Source Habitats Research Articles

A new species of Pista Malmgren, 1866 (Polychaeta, Terebellidae) from the north-western Mediterranean Sea.

A new species of Terebellidae, Pistacolinisp. n., has been identified from the harbour of Banyuls-sur-Mer, north-western Mediterranean Sea. This new species was found in very high densities, exclusively in gravelly sand deposited manually, and was not found in the original source habitat of the gravel. This species is characterized by the colour of the ventral shields with pinkish anterior part and a blood red posterior part in live specimens, a pair of unequal-sized plumose branchiae inserted on segment II and anterior thoracic neuropodia with long-handled uncini. The presence of long-handled uncini even in the smallest specimens constitutes the major difference between Pistacolinisp. n. and other Pista species with a single pair of branchiae such as P.lornensis and P.bansei.

Landscape heterogeneity increases the spatial stability of pollination services to almond trees through the stability of pollinator visits

High pollinator reliability is essential to maintain a stable and predictable crop production. However, still few studies have considered landscape effects on the stability (low variability) of the pollination service to crops. The stability of pollination services may increase in heterogeneous landscapes with high availability and diversity of alternative habitats. By using data on pollinator visitation and fruit production in 18 almond tree fields in Mallorca Island, we related landscape heterogeneity (richness, evenness and diversity of land-cover classes) at 1 and 2 km-radius buffer zone to the spatial (among-tree) stability of their pollination services (total visit rates, wild pollinators’ visit rates, pollinator richness and fruit set). Overall, landscape heterogeneity increased the spatial stability (i.e., decreased spatial variability) of pollination services to almond trees. Interestingly different components of heterogeneity influenced diverse components of this service. Thus, increasing landscape evenness at the 2 km buffer zone increased the spatial stability of both total pollinator visitation and fruit set. However, the stability of wild-pollinators’ visit rate as well as the stability of pollinator richness increased instead with the percentage of natural habitat in the buffers, as the abundance of wild pollinators might depend on the total availability of habitat in the field surroundings. The stability in pollinator richness had a further positive effect on the stability of fruit set, indicating the importance of diversity maintaining stable crop production. Lastly, fruit set was also negatively affected by landscape richness, probably because of a loss of pollinator source habitat when the number of land uses is too high. Preserving a heterogeneous habitat of high quality in the surroundings of crop fields may help to maintain a stable fruit production.

Short-term accumulation of fauna colonising natural versus artificial seagrass floating near to shore

Detached and floating macrophytes are commonly found along beaches in Southern Australia, but few studies have investigated their associations with animals along the drift pathway, particularly in the southern hemisphere. This study investigated the colonisation by macroinvertebrates and fish of natural and artificial tagged seagrass within 6 h of release and compared this to fauna found with in situ floating macrophyte clumps netted at different distances from shore in Southern Australia. We found some evidence that more macroinvertebrates may colonise floating macrophytes at distances closer to shore (i.e., 0.25 km) potentially due to shallower depths and increased proximity of source habitats. Particular fauna may stay with macrophytes as they arrive and accumulate as wrack in the surf-zone, while others may leave for more suitable habitats. Colonisation by fish to floating macrophytes was judged more likely to be for habitat and shelter rather than food resources. This study provides some further evidence for rapid colonisation of fauna and hence an important habitat function of detached and floating macrophytes along nearshore coastlines in Southern Australia.

Historical Factors Associated With Past Environments Influence the Biogeography of Thermophilic Endospores in Arctic Marine Sediments

Selection by the local, contemporary environment plays a prominent role in shaping the biogeography of microbes. However, the importance of historical factors in microbial biogeography is more debatable. Historical factors include past ecological and evolutionary circumstances that may have influenced present-day microbial diversity, such as dispersal and past environmental conditions. Diverse thermophilic sulfate-reducing Desulfotomaculum are present as dormant endospores in marine sediments worldwide where temperatures are too low to support their growth. Therefore, they are dispersed to here from elsewhere, presumably a hot, anoxic habitat. While dispersal through ocean currents must influence their distribution in cold marine sediments, it is not clear whether even earlier historical factors, related to the source habitat where these organisms were once active, also have an effect. We investigated whether these historical factors may have influenced the diversity and distribution of thermophilic endospores by comparing their diversity in 10 Arctic fjord surface sediments. Although community composition varied spatially, clear biogeographic patterns were only evident at a high level of taxonomic resolution (>97% sequence similarity of the 16S rRNA gene) achieved with oligotyping. In particular, the diversity and distribution of oligotypes differed for the two most prominent OTUs (defined using a standard 97% similarity cutoff). One OTU was dominated by a single ubiquitous oligotype, while the other OTU consisted of ten more spatially localized oligotypes that decreased in compositional similarity with geographic distance. These patterns are consistent with differences in historical factors that occurred when and where the taxa were once active, prior to sporulation. Further, the influence of history on biogeographic patterns was only revealed by analyzing microdiversity within OTUs, suggesting that populations within standard OTU-level groupings do not necessarily share a common ecological and evolutionary history.

Paleocommunity mixing increases with marine transgression in Dinosaur Park Formation (Upper Cretaceous) vertebrate microfossil assemblages

AbstractVertebrate microfossil assemblages in a stratigraphic sequence often yield similar assortments of taxa but at different relative abundances, potentially indicative of marginal paleocommunity changes driven by paleoenvironmental change over time. For example, stratigraphically younger assemblages in the Dinosaur Park Formation (DPF) yield proportionally more aquatic taxa, consistent with marine transgression. However, individual deposits may have received specimens from multiple source paleocommunities over time, limiting our ability to confidently identify ecologically significant, paleocommunity differences through direct assemblage comparisons. We adapted a three-source, two-tracer Bayesian mixing model to quantify proportional contributions from different source habitats to DPF microfossil assemblages. Prior information about the compositions of separate, relatively unmixed terrestrial, freshwater, and marine assemblages from the Belly River Group allowed us to define expected taxon percent abundances for the end-member habitats likely contributing specimens to the mixed deposits. We compared the mixed assemblage and end-member distributions using 21 different combinations of vertebrate taxa. Chondrichthyan, dinosaur, and amphibian occurrence patterns ultimately allowed us to parse the contributions from the potential sources to 14 of the 15 mixed assemblages. The results confirmed a significant decline in terrestrial contributions at younger DPF sites, driven primarily by increased freshwater specimen inputs—not incursions from the adjacent marine paleocommunity. A rising base level likely increased lateral channel migration and the prevalence of freshwater habitats on the landscape, factors that contributed to increased paleocommunity mixing at younger channel deposit sites. Bayesian methods can account for source-mixing bias, which may be common in assemblages associated with major paleoenvironmental changes.

Different cutting regimes improve species and functional diversity of insect‐pollinated plants in power‐line clearings

AbstractTo mitigate biodiversity loss, it is essential to understand how areas altered by human land use can act as alternative habitats for functional groups of species, which are in decline. In forested landscapes, power‐line clearings can be valuable habitats for early successional plant species, which in turn provide important food resources for pollinating insects. However, we know little about how management practices affect plant diversity, or how changes in species diversity translate into the functional diversity of floral resources. We conducted an experiment at 19 sites in power‐line clearings across southeast Norway where the woody vegetation was (1) cut and left to decay, (2) cut and removed, or (3) uncut. We assessed the effects of treatments on species diversity (richness, evenness, diversity) and functional diversity (functional evenness, functional dispersion) of understory plant communities of insect‐pollinated plants. We also investigated the influence of environmental conditions within the power‐line clearings, the surrounding landscape, and climatic factors on species and functional diversity. We found that the cut and cut–remove treatments were effective in increasing biological diversity of insect‐pollinated plants. The species and functional diversity showed contrasting responses to treatments, and the treatment effects depended on the environmental context. This shows that ecosystem functioning is not necessarily predictable from the ecological processes that drive species composition. The treatment effects on species diversity were partly explained by the stress‐gradient hypothesis; species richness was higher in the cleared plots in areas of low environmental stress from precipitation and elevation. In contrast, the treatment effects on functional diversity were positively influenced by productivity, stem density, temperature, available source habitats, elevation, and canopy density. Functional diversity, based on effect traits, should be emphasized when the aim is to maintain a broad range of pollination functions and services in power‐line clearings. This study shows that inclusion of power‐line clearings in conservation plans can mitigate biodiversity decline in forested landscapes. We recommend the cut–remove treatment in productive areas with available source habitats and high stem density. In low productive areas, with high stem density and high temperatures, the standard cut treatment is sufficient, but a higher cutting frequency is recommended.

Habitat preference of an herbivore shapes the habitat distribution of its host plant.

Plant distributions can be limited by habitat-biased herbivory, but the proximate causes of such biases are rarely known. Distinguishing plant-centric from herbivore-centric mechanisms driving differential herbivory between habitats is difficult without experimental manipulation of both plants and herbivores. Here we tested alternative hypotheses driving habitat-biased herbivory in bittercress (Cardamine cordifolia), which is more abundant under shade of shrubs and trees (shade) than in nearby meadows (sun) where herbivory is intense from the specialist fly Scaptomyza nigrita. This system has served as a textbook example of habitat-biased herbivory driving a plant's distribution across an ecotone, but the proximate mechanisms underlying differential herbivory are still unclear. First, we found that higher S. nigrita herbivory in sun habitats contrasts sharply with their preference to attack plants from shade habitats in laboratory choice experiments. Second, S. nigrita strongly preferred leaves in simulated sun over simulated shade habitats, regardless of plant source habitat. Thus, herbivore preference for brighter, warmer habitats overrides their preference for more palatable shade plants. This promotes the sun-biased herbivore pressure that drives the distribution of bittercress into shade habitats.

Changes in bryophytes assemblages along a chronosequence in eastern boreal forest of Quebec

Old-growth forests are often considered as biodiversity hotspots for bryophytes because of their diversity in environmental niches or microhabitats and forest continuity. Following this hypothesis, old-growth forests would be expected to house species and functional traits associated with species dispersal different from mature forests. In this study, we compared bryophytes in old-growth and younger forests in terms of species composition, functional trait values, and microhabitat associations. We studied bryophytes in 22 sites distributed across three age classes (18 to >200 years) in boreal forests (eastern Quebec). Richness of liverworts, vegetative-reproducing species, and species with infrequent sexual reproduction were higher in the oldest age class. Species richness was best explained by the availability of coarse woody material (CWM) and other microhabitats, and community structure was best explained by balsam fir basal area. Microhabitats most often associated with indicator species were organic matter, CWM, and pits. Our results indicate that communities associated with older forests are potentially sensitive to forest management as they differ in composition and functional traits from other age classes, with many species characterized by reduced dispersal capabilities and tolerance to competition. An approach that combines critical source habitat protection for dispersal-limited species with protection of critical microhabitats in neighboring managed stands are necessary to allow successful recolonization and maintain bryophyte diversity in managed landscapes.

Aerial dispersal ability does not drive spider success in a crop landscape

1. Although spiders can colonise ecosystems by air, dispersal capabilities differ among spider species. Web‐building spiders are thought to balloon at higher rates than hunting spiders. Spider success in agricultural systems may also depend on habitat preferences. Few studies have examined the success of aerially dispersing spiders in crop systems, and information about the dispersal capabilities of spiders in putative source habitats is limited.2. Spiders were monitored in the air and on the foliage of vineyards and adjacent oak woodland in order to compare the aerial spider faunas between these disparate habitats and to determine whether highly dispersive species contributed disproportionately to the spider community in vineyards.3. The results show that most aerially dispersing spiders in both habitats were web‐building dwarf spiders, Erigone spp. (Linyphiidae), although hunting spiders were also well represented in the air, especially in oak woodland. Most woodland spiders in the air appeared to be residents of oak woodland and probably dispersed only short distances.4. Conversely, only a subset of the aerial spider fauna established in vineyards in high numbers. Spiders that dominated the aerial fauna were under‐represented on vineyard foliage, whereas several hunting spiders dispersed aerially at low rates but dominated vineyard spider composition.5. These results suggest that aerial dispersal ability may allow spiders to reach crop systems, but that establishment depends on habitat preferences and/or competitive ability.

Sequestration of macroalgal carbon: the elephant in the Blue Carbon room.

Macroalgae form the most extensive and productive benthic marine vegetated habitats globally but their inclusion in Blue Carbon (BC) strategies remains controversial. We review the arguments offered to reject or include macroalgae in the BC framework, and identify the challenges that have precluded macroalgae from being incorporated so far. Evidence that macroalgae support significant carbon burial is compelling. The carbon they supply to sediment stocks in angiosperm BC habitats is already included in current assessments, so that macroalgae are de facto recognized as important donors of BC. The key challenges are (i) documenting macroalgal carbon sequestered beyond BC habitat, (ii) tracing it back to source habitats, and (iii) showing that management actions at the habitat lead to increased sequestration at the sink site. These challenges apply equally to carbon exported from BC coastal habitats. Because of the large carbon sink they support, incorporation of macroalgae into BC accounting and actions is an imperative. This requires a paradigm shift in accounting procedures as well as developing methods to enable the capacity to trace carbon from donor to sink habitats in the ocean.

The extent of wind-mediated dispersal of small metazoans, focusing nematodes

Wind-mediated transport is an important mechanism in the dispersal of small metazoans. Yet, concrete dispersal rates have hardly been examined. Here we present the results of an one-year field experiment investigating the composition and dispersal rates of aeroplankton. To gain insights into the dynamics of dispersal at the species level, we focused on nematodes, worldwide the most common metazoan taxon. Among the six taxa collected in this study (nematodes, rotifers, collembolans, tardigrades, mites, and thrips), nematodes had the highest dispersal rates (up to >3000 individuals m−2 in 4 weeks, 27 species identified) and represented >44% of aeroplankton. Only living nematodes, and no propagules, were dispersed. All taxa had a higher dispersal potential in environments linked to the source habitat, evidenced by the much higher deposition of organisms in funnels placed on the ground than on the rooftop of a ten-story building. Nematodes under conditions of high humidity and wind speed had the highest dispersal rates, while increasing temperatures and dryness had a significantly positive impact on the wind drift of mites and thrips. The results indicated that wind dispersal over long distances is possible. The notable organismal input by wind dispersal may contribute to biodiversity and ecosystem functions.

Macrophyte wrack on sandy beaches of the US Pacific Northwest is linked to proximity of source habitat, ocean upwelling, and beach morphology

Macrophyte wrack on sandy beaches of the US Pacific Northwest is linked to proximity of source habitat, ocean upwelling, and beach morphology

A multispecies test of source-sink indicators to prioritize habitat for declining populations.

For species at risk of decline or extinction in source-sink systems, sources are an obvious target for habitat protection actions. However, the way in which source habitats are identified and prioritized can reduce the effectiveness of conservation actions. Although sources and sinks are conceptually defined using both demographic and movement criteria, simplifications are often required in systems with limited data. To assess the conservation outcomes of alternative source metrics and resulting prioritizations, we simulated population dynamics and extinction risk for 3 endangered species. Using empirically based habitat population models, we linked habitat maps with measured site- or habitat-specific demographic conditions, movement abilities, and behaviors. We calculated source-sink metrics over a range of periods of data collection and prioritized consistently high-output sources for conservation. We then tested whether prioritized patches identified the habitats that most affected persistence by removing them and measuring the population response. Conservation decisions based on different source-sink metrics and durations of data collection affected species persistence. Shorter time series obscured the ability of metrics to identify influential habitats, particularly in temporally variable and slowly declining populations. Data-rich source-sink metrics that included both demography and movement information did not always identify the habitats with the greatest influence on extinction risk. In some declining populations, patch abundance better predicted influential habitats for short-term regional persistence. Because source-sink metrics (i.e., births minus deaths; births and immigrations minus deaths and emigration) describe net population conditions and cancel out gross population counts, they may not adequately identify influential habitats in declining populations. For many nonequilibrium populations, new metrics that maintain the counts of individual births, deaths, and movement may provide additional insight into habitats that most influence persistence.

Appreciating interconnectivity between habitats is key to blue carbon management

We welcome the recent synthesis by Howard et al. (2017), which drew attention to the role of marine systems and natural carbon sequestration in the oceans as a fundamental aspect of climate-change mitigation. The importance of long-term carbon storage in marine habitats (ie “blue carbon”) is rapidly gaining recognition and is increasingly a focus of national and international attempts to mitigate rising atmospheric emissions of carbon dioxide. However, effectively managing blue carbon requires an appreciation of the inherent connectivity between marine populations and habitats. More so than their terrestrial counterparts, marine ecosystems are “open”, with high rates of transfer of energy, matter, genetic material, and species across regional seascapes (Kinlan and Gaines 2003). We suggest that policy frameworks, and the science underpinning them, should focus not only on carbon sink habitats but also on carbon source habitats, which play critical roles in marine carbon cycling and natural carbon sequestration in the oceans.

Bibliometrics analysis on identification of molecula pharmacognosyin based on Web of Science

Objective To analyze the literature characteristics on molecular identification of pharmacognosy, summarize the current research situation and trend in the field and to provide a reference for relative researchers. Methods The papers relevant to molecular identification included in SCIE were statistically analyzed by biblimetric methods from the aspects of publishing year,journals disbution, author’s unit,author’s country or region and technique.And the papers also use the visualization techonology to visual the links between the keywords. Results The total number of the literature for analyzing was 5 108, the numbers of papers increased gradually.These paper involved 3 720 authors, 1 695 organizations. and 421 journals. Authors of the papers mainly from China, the United States and Korea. The traditional Chinese medicine involved were Catharanthusroseus, Panax ginseng, Tobacco,wheat, Artemisia annua. The relative identification technology top 5 were RAPD, microsatellite, AFLP, ISSR, HPLC.Based on visiualization technology, we found the current research hotspots were base source identification, habitats identification, population genetics and molecular phylogeography. Conclusions The research of molecular identification of pharmacognosyin were on the rise. The identification technology and species studied will extend ulteriorly. Key words: Molecular pharmacognosy; Molecular pharmacognosy and identification; Visiualization; Bibliometrics

Alfalfa and Pastures: Sources of Pests or Generalist Natural Enemies?

Pierce's disease of grapevine and almond leaf scorch disease are both caused by the bacterial pathogen Xylella fastidiosa Wells et al. In the Central Valley of California, Draeculacephala minerva Ball (Hemiptera: Cicadellidae) is the most common vector of X. fastidiosa. As alfalfa fields and pastures are considered source habitats for D. minerva, it is recommended that almond orchards and vineyards should be distanced from alfalfa and pastures. Here, risk of alfalfa and pastures serving as sources of D. minerva was compared to the potential benefit of alfalfa and pastures serving as sources of generalist natural enemies belonging to the families Chrysopidae and Coccinellidae. Populations of D. minerva were greatest in pastures, whereas chrysopids were least abundant in pastures, and coccinellids were only moderately more abundant in pastures than in vineyards or almond orchards. Accordingly, risk of pastures serving as a source of D. minerva was not offset by any potential benefit of pastures serving as a source of chrysopids or coccinellids. Abundance of D. minerva in alfalfa was low, whereas abundance of chrysopids and coccinellids in alfalfa was high. Thus, well-maintained alfalfa fields were a minor source of D. minerva that may contribute chrysopids and coccinellids to surrounding habitats. Spissistilus festinus (Say) (Hemiptera: Membracidae), a recently identified vector of grapevine red blotch virus, was abundant in alfalfa fields and was observed in vineyards. Thus, a full evaluation of the risk of planting vineyards near alfalfa may require considering risk associated with movement of S. festinus.

Source–sink dynamics explain the distribution and persistence of an invasive population of common carp across a model Midwestern watershed

Source–sink theory is an ecological framework that describes how site and habitat-specific demographic rates and patch connectivity can explain population structure and persistence across heterogeneous landscapes. Although commonly used in conservation planning, source–sink theory has rarely been applied to the management of invasive species. This study tested whether the common carp, one of the world’s most invasive species, exhibits source–sink dynamics in a representative watershed in the Upper Mississippi River Basin comprised of a dozen interconnected ponds and lakes. To test for source–sink population structure, we used standard fish sampling techniques, tagging, and genetic assignment methods to describe habitat-specific recruitment rates and dispersal. Five years of sampling revealed that while adult carp were found across the entire watershed, reproductive success (the presence of young carp) was restricted to shallow ponds. Additionally, nearly a third of the carp tagged in a representative pond dispersed into the connected deeper lakes, suggesting that ponds in this system serve as sources and lakes as sinks. This possibility was confirmed by microsatellite analysis of carp tissue samples (n = 1041) which revealed the presence of two distinct strains of carp cohabitating in the lakes, whose natal origins could be traced back to one of two pond systems, with many adult carp attempting to migrate back into these natal ponds to spawn. We conclude that the distribution and persistence of invasive carp in complex interconnected systems may often be driven by source–sink dynamics and that their populations could be controlled by suppressing reproduction in source habitats or by disrupting dispersal pathways, instead of culling individuals from sink habitats.

Temporal trends in arthropod abundances after the transition to organic farming in paddy fields.

Organic farming aims to reduce the effect on the ecosystem and enhance biodiversity in agricultural areas, but the long-term effectiveness of its application is unclear. Assessments have rarely included various taxonomic groups with different ecological and economic roles. In paddy fields with different numbers of years elapsed since the transition from conventional to organic farming, we investigated changes in the abundance of insect pests, generalist predators, and species of conservation concern. The abundance of various arthropods exhibited diverse trends with respect to years elapsed since the transition to organic farming. Larval lepidopterans, Tetragnatha spiders, and some planthoppers and stink bugs showed non-linear increases over time, eventually reaching saturation, such as the abundance increasing for several years and then becoming stable after 10 years. This pattern can be explained by the effects of residual pesticides, the lag time of soil mineralization, and dispersal limitation. A damselfly (Ischnura asiatica) did not show a particular trend over time, probably due to its rapid immigration from source habitats. Unexpectedly, both planthoppers and some leafhoppers exhibited gradual decreases over time. As their abundances were negatively related to the abundance of Tetragnatha spiders, increased predation by natural enemies might gradually decrease these insect populations. These results suggest that the consideration of time-dependent responses of organisms is essential for the evaluation of the costs and benefits of organic farming, and such evaluations could provide a basis for guidelines regarding the length of time for organic farming to restore biodiversity or the economic subsidy needed to compensate for pest damage.

Mobility and resource use influence the occurrence of pollinating insects in restored seminatural grassland fragments

AbstractAfter habitat restoration, species need to recolonize from existing populations. The ability of species to recolonize restored habitats likely depends on their traits. This study aimed to test if species traits and isolation from source habitat can explain the presence of insects in restored grasslands. We surveyed the occurrence of hoverflies and bees in 14 restored seminatural pastures as well as in intact seminatural grasslands in the surrounding landscape. We tested how connectivity, time since restoration, and species traits influence if species that are present in the surrounding landscape also occur in restored pastures. Solitary bee species present in the landscape were less likely to occur in restored pastures compared to bumblebees and hoverflies. The occurrence of bumblebees, but not solitary bees or hoverflies, decreased with time since restoration. The occurrence of solitary bees increased but the occurrence of hoverflies decreased with high connectivity. Migratory hoverflies were more likely to occur in restored pastures than nonmigratory hoverflies, especially in pastures with low connectivity. Among both bumblebees and solitary bees, the occurrence was influenced by nesting traits, with the lowest occurrence of parasitic species and of species digging nests in the ground. The subset of the landscape's species pool that occurs in restored pastures has a contrasting set of traits compared with species in intact source habitats. Both mobility and resource use act as filters that influence the assembly of pollinator communities after restoration. A full recovery of pollinator communities is more likely if source populations are available nearby.

Body size and hosts of Triatoma infestans populations affect the size of bloodmeal contents and female fecundity in rural northwestern Argentina.

Human sleeping quarters (domiciles) and chicken coops are key source habitats of Triatoma infestans—the principal vector of the infection that causes Chagas disease—in rural communities in northern Argentina. Here we investigated the links among individual bug bloodmeal contents (BMC, mg), female fecundity, body length (L, mm), host blood sources and habitats. We tested whether L, habitat and host blood conferred relative fitness advantages using generalized linear mixed-effects models and a multimodel inference approach with model averaging. The data analyzed include 769 late-stage triatomines collected in 120 sites from six habitats in 87 houses in Figueroa, Santiago del Estero, during austral spring. L correlated positively with other body-size surrogates and was modified by habitat type, bug stage and recent feeding. Bugs from chicken coops were significantly larger than pig-corral and kitchen bugs. The best-fitting model of log BMC included habitat, a recent feeding, bug stage, log Lc (mean-centered log L) and all two-way interactions including log Lc. Human- and chicken-fed bugs had significantly larger BMC than bugs fed on other hosts whereas goat-fed bugs ranked last, in consistency with average blood-feeding rates. Fecundity was maximal in chicken-fed bugs from chicken coops, submaximal in human- and pig-fed bugs, and minimal in goat-fed bugs. This study is the first to reveal the allometric effects of body-size surrogates on BMC and female fecundity in a large set of triatomine populations occupying multiple habitats, and discloses the links between body size, microsite temperatures and various fitness components that affect the risks of transmission of Trypanosoma cruzi.