Large-scale geographical variation confirms that climate change causes birds to lay earlier.

Advances in the phenology of organisms are often attributed to climate change, but alternatively, may reflect a publication bias towards advances and may be caused by environmental factors unrelated to climate change. Both factors are investigated using the breeding dates of 25 long-term studied populations of Ficedula flycatchers across Europe. Trends in spring temperature varied markedly between study sites, and across populations the advancement of laying date was stronger in areas where the spring temperatures increased more, giving support to the theory that climate change causally affects breeding date advancement.

Selective fetal hypophysectomy in utero: microsurgical technique and comparisons with hypophysectomy by decapitation.

A detailed description is given of a surgical technique for selectively removing the pituitary anlage from the intrauterine fetal rat as an alternative to the more generally applied fetal hypophysectomy by decapitation. Fetuses on the 17th day of gestation were approached through a narrow opening in the uterine wall and fetal membranes. The pituitary gland was sucked out with a fine glass tube introduced from the side of the head into the space between the pons and the ventral hypothalamus, where the gland is situated. The female rat was sacrificed on the 22nd day of gestation (the day before delivery) and the surviving fetuses were preserved. On average, 20% of the operated fetuses survived until that day, 20% of which were completely hypophysectomized (microscopical examination). Operated fetuses with intact pituitaries served as surgical controls for the evaluation of selected effects of the total hypophysectomy. Initial comparisons were made with published results based on hypophysectomy by decapitation, evaluated without access to surgical controls. The two methods of fetal pituitary removal provide consistent results as regards the weight increase of adrenal and thyroid glands (retardation), thymus gland (stimulation) and testicles (no effect). On the other hand, body weight increase was not affected by selective hypophysectomy but instead slowed down after decapitation, whereas the growth in length of the humerus bone was stimulated and retarded, respectively.

On the Development of the Eminentia Mediana of the Hypophysis in Rana temporaria, Studied in Normal, Hypophysectomized, and Thyroidectomized Tadpoles.

In the Rana temporaria tadpole, the part of the infundibular floor that eventually becomes the eminentia mediana is very thin throughout premetamorphosis; the supply of aminergic and neurosecretory nerves is poor, and the area is covered by a few fenestrated capillaries. The organ begins to thicken around mid-prometamorphosis owing to a marked invasion of nerves. At this stage it is also penetrated by capillaries and perivascular space extensions, which together form the neurovascular link structures. These become more pronounced during metamorphic climax, when the eminentia mediana attains the adult appearance. Development of the organ is arrested at the premetamorphic stage after thyroidectomy in the young premetamorphic tadpole. Removal of the adenohypophysial primordium from the embryo of the tailbud stage prevents the vascular-but not the neural-component of the eminentia from developing beyond the premetamorphic stage. By contrast, in the American Rana-species investigated the neural component also fails to develop after hypophysectomy.