Biology subjects

Bahlai, C.

Publications and source records attributed to Bahlai, C..

8 recordsLinked to original sources

bioRxiv2025

Differential Capture Modalities of Insect Traps Produce Contrasting Biodiversity Patterns

Describing insect community and population trends is essential to their conservation. To assess insect populations and communities and identify potential drivers of change in insect populations, we often need to measure in a variety of ways and in a variety of ecosystems. Insect sampling is not standardized: data is frequently collected via different types of insect traps with different targets and modes of capture to sample the insect community. However, different traps may identify contrasting ecological signals, depending on their structure, deployment, and their effective range, and further, these differences may interact with the habitats they are deployed in. Here, we aim to assess the consistency of biodiversity patterns produced from different trapping methods deployed in array across several habitats. We investigated three trapping methods: an ant bait trap, a malaise trap, and a fermentation trap. We deployed these traps in a suburban forested area and at a restored forest. We computed richness and relative abundance of insects captured in each trap and assessed community compositional differences between traps and habitats. We found that each trap type produced differential patterns of richness, abundance, and composition from each other, and these patterns also varied between sites for most trap types. The contrasting patterns observed among traps is likely due to differing effective capture ranges of each trap; traps with smaller effective capture ranges were more sensitive to local habitat conditions than traps with broader effective capture ranges.

ecology↗

bioRxiv2023

Adapting to changing methodology in a long-term experiment

Long-term experiments are critical for understanding ecological processes, but their management comes with unique challenges. As time passes, projects may encounter unavoidable changes due to external factors, like availability of materials, affecting aspects of their research methodology. At the Kellogg Biological Station Long-Term Ecological Research Site, one of many National Science Foundation-funded long-term research stations, a three-decade project recently experienced a supply-chain-induced change in insect sampling methodology in their lady beetle observation study. Since 1989, lady beetles (Coleoptera: Coccinellidae) have been sampled weekly over the growing season using yellow sticky cards. In 2021, the original sticky traps were discontinued by the manufacturer and replaced with a similar, but not identical trap. We conducted a 3-year study while the new traps were phased in to examine how the trap change would impact the observed biodiversity patterns at the site. We examined community metrics and individual taxa captures to examine within year and between year differences in performance between the card types. Overall, we noted several small but statistically detectable differences in capture patterns between the two trap types. After accounting for other sources of variation, we observed a difference in Shannon diversity of insects captured on the two card types, but not richness or abundance, in the overall insect community. Yet, these differences were dwarfed by the magnitude of difference observed between years within card types. For individual taxa, similar patterns held: between trap differences could be detected statistically, but the number of differences between capture rates of traps was less than the number of differences observed for the same trap, between years. Thus, we conclude that while subtle changes in methodology could impact data produced in long-term experiments, in this case the magnitude of this change is smaller than other factors such as time and plant treatment. However, if sustained changes in the capture rates of focal taxa are observed, future data users may use our observations to specifically quantify and correct for these shifting patterns related to the protocol change.

ecology↗

bioRxiv2022

Characterizing insect communities within thin-soil environments

Natural thin-soil environments are those which have little to no soil accumulation atop hard substrates. Many of these natural thin-soil environments, such as alvars, rocky lakeshores or glades, cliffs and cliff bluffs, and barrens, are found in the Great Lakes Region of North America. Due to their ubiquity and ecosystem services they provide, characterizing insects in sensitive environments such as these is important. This study monitored insects in nine thin-soil sites, within three regions, on a 630 km latitudinal gradient in the Southeastern Great Lakes Region of North America from June - August 2019. Over 22,000 insect specimens collected were identified to order or family, and bee specimens were identified to genus or species. We found that overall insect community composition and biodiversity characteristics were similar between the three regions examined. However, the central region had higher taxonomic richness than the southern region. Although unique bee taxa were observed in each region, diversity metrics and community composition of bees were similar among sites. This study provides taxonomic information about the insect, particularly bees, and plant communities in thin-soil environments in this region, which could support conservation and management efforts.

ecology↗

bioRxiv2022

Coexistence between similar invaders: The case of two cosmopolitan exotic insects

Biological invasions are usually examined in the context of their impacts on native species. However, few studies have examined the dynamics between invaders when multiple exotic species successfully coexist in a novel environment. Yet, long-term coexistence of now established exotic species has been observed in North American lady beetle communities. Exotic lady beetles Harmonia axyridis and Coccinella septempunctata were introduced for biological control in agricultural systems and have since become dominant species within these communities. In this study, we investigated coexistence via spatial and temporal niche partitioning among H. axyridis and C. septempunctata using a 31-year dataset from southwestern Michigan, USA. We found evidence of long-term coexistence through a combination of small-scale environmental, habitat, and seasonal mechanisms. Across years, H. axyridis and C. septempunctata experienced patterns of cyclical dominance likely related to yearly variation in temperature and precipitation. Within years, populations of C. septempunctata peaked early in the growing season at 550 degree days, while H. axyridis populations grew in the season until 1250 degree days, and continued to have high activity after this point. Coccinella septempunctata was generally most abundant in herbaceous crops, whereas H. axyridis did not display strong habitat preferences. These findings suggest that within this region H. axyridis has broader habitat and abiotic environmental preferences, while C. septempunctata thrives under more specific ecological conditions. These ecological differences have contributed to the continued coexistence among these two invaders. Understanding mechanisms that allow coexistence of dominant exotic species contributes to native biodiversity conservation management of invaded ecosystems. Open research statementData are already published and publicly available, with those items properly cited in this submission. This submission uses novel code, which is provided, per our requirements, in an external repository to made available in perpetuity, and are available at https://github.com/ReproducibleQM/space_invader. Data sets utilized for this research (Landis 2020) are housed at EDI here: https://portal.edirepository.org/nis/mapbrowse?packageid=knb-lter-kbs.23.30 (doi:10.6073/pasta/f0776c1574808b08c484c1f7645a7357). Weather data was downloaded directly from the Kellogg Biological Station data repository (https://lter.kbs.msu.edu/datatables/7) and downloading the full record. An archival record of these data are available at https://portal.edirepository.org/nis/mapbrowse?packageid=knb-lter-kbs.2.107 (doi:10.6073/pasta/4c30523bae14c4340e4d9c90e72f90c4). Because both databases are living and subject to update as data is collected, databases as used within this study are mirrored within the code repository as CSV files.

ecology↗

bioRxiv2021

Experimental calibration of trapping methods for addressing bias in arthropod biodiversity monitoring

Sampling approaches are commonly adapted to reflect the study objectives in biodiversity monitoring projects. This approach optimizes findings to be locally relevant but comes at the cost of generalizability of findings. Here, we detail a comparison study directly examining how researcher choice of arthropod trap and level of specimen identification affects observations made in small-scale arthropod biodiversity studies. Sampling efficiency of four traps: pitfall traps, yellow ramp traps, yellow sticky cards, and a novel jar ramp trap were compared with respect to an array of biodiversity metrics associated with the arthropods they captured at three levels of identification. We also outline how to construct, deploy, and collect jar ramp traps. Trapping efficiency and functional groups of arthropods (flying, crawling, and intermediate mobility) varied by trap type. Pitfalls and jar ramp traps performed similarly for most biodiversity metrics measured, suggesting that jar ramp traps provide a more comparable measurement of ground-dwelling arthropod communities to pitfall sampling than the yellow ramp traps. The jar ramp trap is a simple, inexpensive alternative when the physical aspects of an environment do not allow the use of pitfalls. This study illustrates the implications for biodiversity sampling of arthropods in environments with physical constraints on trapping, and the importance of directly comparing adapted methods to established sampling protocol. Future biodiversity monitoring schemes should conduct comparison experiments to provide important information on performance and potential limitations of sampling methodology.

ecology↗

bioRxiv2021

Longer study length, standardized sampling techniques, and broader geographic scope leads to higher likelihood of detecting stable abundance patterns in long term deer tick (Ixodes scapularis) studies

BackgroundUnderstanding how study design and monitoring strategies shape inference within, and synthesis across, studies is critical across biological disciplines. Many biological and field studies are short term and limited in scope. Monitoring studies are critical for informing public health about potential vectors of concern, such as Ixodes scapularis (black-legged ticks). Black-legged ticks are a taxon of ecological and human health concern due to their status as primary vectors of Borrelia burgdorferi, which causes Lyme disease. However, variation in black-legged tick monitoring, and gaps in data, are currently considered major barriers to understanding population trends and in turn, predicting Lyme disease risk. To understand how variable methodology in black-legged tick studies may influence which population patterns researchers find, we conducted a data synthesis experiment. Materials and MethodsWe searched for publicly available black-legged tick abundance datasets that had at least 9 years of data, using keywords about ticks in internet search engines, literature databases, data repositories and public health websites. Our analysis included 289 datasets from 7 surveys from locations throughout the US, ranging in length from 9 to 24 years. We used a moving window analysis, which is a kind of non-random resampling approach, to investigate the temporal stability of black-legged tick population trajectories across the US. We then used t-tests to assess differences in stability time across different study parameters. ResultsAll of our sampled datasets required 4 or more years to reach stability. We also found that several study factors can have an impact on the likelihood of a study reaching stability and of data resulting in misleading results if the study does not reach stability. Specifically, datasets collected via dragging reached stability significantly faster than data collected via opportunistic sampling. Datasets that sampled larva reached stability significantly later than those that sampled adults or nymphs. Additionally, datasets collected at the broadest spatial scale (county) reached stability fastest. ConclusionWe used 289 datasets from 7 long term black-legged tick studies to conduct a non-random data resampling experiment, revealing that sampling design does shape inferences in black-legged tick population trajectories and how many years it takes to find stable patterns. Specifically, our results show the importance of study length, sampling technique, life stage, and geographic scope in understanding black-legged tick populations, in the absence of standardized surveillance methods. Current public health efforts based on existing black-legged tick datasets must take monitoring study parameters into account, to better understand if and how to use monitoring data to inform decision making. We also recommend that potential forecasting initiatives consider these parameters when projecting black-legged tick population trends.

bioinformatics↗

bioRxiv2019

Long-term research needed to avoid spurious and misleading trends in sustainability attributes of no-till

Agricultural management recommendations based on short-term studies can produce findings inconsistent with long-term reality. Here, we test the long-term relative profitability and environmental sustainability of continuous no-till agriculture practices on crop yield, soil moisture, and N2O fluxes. Using a moving window approach, we investigate the development and stability of several attributes of continuous no-till as compared to conventional till agriculture over a 29-year period at a site in the upper Midwest, U.S. We find that over a decade is needed to detect the consistent benefits of no-till on important attributes at this site. Both crop yield and soil moisture required periods 15 years or longer to generate patterns consistent with 29-year trends. Only marginally significant trends for N2O fluxes appeared in this period. Importantly, significant but misleading short-term trends appeared in more than 20% of the periods examined. Relative profitability analysis suggests that 10 years after initial implementation, 86% of periods recuperated the initial expense of no-till implementation, with the probability of higher relative profit increasing with longevity. Results underscore the essential importance of decade and longer studies for revealing the long-term dynamics and emergent outcomes of agricultural practices for different sustainability attributes and are consistent with recommendations to support the long-term adoption of no-till management.\n\nGRAPHICAL ABSTRACT\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=187 SRC=\"FIGDIR/small/788240v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (42K):\norg.highwire.dtl.DTLVardef@1e7529eorg.highwire.dtl.DTLVardef@1e11268org.highwire.dtl.DTLVardef@17f8995org.highwire.dtl.DTLVardef@2196fe_HPS_FORMAT_FIGEXP M_FIG C_FIG HIGHLIGHTSO_LIWe test long-term effects of no-till on yield, soil moisture, and N2O fluxes\nC_LIO_LIWe examine 29 years of data with a moving window and relative profitability method\nC_LIO_LIIt takes at least a decade to detect consistent benefits of no-till\nC_LIO_LIShorter studies can produce significant but misleading findings\nC_LIO_LILong studies are essential to reveal the dynamics of agricultural management\nC_LI

ecology↗

bioRxiv2019

Evidence of adaptive host and vector manipulation by plant viruses revealed through combined meta-analysis and modeling approaches.

A growing number of studies indicate that plant viruses enhance their own transmission by modifying host phenotypes and vector behavior, leading to the hypothesis that such effects are manipulations resulting from virus adaptations. However, few studies have linked putative manipulations with virus components, and the true frequency and magnitude of host and vector manipulation across virus taxa remains unknown. To address this knowledge gap, we performed a meta-analysis to quantify convergence in virus effects on hosts and vectors across taxonomic groups that share transmission mechanism traits, and thereby stand to benefit from similar sequences of vector behavior. We then combined meta-analysis outputs with an epidemiological model to assess consequences of manipulation for virus spread. Overall, transmission mechanism traits strongly predicted the magnitude and nature of virus effects on vector preferences and performance. Models parameterized with meta-analysis data demonstrate that manipulation effects enhance virus spread, and that viruses with long acquisition times and retention durations are under strong selection pressure to manipulate transmission. By combining meta-analysis with epidemiological modeling, our results confirm that host and vector manipulation are important aspects of plant virus ecology and evolution while emphasizing the need to incorporate more pathosystems and transmission mechanism traits in future studies.

ecology↗