatial and temporal dispersal in fragmented grasslands. This results in increased species diversity in the vegetation and the seed bank of grazed grasslands compared to those maintained by mowing only. Functional connectivity provided by grazing management increases the possibility for species establishment from both the below‐ground seed bank and the surrounding landscape, thus increasing the resilience of plant communities against disturbances or climatic changes.

Temporal Dispersal Patterns of Phaeomoniella chlamydospora, Causal Agent of Petri Disease and Esca, in Vineyards.

Although the fungus Phaeomoniella chlamydospora is the most commonly detected causal agent of Petri disease and esca, two important fungal grapevine trunk diseases, little is known about the dispersal patterns of P. chlamydospora inoculum. In this work, we studied the dispersal of P. chlamydospora airborne inoculum from 2016 to 2018 in two viticultural areas of eastern (Ontinyent) and northern (Logroño) Spain. The vineyards were monitored weekly from November to April using microscope slide traps, and P. chlamydospora was detected and quantified by a specific real-time quantitative (qPCR) method set up in this work. The method was found to be sensitive, and a good correlation was observed between numbers of P. chlamydospora conidia (counted by microscope) and DNA copy numbers (quantified by qPCR). We consistently detected DNA of P. chlamydospora at both locations and in all seasons but in different quantities. In most cases, DNA was first detected in the last half of November, and most of the DNA was detected from December to early April. When rain was used as a predictor of P. chlamydospora DNA detection in traps, false-negative detections were observed, but these involved only 4% of the total. The dispersal pattern of P. chlamydospora DNA over time was best described (R2 = 0.765 and concordance correlation coefficient = 0.870) by a Gompertz equation, with time expressed as hydrothermal time (a physiological time accounting for the effects of temperature and rain). This equation could be used to predict periods with a high risk of dispersal of P. chlamydospora.

Dormancy in Metacommunities.

Although metacommunity ecology has improved our understanding of how dispersal affects community structure and dynamics across spatial scales, it has yet to adequately account for dormancy. Dormancy is a reversible state of reduced metabolic activity that enables temporal dispersal within the metacommunity. Dormancy is also a metacommunity-level process because it can covary with spatial dispersal and affect diversity across spatial scales. We develop a framework to integrate dispersal and dormancy, focusing on the covariation they exhibit, to predict how dormancy modifies the importance of species interactions, dispersal, and historical contingencies in metacommunities. We used empirical and modeling approaches to demonstrate the utility of this framework. We examined case studies of microcrustaceans in ephemeral ponds, where dormancy underlies metacommunity dynamics, and identified constraints on the dispersal and dormancy strategies of bromeliad-dwelling invertebrates. Using simulations, we showed that dormancy can alter classic metacommunity patterns of diversity in ways that depend on dispersal-dormancy covariation and spatiotemporal environmental variability. We propose that dormancy may also facilitate evolution-mediated priority effects if locally adapted seed banks prevent colonization by more dispersal-limited species. Last, we present testable predictions for the implications of dormancy in metacommunities, some of which may fundamentally alter our understanding of metacommunity ecology.

Advantages of Small-Seeded Species in Forests: Win-Win for Temporal and Spatial Dispersal among Seeds in Rhododendron

There is little consistent evidence for evolutionary associations from seed production to seedling fitness. In this study, 20 species of Rhododendron genus were selected from subtropical forests of southwest China; the life-history functional traits such as the seed size, seed number per twig, germination traits, dispersal and seedling survival were investigated, the ecological relationships among them were tested and the advantages of small-seeded species were discussed. The results show that the quantitative parameters of germination, such as the germination rate, potential, and index are positively correlated with seed number produced per stem, while temporal parameters, such as germination peak timing and duration are positively correlated with seed size. The two results indicate that different Rhododendron species with different seed sizes and relative seed number can deal with varying environments according to spatial dispersal or time dispersal, respectively, and the advantages of smaller seeds in the aspect of sprouting vigour, dispersal ability and seedling survival may lay the foundation for the establishment of small-seeded plants in the forest.

Cover Caption

The seed wasp Megastigmus schimitscheki (Hymenoptera: Torymidae) is a highly specialized predispersal seed predator of cedars (Cedrus spp.) that occurs in Middle East as a native species and in southern France as an invasive species. Heterogeneous spatio‐temporal patterns of seed production by its obligate host have been important selective forces shaping the wasp's life‐cycle towards propensities to both temporal and spatial dispersal. Predispersal predator‐tree interactions provide many ways to assess the mechanisms involved in evolutionary diversification and ecological specialization of insects (see pages 182–198). Photo provided by Thomas Boivin.

Temporal conidial dispersal pattern of Botryosphaeriaceae species in table-grape vineyards in Northeastern Brazil

A field experiment was conducted between mid-August 2016 and mid-October 2017 in four table-grape vineyards in the Siriji Valley, Pernambuco State (Northeastern Brazil), to study the conidial dispersal dynamics of Botryosphaeriaceae fungi, causing grapevine trunk diseases (GTDs). Conidial dispersal was assessed by exposing microscope slides coated with Vaseline close to symptomatic plants and pruning debris. The slides were replaced every 2 weeks for a total of 30 sampling periods. Conidia of the genera Diplodia , Lasiodiplodia and Neofusicoccum were enumerated based on morphological characters. Conidia were collected from all four table-grape vineyards, confirming that these fungi are present as aerial inoculum and could be associated with GTDs in the region. Conidia of Diplodia and Lasiodiplodia were present in all the sampling periods, and those of Lasiodiplodia were the most abundant. Conidia of Neofusicoccum were found less frequently, and in less numbers than the other genera. Significant correlation between the number of conidia sampled and the amount of rain was observed for Diplodia only. Greater numbers of conidia were collected from pruning debris than from symptomatic plants. For Diplodia and Lasiodiplodia , the numbers of conidia gradually increased in September, increased sharply between March and June, and then decreased. These dynamics were described by a logistic equation, with hydro-thermal time (i.e., a combination of degree-days and relative humidity) as the independent variable ( R 2 > 0.998).

Employing molecular taxonomy for understanding ichthyoplankton diversity in the upper water layers of the Eastern Mediterranean Sea

Event Abstract Back to Event Employing molecular taxonomy for understanding ichthyoplankton diversity in the upper water layers of the Eastern Mediterranean Sea Nir Stern1* 1 Israel Oceanographic and Limnological Research, Israel The marine ichthyoplankton are mainly found throughout the photic layer of the water column, albeit constitutes a crucial component in the ecological cycle of the entire marine ecosystem. In the Eastern Mediterranean Sea, our general knowledge on the ichthyoplankton community and biodiversity is remarkably scarce, especially considering the ongoing influx of understudied thermophilic invasive species. This study aims to identify and characterize the species diversity of fish eggs and larvae in the neuston layer of the eastern Mediterranean Sea, in a search for new insights of temporal and spatial dispersal patterns in multi-species communities. Ichthyoplankton samplings have been conducted above and beyond the continental shelf of the Israeli Mediterranean coast, using horizontal hauls of 300 µl mesh size Manta net, filtering the very top surface layer of the water. In order to identify the different species, common molecular taxonomy techniques were used. After imaging the specimens, DNA was extracted from the fish eggs and larvae, then the mtDNA COI gene was amplified, commonly referred to as the 'Barcoding gene'. Finally, contiguous sequences were compared with taxonomically confirmed genetic vouchers for specific identification. The present preliminary results of this study can be separated to three main findings: (1) the obtainment of novel information regarding the invasive ichthyoplankton. Throughout the examined material, high diversity of invasive fish eggs and larvae was found. Some of the invasive larvae have been found beyond the continental shelf, far from their permanent habitat (10-30 km), thus demonstrating efficient dispersal abilities. Moreover, such findings enabled fine-tuning of the present temporal knowledge of the reproduction seasonality. (2) Detecting the existence of reproduction products of uncommon species. Genetically identified eggs of the bullet tuna Auxis rochei and Atlantic pomfret Brama brama confirmed the existence of these two highly infrequent species. This finding exemplified the lack of knowledge regarding temporal and spatial reproduction of pelagic species around the Israeli coast. (3) First documentation of the grey mullet Mugil cephalus reproduction cycle. Although well known in the western Mediterranean, the finding of M. cephalus larvae in the upper water above the continental slope (more than 30 km from the coast) provided the first evidence of its reproduction cycle in the Eastern Mediterranean. These somewhat random findings emphasized the hidden, though informative, knowledge that is stored within the marine ichthyoplankton. Moreover, by employing molecular taxonomy on the hardly discernable fish eggs and larvae, maximum certainty can be obtained that will improve our understanding the population dynamics within the early life history of fishes. Acknowledgements I would like to acknowledge Gal Lipson, Hadeel Hamdan, Marwa Nemer and Jessica Guerchon for incorporating their preliminary results for this study. Keywords: DNA barcoding, fish larvae, Integrative taxonomy, Marine invasion, Levant (eastern Mediterranean) Conference: XVI European Congress of Ichthyology, Lausanne, Switzerland, 2 Sep - 6 Sep, 2019. Presentation Type: Oral Topic: TAXONOMY, PHYLOGENY AND ZOOGEOGRAPHY Citation: Stern N (2019). Employing molecular taxonomy for understanding ichthyoplankton diversity in the upper water layers of the Eastern Mediterranean Sea. Front. Mar. Sci. Conference Abstract: XVI European Congress of Ichthyology. doi: 10.3389/conf.fmars.2019.07.00106 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 May 2019; Published Online: 14 Aug 2019. * Correspondence: Dr. Nir Stern, Israel Oceanographic and Limnological Research, Haifa, Israel, nirstern@ocean.org.il Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Nir Stern Google Nir Stern Google Scholar Nir Stern PubMed Nir Stern Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Off-host longevity of the winged dispersal stage of Carnus hemapterus (Insecta: Diptera) modulated by gender, body size and food provisioning.

Highlighting the dispersal ecology of parasites is important for understanding epidemiological, demographic and coevolutionary aspects of host-parasite interactions. Yet, critical aspects of the dispersal stage of parasites, such as longevity and the factors influencing it, are poorly known. Here we study the lifespan of the dispersal stage of an ectoparasitic dipteran, Carnus hemapterus, and the impact of gender, body size and food provisioning on longevity. We found that freshly emerged imagoes survive at most less than 4 days. Longevity increased with body size and, since this parasite exhibits sexual size dimorphism, the bigger females lived longer than males. However, controlling for body size suggests that males lived relatively longer than females. Furthermore, a humid environment and food provisioning (flowers) significantly increased individual life spans. We discuss the relative importance of spatial and temporal dispersal in relation to the infectious potential of this parasite.

Pre‐dispersal context and presence of opposite sex modulate density dependence and sex bias of dispersal

Density‐dependent dispersal (DDD) has been observed across taxa, and is expected to affect phenomena such as population dynamics, biological invasions, range expansions, and community assembly. However, little is known about whether the patterns of DDD are robust to changes in the environment. For example, the pre‐dispersal context could affect the physiology of organisms, which in turn could alter their DDD. Similarly, in sexually reproducing organisms, males and females might be differentially affected by the environment, with possible changes in their dispersal properties. To investigate some of these issues, we performed three independent experiments using laboratory populations of Drosophila melanogaster, which tested the effects of pre‐dispersal context, sex of the dispersers and presence of mates on DDD. A two‐patch dispersal setup was used to estimate the dispersal propensity and temporal dispersal profile of adult fruit flies. Comparing the data from two different pre‐dispersal contexts (variable and uniform pre‐dispersal adult densities), we found that longer pre‐dispersal exposure to higher densities led to stronger negative DDD in both males and females. Surprisingly, this change in DDD strength was accompanied by a switch in the direction of sex‐biased dispersal: from female‐biased dispersal at a low density to male‐biased dispersal at a high density. Moreover, we found that patterns of both density dependence and sex bias were contingent upon the interaction of males and females, as neither sex exhibited DDD in the absence of the other. Taken together, these results suggest that DDD and sex‐biased dispersal can be labile and be driven by the environmental context. Finally, we discuss the potential implications of these findings in terms of various ecological and evolutionary processes.