Faculty Opinions recommendation of Decades of field data reveal that turtles senesce in the wild.

Author(s):  
Thomas Flatt
Keyword(s):  
2001 ◽  
Vol 24 (2) ◽  
pp. 360-373 ◽  
Author(s):  
Luke Rendell ◽  
Hal Whitehead

Although the majority of commentators implicitly or explicitly accept that field data allow us to ascribe culture to whales, dolphins, and other nonhumans, there is no consensus. While we define culture as information or behaviour shared by a population or subpopulation which is acquired from conspecifics through some form of social learning, some commentators suggest restricting this by requiring imitation/teaching, human analogy, adaptiveness, stability across generations, progressive evolution (ratchetting), or specific functions. Such restrictions fall down because they either preclude the attribution of culture to nonhumans using currently available methods, or exclude parts of human culture. The evidence for cetacean culture is strong in some cases, but weak in others. The commentaries provide important information on the social learning abilities of bottlenose dolphins and some interesting speculation about the evolution of cetacean cultures and differences between the cultures of different taxa. We maintain that some attributes of cetacean culture are currently unknown outside humans. While experimental studies, both in the laboratory and in the wild, have an important role in the study of culture in whales and dolphins (for instance in determining whether dolphins have a Theory-of-Mind), the real treasures will be uncovered by long-term observational studies at sea using new approaches and technologies.


2017 ◽  
Vol 10 (4) ◽  
pp. 259-263
Author(s):  
Sahas Barve ◽  
Soham Dixit ◽  
André A. Dhondt ◽  
Farah Ishtiaq

Quantitative field data on sexual dimorphism is scant for most bird species. In this first field study of a western Himalayan population of Green-backed Tits ( Parus monticolus), we demonstrate that breast stripe width is a dimorphic trait that is a reliable measure to sex this species in the wild. Based on our ability to sex the birds in hand, we describe the sexual dimorphism in eco-morphological variables in our study population. Sexual dimorphism in beak morphology changed from winter to summer due to males having shorter beaks (4.5%) in summer; however, there was little change in female beak measurements. Our study on this Himalayan congener of a widely studied European species can be used to inform studies of the evolutionary ecology of morphological traits in closely-related species inhabiting vastly different habitats.


Author(s):  
Constantí Stefanescu ◽  
Andreu Ubach ◽  
Christer Wiklund

AbstractIn many migratory insects, migration occurs during the pre-reproductive phase of the life cycle. This trait probably arises from a trade-off between migration and reproduction and in females has been termed as the ‘oogenesis-flight syndrome’. However, the generality of this syndrome has been questioned, especially for monomorphic insects. We studied the relationship between migration and reproduction in the highly cosmopolitan painted lady butterfly, which in the Palaearctic undertakes the longest known multi-generational migration circuit of any insect. We tested for the oogenesis-flight syndrome in both spring and autumn migrants in two regions linked by migration, North Africa and northern Spain. Field observations were combined with laboratory experiments to determine the lifespan and the age at first mating to unravel the reproductive strategy observed in individuals captured in the wild. Females and males wait on average around 5–6 days before mating, and field data revealed that mating frequencies increase rapidly once females reach a medium wing wear category. There were seasonal differences in mating frequencies in the study regions depending on whether the region acted as a source or as a destination for migrants, and in the latter case there were almost twice as many mated females. Moreover, about 80% of females collected during migratory flights were unmated, the remaining females having mated only very recently. Our results thus strongly indicate that the painted lady fulfils the oogenesis-flight syndrome, as migration is concentrated in its relatively short pre-reproductive period. Field data also showed a high positive correlation between mating frequency and host plant abundance, which suggests that mated females have the ability to locate potential breeding areas. This, together with the very high fecundity estimated from over 1000 eggs in laboratory trials, makes the painted lady one of the most successful migratory insects on Earth.


Author(s):  
Jordan Donini ◽  
J. Sean Doody

South American Cane Toads (Rhinella marina) have been introduced into several regions outside of their native distribution. Outside of their native range, few predators have been documented preying upon R.marina due to their potent toxins secreted in defense. However, prevalence of a toxin resistance gene makes it possible for some snakes of the sub-family Natricinae to consume native toads. We documented successful consumption of the invasive cane toad by the Southern Watersnake (Nerodia fasciata) in southwest Florida, both in the wild and in the laboratory. Southern Watersnakes from populations that existed both with and without cane toads successfully consumed toad prey without obvious ill-effect. Southern Watersnakes in southwest Florida are thus resistant to, and readily consume cane toads, an otherwise relatively predator-free invasive species in Florida. More dietary field data and controlled experiments that measure resistance to multiple prey items, sizes, and frequency will serve to determine the extent to which Southern Watersnakes can impact the size and structure of sympatric populations of cane toads.


2012 ◽  
Vol 35 (1) ◽  
pp. 32-33 ◽  
Author(s):  
Nikos Nikiforakis

AbstractThe rarity of altruistic punishment in small-scale societies should not be interpreted as evidence that altruistic punishment is not an important determinant of cooperation in general. While it is essential to collect field data on altruistic punishment, this kind of data has limitations. Laboratory experiments can help shed light on the role of altruistic punishment “in the wild.”


Author(s):  
Thecan Caesar-Ton That ◽  
Lynn Epstein

Nectria haematococca mating population I (anamorph, Fusarium solani) macroconidia attach to its host (squash) and non-host surfaces prior to germ tube emergence. The macroconidia become adhesive after a brief period of protein synthesis. Recently, Hickman et al. (1989) isolated N. haematococca adhesion-reduced mutants. Using freeze substitution, we compared the development of the macroconidial wall in the wild type in comparison to one of the mutants, LEI.Macroconidia were harvested at 1C, washed by centrifugation, resuspended in a dilute zucchini fruit extract and incubated from 0 - 5 h. During the incubation period, wild type macroconidia attached to uncoated dialysis tubing. Mutant macroconidia did not attach and were collected on poly-L-lysine coated dialysis tubing just prior to freezing. Conidia on the tubing were frozen in liquid propane at 191 - 193C, substituted in acetone with 2% OsO4 and 0.05% uranyl acetate, washed with acetone, and flat-embedded in Epon-Araldite. Using phase contrast microscopy at 1000X, cells without freeze damage were selected, remounted, sectioned and post-stained sequentially with 1% Ba(MnO4)2 2% uranyl acetate and Reynold’s lead citrate. At least 30 cells/treatment were examined.


2001 ◽  
Author(s):  
Denis Morichon ◽  
Barbara Boczar-Karakiewicz ◽  
Edward B. Thornton
Keyword(s):  

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