Porcupine feeding scars and climatic data show ecosystem effects of the solar cycle

Using North American porcupine (Erethizon dorsatum) feeding scars on trees as an index of past porcupine abundance, we have found that porcupine populations have fluctuated regularly over the past 130 years in the Bas St. Laurent region of eastern Quebec, with superimposed periodicities of 11 and 22 years. Coherency and phase analyses showed that this porcupine population cycle has closely followed the 11- and 22-year solar activity cycles. Fluctuations in local precipitation and temperature were also cyclic and closely related to both the solar cycle and the porcupine cycle. Our results suggest that the solar cycle indirectly sets the rhythm of population fluctuations of the most abundant vertebrate herbivore in the ecosystem we studied. We hypothesize that the solar cycle has sufficiently important effects on the climate along the southern shore of the St. Lawrence estuary to locally influence terrestrial ecosystem functioning. This constitutes strong evidence for the possibility of a causal link between solar variability and terrestrial ecology at the decadal timescale and local spatial scale, which confirms results obtained at greater temporal and spatial scales.     

Predation as a probable mechanism relating winter weather to population dynamics in a North American porcupine population

An abundance index of an eastern Quebec population of North American porcupines (Erethizon dorsatum) has cycled with superimposed periodicities of 11 and 22 years from 1868 to 2000. This cycle closely followed 11- and 22-year cycles in solar irradiance and local weather (e.g., winter precipitation and spring temperature), generating the hypothesis that solar activity may affect porcupine abundance through effects on local weather. We investigated the mechanisms linking porcupine abundance to local weather conditions using a 6-year study (2000–2005) involving individual mark-recapture, radio tracking, seasonal survival analyses and identification of mortality causes. Summer (May–August) survival was high and constant over the study period, whereas winter (August–May) survival was lower and varied during the duration of our study. Variations in local winter precipitation explained 89% of the variation in winter survival. Porcupine predation rates appeared strongly related to snow conditions; 95% of depredated porcupines were killed when snow was covering the ground, and predation rates were higher in years with increased winter precipitation. Our data thus support the hypothesis that changes in predation rates under different snow conditions were the mechanism relating climate to porcupine population dynamics, via modifications of the local predator–prey interactions and impacts on porcupine winter survival. Our study adds to the growing body of evidence supporting an effect of climate on predator–prey processes. Also, it identifies one possible mechanism involved in the relationship between solar irradiance and porcupine population cycles observed at this study site over a 130-year period.     

Rongements sélectifs des os par les porcs-épics et autres rongeurs : cas de la grotte Tianyuan, un site avec des restes humains fossiles récemment découvert près de Zhoukoudian (Choukoutien)

The Tianyuan cave near Zhoukoudian is among the most special localities in North China for its many porcupine gnawing marks on the bones, as is often the case acknowledged only in South China. But porcupines did not gnaw all the bones, that is gnawing is selective. Skulls, mandibles, tooth roots and long bones are frequently gnawed. The short bones are almost free from gnawing. The selection indicates that, for porcupines, bone gnawing is not only a necessity for attrition of incisors, but also a process of extracting nutrients from the marrow. Additionally, the porcupine gnawing marks can also be employed to determine the provenance of the fossils that were discovered by the local people before the systematic excavation. Those bearing porcupine tooth marks only appear in the upper assemblage. The other significance of the gnawing marks is to infer the habitant of the cave. The bones from the human fossil bearing layer have few tooth marks, which may represent a period of human occupation of the cave. In the upper assemblage, the gnawing marks appear frequently, it may indicate that porcupine and other rodents lived in the cave during this time span.     

Mathematical conservation ecology: A one-predator-two-prey system as case study

A method is presented to analyse the long-term stochastic dynamics of a biological population that is at risk of extinction. From the full ecosystem the method extracts the minimal information to describe the long-term dynamics of that population by a stochastic logistic system. The method is applied to a one-predator-two-prey model. The choice of this example is motivated by a study on the near-extinction of a porcupine population by mountain lions whose presence is facilitated by mule deer taking advantage of a change in land use. The risk of extinction is quantified by the expected time of extinction of the population.     

Design,synthesis, and evaluation of novel porcupine inhibitors featuring a fused 3-ring system based on the ‘reversed’ amide scaffold

The Wnt signaling pathway is an essential signal transduction pathway which leads to the regulation of cellular processes such as proliferation, differentiation and migration. Aberrant Wnt signaling is known to have an association with multiple cancers. Porcupine is an enzyme that catalyses the addition of palmitoleate to a serine residue in Wnt proteins, a process which is required for the secretion of Wnt proteins. Here we report the synthesis and structure–activity-relationship of the novel porcupine inhibitors based on a ‘reversed’ amide scaffold. The leading compound 53 was as potent as the clinical compound LGK974 in a cell based STF reporter gene assay. Compound 53 potently inhibited the secretion of Wnt3A, therefore was confirmed to be a porcupine inhibitor. Furthermore, compound 53 showed excellent chemical and plasma stabilities. However, the clearance of compound 53 in liver microsomal tests was moderate to high, and the solubility of compound 53 was suboptimal. Collective efforts toward further optimization of this novel tricyclic template to develop better porcupine inhibitors will be subsequently undertaken and reported in due course.     

Chemical immobilization of crested porcupines with tiletamine HCl and zolazepam HCl (Zoletil) under field conditions

The combination of tiletamine HCl and zolazepam HCl has been used on many species of wild mammals. Short induction time, low dosage, satisfactory safety margins, relatively constant immobilization time, and smooth recovery are benefits reported. This combination (Zoletil 100) was used during a study on behavioural ecology of the crested porcupine (Hystrix cristata) in a Mediterranean coastal area (Maremma Regional Park, Tuscany, Italy). We used this mixture 42 times on 31 individuals. Mean adult dose was (+/- SE) 7.24 +/- 0.37 mg/kg (74.0 +/- 3.0 mg/individual). Average adult induction time was 5.3 min (+/- 1.1) and average adult immobilization time was 22.6 min (+/- 6.0). One adult male porcupine died after chemical restraints. The use of tiletamine-zolazepam seems adequate for chemical immobilization of crested porcupines under field conditions, mainly because of its short induction time, small volume to be injected and wide safety margin.     

Porcupine-mediated lipid-modification regulates the activity and distribution of Wnt proteins in the chick neural tube

A long-term goal of developmental biology is to understand how morphogens establish gradients that promote proper tissue patterning. A number of reports describe the formation of the Wg (Wnt1) gradient in Drosophila and have shown that Porcupine, a predicted membrane-bound O-acyl transferase, is required for the correct distribution of Wg protein. The discovery that Wnts are palmitoylated on a conserved cysteine residue suggests that porcupine activity and Wnt palmitoylation are important for the generation of Wnt gradients. To establish the role of porcupine in Wnt gradient formation in vertebrates, we tested the role of porcupine/Wnt palmitoylation in human embryonic kidney 293T cells and in the chick neural tube. Our results lead us to conclude that: (1) vertebrate Wnt1 and Wnt3a possess at least one additional site for porcupine-mediated lipid-modification; (2) porcupine-mediated lipid-modification of Wnt proteins promotes their activity in 293T cells and in the chick neural tube; and (3) porcupine-mediated lipid-modification reduces the range of activity of Wnt1 and Wnt3a in the chick neural tube. These findings highlight the importance of porcupine-mediated lipid modifications in the formation of vertebrate Wnt activity gradients.     

Étude taphonomique, paléoécologique et archéozoologique des faunes de grands mammifères de la seconde moitié du Pléistocène inférieur de la grotte du Vallonnet (Roquebrune-Cap-Martin, Alpes-Maritimes, France)

Vallonnet cave (Alpes-Maritimes, France) provided archaic lithic tools together with a big amount of large mammals of the end of lower pleistocene. At the crossing of diverse ecological niches in time and space, three main levels and within them several smaller units were distinguished. The poorly mineralized bones witnessed a huge diagenetic fragmentation. The presence of the animals in the cave seems to be linked to the reasons of their death. The exhaustive and systematic observation of the bones, like the bears probably used to die inside the cave. Some other carnivores especially hyenas, used the cave as a nursery. Man also occupied the cave and had an activity mainly on large cervid bones and on some other species as well. The very progressive deposit gave a way for carnivores and porcupine to gnaw the bones on the ground before their burial. The succession of actions (man, carnivores and porcupine) on the same bones is characteristic on Vallonnet large mammals bones.     

Structure and evolution of opossum,guinea pig,and porcupine cytochrome b genes

Summary We have sequenced the mitochondrial cytochrome b gene from the guinea pig, the African porcupine, and a South American opossum. A phylogenetic analysis, which includes 22 eutherian and four other vertebrate cytochrome b sequences, indicates that the guinea pig and the porcupine constitute a natural clade (Hystricomorpha) that is not a sister group to the clade of mice and rats (Myomorpha). Therefore, the hypothesis that the Rodentia is paraphyletic receives additional support. The artiodactyls, the perissodactyls, and the cetaceans form a group that is separated from the primates and the rodents. The 26 sequences are used to study the structure/function relationships in cytochrome b, whose function is electron transport. Most of the amino acid residues involved in the two reaction centers are well conserved in evolution. The four histidines that are believed to ligate the two hemes are invariant among the 26 sequences, but their nearby residues are not well conserved in evolution. The eight transmembrane domains represent some of the most divergent regions in the cytochrome b sequence. The rate of nonsynonymous substitution is considerably faster in the human and elephant lineages than in other eutherian lineages; the faster rate might be due to coevolution between cytochrome b and cytochrome c. Offprint requests to: W.-H. Li     

Fossil Asiatic Brush-Tailed Porcupine Atherurus macrourus (Hystricidae,Rodentia) from Northern Vietnam (Bud Cave,Pleistocene–Holocene Transition)

Doklady Biological Sciences - The lower jaw and dental remains of the brush-tailed porcupine are described from the Pleistocene–Holocene boundary deposits of the Bud cave in northern Vietnam....     

Functional anatomy of the ovaries of pregnant and lactating Cape porcupines, Hystrix africaeaustralis

The constituent cell types of the ovary of the porcupine were similar to those of New World hystricomorph rodents and accessory corpora lutea and luteal bodies were formed through the luteinization of the membrana granulosa or theca interna of antral follicles. All luteal bodies were histologically similar. The total volume of luteal tissue per female was not affected by fetal age and was unrelated to circulating concentrations of maternal plasma progesterone. Maternal plasma progesterone concentrations were correlated with fetal age. Follicular activity occurred throughout pregnancy but was not affected by fetal age or related to circulating values of oestradiol-17 beta. The formation of accessory corpora lutea during pregnancy is regarded as important in supplementing progesterone during pregnancy.     

Influences of porcupine (Hystrix indica) activity on the slopes on the northern Negev mountains — Germination and vegetation renewal in different geomorphological types and slope directions

Summary Preliminary results show that the number and survival of seedlings within the diggings of the Indian crested porcupine (Hystrix indica) is usually higher than in the surrounding area. Species like Erodium hirtum (Willd.) (hemicryptophyte), Helianthemum vesicarium Boiss. (perennial), and Diplotaxis harra (Forssk.) Boiss. are conspicuous by their appearance in the diggings of the porcupine more than between the diggings. In contrast there are plants like Helianthemum ledifolium (L.) Mill. (annual), that appear in high numbers outside the diggings. In the case of Erodium hirtum, it appears that the porcupines help in rejuvenating the population. The porcupines feed on the older underground plant bulbs and the pockets formed by their diggings are convenient habitats for germination and growth of the young seedlings.     

Disseminated pulmonary adiaspiromycosis in a crested porcupine (Hystrix cristata Linnaeus, 1758)

Adiaspiromycosis is primarily a necrotizing granulomatous pneumonia caused by a dimorphic fungus of the genus Emmonsia. A young crested porcupine (Hystrix cristata) found dead showed multiple fractures, chronic pleuritis, and granulomatous pneumonia. Microscopically, cystic structures were consistent with adiaspiromycosis by Emmonsia crescens. The diagnosis was confirmed using molecular methods.     

云南禄丰古猿化石地点的豪猪化石

描述了产自云南禄丰古猿化石地点的豪猪化石禄丰豪猪 (新种 ) (Hystrixlufengensissp .nov.)。这是一种较原始的豪猪。它的个体中等 ;两上颊齿列往前靠近 ;下颌骨骨体较低 ,齿隙稍凹 ,其前端高于下颊齿冠面 ;颊齿齿冠较低 ;上颊齿舌侧沟横向较短 ;P4大 ,前尖通常孤立 ,中附尖很发达 ,不与中脊连 ;M3较少退化 ;上颊齿具 3齿根 ,大的内侧齿根具明显纵沟 ;下颊齿通常具 4齿根等。形态结构分析表明 ,H .lufengensis仅比H .parvae进步 ,比H .primigenia和H .sivalensis及其他种都原始。它可能代表亚洲目前已知最早、最原始的豪猪。其产出时代为晚中新世保德期 (狭义 )的较早期 (距今约 8Ma)。     

Cardiorespiratory responses of the woodchuck and porcupine to CO2 and hypoxia

Summary The burrow-dwelling woodchuck (Marmota monax) (mean body wt.=4.45±1 kg) was compared to a similar-sized (5.87±1.5 kg) but arboreal rodent, the porcupine (Erithrizon dorsatum), in terms of its ventilatory and heart rate responses to hypoxia and hypercapnia, and its blood characteristics.V _T,f,T _I andT _E were measured by whole-body plethysmography in four awake individuals of each species. The woodchuck has a longerT _E/T _TOT (0.76±0.03) than the porcupine (0.61±0.03). The woodchuck had a higher threshold and significantly smaller slope to its CO₂ ventilatory response compared to the porcupine, but showed no difference in its hypoxic ventilatory response. The woodchuck P₅₀ of 27.8 was hardly different from the porcupine value of 30.7, but the Bohr factor, –0.72, was greater than the porcupine's, –0.413. The woodchuck breathing air has PaCO₂=48 (±2) torr, PaO₂=72 (±6), pHa=7.357 (±0.01); the porcupine blood gases are PaCO₂=34.6 (±2.8), PaO₂=94.9 (±5), pHa=7.419 (±0.03), suggesting a difference in PaCO₂/pH set points. The woodchuck exhibited no reduction in heart rate with hypoxia, nor did it have the low normoxic heart rate observed in other burrowing mammals.     

The taxonomic status of the endangered thin-spined porcupine, Chaetomys subspinosus (Olfers, 1818), based on molecular and karyologic data

Background  

The thin-spined porcupine, also known as the bristle-spined rat, Chaetomys subspinosus (Olfers, 1818), the only member of its genus, figures among Brazilian endangered species. In addition to being threatened, it is poorly known, and even its taxonomic status at the family level has long been controversial. The genus Chaetomys was originally regarded as a porcupine in the family Erethizontidae, but some authors classified it as a spiny-rat in the family Echimyidae. Although the dispute seems to be settled in favor of the erethizontid advocates, further discussion of its affinities should be based on a phylogenetic framework. In the present study, we used nucleotide-sequence data from the complete mitochondrial cytochrome b gene and karyotypic information to address this issue. Our molecular analyses included one individual of Chaetomys subspinosus from the state of Bahia in northeastern Brazil, and other hystricognaths.     

Circulating progesterone and oestradiol-17 beta concentrations in cyclic Cape porcupines, Hystrix africaeaustralis

The general pattern of steroid secretion during the 30-day oestrous cycle of the Cape porcupine is that of a surge (25-176 pg/ml) in oestradiol-17 beta secretion at the time of perforation of the vaginal closure membrane, followed by an increase in progesterone concentrations, the latter attaining peak values (mean 5.9 +/- 2.1 ng/ml) 8-19 days (13.8 +/- 2.8 days) after vaginal opening. Copulation occurred after the oestradiol-17 beta surge and the length of the luteal phase of the cycle varied from 21 to 35 days (29.3 +/- 4.7 days), this representing 93% of the length of the cycle. Perforation of the vaginal closure membrane was not always accompanied by an increase in oestradiol-17 beta levels and some instances (19%) of vaginal opening were not followed by an increase in progesterone secretion. The hormonal characteristics of the oestrous cycle of females housed with vasectomized males were similar to those of females housed with intact males.     

Modelling the surface lattice of alpha-keratin filaments

A recently-proposed model for the distribution of scattering material on the surface lattice of alpha-keratin intermediate filaments in dry porcupine quill is examined in detail. It is shown that, while retaining the basic form of the model (namely a dislocated helix with finite lattice spacing of 198.2 A), alternative meridonal distributions of scattering material within the finite lattice unit cell can be obtained which are consistent with the low-angle meridional X-ray pattern. The Gaussian shape function used to demonstrate the finite lattice in the model is questioned. The meridional diffraction pattern from hydrated porcupine quill is also examined and, apart from the intense fifth order reflection, can be modelled by distortion of the dry species scattering material distribution.     

Behavior, movements, and demographics of rabid raccoons in Ontario, Canada: management implications

During 1999-2003, 127 cases of raccoon variant rabies were reported in raccoons (Procyon lotor) and striped skunks (Mephitis mephitis) in Ontario, Canada. Raccoons accounted for 98% (125/127) of the reported cases with behaviors/conditions including aggression, fighting with dogs, ataxia, vocalizations, appearance of being sick, and the presence of porcupine (Erethizon dorsatum) quills. Seventy-eight percent of the rabid raccoons were adults. Juveniles were underrepresented (22%) compared with the adult/juvenile ratios found in nonrabid Ontario raccoon populations. Of the known aged raccoons, 83% were < or = 3 yr of age, and 22% of the rabid adult female raccoons had evidence of having had a litter during the year in which they were found to be rabid. The majority of rabid raccoons were reported during the fall, winter, and spring, suggesting a relationship between raccoon behavioral activities such as denning and breeding and the timing of rabies outbreaks. Multiple cases of raccoon rabies occurred at several barns, suggesting that those structures serve as focal points of rabies transmission as a result of denning activities. Movements of five rabid raccoons (range 1,564-4,143 m) were not different from movements of nonrabid raccoons in Ontario. Sixty-six percent of the rabid animals were submitted by government staff, stressing the importance of those agencies in rabies control and surveillance operations. Increased knowledge of the behaviors of rabid raccoons should assist in the development of management strategies for rabies.     

Spotted hyena (Crocuta crocuta) coexisting at high density with people in Wukro district,northern Ethiopia

We surveyed density and abundance of spotted hyena (Crocuta crocuta) in the highly degraded and prey depleted Wukro district, northern Ethiopia, with a human population density of 98 persons per square kilometer. A total of 117 spotted hyenas responded to callups, giving a hyena density of 52 hyenas per 100 km² or a total population of 535 hyenas in the district. We quantified the economic impact of spotted hyena predation on livestock using semi structured interviews with randomly selected households. Respondents indicated a total loss of 203 domestic animals to hyena depredation over the past five years. Average annual depredation per household was 0.13 livestock worth US$ 6.1. The diet of spotted hyenas was assessed in three sub-districts by scat analysis and showed 99% prey items of domestic origin, only three of 211 scat contained hair of Ethiopian hare (Lepus fagani) and porcupine (Hystrix cristata). We conclude that hyenas in northern Ethiopia live at high density and eat almost exclusively anthropogenic food and are not dependent on conservation areas.