Neotropical Environments Research Articles

Diet overlap of overwintering migratory birds on the northern coast of the Yucatan Peninsula

Previous studies of overwintering migratory birds in neotropical environments have found that species co-occur in the same habitats despite high diet overlap. Hence, discovering subtle diet differences within habitats can help explain patterns in bird species diversity. The Yucatan Peninsula in Mexico is an important region for overwintering migratory birds, but little is known about how habitat differences in food resources contribute to bird diversity. To address the knowledge gap, we compared the degree of overlap in the diet of all terrestrial migratory birds within and between mangrove and tropical dry forests on the Yucatan Peninsula’s northern coast. We collected data on the consumption of food items through direct observation of birds feeding on four transects in each habitat every week (12 weeks) during the non-breeding season (i.e., overwinter, December-February). We recorded 19 species, 15 species in mangrove and 15 species in forest, with 11 of those found in both habitats. In both habitats, diet overlap was high. However, species present only in the tropical dry forest had less overlap than species occurring in both habitats, indicating that diet specialization might restrict the range of habitats that a species can occupy. On the other hand, species present only in the mangrove had similar diet overlap to species present in both habitats. The diet variation that did exist was greater within than between habitats possibly due to intraspecific diet differences among different geographic locations. Although small, within-habitat diet differences might be key to allowing species to coexist locally in the Yucatan, thus supporting studies demonstrating a similar mechanism in other neotropical regions. More generally, the information we provide on bird diet can be used to discover whether threats like anthropogenic development precipitate species loss via altering the resource base upon which birds rely.

Endoparasitic helminth fauna and diet of Geophagus sveni (Pisces) in Upper Paraná River basin.

In freshwater ecosystems, parasite infection patterns are influenced by factors including spatial-temporal variations, host diet, and habitat. Fish often change diets, affecting their parasite communities. This study focused on non-native host fish Geophagus sveni, aiming to characterize diet and endoparasitic helminth fauna patterns in the invaded area, investigating spatial and seasonal possible differences of endoparasite infections and correlating with host diet, in São José dos Dourados River and Tietê River areas. The host fish were collected in these areas during the dry and rainy season using gillnets. The endoparasites were collected and preserved in alcohol and identified using taxonomic methods, and stomach contents were examined for diet analysis. Parasitism descriptors were calculated and evaluated spatially and seasonally by ANOVA and the Kruskal-Wallis tests. PERMANOVA assessed G. sveni diet differences, and RDA correlated the endohelminth abundance with the host diet. Two endoparasites were recorded: metacercariae of Austrodiplostomum compactum (Trematoda) and larvae and adults of Raphidascaris (Sprentascaris) lanfrediae (Nematoda). Spatial differences were observed for the mean abundance and prevalence of R. (S.) lanfrediae and A. compactum prevalence. Seasonal variations of parasitic descriptors occurred for the nematode in the Tietê River area. The detritus and aquatic insects were the most consumed items by G. sveni. Detritus consumption positively correlates with nematode abundance. The findings indicate that factors such as artificial channels and rainfall, which can influence resource availability, may affect the fish's diet and potentially influence the structure of its endoparasite community. The study emphasizes the importance of understanding trophic chain-transmitted parasites and calls for further research in Neotropical environments.

Guiding the path of larvae: The potential of light traps in Neotropical freshwater fish research

Light traps are devices utilized in biomonitoring studies across various aquatic environments. Although light traps are used globally, few studies report their efficacy in capturing fish larvae in the Neotropics. To address this gap, this study aimed to assess the efficacy of light traps in capturing larvae of six fish species commonly found in Neotropical rivers. Additionally, we aimed to evaluate the effect of light color on larval capture. To accomplish this, we selected larvae from six species: Cyprinus carpio, Ctenopharingodon idella, Piaractus mesopotamicus, Pimelodus maculatus, Prochilodus lineatus, and Rhamdia quelen. Each experiment lasted seven days, and six types of traps were tested, including those without light (control) and those with light (green, red, yellow, white, and blue), and installed in triplicate. A total of 18 traps were randomly positioned in earthen ponds containing the six species of interest. Each species was assessed separately in six experiments. Larvae were counted, measured, and identified daily according to their developmental stage. The light traps collected 30,498 larvae, whereas the control traps only collected 39 larvae by the end of the experiment. Larvae from species of the Cypriniformes order were the most captured, while those from the Siluriformes order were least captured. The light traps exhibited selectivity in capturing larvae at different developmental stages, which varied according to species. Traps installed with green lights captured a greater number of larvae and were more efficient at capturing larvae from a wider variety of species. In contrast, traps installed with red light led to the capture of fewer larvae. Therefore, by their ability to attract a greater number of larvae, compared to control, and selectively capture larvae at different developmental stages at variable rates, depending on light source, light traps can be a valuable tool in biomonitoring and managing fish larvae in Neotropical environments.

Do root secondary xylem functional traits differ between growth forms in Fabaceae species in a seasonally dry Neotropical environment?

Whole-plant performance in water-stressed and disturbance-prone environments depends on a suitable supply of water from the roots to the leaves, storage of reserves during periods of shortage, and a morphological arrangement that guarantees the maintenance of the plants anchored to the soil. All these functions are performed by the secondary xylem of roots. Here, we investigate whether different growth forms of Fabaceae species from the seasonally dry Neotropical environment have distinct strategies for water transport, mechanical support and non-structural carbon and water storage in the root secondary xylem. We evaluated cross-sections of root secondary xylem from species of trees, shrubs and subshrubs. We applied linear models to verify the variability in secondary xylem anatomical traits among growth forms. Secondary xylem with larger vessels and lower vessel density was observed in tree species. Vessel wall thickness, vessel grouping index, potential hydraulic conductivity and cell fractions (vessels, fibres, rays and axial parenchyma) were not statistically different between growth forms, owing to the high interspecific variation within the groups studied. Our results showed that the variability in anatomical traits of the secondary xylem of the root is species specific. In summary, the cellular complexity of the secondary xylem ensures multiple functional strategies in species with distinct growth forms, a key trait for resource use in an environment with strong water seasonality.

Similar survival of birds between wet and seasonally dry Neotropical environments

Studies in the tropics suggest a regional similarity in survival rates of adult birds; however, this literature often overlooks species in semi‐arid tropical environments. Bird survival in seasonally dry environments (e.g. seasonally dry tropical forests (SDTFa)) may be lower than that in more constantly wet areas (e.g. tropical rainforests (TRFs)), especially if the birds are negatively affected by seasonal rainfall or food‐limitation. However, survival could be similar across these tropical environments, as the asymmetry between young and adult mortality tends to be high in all tropical areas, and the higher risk of mortality in young animals may favour adult survival (residual reproductive investment) regardless of the local climatic conditions. To fill this knowledge gap, we tested the hypothesis that bird survival is similar between seasonally dry (SDTF) and constantly wet (TRF) Neotropical environments. We estimated the apparent survival of 27 South American bird populations from three SDTF areas and 39 populations from a TRF. Apparent survival was estimated from Cormack–Jolly–Seber (CJS) models fitted using a Bayesian structure and the resulting variation in survival rates between study areas and with body mass was explored using a Bayesian phylogenetic mixed model. Apparent annual survival of passerines did not differ between areas (geometrical mean of survival: SDTF = 0.50, 0.56, 0.64; TRF = 0.58), but body mass was positively associated with survival. The variation in bird survival was partially explained by phylogenetic relationships among species. Our results suggest that bird survival is regionally similar in Neotropical forests, despite the climatic variation. We discuss possible physiological and behavioural mechanisms adopted by birds in SDTFs to attenuate effects of environmental seasonality on survival.

Unraveling the genomic complexity of sylvatic mosquitoes in changing Neotropical environments

Sylvatic New World mosquitoes (e.g. Old-growth Forest species) can transmit viruses among non-human primates. This could be a continuous source of viral cycling and spillover events from animals to humans, particularly in changing environments. However, most species of Neotropical sylvatic mosquitoes (genera Aedes, Haemagogus, and Sabethes), which include vector and non-vector species, currently lack genomic resources because there is no reliable and accurate approach for creating de novo reference genomes for these insects. This is a major knowledge gap in the biology of these mosquitoes, restricting our ability to predict and mitigate the emergence and spread of novel arboviruses in Neotropical regions. We discuss recent advances and potential solutions for generating hybrid de novo assemblies from vector and non-vector species using pools of consanguineous offspring. We also discussed research opportunities likely to emerge from these genomic resources.

Inter-annual prey fluctuation of Odocoileus virginianus in Maya group hunting (batida) in the Yucatan Peninsula

In Neotropical environments, we know little about the abundance of wild vertebrates traditionally hunted. Based on subsistencehunting records (2005-2019) as well as ethnographic information from Maya peasant-hunters, we assessed the inter-annual capture rate of white-tailed deer (Odocoileus virginianus) in a rural community in the northwest of the Yucatan Peninsula. We found that the number of prey decreased over the years, showing a declining capture rate (prey/trip) that decreased by as much as 50% from the first (2005-2006) to the third period (2010-2011) of records. The majority of peasant-hunters interviewed (74%; N = 31) perceived this reduction in deer to have taken place mainly over the past 10 years as consequence of hunting (71%). The agreement between the hunting trend and peasants’ perceptions regarding the abundance of white-tailed deersuggests that this species may be at risk in future scenarios of use in northwest of contemporary Mayab.

The first genomic resource for the ‘near threatened’ Neotropical otter Lontra longicaudis (Carnivora: Mustelidae): mitochondrial genome characterisation and insights into phylomitogenomic relationships in the family Mustelidae

ABSTRACT The Neotropical otter Lontra longicaudis is a top predator in aquatic ecosystems from North, Central, and South America and is subjected to substantial environmental distress due to historic and contemporary anthropogenic disturbance. Currently, L. longicaudis is considered ‘near threatened’ by the International Union for Conservation of Nature Red List of Threatened Species. This study renders the first genomic resource for L. longicaudis; its mitochondrial genome was assembled and characterised in detail. The AT-rich mitochondrial genome of L. longicaudis was 16,436 bp in length and encoded 13 protein coding genes (PCGs), 22 transfer RNA genes, two ribosomal RNA genes, and a 994 bp long putative control region (CR). The heavy use of CTA (Leu), ATA (Met), and ATC (Ile) codons in PCGs contributes to the AT-rich nature of this genome. Out of 22 tRNAs, tRNA-Ser (AGY) (trnS1) lacked a typical ‘cloverleaf’ secondary structure. In the CR, numerous microsatellites and two tandem repeats were detected as well as multiple ‘hairpin’ structures. Ka/Ks values estimated for all but one PCG were < 1, indicating purifying selection in most PCGs. atp8 experienced neutral selection. A phylogenomic analysis based on PCGs confirms the monophyly of the family Mustelidae and also supports the monophyletic status of the subfamilies Guloinae, Helictidinae, Melinae, Mustelinae and Lutrinae; Ictonychinae was found to be polyphyletic. In the Lutrinae, L. longicaudis had an early branching position. The characterisation of a complete mitochondrial genome in the Neotropical otter L. longicaudis constitutes the first step towards supporting conservation efforts using genomic tools in this and other mustelids inhabiting aquatic neotropical environments under considerable contemporary anthropogenic disturbance.

Mutualistic interaction network structure between bird and plant species in a semi-arid Neotropical environment

Mutualistic interactions between animals and plants are essential for ecosystem functioning, providing ecosystem services such as pollination and seed dispersal. The temporal dynamics of plant phenology and animal abundance, induced by seasonal variation in precipitation and resource availability, may influence the structure of animal-plant interaction network. In this paper, we analyzed the mutualistic network structure between birds and plants in a seasonally tropical dry forest in Brazil during the dry and rainy seasons. We recorded 160 interactions between 21 bird species and 11 plant species. In general, networks had low connectance (C = 26%), nestedness (wNODF = 27.54), and modular pattern (Qw = 0.33). Despite the number of interactions being higher in the rainy season, network parameters were consistent across the seasons and presented no explicit differences. However, the network connectance was slightly higher in the rainy season than in the dry season, while the specialization index was higher in the dry season than in the rainy season. Elaenia sp., Mimus saturninus, and Cyanocorax cyanopogon were the bird species that presented the highest number of links. On the other hand, Xiquexique gounellei, Cereus jamacaru, and Pilosocereus pachycladus were the most consumed plant species. The generalized pattern observed suggests that bird-plant interaction in Caatinga may be appropriate to the variable and irregular patterns found in dry forests. Our data reinforce the role of species of the Cactaceae family in maintaining bird communities in semiarid environments. Therefore, due to the high functional importance of those cacti species in influencing both the network stability and the species maintenance in the community, priority attention should be given to them in conservation programs.

Biological Detoxification Pattern Responses by a Sentinel Bivalve to Metalliferous Atmospheric Particulate Matter in Neotropical Estuarine Environments

Biological Detoxification Pattern Responses by a Sentinel Bivalve to Metalliferous Atmospheric Particulate Matter in Neotropical Estuarine Environments

Myxomycetes associated with three different types of Neotropical urban landscapes

Urban ecology is a research field gaining momentum due to contextual pressures to study macroecological effects on biodiversity. Herein, we evaluated the occurrence of myxomycetes in three urban Neotropical environments representing different levels of conurbation within different life zones. We used the moist chamber technique set up with ground litter collected by public roads for such evaluation. Results showed that 79% of the 420 moist chambers yielded myxomycetes and the same number of samples generated 570 records. The highest number of records and species were found in the cornurbated widespread city of the premontane moist forest life zone; and fewer records and species were recorded in the two non-conurbated compact cities. The lowest number of records was associated with the lowland dry forest life zone, whereas the lowest number of species was recorded in the desertic context. In general, more records and more species were observed in the outer zones relative to the urban centre but no significant differences were observed in either case. It is unlikely that the life zone characteristics could have primarily determined the results and highly likely played a secondary role. Also, previous geographical analyses in cities have reported no differences in myxomycete abundance or species richness in relation to the central parts of the urban landscape. The results presented herein support the latter idea, but also suggest that the presence of inter-conurbated green spaces and availability of substrates might play a role in the occurrence of sporocarps of myxomycetes in urban environments.

Ichthyofauna of the Água das Araras stream, Paranapanema River basin, upper Paraná River system, Southern Brazil

ABSTRACT This study comprises the first fish inventory of the Água das Araras stream, a small tributary of the Laranjinha River, in the upper Paraná River basin. Four samplings were carried out seasonally between June 2010 and July 2011, in 12 collecting sites distributed from the headwater to the mouth of Água das Araras stream and its tributaries, using seines and gill nets to capture specimens. A total of 5,328 specimens were collected, distributed in six orders, 15 families, 33 genera, and 41 species. The most representative orders, in terms of species richness, were Siluriformes and Characiformes. Among the families, Characidae (eight species) and Loricariidae (seven species) presented higher richness contributing together with approximately 36.6% of all collected species. The most frequent species captured in ≥75% of the sampled sites were Astyanax lacustris, Characidium aff. zebra, Corydoras aeneus, and Imparfinis schubarti. The classification of species with the Kendeigh Index highlighted the following ranking of the more abundant species: Phalloceros harpagos, C. aeneus, A. lacustris, and I. schubarti. Finally, our results emphasize the importance of sampling small aquatic bodies, revealing their potential for maintaining a significant portion of fish diversity in Neotropical freshwater environments.

Amazonian mammal monitoring using aquatic environmental DNA.

Environmental DNA (eDNA) metabarcoding has emerged as one of the most efficient methods to assess aquatic species presence. While the method can in theory be used to investigate nonaquatic fauna, its development for inventorying semi-aquatic and terrestrial fauna is still at an early stage. Here we investigated the potential of aquatic eDNA metabarcoding for inventorying mammals in Neotropical environments, be they aquatic, semi-aquatic or terrestrial. We collected aquatic eDNA in 96 sites distributed along three Guianese watersheds and compared our inventories to expected species distributions and field observations derived from line transects located throughout French Guiana. Species occurrences and emblematic mammalian fauna richness patterns were consistent with the expected distribution of fauna and our results revealed that aquatic eDNA metabarcoding brings additional data to line transect samples for diurnal nonaquatic (terrestrial and arboreal) species. Aquatic eDNA also provided data on species not detectable in line transect surveys such as semi-aquatic, aquatic and nocturnal terrestrial and arboreal species. Although the application of eDNA to inventory mammals still needs some developments to optimize sampling efficiency, it can now be used as a complement to traditional surveys.

Hummingbird (Aves: Trochilidae) assemblage using resources from the exotic African tuliptree, Spathodea campanulata (Bignoniaceae) in a Neotropical altered environment, southeastern Brazil.

The non-native African tuliptree, Spathodea campanulata (P. Beauv), is widely distributed in altered Neotropical environments, where hummingbirds are important pollinators. We investigated the assemblage of hummingbirds which fed on its nectar and described their behavior, to understand possible influences of the exotic tree on the territorial behavior in an altered environment in southeastern Brazil. Seven species fed on flower resources, mainly Eupetomena macroura (Gmelin, 1788), Amazilia lactea (Lesson, 1832), and Florisuga fusca (Vieillot, 1817). Visiting time was positive correlated with number of flowers accessed, but in most visits, hummingbirds get the nectar by pillage, instead of frontal access. Flower availability varied throughout months; however, we found no evidence of significative correlation between available flowers and number of agonistic encounters. Despite a high number of animal-plant interactions and a strong territorialism of some species observed in African tuliptree foraging site, there may be other plants at local scale influencing the behavioral patterns observed.

Seasonality and interspecific competition shape individual niche variation in co‐occurring tetra fish in Neotropical streams

AbstractThe drivers of intraspecific niche variation and its effects on species interactions are still unclear, especially in species‐rich Neotropical environments. Here, we investigated how ecological opportunity and interspecific competition affect the degree of individual trophic specialization and the population niche breadth in tetra fish. We studied the four ecologically similar species (Psalidodon aff. gymnodontus, P. aff. paranae, P. bifasciatus, and Bryconamericus ikaa) in subtropical headwater streams (three sites with two co‐occurring species and three sites with only one species). We sampled fish in two contrasting seasons (winter/dry and summer/wet) and quantified their trophic niches using gut content analysis. Psalidodon bifasciatus was the only species distributed over all the sampled streams. We observed seasonal differences in population trophic niche breadth of P. bifasciatus just when this species co‐occurred with P. aff. gymnodontus. These findings confirm the complex nature of the effects of interspecific competition, depending, for instance, on the identity of the competitor. The degree of individual specialization of P. bifasciatus was higher in the winter, and it was not influenced by the presence of another species. Conversely, the other two Psalidodon species studied presented greater individual specialization in the summer, when fish consumed a higher proportion of allochthonous items (terrestrial insects and seeds), and there were no effects only for B. ikaa. Herein, our results suggest that seasonality in food‐resource availability is a major driver of niche variation and it has the potential to play an important role in how these similar tetra species interact and coexist.Abstract in Portuguese is available with online material.

A new bat species of the genus Myotis with comments on the phylogenetic placement of M. keaysi and M. pilosatibialis

Molecular studies of Neotropical Myotis (Chiroptera, Vespertilionidae) in the last decade have uncovered substantial cryptic diversity. One example is M. keaysi pilosatibialis , which is characterized by a complex taxonomy derived from low morphological variation. Herein, we studied cryptic diversity of a high elevation clade from premontane and montane forest of Chiriqui Province (Panama), Cordillera Oriental (Ecuador), and Valle del Silencio (Costa Rica). Additionally, we disentangle relationships of M. k. keaysi and M. k. pilosatibialis by determining their phylogenetic placement within the Neotropical Myotis radiation. In the process, we identified a new lineage of species level hierarchy that is described herein. We used an integrative taxonomy approach, using a combination of linear morphometrics, qualitative morphology, molecular phylogenetics, and climatic analysis. The newly identified lineage is a sister species to M. pilosatibialis str., but differs from M. sp. (Quintana Roo, Mexico), M. keaysi str. , and M . oxyotus gardneri in size and other quantitative morphological characters in addition to both nuclear and mitochondrial DNA sequence divergence. Based on our phylogenetic analysis of partial cytochrome b sequence, the polyphyly of M . keaysi str. and M. pilosatibialis str. is resolved, with M . keaysi str. paraphyletic to M . ruber and M . simus . Myotis pilosatibialis is part of a monophyletic clade that is sister to the newly identified species. This report refines our understanding of taxonomy and systematics of the Myotis pilosatibialis complex of bats, identifies and describes a new species of Myotis, and more broadly it contributes to efforts to characterize species in this genus in Neotropical environments. Based on its distribution, we classified this newly described species as paramontane due to its restriction to premontane and montane forest of Chiriqui Province (Panama), Valle del Silencio (Costa Rica), and Cordillera Oriental (Ecuador). These habitats are susceptible to the effects of climate change, in addition to ongoing habitat destruction.

The effects of rainfall and arthropod abundance on breeding season of insectivorous birds, in a semi-arid neotropical environment

Rainfall in tropical semi-arid areas may act as a reliable cue for timing bird reproduction, since it precedes future food supply. With this in mind, we set-up a study to test the reproductive response of insectivorous bird to arthropod abundance and rainfall patterns. Sampling occurred in a seasonally dry Neotropical forest, in north-eastern Brazil, between October, 2015 and October 2016, at 14-day intervals. We used brood patch to assess reproductive periodicity of insectivorous birds (eight species, 475 captures, 121 patch records). We sampled arthropods to quantify abundance, using biomass and number of individuals (1755 individuals, 15 Orders). Rainfall temporal distribution was analyzed using daily precipitation data. We used a cross-correlation function to test for correlation and time-lags between the covariates under study. Both the number of reproductively-active birds and arthropod abundance were higher in time periods close to the rainy season. Increase in arthropod biomass in the aerial stratum preceded the period of greatest rainfall by one (14 days, r = 0.44) to three sampling periods (0.47). In contrast, the highest proportion of individuals with brood patches occurred after the main rainfall peak, with the strongest relationship occurring after two (0.52) to four (0.50) time lags. Finally, the proportion of individuals with brood patches was positively correlated with aerial stratum arthropod biomass when five time lags were considered (0.55). Our results support the hypothesis of a temporal process involving rainfall, arthropods and reproduction of insectivorous birds in the wet/dry tropics. However, rainfall did not appear to act as a cue for the timing of reproduction, since records indicated higher arthropod biomass before the main rainfall peak. At least occasionally in the study area, insectivorous bird reproduction peaks after food abundance.

In the Spotlight-Postdoc.

Maryna Lesoway received the 1st place for a Postdoctoral Oral Presentation at the 2019 meeting of the Pan-American Society for Evolutionary Developmental Biology. She is a recipient of Whitman Center Early Career Investigator Awards at the Marine Biological Laboratory, Woods Hole (2017, 2018), of an Emerging Models Grant of the Society for Developmental Biology (2017), and of an EDEN: Evo-Devo-Eco Network Research Exchange Award (2011) Website: https://marynalesoway.com With whom and where did you study? Right now, I am working with Jonathan Henry in Illinois, where we've been building infrastructure to support growing marine animals like calyptraeids (slipper snails) in non-marine labs, and digging into the sexual development of these crazy snails. Before that, I did my PhD in Biology as a student in the Neotropical Environment Option, a joint program between McGill University in Montreal and the Smithsonian Tropical Research Institute in Panama. This gave me the opportunity to build a project combining my interests in larval biology with EvoDevo approaches. At McGill, I was supervised by Ehab Abouheif, who taught me everything I know about eco-evo-devo. At STRI, I was supervised by Rachel Collin, who showed me the diversity of the calyptraeids and what a great system they are to work with. Before that, I did a Master's degree at the University of Victoria with Louise Page, who introduced me to EvoDevo and patiently taught me microscopy and imaging. What got you interested in Biology? When did you know EvoDevo was for you? It started with an undergraduate field course. In school, I had always liked my biology classes, but until that point I was planning to go into medicine, because that's what smart kids who were good at biology did. I had taken all the invertebrate biology courses offered at the University of Calgary during my bachelor's degree, so I signed up to take Invertebrate Biology at the Bamfield Marine Sciences Center (BC, Canada) too. It didn't hurt that there was a scholarship to help with the costs. That summer, it was taught by Sally Leys (University of Alberta), and it was the first time I encountered living invertebrates in their natural habitat—such a difference from the preserved specimens in my lab courses in landlocked Calgary! It was also the first time that I designed my own research project (I spent a long time looking for penis-fencing behavior in the local flatworms) and realized that research was a career option. I wrote the MCAT that same summer, but applied to graduate school instead of medical school. What makes an EvoDevo lab particularly welcoming? In my experience, the best places to work have a diversity of people, organisms, and approaches. EvoDevo labs usually have this feature by default. There are many ways to do and think about EvoDevo, and it is this openness to new things—new models, new tools, new approaches—that makes it exciting to work in an EvoDevo lab. The best labs that I've worked in have been collaborative and supportive, and excited about the biology of the whole organism. I love working with people who share tools and ideas. That's how we advance the field the fastest—by collaboration, and not by competition. What is the biggest challenge you face as a postdoc? What are issues that you feel the discipline still needs to address? The hardest part of being a postdoc is the uncertainty of what happens next. The academic job market is hard, and what with the COVID-19 pandemic, US immigration issues, and everything else going on in the world, it just got much harder. On a career level, I worry about how long it takes to build new tools and techniques in nontraditional models, especially in such a competitive environment. Experiments can take longer in new models because you often have to start from scratch, and making multi-species comparisons only adds to this. Expectations (often my own) can be unrealistic. I have also been told by that I haven't specialized enough on a single area of research and that this will make it difficult to be hired. I don't believe that, but sometimes it can feel like search committees are only excited about interdisciplinarity in theory. I've also been thinking a lot more about equity and social justice issues. These are big challenges that have not been seriously addressed in academia. As a white woman I am not an underrepresented minority in biology, so the challenge is how I can use my privilege to change structural issues.

Structural features and contribution of belowground buds to conservation of Fabaceae species in a seasonally dry Neotropical environment

Resprouting from belowground buds is an important mechanism to increase aboveground branching. This trait is particularly frequent in various members of Fabaceae. However, there are scant anatomical studies on belowground buds including information about their location in the plant body in these species. Herein we examined the anatomy of belowground buds and organs that support these buds in herbaceous and woody Fabaceae species. Adventitious buds located in the root-shoot transition zone (root crown) were the predominant type of belowground buds in herbaceous and subshrubby species. Moreover, some woody species showed lateral roots with root buds growing near the soil surface. The root structure was confirmed by the centripetal maturation of the primary xylem (exarch xylem). Anatomical analyses of Cenostigma pluviosum and Senna pilifera roots revealed numerous reparative buds that develop from calli. Reparative buds were formed only after injury to root tissues or shoot removal. On the other hand, the roots of Machaerium eriocarpum and Muellera nudiflora showed additional buds with bud traces connected to the primary xylem. Additional buds were found in uninjured young roots and in root segments that were kept in a greenhouse condition. Our findings show that the species examined of Fabaceae are able to resprout from adventitious buds located in roots and root crowns. This trait seems to be advantageous for conservation of these species in the Brazilian Chaco, which is characterised by dry seasons associated with frost and extensive cattle raising.

Colonization of benthic invertebrates on artificial and natural substrate in a Neotropical lotic environment in Southern Brazil

The objective of this research was to validate the colonization process on natural and artificial substrates by benthic invertebrates in a tropical stream in South Brazil. The samples were performed in July and August-2012, and 32 samplers were used, being 16 natural and 16 artificial substrates. In each sample, two replicas were taken for each substrate at the 2th, 4th, 7th, 14th, 21th 28th, 35th and 42th days of colonization. The organisms were identified to the lowest possible taxonomic level. In both substrates 3,070 benthic invertebrates were detected, of which 1,753 individuals were collected on the natural substrate, and 1,317 on the artificial substrate. From the identified taxa 8.5% were not dominant (Anacroneuria, Orthocladiinae, Tupiara, Smicridea, Baetodes, Tupiperla, Macrogynoplax, Gripopteryx, Cylloepus, Macrelmis, Microcylloepus, Hetaerina, Argia, Coryphaeschna, Atopsyche, Pomacea, Corydalus, Leptohyphes and Eccoptura), and 31.5% were dominant (Tanypodinae, Chironominae, and Paragripopteryx). The genus Simulium was very common, dominant and abundant, representing 65% of the collected individuals. No significant difference was found in the abundance and species composition between artificial and natural substrates. On the natural substrate, the higher colonization index was at the 35th day with 459 individuals, and the lowest was at the 14th day, with 87. On the artificial substrate the highest index was at the 42th day with 337 individuals, and the lowest was at the 4th day, with 85. Both natural and artificial substrates are efficient in characterizing the benthic community. In the evaluation of the ecological succession, it was not possible to observe a pattern that described the process, since the composition was nearly constant throughout the study period.