Diplochory in western chokecherry: you can��t judge a fruit by its mesocarp

Western chokecherry (Prunus virginiana var. demissa, Rosaceae) is dispersed by frugivorous birds and carnivores, but it has large seeds that are potentially attractive to rodents that could act as seed predators and dispersers. Here, we quantify the benefits of primary dispersal by birds and secondary dispersal by scatter-hoarding rodents. In the fall, avian frugivores (mostly American robins, Turdus migratorius, and cedar waxwings, Bombycilla cedrorum) consumed 87% of the fruit crop and dispersed 67% of the fruit crop away from parent plants. Rodents removed 89% of seeds that simulated bird-dispersed seed rain from transects in riparian zones and 58% from transects in upland habitats. Rodents scatter-hoarded 91.6% of the seeds they removed, burying most in small caches (two to eight seeds) 8?C25?mm deep. About 39% of the seeds in spring caches produced seedlings. Inside rodent-proof exclosures, 52.1% of seeds buried to simulate rodent caches produced seedlings, 29.7% of which were still alive after 1?year. In contrast, only 3.8% of seeds placed on the soil surface, simulating dispersal by avian frugivores, produced seedlings. Seed dispersal by frugivorous birds likely contributes to colonization of unoccupied habitat through long-range dispersal and to escape from distance-dependent seed mortality near the parent plant. Despite seed losses, rodents offer short-range seed dispersal and bury seeds in more favorable sites for germination, improving seedling emergence and establishment. The combined mechanisms of seed dispersal significantly enhanced chokecherry seedling recruitment by providing more dispersal-related benefits than either frugivorous bird or scatter-hoarding rodents could provide alone.     

If you can’t stand the heat,stay out of the city: Thermal reaction norms of chitinolytic fungi in an urban heat island

Elevated soil and air temperatures in urban heat islands have been exerting evolutionary pressure on organisms for decades in some cities. We measured thermal reaction norms (18–26 °C) for growth rate of four species of common chitinolytic fungi from an oak forest in an urban heat island and a corresponding rural area. Urban isolates of Chrysosporium pannorum and Trichoderma koningii grew faster than rural isolates at 26 °C, but grew slower than rural isolates at 18 °C. Urban isolates of Torulomyces lagena and Penicillium bilaii grew as fast or faster than rural isolates at all temperatures. These differences in thermal reaction norms between urban and rural isolates suggest that urbanization has caused both thermal specialization and counter-gradient variation in the fungal community.     

“You don’t see any violence here but it leads to very ugly things”: forced solidarity and silent violence in Michoacán,Mexico

Mexico has become an ideal laboratory for anthropology interested in studying the transformations of drug trafficking, its economies, and its cultures. Certainly, the challenges are complex and difficult, since criminal violence affects fieldwork and its results. However, when one delves into regions where drug trafficking and organized crime are present, what we can grasp ethnographically are fundamental questions about the relationships that are being generated between the state, neoliberalism, and illegality. In this article, we will analyze the expansion of drug cartels in one of the states most affected by criminal violence: the state of Michoacán, with special reference to the Caballeros Templarios—the Knights Templar. Understanding the origins and structures of this organization can teach us how the transformations of the state and criminal economies are being redrawn in neoliberal spaces.     

How to leave or stay on the substratum when you can’t swim? Evidence of the role of mucus thread secretion by postlarvae of Pectinaria koreni (Malmgren) in still water and flume experiments

Through an experimental approach we investigate the role of mucus secretion in postlarvae of Pectinaria koreni (tubicolous polychaete) on their ability to drift within the benthic boundary layer or to stay at the water–substratum interface. Fall velocity measurements were conducted with either living or dead postlarvae which were allowed to sink into a 2 m long Plexiglas cylindrical chamber. Five groups of increasing size-classes were tested ranging from the very first benthic stage (1 mm < Tube_length < 2 mm: membranous tube present accounting for more than 75% of the total tube length) to older stages (6 mm < Tube_length < 10 mm: membranous tube absent). We used these results to propose the first estimates of dispersal distances by several post-larval stages secreting mucus or sinking passively through the water column. Experiments were carried out in the HYCOBENTHOS flume to determine values of critical shear velocity (u _*c) inducing bedload transport and further resuspension of postlarvae of increasing sizes. The influence of mucus secretion by recruits on their ability to stay or quit a ‘suitable’ substratum was investigated by using either living or dead individuals. Results showed that: (a) the ability to secrete mucus rapidly is limited to the younger stages; (b) fall velocity of postlarvae is drastically lowered by mucus secretion (5 orders of magnitude) and is higher for the older stages; (c) dead recruits behave similarly to ‘passive’ recruits; (d) horizontal distances of drift dispersal may be considerable (up to 800 m for a single 22 min trip); (e) mucus secretion may be used by the postlarvae to anchor themselves to the substratum. Cost-benefit of using the mucus secretion as a tool for recruitment and the related spatial scales are discussed.