An Improved Approach to Measuring Sexual Dimorphism in Snakes: Morphological Variation in the Bahamian Racer (Cubophis vudii vudii)

Sexual dimorphism in animals exists in many forms, including overall size difference between the sexes (sexual size dimorphism, SSD) and size and structural differences in body components (sexual body component dimor­phism, SBCD). Studies of sexual dimorphism seek to determine whether dimorphic traits result from sexual selection, natural selection, or non-adaptive processes. Characterizing sexual dimorphism depends on identifying an unbiased character for overall body size, which can then be used to assess both SSD and SBCD. Most studies of snakes use snout-vent length (SVL) for this purpose, but SVL may itself be dimorphic. In this study, we examined SSD and SBCD in three island populations of the Bahamian Racer (Cubophis vudii vudii). Discriminant function analysis (DFA) showed that head width (females wider) and tail length (males longer) best discriminated between the sexes, and total length provided the least discrimination. Linear models using total length as the least-biased measure for overall size revealed an absence of SSD, but SBCD existed for head size (width 8.9% greater in females, length similar), trunk length (4.3% longer in females), and tail length (9.8% longer in males). Linear models also revealed differences among island populations for total length (New Providence < Eleuthera = Allen Cay) and head length (Allen Cay < Eleuthera < New Providence), but not head width or tail length. Extent of SBCD varied depending on choice of character to control for overall body size, with total length yielding the most female-biased values, and geometric mean, principal component 1 (PC1) of a principal components analysis, and SVL providing increasingly more male-biased values, respectively. Body condition was statistically similar for the two sexes and three seasons (spring, summer-fall, winter), but the mod­erate and large effect sizes, respectively, suggest that females were heavier than males, and both sexes were heaviest in spring. Females, which represented 64.9 of all snakes, suffered injuries disproportionately to males (19.7% and 3.1%, respectively), but no differences in sex ratio or frequency of injury existed among the island populations. Collectively, these findings illustrate the utility of using DFA and other approaches (geometric mean, PC1) to identify a relatively unbiased reference character for overall body size and suggest that sexual and natural selection interact to shape the morphology of these snakes

Conservation taxonomy of the Greater Antillean Oriole (Icterus dominicensis): diagnosable plumage variation among allopatric populations supports species status

Allopatric populations, such as those present on islands, pose special challenges to identifying taxonomic boundaries which can be practically addressed using diagnostic criteria. To assess the taxonomic and, hence, conservation status of the four island populations of the Greater Antillean Oriole (Icterus dominicensis), we examined 156 male specimens of I. dominicensis for six discrete and three continuous plumage characters. The four island populations proved to be 100% diagnosable. Icterus d. northropi differed from all other taxa by having the greatest extent of yellow on the venter (non-overlapping with other taxa). Icterus d. portoricensis was distinguished from all other taxa by the presence of a black upper rump (yellow in other taxa) and the least extent of yellow on the rump (non-overlapping with other taxa). Icterus d. melanopsis and I. d. dominicensis were fully discriminated from I. d. northropi and I. d. portoricensis by the aforementioned characters and from each other by upper-tail covert color (black and ≥ 50% yellow, respectively). Our findings support recent studies suggesting that the four island groups represent distinct allospecies consistent with interpretations of both the phylogenetic and evolutionary species concepts. With elevation to full species, conservation priorities need to be revisited, particularly for the critically endangered Bahamas taxon (I. d. northropi)

Population status, habitat dependence, and reproductive ecology of Bahama Orioles: a critically endangered synanthropic species.

Recent elevation of critically endangered Bahama Orioles (Icterus northropi) to species status promptedustoevaluate theirpopulation status,habitatuse,andbreedingecology.Fromsurveys,weestimatedthat at least 141 to 254 individuals remain globally, with 90 to 162, 24 to 44, and 27 to 48 individuals remaining on North Andros Island, Mangrove Cay, and South Andros Island, The Bahamas, respectively. Orioles were observed nesting exclusively in anthropogenic habitat (residential and agricultural land), but home ranges also included nearby pine forest and coppice (dry broadleaf forest). Most nests (40 of 46, or 87%) were in nonnative coconut palm (Cocos nucifera), with native Sabal palmetto and Thrinax morrisii, and an introduced Brassaia actinophylla also used. Trees selected by orioles for nesting were significantly taller, less likely to have shrubs underneath, further from cover, and had more palm trees nearby than randomly selected palm trees. Three of eight nests with known contents were parasitized by Shiny Cowbirds (Molothrus bonariensis). Lethal yellowing disease recently devastated coconutpalmsandreducedthenumberoforiolesonNorthAndros,butpalmsonMangroveCayandSouthAndros remain healthy. The juxtaposition of anthropogenic habitat to suitable native habitats may be more important than any single factor for Bahama Orioles, especially for breeding adults and fledged young. Conservation of coppice habitat, at high risk for agricultural and residential development, is crucial for survival of this critically endangered synanthropic species

An Analysis of the CAP Reform

The Treaty of Rome, which established the European Economic Community in 1957, defined the objectives of the Common Agricultural Policy (CAP). These objectives, contained in Article 39, follow: 1) Increase agricultural productivity by promoting technical progress and by ensuring rational development of agricultural production and optimum use of the production factors, particularly labor. 2) Ensure a fair standard of living for the agricultural community, in particular by increasing the individual earning of the persons engaged in agriculture. 3) Stabilize markets. 4) Assure the availability of supplies. 5) Ensure that supplies reach consumers at reasonable prices. The objectives of the CAP have been met, mostly through price policies that traditionally have been tied to production. The result of these policies is that production of many agricultural commodities has increased beyond levels necessary to meet CAP objectives and excess supplies have accumulated, been exported with subsidies, or both, at great expense to the European Community

Implications of a GATT Agreement for World Commodity Markets, 1993-98: An Analysis of the Dunkel Text on Agriculture

The Food and Agricultural Policy Research Institute (FAPRI) received a request in mid-February to analyze the proposed changes to agriculture and agricultural trade made by Arthur Dunkel. These changes essentially fall into three areas. 1) Export Competition. Subsidies are subject to reduction in two ways. Expenditures are to be reduced by 36 percent and quantities exported with the benefit of subsidies are to be reduced by 24 percent from 1986-90 average levels. 2) Internal Support. Using a world reference price based on the 1986-88 average levels, internal supports as measured by an aggregate measure of support (AMS) are to be reduced by 20 percent from 1986 levels. Credit will be given for support reductions made since 1986. 3) Market Access. Import restrictions are to be converted to tariffs and reduced across the board by a simple average of 36 percent. Tariffs on individual commodities are to be reduced by at least 15 percent. Where import barriers are in place, either minimum access of 3 percent of domestic consumption in 1993, rising to 5 percent in 1999, or minimum access of 1986-88 average import levels is to be provided, whichever is greater

Population status of the Chuck-will’s-widow (Caprimulgus carolinensis) in the Bahamas.

The Chuck-will’s-widow (Caprimulgus carolinensis) in the Bahama Islands has been regarded as a rare to uncommon winter visitor. We conducted breeding season surveys on the three largest northern islands (North Andros, Grand Bahama, and Great Abaco) to examine the status of this species. We encountered singing birds on most survey routes on all three islands, suggesting that sizeable breeding populations are widespread in the northern Bahamas with an aggregate estimate of 500–1,000 pairs. Our density estimates were somewhat less than those from the primary range in the United States, suggesting either a lower carrying capacity in the Bahama Islands or recently established populations that have yet to reach carrying capacity

Population status of chuck-will’s-widow (Caprimulgus carolinensis) in the bahamas

The Chuck-will’s-widow (Caprimulgus carolinensis) in the Bahama Islands has been regarded as a rare to uncommon winter visitor. We conducted breeding season surveys on the three largest northern islands (North Andros, Grand Bahama, and Great Abaco) to examine the status of this species. We encountered singing birds on most survey routes on all three islands, suggesting that sizeable breeding populations are widespread in the northern Bahamas with an aggregate estimate of 500–1,000 pairs. Our density estimates were somewhat less than those from the primary range in the United States, suggesting either a lower carrying capacity in the Bahama Islands or recently established populations that have yet to reach carrying capacity. Received 24 August 2009. Accepted 3 January 2010

Crotalus atrox venom preconditioning increases plasma fibrinogen and reduces perioperative hemorrhage in a rat model of surgical brain injury.

Perioperative bleeding is a potentially devastating complication in neurosurgical patients, and plasma fibrinogen concentration has been identified as a potential modifiable risk factor for perioperative bleeding. The aim of this study was to evaluate preconditioning with Crotalus atrox venom (Cv-PC) as potential preventive therapy for reducing perioperative hemorrhage in the rodent model of surgical brain injury (SBI). C. atrox venom contains snake venom metalloproteinases that cleave fibrinogen into fibrin split products without inducing clotting. Separately, fibrinogen split products induce fibrinogen production, thereby elevating plasma fibrinogen levels. Thus, the hypothesis was that preconditioning with C. atrox venom will produce fibrinogen spilt products, thereby upregulating fibrinogen levels, ultimately improving perioperative hemostasis during SBI. We observed that Cv-PC SBI animals had significantly reduced intraoperative hemorrhage and postoperative hematoma volumes compared to those of vehicle preconditioned SBI animals. Cv-PC animals were also found to have higher levels of plasma fibrinogen at the time of surgery, with unchanged prothrombin time. Cv-PC studies with fractions of C. atrox venom suggest that snake venom metalloproteinases are largely responsible for the improved hemostasis by Cv-PC. Our findings indicate that Cv-PC increases plasma fibrinogen levels and may provide a promising therapy for reducing perioperative hemorrhage in elective surgeries