Isolation of highly polymorphic autosomal microsatellite loci and a sex‐linked locus from sugarbirds

We describe the isolation of six tetranucleotide microsatellites from the Cape sugarbird (Promerops cafer) using an enrichment protocol. All loci were highly variable with number of alleles ranging from nine to 26 and values of observed heterozygosity ranging from 0.534 to 0.931. All loci were in Hardy–Weinberg equilibrium with the exception of Pro66 and Pro86. Further analysis of Pro86 indicated it was Z‐linked. All loci amplified and were variable in the congeneric Gurneys sugarbird (Promerops gurneyi). These loci will be used in mating system and phylogeographic studies of Cape sugarbirds in South Africa.     

Statistical Confusion Among Graduate Students: Sickness or Symptom?

Abstract: Statistics is one of the most important yet difficult subjects for many ecology and wildlife graduate students to learn. Insufficient knowledge about how to conduct quality science and the ongoing debate about the relative value of competing statistical ideologies contribute to uncertainties among graduate students regarding which statistical tests are most appropriate. Herein, we argue that increased education of the available statistical tests alone is unlikely to ameliorate the problem. Instead, we suggest that statistical uncertainties among graduate students are a secondary symptom of a larger problem. We believe the root cause lies in the lack of education on how to conduct science as an integrated process from hypothesis creation through statistical analysis. We argue that if students are taught to think about how each step of the process will affect all other steps, many statistical uncertainties will be avoided.     

Patterns of morphological variation in two sexually dimorphic bird species with different tail shapes

Many studies have focused on tail ornamentation in birds, but not all tail shapes have been studied in depth. Graduated and pin tails have received less attention than forked tails, despite being more likely, in terms of aerodynamic theory, to be honest signals. We report morphological variation in live specimens of two sexually dimorphic passerines from the same site with different tail shapes: graduated (Cape sugarbird Promerops cafer ) and pin (orange-breasted sunbird Antobaphes violacea ). Coefficients of variation (CVs) were calculated for all morphological traits, both non-ornamental (range 1.91–5.72) and ornamental (range 5.83–21.71). Males and females did not differ in CV for any non-ornamental trait. Ornamental traits in males of both species were significantly more variable than all non-ornamental traits. Cape sugarbird ornamental traits were significantly more variable than those of orange-breasted sunbirds. The high levels of variation in graduated tails relative to pintails suggest that these traits have been driven mainly by sexual selection. In contrast, both constraining natural and multiple ornament selection could be responsible for the relatively low levels of variation in pintails.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 91 , 437–443.     

Amphipod Life Histories: Community Structure, Impact of Temperature on Decoupled Growth and Maturation Rates, Productivity, and P:B Ratios

Data are presented on northern Bering Sea benthic amphipod growthrates and age at maturity, indicating that high latitude speciesgrow slowly, require 2 to 4 years to mature, reach a large size,and have long lifespans. Data are also presented demonstratingpredation by benthic amphipods on newly metamorphosed juvenilesof a potential space competitor, the northern sand dollar Echinarachniusparma. Such facultative predation by the predominantly herbivorousamphipods may, in part, explain the existence of alternativebenthic communities in the eastern Bering Sea. Incorporationof the high latitude results into a review of benthic amphipodlife histories revealed several important patterns. Amphipodgrowth rates and molting rates appear to be decoupled, resultingin small adults at warm temperatures and large adults at lowertemperatures. We posit that molting rate is temperature- sensitive,that at warm temperatures molting occurs rapidly regardlessof limited instar tissue growth, and that the amphipods reachsexual maturity after a fixed number of molts. Alternatively,gonad development is also temperature-dependent and may drivematuration, regardless of the number of molts experienced. Amphipodshave linear or exponential growth rates, as opposed to the familiarasymptotic curve. Consequently, secondary production is highlydependent upon the proportion of large individuals in the population,in contrast to organisms with asymptotic growth in which productionis largely determined by the proportion of young, growing individualspresent. Production in amphipods is significantly correlatedwith standing stock. P:B ratios are not correlated with productionin amphipods, and probably are not in other organisms with linearor exponential growth rates, and thus appear to have no comparativevalue other than as a possible index of generation times.