Large-scale Population Dynamics Research Articles

Biological and Physical Interactions at Local Ocean Scales: Coupled Systems

Physical and biogeochemical processes that influence primary production set Earth’s carbon and heat budgets. While these processes have long been the focus of research, high resolution models to investigate local phenomena have only recently been developed, and two-way coupling between oceanic physics and biology is only recently getting attention due to computational power. With these new developments, it is possible to study the mechanisms through which these processes interact at both global and regional scales to shape Earth’s climate, which is the goal of this paper. This paper introduces oceanic physical phenomena at submesoscales to global scales –like mixed layer depth and turbulent structures–and the relationship of smaller scale events with biological factors. It discusses the implications of these relationships for primary production. After an introductory explanation of turbulence, primarily in the form of eddies and fronts, and the effects of internal instability and surface forcing, this paper emphasizes the contributions of those phenomena (turbulence, internal instability, and surface forcing)to vertical velocities and the influence of vertical transport on biology. Next, it introduces biogeochemical feedbacks, concerning both large scale population dynamics and increased absorption of radiation at the submesoscale, to consider their impacts on physical dynamics and regional climates. Finally, the paper compiles equations of irradiance and variables of significance, suggesting terms that could produce meaningful responses to variations in phytoplankton populations. The paper highlights the importance of understanding physical-biogeochemical relationships and suggests directions for future research, particularly areas related to global warming or abrupt climate change.

Population size and spatial distribution of the white stork Ciconia ciconia in Poland in 1958 with insights into long-term trends in regional and global population

Although white stork Ciconia ciconia counts go back to the XIX century, making the species a model in population investigations, substantial gaps remain in the knowledge of its large-scale population dynamics. In particular, incomplete past estimates from the core breeding areas leave the long-term changes uncertain. In this paper, we provide the earliest estimation of population size and spatial distribution of the white stork in its main stronghold (Poland) to reconstruct the species long-term trends. Based on original survey data collected during the 2nd (1958, incomplete in Poland) and 3rd (1974, successful) International White Stork Census (IWSC) we compared stork numbers in a random sample of villages surveyed on both occasions. We applied linear models to estimate the population growth rate between 1958 and 1974 and to assess spatial variation in population change across the country. Finally, we collated worldwide stork numbers obtained from all IWSCs and discuss the long-term population trends in light of new data. The stork population in Poland in 1958 was estimated at 46,100 breeding pairs and the nationwide density at 14.7 pairs/100 km2. A strong decline (by 30.2%, 1.88% per year) was noted between 1958 and 1974 across Poland with prominent spatial variation reflecting differences in local densities. The strongest declines in absolute terms affected the most abundant populations in Eastern Poland. Our data show that in the mid-20th century, the stork population in Poland was close to the current level, but it experienced a massive decline during the 1960s–1980s. This decline was consistent with trends in the worldwide and regional European populations, contrary to earlier statements indicating limited, if any, changes in the core European area. Overall, our data expand knowledge on the long-term dynamics in the white stork numbers and show that even massive changes may easily go undetected if based on non-solid data.

Ten recommendations for supporting open pathogen genomic analysis in public health.

Increasingly, public-health agencies are using pathogen genomic sequence data to support surveillance and epidemiological investigations. As access to whole-genome sequencing has grown, greater amounts of molecular data have helped improve the ability to detect and track outbreaks of diseases such as COVID-19, investigate transmission chains and explore large-scale population dynamics, such as the spread of antibiotic resistance. However, the wide adoption of whole-genome sequencing also poses new challenges for public-health agencies that must adapt to support a new set of expertise, which means that the capacity to perform genomic data assembly and analysis has not expanded as widely as the adoption of sequencing itself. In this Perspective, we make recommendations for developing an accessible, unified informatic ecosystem to support pathogen genomic analysis in public-health agencies across income settings. We hope that the creation of this ecosystem will allow agencies to effectively and efficiently share data, workflows and analyses and thereby increase the reproducibility, accessibility and auditability of pathogen genomic analysis while also supporting agency autonomy.

Spatial heterogeneity in climate change effects decouples the long-term dynamics of wild reindeer populations in the high Arctic.

The ‘Moran effect’ predicts that dynamics of populations of a species are synchronized over similar distances as their environmental drivers. Strong population synchrony reduces species viability, but spatial heterogeneity in density dependence, the environment, or its ecological responses may decouple dynamics in space, preventing extinctions. How such heterogeneity buffers impacts of global change on large‐scale population dynamics is not well studied. Here, we show that spatially autocorrelated fluctuations in annual winter weather synchronize wild reindeer dynamics across high‐Arctic Svalbard, while, paradoxically, spatial variation in winter climate trends contribute to diverging local population trajectories. Warmer summers have improved the carrying capacity and apparently led to increased total reindeer abundance. However, fluctuations in population size seem mainly driven by negative effects of stochastic winter rain‐on‐snow (ROS) events causing icing, with strongest effects at high densities. Count data for 10 reindeer populations 8–324 km apart suggested that density‐dependent ROS effects contributed to synchrony in population dynamics, mainly through spatially autocorrelated mortality. By comparing one coastal and one ‘continental’ reindeer population over four decades, we show that locally contrasting abundance trends can arise from spatial differences in climate change and responses to weather. The coastal population experienced a larger increase in ROS, and a stronger density‐dependent ROS effect on population growth rates, than the continental population. In contrast, the latter experienced stronger summer warming and showed the strongest positive response to summer temperatures. Accordingly, contrasting net effects of a recent climate regime shift—with increased ROS and harsher winters, yet higher summer temperatures and improved carrying capacity—led to negative and positive abundance trends in the coastal and continental population respectively. Thus, synchronized population fluctuations by climatic drivers can be buffered by spatial heterogeneity in the same drivers, as well as in the ecological responses, averaging out climate change effects at larger spatial scales.

Non-ergodic delocalized phase in Anderson model on Bethe lattice and regular graph

We develop a novel analytical approach to the problem of single particle localization in infinite dimensional spaces such as Bethe lattice and random regular graph models. The key ingredient of the approach is the notion of the inverted order thermodynamic limit (IOTL) in which the coupling to the environment goes to zero before the system size goes to infinity. Using IOTL and Replica Symmetry Breaking (RSB) formalism we derive analytical expressions for the fractal dimension D1 that distinguishes between the extended ergodic, D1=1, and extended non-ergodic (multifractal), 0<D1<1 states on the Bethe lattice and random regular graphs with the branching number K. We also employ RSB formalism to derive the analytical expression lnStyp−1=−〈lnS〉∼(Wc−W)−1 for the typical imaginary part of self-energy Styp in the non-ergodic phase close to the Anderson transition in the conventional thermodynamic limit. We prove the existence of an extended non-ergodic phase in a broad range of disorder strength and energy and establish the phase diagrams of the models as a function of disorder and energy. The results of the analytical theory are compared with large-scale population dynamics and with the exact diagonalization of Anderson model on random regular graphs. We discuss the consequences of these results for the many body localization.

Life history and dynamics of a platypus (Ornithorhynchus anatinus) population: four decades of mark-recapture surveys.

Knowledge of the life-history and population dynamics of Australia’s iconic and evolutionarily distinct platypus (Ornithorhynchus anatinus) remains poor. We marked-recaptured 812 unique platypuses (total 1,622 captures), over four decades (1973–2014) in the Shoalhaven River, Australia. Strong sex-age differences were observed in life-history, including morphology and longevity. Apparent survival of adult females (Φ = 0.76) were higher than adult males (Φ = 0.57), as in juveniles: females Φ = 0.27, males Φ = 0.13. Females were highly likely to remain in the same pool (adult: P = 0.85, juvenile: P = 0.88), while residency rates were lower for males (adult: P = 0.74, juvenile: P = 0.46). We combined survival, movement and life-histories to develop population viability models and test the impact of a range of life-history parameters. While using estimated apparent survival produced unviable populations (mean population growth rate r = −0.23, extinction within 20 years), considering residency rates to adjust survival estimates, indicated more stable populations (r = 0.004, p = 0.04 of 100-year extinction). Further sensitivity analyses highlighted adult female survival and overall success of dispersal as most affecting viability. Findings provide robust life-history and viability estimates for a difficult study species. These could support developing large-scale population dynamics models required to underpin a much needed national risk assessment for the platypus, already declining in parts of its current distribution.

Comparative analysis of abundance–occupancy relationships for species at risk at both broad taxonomic and spatial scales

The abundance–occupancy relationship is one of the most well-examined relationships in ecology. At the species level, a positive association has been widely documented. However, until recently, research on the nature of this relationship at broad taxonomic and spatial scales has been limited. Here, we perform a comparative analysis of 12 taxonomic groups across a large spatial scale (Canada), using data on Canadian species at risk: amphibians, arthropods, birds, freshwater fishes, lichens, marine fishes, marine mammals, molluscs, mosses, reptiles, terrestrial mammals, and vascular plants. We find a significantly positive relationship in all taxonomic groups with the exception of freshwater fishes (negative association) and lichens (no association). In general, our work underscores the strength and breadth of this apparently fundamental relationship and provides insight into novel applications for large-scale population dynamics. Further development of species-independent abundance–occupancy relationships, or those of a similar nature, might well prove instrumental in serving as starting points for developing species-independent reference points and recovery strategies.

A high-density, high-channel count, multiplexed μECoG array for auditory-cortex recordings.

Our understanding of the large-scale population dynamics of neural activity is limited, in part, by our inability to record simultaneously from large regions of the cortex. Here, we validated the use of a large-scale active microelectrode array that simultaneously records 196 multiplexed micro-electrocortigraphical (μECoG) signals from the cortical surface at a very high density (1,600 electrodes/cm(2)). We compared μECoG measurements in auditory cortex using a custom "active" electrode array to those recorded using a conventional "passive" μECoG array. Both of these array responses were also compared with data recorded via intrinsic optical imaging, which is a standard methodology for recording sound-evoked cortical activity. Custom active μECoG arrays generated more veridical representations of the tonotopic organization of the auditory cortex than current commercially available passive μECoG arrays. Furthermore, the cortical representation could be measured efficiently with the active arrays, requiring as little as 13.5 s of neural data acquisition. Next, we generated spectrotemporal receptive fields from the recorded neural activity on the active μECoG array and identified functional organizational principles comparable to those observed using intrinsic metabolic imaging and single-neuron recordings. This new electrode array technology has the potential for large-scale, temporally precise monitoring and mapping of the cortex, without the use of invasive penetrating electrodes.

Trajectory of the main GABAergic interneuron populations from early development to old age in the rat primary auditory cortex.

In both humans and rodents, decline in cognitive function is a hallmark of the aging process; the basis for this decrease has yet to be fully characterized. However, using aged rodent models, deficits in auditory processing have been associated with significant decreases in inhibitory signaling attributed to a loss of GABAergic interneurons. Not only are these interneurons crucial for pattern detection and other large-scale population dynamics, but they have also been linked to mechanisms mediating plasticity and learning, making them a prime candidate for study and modeling of modifications to cortical communication pathways in neurodegenerative diseases. Using the rat primary auditory cortex (A1) as a model, we probed the known markers of GABAergic interneurons with immunohistological methods, using antibodies against gamma aminobutyric acid (GABA), parvalbumin (PV), somatostatin (SOM), calretinin (CR), vasoactive intestinal peptide (VIP), choline acetyltransferase (ChAT), neuropeptide Y (NPY), and cholecystokinin (CCK) to document the changes observed in interneuron populations across the rat's lifespan. This analysis provided strong evidence that several but not all GABAergic neurons were affected by the aging process, showing most dramatic changes in expression of parvalbumin (PV) and somatostatin (SOM) expression. With this evidence, we show how understanding these trajectories of cell counts may be factored into a simple model to quantify changes in inhibitory signaling across the course of life, which may be applied as a framework for creating more advanced simulations of interneuronal implication in normal cerebral processing, normal aging, or pathological processes.

Exploitation by Common Carp (Cyprinus Carpio) of A Floodplain Wetland of The Lower River Murray Under Drought and Flooding Conditions

Common carp Cyprinus carpio are a declared pest fish throughout the Murray-Darling Basin. Successful management of this highly-invasive species aimed at mitigating its detrimental effects on aquatic ecosystems is therefore a priority issue for wetland restoration and rehabilitation programmes for the benefit of native fish communities. as part of a large-scale, field-based experiment on carp impacts, a population of carp was extensively sampled from 2009 to 2011 at Brenda Park wetland (lower River Murray, South Australia) under both drought and flooding conditions. a consistent young-of-year (YoY) cohort was present in the 2009–10 breeding season, indicating successful spawning within the wetland. However, the same cohort appeared not to leave the wetland later in the season, possibly as a result of drought-induced low-flow conditions. Conversely, there was no evidence for within-wetland spawning in 2010–11 and 2011–12. Following a major flood event in Summer/autumn 2011, a consistent stock-size (210–440 mm TL) component was present in the carp population. Despite one successful spawning event out of the three breeding seasons of sampling, it cannot be ruled out that Brenda Park can act as a recruitment hot-spot for carp, especially in light of the large-scale population dynamics of this species. Measures for wetland rehabilitation should account for this and rely on a combination of flow regulation practices, enhancement of native fish passage and integrated carp management/control measures involving use of selective traps or exclusion screens, removal programmes and, whenever feasible, water draw-downs.

Coupling in goshawk and grouse population dynamics in Finland

Different prey species can vary in their significance to a particular predator. In the simplest case, the total available density or biomass of a guild of several prey species might be most relevant to the predator, but behavioural and ecological traits of different prey species can alter the picture. We studied the population dynamics of a predator-prey setting in Finland by fitting first-order log-linear vector autoregressive models to long-term count data from active breeding sites of the northern goshawk (Accipiter gentilis; 1986-2009), and to three of its main prey species (1983-2010): hazel grouse (Bonasa bonasia), black grouse (Tetrao tetrix) and capercaillie (T. urogallus), which belong to the same forest grouse guild and show synchronous fluctuations. Our focus was on modelling the relative significance of prey species and estimating the tightness of predator-prey coupling in order to explain the observed population dynamics, simultaneously accounting for effects of density dependence, winter severity and spatial correlation. We established nine competing candidate models, where different combinations of grouse species affect goshawk dynamics with lags of 1-3 years. Effects of goshawk on grouse were investigated using one model for each grouse species. The most parsimonious model for goshawk indicated separate density effects of hazel grouse and black grouse, and different effects with lags of 1 and 3 years. Capercaillie showed no effects on goshawk populations, while the effect of goshawk on grouse was clearly negative only in capercaillie. Winter severity had significant adverse effects on goshawk and hazel grouse populations. In combination, large-scale goshawk-grouse population dynamics are coupled, but there are no clear mutual effects for any of the individual guild members. In a broader context, our study suggests that pooling data on closely related, synchronously fluctuating prey species can result in the loss of relevant information, rather than increased model parsimony.

SAPling: a Scan-Add-Print barcoding database system to label and track asexual organisms

We have developed a 'Scan-Add-Print' database system, SAPling, to track and monitor asexually reproducing organisms. Using barcodes to uniquely identify each animal, we can record information on the life of the individual in a computerized database containing its entire family tree. SAPling has enabled us to carry out large-scale population dynamics experiments with thousands of planarians and keep track of each individual. The database stores information such as family connections, birth date, division date and generation. We show that SAPling can be easily adapted to other asexually reproducing organisms and has a strong potential for use in large-scale and/or long-term population and senescence studies as well as studies of clonal diversity. The software is platform-independent, designed for reliability and ease of use, and provided open source from our webpage to allow project-specific customization.

Mean-field theory of collective motion due to velocity alignment

Establishing a direct link between individual based models and the corresponding population description is a common challenge in theoretical ecology. Swarming is a prominent example, where collective effects arising from interactions of individuals are essential for the understanding of large-scale spatial population dynamics, and where both levels of modeling have been often employed without establishing this connection.Here, we consider a system of self-propelled agents with velocity alignment in 2D and derive a mean-field theory from the microscopic dynamics via a nonlinear Fokker–Planck equation and a moment expansion of the probability density. We analyze the stationary solutions corresponding to macroscopic collective motion (ordered state) and the disordered solution with no collective motion in the spatially homogeneous system. In particular, we discuss the impact of different propulsion functions governing individual dynamics. Our results predict a strong impact of individual dynamics on the mean field onset of collective motion (continuous vs discontinuous). In addition to the macroscopic density and velocity fields, we consider the effective “temperature” field, measuring velocity fluctuations around the mean velocity. We show that the temperature decreases strongly with increasing level of collective motion despite constant fluctuations on individual level, which suggests that extreme caution should be taken in deducing individual behavior, such as, state-dependent individual fluctuations from mean-field measurements (Yates et al., 2009).

Are population outbreaks in sub‐arctic geometrids terminated by larval parasitoids?

1. Larval parasitoids (i.e. parasitoids attacking host larvae) constitute a major source of mortality in many ecologically and economically important forest insects, but how this mortality affects spatio-temporal population dynamics is often not clear. 2. In sub-arctic Fennoscandian birch forest, the two geometrids Epirrita autumnata and Operophtera brumata exhibit pronounced outbreak cycles with significant ecosystem impacts. As mortality owing to larval parasitoids often is very high, the hypothesis that parasitism terminates outbreaks has been advocated, but without decisive empirical evidence. 3. We analysed the altitude- and species-specific timing of population outbreaks typically seen in the coastal section of the sub-arctic birch forest ecosystem to evaluate the critical premise that parasitoid-inflicted larval mortality ought to predict geometrid population growth. 4. However, despite temporally high rates of parasitism, this did not influence the strongly species- and altitude-patterned geometrid outbreaks. We therefore conclude that termination of cyclic outbreaks in these geometrids is caused by other regulatory mechanisms than larval parasitoids. 5. Regardless of their lack of effect on the altitude-specific outbreak dynamics, larval parasitoids accounted for some of the local spatial variance in the temporal dynamics. This implies that results from spatially localized observations and experiments, which dominate research on parasitoid-host interaction, may be misinterpreted with respect to their relevance for large-scale and long-term population dynamics.

Climate, trophic interactions, density dependence and carry-over effects on the population productivity of a migratory Arctic herbivorous bird

Several driving forces can affect recruitment rates in bird populations. However, our understanding of climate-induced effects or bottom–up vs top–down biological processes on breeding productivity typically comes from small-scale studies, and their relative importance is rarely investigated at the population level. Using a 31-year time series, we examined the effects of selected environmental parameters on the annual productivity of a key Arctic herbivore, the greater snow goose Anser caerulescens atlanticus. We determined the extent to which breeding productivity, defined as the percentage of juveniles in the fall population, was affected by 1) climatic conditions, 2) fluctuations in predation pressure caused by small rodent oscillations, and 3) population size. Moreover, we took advantage of an unplanned large-scale manipulation (i.e. management action) to examine the potential non-lethal carry-over effects caused by disturbance on spring staging sites. The most parsimonious model explained 66% of the annual variation in goose productivity. The spring North Atlantic Oscillation and Arctic snow depth were the primary climatic parameters inversely affecting the production of juveniles, likely through bottom–up processes. Indirect trophic interactions generated by fluctuations in lemming abundance explained 18% of the variation in goose productivity (positive relationship). Mean temperature during brood-rearing and disturbance on staging sites (carry-over effects) were the other important factors affecting population recruitment. We observed a strong population increase, and found no evidence of density-dependent effects. Spatially restricted studies can identify factors linking environmental parameters to local bird reproduction but if these factors do not act synchronously over the species range, they may fail to identify the relative importance of mechanisms driving large-scale population dynamics.

Adaptive foragers and community ecology: linking individuals to communities and ecosystems

Adaptive foragers and community ecology: linking individuals to communities and ecosystems

Coexistence of competing parasitoids: which is the fugitive and where does it hide?

Most insects harbour a community of parasitoids that coexist in spite of competition for resources. One potential mechanism for coexistence of competitors is a tradeoff between dispersiveness and local competitive ability. Here we present a study of competition between the specialized parasitoids Hyposoter horticola and Cotesia melitaearum sharing the Glanville fritillary butterfly, Melitaea cinxia. Within one host generation, the parasitoid larvae interact inside the host during each of the three C. melitaearum generations. We founds that in the summer when the host is small, the solitary H. horticola is the superior competitor, suppressing the gregarious C. melitaearum as eggs or small larvae. When multiparasitism occurs in the autumn the two parasitoid species engage in physical combat and C. melitaearum is favoured. Finally, a previous study showed that in the third C. melitaearum generation the univoltine H. horticola grows quickly during its final instar, excluding young C. melitaearum simply through limited time and resources. We found that contrary to expectations of the evolution of gregariousness, C. melitaearum, which lives in sibling groups, has biting mandibles in the first instar while the solitary H. horticola has suctorial mouthparts. Previous studies suggest that the two parasitoids co-exist because H. Horticola is dispersive and C. melitaearum is a strong local competitor. However, putting together the results of this experiment and out recent understanding of the adult wasp foraging behaviours and large scale population dynamics, we conclude that H. horticola is both a superior local competitor and more dispersive than C. melitaearum. Cotesia melitaearum has no impact on the population dynamics of H. horticola, persisting as a fugitive using a small fraction the larvae left unparasitized by H. horticola.

The consistency and stability of abundance–occupancy relationships in large‐scale population dynamics

1. Abundance-occupancy relationships comprise some of the most general and well-explored patterns in macro-ecology. The theory governing these relationships predicts that species will exhibit a positive interspecific and intraspecific relationship between regional occupancy and local abundance. Abundance-occupancy relationships have important implications in using distributional surveys, such as atlases, to understand and document large-scale population dynamics and the consequences of environmental change. A basic need for interpreting such data bases is a better understanding of whether changes in regional occupancy reflect changes in local abundance across species of varying life-history characteristics. 2. Our objective was to test the predictions of the abundance-occupancy rule using two independent data sets, the New York State Breeding Bird Atlas and the North American Breeding Bird Survey. The New York State Breeding Bird Atlas consists of 5332 25-km(2) survey blocks and is one of the first atlases in the USA to be completed for two time periods (1980-85 and 2000-05). The North American Breeding Survey is a large-scale annual survey intended to document the relative abundance and population change of songbirds throughout the USA. 3. We found that regional occupancy was positively correlated with relative abundance across 98 (beta = 0.60 +/- 0.11 SE, P < 0.001, R(2) = 0.60) and 85 species (beta = 0.67 +/- 0.06 SE, P < 0.001, R(2) = 0.57) in two separate time periods. This relationship proved stable over time and was notably consistent between breeding habitat groups and migratory guilds. 4. Between 1980 and 2005, changes in regional occupancy were highly correlated with long-term abundance trend estimates for 75 species (beta = 5.73 +/- 0.24 SE, P < 0.001, R(2) = 0.88). Over a 20-year period, woodland and resident birds showed an increase in occupancy while grassland species showed the greatest decline; these patterns were mirrored by changes in local abundance. 5. Although exceptions existed, we found most changes in occupancy parallel changes in local abundance. These findings support the basic predictions of the abundance-occupancy rule and demonstrate its consistency and stability in species and groups of varying life-history characteristics.

FIELD-SCALE ROLES OF DENSITY, TEMPERATURE, NITROGEN, AND PREDATION ON APHID POPULATION DYNAMICS

Robust analyses of noisy, stage-structured, irregularly spaced, field-scale data incorporating multiple sources of variability and nonlinear dynamics remain very limited, hindering understanding of how small-scale studies relate to large-scale population dynamics. We used a novel, complementary Bayesian and frequentist state-space model analysis to ask how density, temperature, plant nitrogen, and predators affect cotton aphid (Aphis gossypii) population dynamics in weekly data from 18 field-years and whether estimated effects are consistent with small-scale studies. We found clear roles of density and temperature but not of plant nitrogen or predators, for which Bayesian and frequentist evidence differed. However, overall predictability of field-scale dynamics remained low. This study demonstrates stage-structured state-space model analysis incorporating bottom-up, top-down, and density-dependent effects for within-season (nearly continuous time), nonlinear population dynamics. The analysis combines Bayesian posterior evidence with maximum-likelihood estimation and frequentist hypothesis testing using average one-step-ahead residuals.

BIOLOGY AND ECOLOGY OF FLOWER THRIPS IN RELATION TO TOMATO SPOTTED WILT VIRUS*

Tomato Spotted Wilt Virus (TSWV) is transmitted exclusively by certain species of thrips. Because TSWV can only be acquired by larvae and transmitted by adults, it is essential to determine the ecology of these different life stages to improve management of thrips and TSWV. Furthermore, interspecific differences among vector species complicate management issues. Herein, aspects of the biology and ecology of thrips vectors of tomato spotted wilt virus are discussed and an overview of vector-pathogens interaction is given. The complex of native and adventive Frankliniella species that occur in the southeastern USA is used as a model system for comparing and contrasting species-specific behavioral attributes that affect large-scale spatial and temporal population dynamics. The common Frankliniella species in the southeastern USA include Frankliniella occidentalis, F. fusca, F. bispinosa, and F. tritici. The western flower thrips, F. occidentalis, is considered the predominant vector of TSWV, but F. bispinosa and F. fusca are also vectors. These Frankliniella species have rapid generation times, and adults are highly polyphagous. Numerous hosts may serve as sources for thrips entering tomato fields, yet tomato is a poor reproductive host. Therefore, most of the thrips infesting fields are immigrants. Consequently, thrips dispersal behavior is a key component of TSWV epidemiology. F. occidentalis is a less mobile species than either F. bispinosa or F. tritici. These interspecific differences in the activity levels of adults affect how the species colonize plants and the field efficacy of insecticides against each species. These results show the importance of understanding interspecific variation among vectors for management of TSWV.