The carbon costs of mitigating high‐severity wildfire in southwestern ponderosa pine

Forests provide climate change mitigation benefit by sequestering carbon during growth. This benefit can be reversed by both human and natural disturbances. While some disturbances such as hurricanes are beyond the control of humans, extensive research in dry, temperate forests indicates that wildfire severity can be altered as a function of forest fuels and stand structural manipulations. The purpose of this study was to determine if current aboveground forest carbon stocks in fire‐excluded southwestern ponderosa pine forest are higher than prefire exclusion carbon stocks reconstructed from 1876, quantify the carbon costs of thinning treatments to reduce high‐severity wildfire risk, and compare posttreatment (thinning and burning) carbon stocks with reconstructed 1876 carbon stocks. Our findings indicate that prefire exclusion forest carbon stocks ranged from 27.9 to 36.6 Mg C ha^?1 and that the current fire‐excluded forest structure contained on average 2.3 times as much live tree carbon. Posttreatment carbon stocks ranged from 37.9 to 50.6 Mg C ha^?1 as a function of thinning intensity. Previous work found that these thinning and burning treatments substantially increased the 6.1 m wind speed necessary for fire to move from the forest floor to the canopy (torching index) and the wind speed necessary for sustained crown fire (crowning index), thereby reducing potential fire severity. Given the projected drying and increase in fire prevalence in this region as a function of changing climatic conditions, the higher carbon stock in the fire‐excluded forest is unlikely to be sustainable. Treatments to reduce high‐severity wildfire risk require trade‐offs between carbon stock size and carbon stock stability.     

Translocation and Metabolism of Leaf Applied Hexachlorophene in Peanuts

Translocation, distribution, metabolism and photolysis of hexachlorophene (HCP) were investigated in peanut plants (Arachis hypogea L., Spanish type) grown under standardized conditions and treated with ^l4C-ring-labeled HCP. Treatment time ranged from 0–114 days. Autoradiographic analyses were performed on all plants. Selected plant tissues were extracted and chromatographed, using both thin layer and gas liquid chromatography. No translocation of HCP was detected in the plant tissue. No HCP metabolites were found. Some HCP was lost from the leaves and inert controls at a specific rate per unit time. The rates were slightly different, being slower on the leaves than on the controls. At the end of the 114-day treatment and based on regression analysis of thin layer chromatographic plates, an average of 68% of the applied HCP remained unaltered on the treated plants and an average of 77% remained on the controls. This indicated that, respectively, 32 and 23% of the original HCP had been altered. This 9% difference was statistically significant. Upon further analyses of the above data, using gas chromatographic methods, as many as 14 peaks were found in the treated samples and the controls, including some parent material. Ultraviolet photolysis seems to be the mechanism responsible for alteration of the HCP on the treated plants and controls. Two photolysis products have been identified by gas liquid chromatography-mass spectral analysis. Twelve other electrophylic compounds have been found in various treated plant or control extracts. Further analyses will be necessary to verify the identification and quantification of the other degradation products.     

Synthesis of Substance P

SUBSTANCE P has been synthesized by the solid-phase procedure of Merrifield^1,2 according to the sequence H-Arg-Pro-LysPro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH₂ reported in the previous letter.     

Alternative Feeding Strategies and Potential Disease Transmission in Wisconsin White-Tailed Deer

ABSTRACT We conducted experimental feeding using 3 feeding methods (pile, spread, trough) and 2 quantities (rationed, ad libitum) of shelled corn to compare deer activity and behavior with control sites and evaluate potential direct and indirect transmission of infectious disease in white-tailed deer (Odocoileus virginianus) in central Wisconsin, USA. Deer use was higher at 2 of the feeding sites than at natural feeding areas (P ≤ 0.02). Deer spent a higher proportion of time (P < 0.01) feeding at pile (49%) and spread (61%) treatments than at natural feeding areas (36%). We found higher deer use for rationed than ad libitum feeding quantities and feeding intensity was greatest at rationed piles and lowest at ad libitum spreads. We also observed closer pairwise distances (≤0.3 m) among deer when corn was provided in a trough relative to spread (P=0.03). Supplemental feeding poses risks for both direct and indirect disease transmission due to higher deer concentration and more intensive use relative to control areas. Concentrated feeding and contact among deer at feeding sites can also increase risk for disease transmission. Our results indicated that restrictions on feeding quantity would not mitigate the potential for disease transmission. None of the feeding strategies we evaluated substantially reduced the potential risk for disease transmission and banning supplemental feeding to reduce transmission is warranted.     

Vocal morphology of the Physalaemus pustulosus species group (Leptodactylidae): morphological response to sexual selection for complex calls

Most male frogs in the genus Physalaemus produce a whine-like advertisement call. Male P. pustulosus , however, add chucks to the call. This enhances the attractiveness of the call to females, and has evolved under the influence of sexual selection despite the increased predation risk from the frog-eating bat ( Trachops cirrhosus ). This complex call is unusual, if not unique, among anurans because the two call components overlap in time. Here we investigate the morphological changes responsible for the production of complex calls.
The Physalaemus purtulosus species group consists of four species. Physalaemus pustulosus and P. petersi are sister species, and recently it has been shown that P. petersi produces chucks. Physalaemus coloradorum and P. purtulatus are sister species and neither is known to produce chucks. Two laryngeal characters vary within the species group. Physalaemus pustulosus has a large fibrous mass (FMI), whose vibration is responsible for production of the chuck. This mass is much smaller in the other three species. In P. pustulosus and P. petersi the FMI is anchored dorsally, deep within the bronchial process, the attachment is more extensive in P. pustulosus. Neither P. pustulatus nor P. coloradorum have such a dorsal attachment associated with their FMI. This character is responsible for allowing the FMI to vibrate independently of the vocal cords, that is, for the production of the complex call. Thus the morphological changes responsible for the evolution of this unusual behavioural innovation, the complex call, are gradual, and almost trival, in nature. This study also shows that the primitive condition of the larynx of the P. pustulosus and P. petersi ancestor, was predisposed to the production of complex calls.
We also document ontogenetic and sexually dimorphic patterns in larynx structure.     

Living on the Edge: Viability of Moose in Northeastern Minnesota

ABSTRACT North temperate species on the southern edge of their distribution are especially at risk to climate-induced changes. One such species is the moose (Alces alces), whose continental United States distribution is restricted to northern states or northern portions of the Rocky Mountain cordillera. We used a series of matrix models to evaluate the demographic implications of estimated survival and reproduction schedules for a moose population in northeastern Minnesota, USA, between 2002 and 2008. We used data from a telemetry study to calculate adult survival rates and estimated calf survival and fertility of adult females by using results of helicopter surveys. Estimated age- and year-specific survival rates showed a sinusoidal temporal pattern during our study and were lower for younger and old-aged animals. Estimates of annual adult survival (when assumed to be constant for ages >1.7 yr old) ranged from 0.74 to 0.85. Annual calf survival averaged 0.40, and the annual ratio of calves born to radiocollared females averaged 0.78. Point estimates for the finite rate of increase (λ) from yearly matrices ranged from 0.67 to 0.98 during our 6-year study, indicative of a long-term declining population. Assuming each matrix to be equally likely to occur in the future, we estimated a long-term stochastic growth rate of 0.85. Even if heat stress is not responsible for current levels of survival, continuation of this growth rate will ultimately result in a northward shift of the southern edge of moose distribution. Population growth rate, and its uncertainty, was most sensitive to changes in estimated adult survival rates. The relative importance of adult survival to population viability has important implications for harvest of large herbivores and the collection of information on wildlife fertility.     

A molecular phylogeny of Phasmatodea with emphasis on Necrosciinae,the most species‐rich subfamily of stick insects

The phasmatodeans or stick and leaf insects are considered to be a mesodiverse insect order with more than 3000 species reported mainly from the tropics. The stick insect subfamily Necrosciinae comprises approximately 700 described species in more than 60 genera from the Oriental and Australian region, forming the most species‐rich subfamily traditionally recognized within Phasmatodea. However, the monophyly of this taxon has never been thoroughly tested and the evolutionary relationships among its members are unknown. We analyse three nuclear (18S and 28S rDNA, histone 3) and three mitochondrial (CO II, 12S and 16S rDNA) genes to infer the phylogeny of 60 species of stick insects that represent all recognized families and major subfamilies sensu Günther and the remarkable diversity within Necrosciinae. Maximum parsimony, maximum likelihood and Bayesian techniques largely recover the same substantial clades, albeit with highly discordant relationships between them. Most members of the subfamily Necrosciinae form a clade. However, the genus Neohirasea – currently classified within Lonchodinae – is strongly supported as subordinate to Necrosciinae, whereas Baculofractum, currently classified within Necrosciinae, is strongly supported within Lonchodinae. Accordingly, we formally transfer Neohirasea and allied taxa (namely Neohiraseini) to Necrosciinae sensu nova (s.n.) and Baculofractum to Lonchodinae s.n. We also provide further evidence that Leprocaulinus, until recently recognized as Necrosciinae, belongs to Lonchodinae, and forms the sister taxon of Baculofractum. Furthermore, Lonchodinae is paraphyletic under exclusion of Eurycantha and Neopromachus. We reinstate the traditional view that Neopromachus and related taxa (Neopromachini sensu Günther) are a subgroup of Lonchodinae and transfer those taxa + the New Guinean Eurycanthinae accordingly. Morphological evidence largely corroborates our molecular‐based findings and also reveals that Menexenus fruhstorferi is a member of the genus Neohirasea and is thus transferred from Menexenus (Lonchodinae) to Neohirasea, as Neohirasea fruhstorferi comb.n . (Necrosciinae s.n. ). Other phylogenetic results include Areolatae and Anareolatae each supported as polyphyletic, Heteropteryginae and Lanceocercata (Bayesian analysis) are monophyletic, albeit with low support, and Necrosciinae s.n. and Lonchodinae s.n. are recovered as sister taxa (Bayesian analysis).     

Rapid cooling triggers forisome dispersion just before phloem transport stops

Phloem transport stops transiently within dicot stems that are cooled rapidly, but the cause remains unknown. Now it is known that (1) rapid cooling depolarizes cell membranes giving a transient increase in cytoplasmic Ca²⁺, and (2) a rise of free calcium triggers dispersion of forisomes, which then occlude sieve elements (SEs) of fabacean plants. Therefore, we compared the effects of rapid chilling on SE electrophysiology, phloem transport and forisomes in Vicia faba. Forisomes dispersed after rapid cooling with a delay that was longer for slower cooling rates. Phloem transport stopped about 20 s after forisome dispersion, and then transport resumed and forisomes re‐condensed within similar time frames. Transport interruption and forisome dispersion showed parallel behaviour – a cooling rate‐dependent response, transience and desensitization. Chilling induced both a fast and a slow depolarization of SE membranes, the electrical signature suggesting strongly that the cause of forisome dispersion was the transient promotion of SE free calcium. This apparent block of SEs by dispersed forisomes may be assisted by other Ca²⁺‐dependent sealing proteins that are present in all dicots.     

Large‐scale molecular phylogeny of Cryptorhynchinae (Coleoptera,Curculionidae) from multiple genes suggests American origin and later Australian radiation

The monophyly of the highly diverse weevil subfamily Cryptorhynchinae is tested with a dataset of 203 taxa representing 159 genera of Curculionoidea, 105 of them Cryptorhynchinae s.l. We construct a phylogeny based on an alignment of 5523 bp, consisting of fragments from two mitochondrial genes (two fragments of COI, 16S) and seven nuclear genes (ArgK, CAD, EF1α, enolase, H4, 18S, 28S). Analyses of maximum likelihood and Bayes inference recovered largely congruent results. Groups with different morphology of the rostral furrow (e.g. Aedemonini, Camptorhinini, Cryptorhynchini, Ithyporini) are not closely related to each other. However, most taxa with a mesosternal receptacle are monophyletic and here defined as Cryptorhynchinae s.s., comprising Cryptorhynchini, Gasterocercini, Torneumatini and Psepholacini, but also Arachnopodini and Idopelma Faust. The genus Phyrdenus LeConte is excluded from Cryptorhynchinae and transferred to Conotrachelini of Molytinae. Thus defined, the group still comprises several thousand species with centres of its diversity in South America and Australia. The early lineages we find in America and the Palearctic, while the extremely diverse faunas of Australia and neighbouring islands mainly belong to a more recent, species‐rich radiation. This also includes a clade comprising the majority of litter‐inhabiting species of New Zealand and the genus Miocalles Pascoe. Flightlessness was attained repeatedly and resulted in convergent evolution of a similar habitus in different zoogeographic regions, mainly exhibited by the polyphyletic genus Acalles Schoenherr.     

THE EUPYRENE-APYRENE DICHOTOMOUS SPERMATOGENESIS OF LEPIDOPTERA. ORGAN CULTURE STUDY ON THE TIMING OF APYRENE COMMITMENT IN THE CODLING MOTH

Lepidopteran spermatogenesis is dichotomous, producing eupyrene (nucleated) and apyrene (anucleated) spermatozoa. The eupyrene precedes the apyrene spermatogenesis. The timing of the switchover from eupyrene to apyrene spermatogenesis was determined by cultivating testes of accurately aged codling moth larvae in a medium containing mammalian serum but neither hemolymph nor insect hormones. In cultures, eupyrene spermatogenesis occurred in testes dissected from either 4th or 5th instar larvae, probably due to macromolecular factor-like activity of the serum of the medium. But apyrene spermatogenesis occurred only in testes explanted during or after the fourth day of the 5th instar larva. It is concluded that: (1) An apyrene spermatogenesis inducing factor (ASIF) becomes active on the fourth day of the 5th instar larva in addition to the already existing macromolecular factor. (2) Primary spermatocytes can develop into either eupyrene or apyrene spermatozoa. (3) The apyrene spermatogenesis commitment and pupal commitment of other tissues coincide about the fourth day of the 5th instar larva.