Size matters: the (negative) allometry of copulatory duration in mammals

The amount of time taken to copulate varies enormously among mammals. Because copulation likely exposes animals to an increased risk of predation, and uses time and energy that could be spent on foraging, smaller mammals (which are vulnerable to more predators and have a shorter time-to-starvation than larger mammals) should spend less time copulating than do larger mammals. Furthermore, if extended copulation reflects competition among males, then the duration of mating (after correction for body size) should be greater in mammals in which females mate with more than one male. We tested these predictions using comparative data from 113 mammalian species in 85 genera, 40 families, and 14 orders, while controlling for the effect of phylogeny. We found: (1) the relationship between duration of copulation and body size to be negative, not positive; (2) no relationship with inferred multiple mating by females (based upon relative testes mass). We suggest that small mammals may find the sustained maneuvering and body positioning of copulation easier than do large mammals. This hypothesis is supported by an apparently isometric relationship between duration of copulation and ratio of power to mass.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 185–193.     

Collective Guilt: International Perspectives

Collective Guilt: International Perspectives . Nyla R. Branscombe and Bertjan Doosje, eds. Cambridge: Cambridge University Press, 2004. 339 pp.     

Gender and Risk in a Matrifocal Caribbean Community: A View from Behavioral Ecology

Matrifocality is a feature of Caribbean communities in which mothers and adult daughters often form the household core. I argue that daughter-biased parental care underlies matrifocality. Parental investment (PI) theory predicts sex-biased care, but factors promoting daughter preference are not always clearly specified. If sons are more likely than daughters to experience unpredictable hazards, then parents may bias their efforts toward daughters. In this study, I examine gender differences in rural Dominica and test PI predictions. Men were more likely to be poor and develop alcoholism and less likely to migrate or attend high school than women were. Educational outcomes showed a Trivers-Willard effect: Boys from unfavorable family environments were less likely to receive secondary education than were other boys, but there was no association for girls. PI variables generally accounted for less variance in men's outcomes than women's, suggesting that unpredictable hazards for sons may promote daughter preference and matrifocality.     

Tracking island colonization history and phenotypic shifts in Indian Ocean bulbuls (Hypsipetes: Pycnonotidae)

Molecular phylogenies of island organisms provide useful systems for testing hypotheses of convergent or parallel evolution, since selectively neutral molecular characters are likely to be independent of phenotype, and the existence of similar environments on multiple isolated islands provides numerous opportunities for populations to evolve independently under the same constraints. Here we construct a phylogenetic hypothesis for Hypsipetes bulbuls of the western Indian Ocean, and use this to test hypotheses of colonization pattern and phenotypic change among islands of the region. Mitochondrial sequence data were collected from all extant taxa of the region, combined with sequence data from relevant lineages in Asia. Data are consistent with a single Hypsipetes colonization of the western Indian Ocean from Asia within the last 2.6 Myr. The expansion of Hypsipetes appears to have occurred rapidly, with descendants found across the breadth of its western Indian Ocean range. The data suggest that a more recent expansion of Hypsipetes madagascariensis from Madagascar led to the colonization of Aldabra and a secondary colonization of the Comoros. Groupings of western Indian Ocean Hypsipetes according to phenotypic similarities do not correspond to mtDNA lineages, suggesting that these similarities have evolved by convergence or parallelism. The direction of phenotypic change cannot be inferred with confidence, since the primary expansion occurred rapidly relative to the rate of mtDNA substitution, and the colonization sequence remains uncertain. However, evidence from biogeography and comparison of independent colonization events are consistent with the persistence of a small grey continental bulbul in India and Madagascar, and multiple independent origins of large size and green plumage in insular island populations of the Comoros, Mascarenes and Seychelles. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85 , 271–287.     

Multidecadal to millennial-scale shifts in drought conditions on the Canadian prairies over the past six millennia: implications for future drought assessment

Three high-resolution climatic reconstructions, based on diatom analyses from lake sediment cores from the Canadian prairies, show that shifts in drought conditions have prevailed on centennial to millennial time scales for at least the past six millennia. These shifts in mean aridity exhibit broad regional synchrony, with particularly pronounced shifts at all sites between ∼1700–2000 cal. yr bp and ∼3600–3900 cal. yr bp , as well as at ∼5400–5500 cal. yr bp for the two sites which extend back to at least 6000 cal. yr bp . The two Saskatchewan lakes exhibited significant coherence in both the timing and direction of these shifts, whereas inferred changes at the westernmost site in Alberta were significantly correlated to the Saskatchewan sites, but opposite in sign, and exhibited more high-frequency variation on the scale of centuries. The mechanisms behind these abrupt shifts in aridity are poorly understood, but may be linked to changes in oceanic–atmospheric interactions that influence the mean position of the jetstream and the associated storm tracks. Natural shifts in mean climatic conditions may accelerate with increasing carbon dioxide levels intensifying the likelihood of extreme droughts in North American prairies.     

One new and one rediscovered species of Strobilanthes Blume (Acanthaceae)

A new species—Strobilanthes matthewiana R.W. Scotland—from Southern India is described and illustrated. The rediscovery of Strobilanthes punctata Nees is reported. Illustrations of Strobilanthes punctata and Strobilanthes anceps Nees are presented. A list of diagnostic differences between Strobilanthes punctata and the closely related Strobilanthes anceps is provided.     

Cranial anatomy of ophiderpetontid aïstopods: Palaeozoic limbless amphibians

Oestocephalus , an ophiderpetontid from the Middle Pennsylvanian of both Europe and North America provides the best known basis for evaluating the relationships of the aïstopods. All aïstopods are united by the unique manner of attachment of the skull and the first cervical in which the articulating surface of the occiput is formed by the narrow circular rim of a notochordal pit. As in other aïstopods (but in contrast with all other early tetrapods), the otic-occipital portion of the braincase is ossified as a single element. The palatoquadrate ossification extends from the orbit to the back of the area of jaw articulation. These two characters may be retained from the osteolepiform sarcopterygians. Few, if any, unique derived characters unite aïstopods with other early tetrapods. Their phylogenetic position remains enigmatic.     

Amino-acid Sequence of Extracellular Ribonuclease (Barnase) of <Emphasis Type="Italic">Bacillus amyloliquefaciens</Emphasis>

THE ribonuclease, barnase, produced by Bacillus amyloliquefaciens has a molecular weight of 12,382, consisting of 110 amino-acid residues. It is one of the smallest proteins containing neither disulphide bonds nor non-peptide cross-Bnks which nevertheless maintain a well defined tertiary structure^1,2. The next smallest reported enzyme of similar nature is the lysozyme of phage T4, with 160 residues. The barnase structure is reversibly destroyed by denaturing solvents or heat², in what approximates a one step, highly cooperative, transition. Studies of this reaction should be very useful in illustration approaching the general problem of sequence-determined folding in proteins. In particular, thermodynamically meaningful quantitative differences in the stability of various genetic variants and chemically modified, or synthetic, barnases could be measured. Some work has been reported on the effect of various environmental parameters on the transition³ as well as the effects of modification by carboxypeptidases⁴. Full utilization of such data requires knowledge of both amino-acid sequence and three dimensional structurs. The complete amino-acid sequence is reported here (Fig. 1). The sequence was obtained by conventional procedures involving analysis of peptides isolated after hydrolysis of the native or modified protein by various proteases.

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