The study of sexual selection has traditionally focused on events and behaviours immediately surrounding copulation. In this study, we examine whether carry-over effects from the non-breeding season can influence the process of sexual selection in a long-distance migratory bird, the American redstart (Setophaga ruticilla). Previous work on American redstarts demonstrated that overwintering in a...

UNLABELLED Polyamines are found in all groups of cyanobacteria, but their role in environmental adaptation has been barely investigated. In Synechocystis sp. strain PCC 6803, inactivation of spermidine synthesis genes significantly reduced the survivability under chill (5°C)-light stress, and the survivability could be restored by addition of spermidine. To analyze the effects of spermidine on ...

Renal adenocarcinomas of the leopard frog, Rana pipiens, collected in Kandiyohi County, Minn., were fixed for electron microscopy prior to and 4, 7, 13, and 16 days after the entry of host frogs into lakes for overwintering. Fifteen tumors were studied. No herpesviruses were detected in 4 tumors of prehibernating frogs. Two tumors of frogs autopsied on Day 4 of overwintering did not show viruse...

Estimates of carbon flux to the deep oceans are essential for our understanding of global carbon budgets. Sinking of detrital material ("biological pump") is usually thought to be the main biological component of this flux. Here, we identify an additional biological mechanism, the seasonal "lipid pump," which is highly efficient at sequestering carbon into the deep ocean. It involves the vertic...

Although the lesser spotted eagle is not listed as endangered by the IUCN, BerndUlrich Meyburg from BirdLife Germany (NABU) knows that the graceful bird of prey’s future is far from assured in Germany. Meyburg explains that the German population has dwindled to just 110 breeding pairs in recent decades, largely due to habitat loss and persecution by poachers during their long migration to their...

A bottom-mounted upward-facing 38-kHz echo sounder was deployed at ~400 m and cabled to shore in Masfjorden (~60°52'N, ~5°24'E), Norway. The scattering layers seen during autumn (September-October) 2008 were identified by trawling. Glacier lanternfish (Benthosema glaciale) were mainly distributed below ~200 m and displayed three different diel behavioral strategies: normal diel vertical migrati...

Since most insects are unable to survive internal ice formation a key factor in their overwintering survival is the regulation of the temperature at which they spontaneously freeze. To enhance their supercooling capacity overwintering insects eliminate endogenous ice nucleators, accumulate low-molecular-weight polyols and sugars, and synthesize hemolymph antifreeze proteins. A number of freeze-...

Morphological differences between the adults of overwintering and non-overwintering generations of the sawfly Pristiphora leucopus (Nematinae) are described and illustrated, as well as characters that distinguish P. leucopus from the closely similar P. armata. In the basal hymenopteran lineages (‘Symphyta’), seasonal polyphenism is so far only definitely recorded in the Sterictiphorinae (Argida...