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1. Intra‐specific variation in migration phenology of American Kestrels ( Falco sparverius ) in response to spring temperatures

   https://doi.org/10.1111/ibi.12953  

   Powers, Breanna F.; Winiarski, Jason M.; Requena‐Mullor, Juan M.; Heath, Julie A. (March 2021, Ibis)

   null (Ed.)

   Abstract In migratory birds, among- and within-species heterogeneity in response to climate change may be attributed to differences in migration distance and environmental cues that affect timing of arrival at breeding grounds. We used eBird observations and a within-species comparative approach to examine whether migration distance (with latitude as a proxy) and weather predictors can explain spring arrival dates at the breeding site in a raptor species with a widespread distribution and diverse migration strategies, the American Kestrel Falco sparverius. We found an interactive effect between latitude and spring minimum temperatures on arrival dates, whereby at lower latitudes (short-distance migrants) American Kestrels arrived earlier in warmer springs and later in colder springs, but American Kestrels at higher latitudes (long-distance migrants) showed no association between arrival time and spring temperatures. Increased snow cover delayed arrival at all latitudes. Our results support the hypothesis that short-distance migrants are better able to respond to conditions on the breeding ground than are long-distance migrants, suggesting that long-distance migrants may be more vulnerable to shifts in spring conditions that could lead to phenological mismatch between peak resources and nesting. 

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2. Characterizing the seasonal abundance and reproductive activity of overwintering Anopheles (Diptera: Culicidae) mosquitoes

   https://doi.org/10.1093/jme/tjae024  

   Dehus, Hannah; Siperstein, Alden; Pomeroy, Laura_W; Meuti, Megan_E; Sallum, ed., Maria_Anice (February 2024, Journal of Medical Entomology)

   Abstract In temperate regions of the United States, female Anopheles mosquitoes respond to low temperatures and short photoperiods by entering an overwintering dormancy or diapause. Diapause in Anopheles results in reduced frequency of blood-feeding and reproductive arrest, indicating a period when pathogen transmission by these mosquitoes is unlikely. However, it is unclear precisely how late into the fall and how early in the spring these mosquitoes are biting, reproducing, and potentially transmitting pathogens. This is further complicated by the lack of clear markers of diapause in Anopheles (e.g., changes in egg follicle length). Our goal was to characterize the seasonal reproductive activity of female Anopheles in central Ohio, United States and evaluate egg follicle length as an indicator of Anopheles diapause. We used traditional mosquito traps and aspirators to collect Anopheles from urban woodlots and culverts, respectively, from late September 2021 through mid-May 2022 in central Ohio. By measuring their egg follicle length, reproductive status, and blood-feeding status, we found that egg follicle length is not a reliable indicator of Anopheles diapause. We also found that a small proportion of An. punctipennis (Say), An. perplexens (Ludlow), and An. quadrimaculatus (Say) continued to bite and reproduce into early November 2021 and that females of these species terminated reproductive dormancy and began biting by mid-March 2022. This period of reproductive activity extends beyond current mosquito surveillance and control in Ohio. Our findings suggest that within temperate regions of North America, Anopheles have the capacity to transmit pathogens throughout the spring, summer, and fall. 

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3. Precipitation timing and soil substrate drive phenology and fitness of Arabidopsis thaliana in a Mediterranean environment

   https://doi.org/10.1111/1365-2435.14391  

   Martínez‐Berdeja, Alejandra; Okada, Miki; Cooper, Martha D.; Runcie, Daniel E.; Burghardt, Liana T.; Schmitt, Johanna (July 2023, Functional Ecology)

   Abstract In Mediterranean climates, the timing of seasonal rains determines germination, flowering phenology and fitness. As climate change alters seasonal precipitation patterns, it is important to ask how these changes will affect the phenology and fitness of plant populations. We addressed this question experimentally with the annual plant speciesArabidopsis thaliana.In a first experiment, we manipulated the date of rainfall onset and recorded germination phenology on sand and soil substrates. In a second experiment, we manipulated germination date, growing season length and mid‐season drought to measure their effects on flowering time and fitness. Within each experiment, we manipulated seed dormancy and flowering time using multilocus near‐isogenic lines segregating strong and weak alleles of the seed dormancy geneDOG1and the flowering time geneFRI. We synthesized germination phenology data from the first experiment with fitness functions from the second experiment to project population fitness under different seasonal rainfall scenarios.Germination phenology tracked rainfall onset but was slower and more variable on sand than on soil. Many seeds dispersed on sand in spring and summer delayed germination until the cooler temperatures of autumn. The high‐dormancyDOG1allele also prevented immediate germination in spring and summer. Germination timing strongly affected plant fitness. Fecundity was highest in the October germination cohort and declined in spring germinants. The late floweringFRIallele had lower fecundity, especially in early fall and spring cohorts. Projections of population fitness revealed that: (1) Later onset of autumn rains will negatively affect population fitness. (2) Slow, variable germination on sand buffers populations against fitness impacts of variable spring and summer rainfall. (3) Seasonal selection favours high dormancy and early flowering genotypes in a Mediterranean climate with hot dry summers. The high‐dormancyDOG1allele delayed germination of spring‐dispersed fresh seeds until more favourable early fall conditions, resulting in higher projected population fitness.These findings suggest that Mediterranean annual plant populations are vulnerable to changes in seasonal precipitation, especially in California where rainfall onset is already occurring later. The fitness advantage of highly dormant, early flowering genotypes helps explain the prevalence of this strategy in Mediterranean populations. Read the freePlain Language Summaryfor this article on the Journal blog. 

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4. Draft Genome Sequence of the Cyanobacterium Synechococcus sp. Strain Nb3U1

   https://doi.org/10.1128/mra.00251-22  

   Pierpont, Christopher L.; Ohkubo, Satoshi; Miyashita, Hideaki; Miller, Scott R. (May 2022, Microbiology Resource Announcements)

   Maresca, Julia A. (Ed.)

   ABSTRACT We report the 3.5-Mb draft genome sequence of the cyanobacterium Synechococcus sp. strain Nb3U1, which was isolated from a microbial mat sample collected from Nakabusa Hot Spring, Nagano, Japan. 

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5. Seasons of Syn

   https://doi.org/10.1002/lno.11374  

   Hunter‐Cevera, Kristen R.; Neubert, Michael G.; Olson, Robert J.; Shalapyonok, Alexi; Solow, Andrew R.; Sosik, Heidi M. (November 2019, Limnology and Oceanography)

   Abstract Synechococcusis a widespread and important marine primary producer. Time series provide critical information for identifying and understanding the factors that determine abundance patterns. Here, we present the results of analysis of a 16‐yr hourly time series ofSynechococcusat the Martha's Vineyard Coastal Observatory, obtained with an automated, in situ flow cytometer. We focus on understanding seasonal abundance patterns by examining relationships between cell division rate, loss rate, cellular properties (e.g., cell volume, phycoerythrin fluorescence), and environmental variables (e.g., temperature, light). We find that the drivers of cell division vary with season; cells are temperature‐limited in winter and spring, but light‐limited in the fall. Losses to the population also vary with season. Our results lead to testable hypotheses aboutSynechococcusecophysiology and a working framework for understanding the seasonal controls ofSynechococcuscell abundance in a temperate coastal system. 

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