Search results for " Anima"
showing 10 items of 3536 documents
Dinosaur Metabolism and the Allometry of Maximum Growth Rate
2016
In his 2016 paper, Myhrvold criticized ours from 2014 on maximum growth rates (Gmax, maximum gain in body mass observed within a time unit throughout an individual’s ontogeny) and thermoregulation strategies (ectothermy, endothermy) of 17 dinosaurs. In our paper, we showed that Gmax values of similar-sized extant ectothermic and endothermic vertebrates overlap. This strongly questions a correct assignment of a thermoregulation strategy to a dinosaur only based on its Gmax and (adult) body mass (M). Contrary, Gmax separated similar-sized extant reptiles and birds (Sauropsida) and Gmax values of our studied dinosaurs were similar to those seen in extant similar-sized (if necessary scaled-up) …
Effect of antibiotic treatment and gamma-irradiation on cuticular hydrocarbon profiles and mate choice in tsetse flies (Glossina m. morsitans).
2018
Background Symbiotic microbes represent a driving force of evolutionary innovation by conferring novel ecological traits to their hosts. Many insects are associated with microbial symbionts that contribute to their host’s nutrition, digestion, detoxification, reproduction, immune homeostasis, and defense. In addition, recent studies suggest a microbial involvement in chemical communication and mating behavior, which can ultimately impact reproductive isolation and, hence, speciation. Here we investigated whether a disruption of the microbiota through antibiotic treatment or irradiation affects cuticular hydrocarbon profiles, and possibly mate choice behavior in the tsetse fly, Glossina mors…
Benefits of immune protection versus immunopathology costs: a synthesis from cytokine KO models.
2017
5 pages; International audience; The inflammatory response can produce damage to host tissues and in several infectious diseases the most severe symptoms are due to immunopathology rather than a direct effect of pathogen multiplication. One hypothesis for the persistence of inflammatory damage posits that the benefits of protection towards infection outweigh the costs. We used data on knocked-out (KO) cytokine models [and the corresponding wild-type (WT) controls] to test this hypothesis. We computed differences in pathogen load and host survival between WT and KO and divided them by the WT values. Using this ratio provides an internal control for variation in pathogen species, host strain,…
Inter- and intra-specific genomic divergence in Drosophila montana shows evidence for cold adaptation
2018
This work was supported by the Academy of Finland to AH (projects 132619 and 267244) and to MK (projects 268214 and 272927) and NERC (UK) funding to MGR (grants NE/E015255/1 and NE/J020818/1) and PhD studentship to DJP (NE/I528634/1). The genomes of species that are ecological specialists will likely contain signatures of genomic adaptation to their niche. However, distinguishing genes related to ecological specialism from other sources of selection and more random changes is a challenge. Here we describe the genome of Drosophila montana, which is the most extremely cold-adapted Drosophila species. We use branch tests to identify genes showing accelerated divergence in contrasts between col…
Invasive parasites are detectable by their abundance-occupancy relationships: the case of helminths from Liza haematocheilus (Teleostei: Mugilidae)
2018
Abstract The biogeographic patterns of abundance and prevalence of helminths from Liza haematocheilus were studied across its native (Sea of Japan) and introduced (Sea of Azov) distribution ranges. Abundance-occupancy relationships (AORs) were tested for the core-satellite and enemy release (ERH) species hypotheses in eight and 14 host samples from the native and introduced host ranges, respectively. The AOR model fitted parasite data extremely well, irrespective of whether the host or the parasite species were native or invasive. Except for co-introduced monogeneans, species were less abundant and prevalent in the introduced host population than in the native one, which agrees well with th…
How many scales on the wings? A case study based on Colias crocea (Geoffroy, 1785) (Hexapoda: Lepidoptera, Pieridae)
2019
Abstract The covering by scales of the wings of Lepidoptera contributes to multiple functions that are critical for their survival and reproduction. In order to gain a better understanding about their distribution, we have exhaustively studied 4 specimens of Colias crocea (Geoffroy, 1785). We have quantified the sources of variability affecting scale density. The results indicate that the scale covering of butterfly wings may be remarkably heterogeneous, and that the importance of the sources of variability differs between forewings and hindwings. Thus, in forewing the greatest variability occurs between sectors, while in the hindwings it occurs between sides, with a higher density of scale…
Early Plasmodium-induced inflammation does not accelerate aging in mice
2019
10 pages; International audience; Aging is associated with a decline of performance leading to reduced reproductive output and survival. While the antagonistic pleiotropy theory of aging has attracted considerable attention, the molecular/physiological functions underlying the early-life benefits/late-life costs paradigm remain elusive. We tested the hypothesis that while early activation of the inflammatory response confers benefits in terms of protection against infection, it also incurs costs in terms of reduced reproductive output at old age and shortened longevity. We infected mice with the malaria parasite Plasmodium yoelii and increased the inflammatory response using an anti-IL-10 r…
Strength of sexual and postmating prezygotic barriers varies between sympatric populations with different histories and species abundances.
2019
The impact of different reproductive barriers on species or population isolation may vary in different stages of speciation depending on evolutionary forces acting within species and through species' interactions. Genetic incompatibilities between interacting species are expected to reinforce prezygotic barriers in sympatric populations and lead to cascade reinforcement between conspecific populations living within and outside the areas of sympatry. We tested these predictions and studied whether and how the strength and target of reinforcement between Drosophila montana and Drosophila flavomontana vary between sympatric populations with different histories and species abundances. All barri…
Gene expression patterns underlying parasite-induced alterations in host behaviour and life history
2015
Many parasites manipulate their hosts' phenotype. In particular, parasites with complex life cycles take control of their intermediate hosts' behaviour and life history to increase transmission to their definitive host. The proximate mechanisms underlying these parasite-induced alterations are poorly understood. The cestode Anomotaenia brevis affects the behaviour, life history and morphology of parasitized Temnothorax nylanderi ants and indirectly of their unparasitized nestmates. To gain insights on how parasites alter host phenotypes, we contrast brain gene expression patterns of T. nylanderi workers parasitized with the cestode, their unparasitized nestmates and unparasitized workers fr…
Need for speed : short lifespan selects for increased learning ability
2019
AbstractIt is generally assumed that an investment into cognitive abilities and their associated cost is particularly beneficial for long-lived species, as a prolonged lifespan allows to recoup the initial investment. However, ephemeral organisms possess astonishing cognitive abilities too. Invertebrates, for example, are capable of simple associative learning, reversal learning, and planning. How can this discrepancy between theory and evidence be explained? Using a simulation, we show that short lives can actually select for an increase in learning abilities. The rationale behind this is that when learning is needed to exploit otherwise inaccessible resources, one needs to learn fast in o…