EXTINCTION SPACE—A METHOD FOR THE QUANTIFICATION AND CLASSIFICATION OF CHANGES IN MORPHOSPACE ACROSS EXTINCTION BOUNDARIES

Three main modes of extinction are responsible for reductions in morphological disparity: (1) random (caused by a nonselective extinction event); (2) marginal (a symmetric, selective extinction event trimming the margin of morphospace); and (3) lateral (an asymmetric, selective extinction event eliminating one side of the morphospace). These three types of extinction event can be distinguished from one another by comparing changes in three measures of morphospace occupation: (1) the sum of range along the main axes; (2) the sum of variance; and (3) the position of the centroid. Computer simulations of various extinction events demonstrate that the pre‐extinction distribution of taxa (random or normal) in the morphospace has little influence on the quantification of disparity changes, whereas the modes of the extinction events play the major role. Together, the three disparity metrics define an “extinction‐space” in which different extinction events can be directly compared with one another. Application of this method to selected extinction events (Frasnian‐Famennian, Devonian‐Carboniferous, and Permian‐Triassic) of the Ammonoidea demonstrate the similarity of the Devonian events (selective extinctions) but the striking difference from the end‐Permian event (nonselective extinction). These events differ in their mode of extinction despite decreases in taxonomic diversity of similar magnitude.     

Deposition of pathogenic Mycoplasma gallisepticum onto bird feeders: host pathology is more important than temperature-driven increases in food intake

Although ambient temperature has diverse effects on disease dynamics, few studies have examined how temperature alters pathogen transmission by changing host physiology or behaviour. Here, we test whether reducing ambient temperature alters host foraging, pathology and the potential for fomite transmission of the bacterial pathogen Mycoplasma gallisepticum (MG), which causes seasonal outbreaks of severe conjunctivitis in house finches (Haemorhous mexicanus). We housed finches at temperatures within or below the thermoneutral zone to manipulate food intake by altering energetic requirements of thermoregulation. We predicted that pathogen deposition on bird feeders would increase with temperature-driven increases in food intake and with conjunctival pathology. As expected, housing birds below the thermoneutral zone increased food consumption. Despite this difference, pathogen deposition on feeders did not vary across temperature treatments. However, pathogen deposition increased with conjunctival pathology, independently of temperature and pathogen load, suggesting that MG could enhance its transmission by increasing virulence. Our results suggest that in this system, host physiological responses are more important for transmission potential than temperature-dependent alterations in feeding. Understanding such behavioural and physiological contributions to disease transmission is critical to linking individual responses to climate with population-level disease dynamics.     

Fatty Acid‐Derived Pro‐Toxicants of the Rat Selective Toxicant Norbormide

Norbormide [5‐(α‐hydroxy‐α‐2‐pyridylbenzyl)‐7‐(α‐2‐pyridylbenzylidene)‐5‐norbornene‐2,3‐dicarboximide] (NRB), an existing but infrequently used rodenticide, is known to be uniquely toxic to rats but relatively harmless to other rodents and mammals. However, as an acute vasoactive, NRB has a rapid onset of action which makes it relatively unpalatable to rats, often leading to sublethal uptake and accompanying bait shyness. A series of NRB‐derived pro‐toxicants ( 3a  –  i , 4a  –  i , and 5a  –  i ) were prepared in an effort to ‘mask’ this acute response and improve both palatability and efficacy. Their synthesis, in vitro biological evaluation (vasocontractile response in rat vasculature, stability in selected rat media) and palatability/efficacy in Sprague–Dawley, wild Norway, and wild ship rats is described. Most notably, pro‐toxicant 3d was revealed to be free of all pre‐cleavage vasoconstrictory activity in rat caudal artery and was subsequently demonstrated to release NRB in the presence of rat blood, liver, and pancreatic enzymes. Moreover, it consistently displayed a high level of acceptance by rats in a two‐choice bait‐palatability and efficacy trial, with accompanying high mortality. On this evidence, fatty acid ester prodrugs would appear to offer a promising platform for the further development of NRB‐derived toxicants with enhanced palatability and efficacy profiles.     

Metabarcoding of fungal communities associated with bark beetles

Many species of fungi are closely allied with bark beetles, including many tree pathogens, but their species richness and patterns of distribution remain largely unknown. We established a protocol for metabarcoding of fungal communities directly from total genomic DNA extracted from individual beetles, showing that the ITS3/4 primer pair selectively amplifies the fungal ITS. Using three specimens of bark beetle from different species, we assess the fungal diversity associated with these specimens and the repeatability of these estimates in PCRs conducted with different primer tags. The combined replicates produced 727 fungal Operational Taxonomic Units (OTUs) for the specimen of Hylastes ater, 435 OTUs for Tomicus piniperda, and 294 OTUs for Trypodendron lineatum, while individual PCR reactions produced on average only 229, 54, and 31 OTUs for the three specimens, respectively. Yet, communities from PCR replicates were very similar in pairwise comparisons, in particular when considering species abundance, but differed greatly among the three beetle specimens. Different primer tags or the inclusion of amplicons in separate libraries did not impact the species composition. The ITS2 sequences were identified with the Lowest Common Ancestor approach and correspond to diverse lineages of fungi, including Ophiostomaceae and Leotiomycetes widely found to be tree pathogens. We conclude that Illumina MiSeq metabarcoding reliably captures fungal diversity associated with bark beetles, although numerous PCR replicates are recommended for an exhaustive sample. Direct PCR from beetle DNA extractions provides a rapid method for future surveys of fungal species diversity and their associations with bark beetles and environmental variables.     

Adverse Effects of Ball-Chain Radio-Collars on Female Mantled Howlers (<Emphasis Type="Italic">Alouatta palliata</Emphasis>) in Panama

The placement of radio- and GPS-collars on primates has advanced the fields of primate behavior and ecology and yielded considerable conservation gains. However, to ensure that the placement of tracking collars remains a humane practice, the reporting of both positive and negative outcomes is required. Here, we evaluate the impacts of radio-collars on the reproduction, behavior, and health of female mantled howlers (Alouatta palliata) on Barro Colorado Island, Panama. In June 2005, as part of a behavioral study, we fitted 16 female howlers with ball-chain radio-collars weighing 1.2% of the mean adult female weight. We monitored these 16 collared females and 64 noncollared females across an annual cycle, and recaptured the collared females in July 2006 for collar removal. The mortality rate for collared females across the study year was 6.3% (N=1), while the net loss of noncollared females from study groups was 15.6% (N=10). All collared females reproduced. The behaviors of collared and noncollared females were not significantly different. However, on recapture to remove all remaining collars (N = 13), 38% of recaptured collared females presented with damage to the dermal layer on the back of the neck and 31% presented with more severe damage extending into the subcutaneous tissue and muscle. Given this physical damage, which was not apparent through binoculars, we cannot recommend using ball-chain radio-collars on female mantled howlers without careful welfare monitoring.     

The influence of AVPR1A genotype on individual differences in behaviors during a mirror self‐recognition task in chimpanzees (Pan troglodytes)

The mark/rouge test has been used to assess mirror self‐recognition (MSR) in many species. Despite consistent evidence of MSR in great apes, genetic or non‐genetic factors may account for the individual differences in behavioral responses that have been reported. We examined whether vasopressin receptor gene (AVPR1A) polymorphisms are associated with MSR‐related behaviors in chimpanzees since vasopressin has been implicated in the development and evolution of complex social relations and cognition and chimpanzees are polymorphic for the presence of the RS3‐containing DupB region. We compared a sample of DupB+/? and DupB?/? chimpanzees on a mark test to assess its role on social behavior toward a mirror. Chimpanzees were administered two, 10‐min sessions where frequencies of mirror‐guided self‐directed behaviors, contingent actions and other social behaviors were recorded. Approximately one‐third showed evidence of MSR and these individuals exhibited more mirror‐guided self‐exploratory behaviors and mouth contingent actions than chimpanzees not classified as passers. Moreover, DupB+/? males exhibited more scratching and agonistic behaviors than other male and female cohorts. Our findings support previous studies demonstrating individual differences in MSR abilities in chimpanzees and suggest that AVPR1A partly explains individual differences in MSR by influencing the behavioral reactions of chimpanzees in front of a mirror.     

Evolution of ASPM coding variation in apes and associations with brain structure in chimpanzees

Studying genetic mechanisms underlying primate brain morphology can provide insight into the evolution of human brain structure and cognition. In humans, loss‐of‐function mutations in the gene coding for ASPM (Abnormal Spindle Microtubule Assembly) have been associated with primary microcephaly, which is defined by a significantly reduced brain volume, intellectual disability and delayed development. However, less is known about the effects of common ASPM variation in humans and other primates. In this study, we characterized the degree of coding variation at ASPM in a large sample of chimpanzees (N = 241), and examined potential associations between genotype and various measures of brain morphology. We identified and genotyped five non‐synonymous polymorphisms in exons 3 (V588G), 18 (Q2772K, K2796E, C2811Y) and 27 (I3427V). Using T1‐weighted magnetic resonance imaging of brains, we measured total brain volume, cerebral gray and white matter volume, cerebral ventricular volume, and cortical surface area in the same chimpanzees. We found a potential association between ASPM V588G genotype and cerebral ventricular volume but not with the other measures. Additionally, we found that chimpanzee, bonobo, and human lineages each independently show a signature of accelerated ASPM protein evolution. Overall, our results suggest the potential effects of ASPM variation on cerebral cortical development, and emphasize the need for further functional studies. These results are the first evidence suggesting ASPM variation might play a role in shaping natural variation in brain structure in nonhuman primates.