A geometric morphometric assessment of the effects of environment and cladogenesis on the evolution of the turtle shell

In the largest group of extant turtles, the Testudinoidea, the acquisition of an aquatic or terrestrial way of life has occurred within two clades, allowing the study of homoplasy linked to environment (commonly named convergence). Here we appraise the respective importance of two sources of morphological variation: a major cladogenetic event and a major environmental shift (aquatic vs. terrestrial). The repeatability of the same evolutionary process (environmental change) allows an assessment of the weights of both natural selection and phylogenetic constraints on several morphological features of the shell. These sources of morphological variance on the complex shell structure were studied using geometric morphometrics. We depict the morphological variation of three parts of the turtle shell: epidermal carapace, bony carapace, and plastron. In the three structures, we found that both phylogeny and environment were significant sources of morphological variation, and geometric morphometrics allowed the pattern of morphological variation due to each effect to be assessed. The assessment of the homoplasy due to environment and of the pattern of morphological variability suggests that the carapace has undergone similar morphological changes between aquatic and terrestrial environments within the two clades. The radiation of the Testudinoidea is interpreted as an adaptive radiation.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 79 , 485–501.     

Evolutionary history of a secondary terrestrial Australian diving beetle (Coleoptera,Dytiscidae) reveals a lineage of high morphological and ecological plasticity

The evolution of a secondary terrestrial lifestyle in diving beetles (Coleoptera: Dytiscidae) has never been analysed in a phylogenetic framework before. Here we study Terradessus caecus Watts, a terrestrial species of the subfamily Hydroporinae endemic to Australia. We infer its phylogenetic placement using Bayesian inference and maximum‐likelihood methods based on a multilocus molecular dataset. We also investigate the divergence time estimates of this lineage using a Bayesian relaxed clock approach. Finally, we infer ancestral ecological preferences using a likelihood approach. We recover T. caecus nested in the genus Paroster Sharp with strong support. Therefore, we establish a synonymy for both species of Terradessus with Paroster: Paroster caecus (Watts) n.comb . and Paroster anophthalmus (Brancucci & Monteith) n.comb . Paroster is an endemic Australian genus that has a remarkable number of subterranean species in underground aquifers with highly derived morphologies. Our results highlight one of the most remarkable radiations of aquatic beetles with independent ecological pathways likely linked to palaeoclimatic disruptions in the Neogene. Paroster caecus (Watts) n.comb . originated from a mid‐Miocene split following the onset of an aridification episode that has been ongoing to the present day. The deep changes in ecological communities in association with the drying‐out of palaeodrainage systems might have pushed this lineage to colonize a new niche in terrestrial habitats.     

Comparative flight performance of the seasonal morphs of the cabbage whitefly, Aleyrodes brassicae (Wlk.), in the laboratory

Abstract. 1. The flight capacity of the summer (non-diapausing) and the winter (diapausing) females of A.brassicae was assessed in terms of the climbing flight directed phototactically toward an overhead source of light in a laboratory flight chamber.
2. The summer morph took off only when prodded and its flight bouts were much briefer than those of the winter morph.
3. Immediately on take-off, the summer morph sank in flight and was negatively phototactic in the horizontal plane whereas the winter morph climbed on take-off, being positively phototactic both vertically and horizontally.
4. Three phases of behaviour during flight were observed in the winter morph: a short period of widely fluctuating rate of climb, a long 'cruising' phase of steady climbing, and a final erratic phase when the rate of climb had fallen to and below zero.
5. In general, the mean rate of climb was significantly higher on re-take-off after a landing than immediately before the landing.     

Influence of host plant Brassica species) and temperature on population increase of the cabbage whitefly Aleyrodes brassicae

Laboratory studies on the influence of host plant species on population growth of the cabbage whitefly Aleyrodes brassicae Walk. showed that greatest longevity occurred on mustard and lowest on turnip. Leaf age did not affect survival. At 20 or 25 °C the survival curves from mustard plants were shortened Slobodkin's type I whereas those from purple sprouts and turnip were typical of Slobodkin's type II. At 15 °C the survival curves from young leaves of all host plants were of Slobodkin's type I but those from mature leaves were of Slobodkin's type III except that of mustard which was of type I. Young leaves induced higher fecundities than mature leaves. Fecundity was highest on mustard followed by purple sprouts and turnip. This affected population rate such that, for example, daily r_m values on young leaves of mustard, purple sprouts, and turnip at 25 °C were 0.206, O.172, and 0.147, respectively.     

Inter-Strain Variability of Insertion/Deletion Events in the Encephalitozoon cuniculi Genome: A Comparative KARD-PFGE Analysis

ABSTRACT. We applied a two-dimensional pulsed-field gel electrophoresis procedure to the genomes of two karyotype variants assigned to two different strains of the microsporidian Encephalitozoon cuniculi , termed D (strain III) and F (strain II). Data obtained for Bss HII and Mlul restriction fragment length polymorphisms in each chromosome are compiled and compared to the reference strain I variant A. Six Insertion/Deletion (InDels) are found in subterminal position, some of these being characteristic of either D or F. Like in strain I, the terminal fragments extending between each telomere and rDNA locus are conserved in length for each chromosome. They are however smaller than in reference variant. This size reduction is estimated to be 2.5 kbp for the strain III isolate and 3.5 kbp for the strain II isolate. We hypothesize that for the three E. cuniculi strains, all chromosome extremities are prone to a constant process of sequence homogenization through mitolic recombination between conserved regions.     

The prevalence and correlates of DSM-IV disorders in the Iraq Mental Health Survey (IMHS)

Data on the prevalence and correlates of anxiety, mood, behavioral, and substance disorders are presented from a 2007-8 national survey of the Iraq population, the Iraq Mental Health Survey (IMHS). The IMHS was carried out by the Iraq Ministry of Health in collaboration with the Iraq Ministry of Planning and the World Health Organization (WHO) World Mental Health (WMH) Survey Initiative. Interviews were administered to a probability sample of Iraqi household residents by trained lay interviewers. The WHO Composite International Diagnostic interview (CIDI) was used to assess DSM-IV disorders. The response rate was 95.2%. The estimated lifetime prevalence of any disorder was 18.8%. Cohort analysis documented significantly increasing lifetime prevalence of most disorders across generations. This was most pronounced for panic disorder and post-traumatic stress disorder, with lifetime-to-date prevalence 5.4-5.3 times as high at comparable ages in the youngest (ages 18-34) as oldest (ages 65+) cohorts. Anxiety disorders were the most common class of disorders (13.8%) and major depressive disorder (MDD) the most common disorder (7.2%). Twelve-month prevalence of any disorder was 13.6%, with 42.1% of cases classified mild, 36.0% moderate, and 21.9% serious. The disorders most often classified serious were bipolar disorder (76.9%) and substance-related disorders (54.9%). Socio-demographic correlates were generally consistent with international epidemiological surveys, with the two exceptions of no significant gender differences in mood disorders and positive correlations of anxiety and mood disorders with education. Only 2.2% of IMHS respondents reported receiving treatment for emotional problems in the 12 months before interview, including 23.7% of those with serious, 9.2% with moderate, and 5.3% with mild disorders and 0.9% of other respondents. Most healthcare treatment, which was roughly equally distributed between the general medical and specialty sectors, was of low intensity. Further analyses of barriers to seeking treatment are needed to inform government efforts to expand the detection and treatment of mental disorders     

Fuelling flight in a parasitic wasp: which energetic substrate to use?

1. Flight is an energy‐demanding behaviour in insects. In parasitic wasps, strategies of nutrient acquisition and allocation, resulting life‐history trade‐offs and relationships with foraging strategies and resource availability have received much attention. However, despite the ecological importance of dispersal between host and food patches, and the great impact energy diverted to flight should have on lifetime reproductive success, the eco‐physiology of flight in parasitoids is poorly understood. 2. The objective of this study is to (i) identify the energetic resources used to fuel flight, and (ii) relate nutrient type and rate of utilisation to selective pressures in terms of resource availability posed by the environment. 3. Using a flight mill and biochemical assays, we compared flight performance and nutrient dynamics during flight between two reproductive modes of the parasitoid Venturia canescens Gravenhorst, which is known to thrive preferentially in contrasted environments (i.e. natural vs. anthropogenic habitat), differing notably in host and food distribution. 4. Biochemical analyses of different nutrient types showed that glycogen is the flight fuel used by this species, yet no significant differences in its dynamics in flight were found between the two reproductive modes. 5. Results suggest that both glycogen quantity and flight performance are related to the diverging ecological conditions experienced by thelytokous and arrhenotokous strains.