I propose that the underlying adaptation enabling the reproductive strategy of birthing live young (viviparity) is retraction of the site of fertilization within the female reproductive tract, and that this evolved as a means of postcopulatory sexual selection. There are three conspicuous aspects associated with viviparity: (i) internal development is a complex trait often accompanied by a suite of secondary adaptations, yet it is unclear how the intermediate state of this trait – egg retention – could have evolved; (ii) viviparity (...) often results in a reduction in fecundity; (iii) viviparity has evolved independently many times across a diverse array of animal groups. Focusing on the Diptera (true flies), I provide explanations for these observations. I further propose that fecundity is not traded‐off to enable potential benefits of viviparity, but rather that loss of fecundity is directly selected and egg retention is an indirect consequence – a model that provides a unifying common basis for the ubiquity of viviparity. (shrink)

According to M. W. Service (1978), prior to Patrick Manson’s (1844–1922) discovery in 1877 that the mosquito Culex fatigans (Diptera: Culicidae) was the intermediate host of Bancroftian filariasis, the association of insects with disease and the nature of disease transmission was almost entirely speculation. As biographers P. H. Manson-Bahr and A. Alcock (1927) put it: “Manson’s investigations were thus the first convincing evidence that the vague beliefs traditional among many untutored races and countenanced from time to time by a (...) few sagacious medical men—beliefs that various specific diseases of the blood are disseminated by bloodsucking insects—were of good pathological report and worthy of further thought” .. (shrink)

In higher eukaryotes, circadian behaviour patterns have been dissected at the molecular level in Drosophila and, more recently, in the mouse. Considerable progress has been made in identifying some of the molecular components of the clock in the fly, where two genes, period (per) and timeless (tim), are essential for behavioural rhythmicity. The PER and TIM proteins show circadian cycles in abundance, and are part of a negative feedback loop with their own mRNAs. Within the pacemaker neurons, the PER and (...) TIM products are believed to form a complex which allows them to translocate to the nucleus, but how they repress their own transcription is unclear. TIM is rapidly degraded by light, a feature which permits a compelling molecular description of both behavioural light entrainment and phase responses to light pulses. The regulation of per and tim is altered in different Drosophila tissues, however, and comparative analyses of the two genes outside the Diptera reveals further unusual patterns of tissue‐specific regulation. Evolution appears to have modified the way in which the two genes are utilised to generate circadian phenotypes. More recently, the cloning of mouse clock genes, including putative per homologues, opens up exciting possibilities for mammalian molecular chronobiology. (shrink)

In higher eukaryotes, circadian behaviour patterns have been dissected at the molecular level in Drosophila and, more recently, in the mouse. Considerable progress has been made in identifying some of the molecular components of the clock in the fly, where two genes, period (per) and timeless (tim), are essential for behavioural rhythmicity. The PER and TIM proteins show circadian cycles in abundance, and are part of a negative feedback loop with their own mRNAs. Within the pacemaker neurons, the PER and (...) TIM products are believed to form a complex which allows them to translocate to the nucleus, but how they repress their own transcription is unclear. TIM is rapidly degraded by light, a feature which permits a compelling molecular description of both behavioural light entrainment and phase responses to light pulses. The regulation of per and tim is altered in different Drosophila tissues, however, and comparative analyses of the two genes outside the Diptera reveals further unusual patterns of tissue‐specific regulation. Evolution appears to have modified the way in which the two genes are utilised to generate circadian phenotypes. More recently, the cloning of mouse clock genes, including putative per homologues, opens up exciting possibilities for mammalian molecular chronobiology. (shrink)

Recently, American Psychologist published a review of the evidence for parapsychology that supported the general claims of psi (the umbrella term often used for anomalous or paranormal phenomena). We present an opposing perspective and a broad-based critique of the entire parapsychology enterprise. Our position is straightforward. Claims made by parapsychologists cannot be true. The effects reported can have no ontological status; the data have no existential value. We examine a variety of reasons for this conclusion based on well-understood scientific principles. (...) In the classic English adynaton, “pigs cannot fly.” Hence, data that suggest that they can are necessarily flawed and result from weak methodology or improper data analyses or are Type I errors. So it must be with psi effects. What we find particularly intriguing is that, despite the existential impossibility of psi phenomena and the nearly 150 years of efforts during which there has been, literally, no progress, there are still scientists who continue to embrace the pursuit. (PsycInfo Database Record (c) 2022 APA, all rights reserved). (shrink)