STUDIES OF FLUCTUATIONS IN INSECT POPULATIONS XIII. AN IMPROVED METHOD OF ASCERTAINING THE CORRECT DATE TO SAMPLE WHEN ASSESSING LARVAL INFESTATIONS OF THE WHEAT-BLOSSOM MIDGES

Fully fed larvae of the wheat-blossom midges need moist conditions in order to descend from the ears to the soil. A dry spell coinciding with the fully fed stage therefore causes an accumulation of larvae, which subsequently leave the ears in a body when rain comes. Conversely, in wet weather each larva leaves the wheat as soon as it finishes feeding, and, since all the eggs are not laid on the same day, the descent will then be a gradual process.
A method is described of taking small samples of wheat ears at frequent intervals, thus facilitating the determination of the correct date on which to take the main sample for the assessment of infestation by the two wheat-blossom midges.     

Ginger and alpha lipoic acid ameliorate age-related ultrastructural changes in rat liver

Because of the important role that oxidative stress is thought to play in the aging process, antioxidants could be candidates for preventing its related pathologies. We investigated the ameliorative effects of two antioxidant supplements, ginger and alpha lipoic acid (ALA), on hepatic ultrastructural alterations in old rats. Livers of young (4 months) and old (24 months) Wistar rats were studied using transmission electron microscopy. Livers of old rats showed sinusoidal collapse and congestion, endothelial thickening and defenestration, and inconsistent perisinusoidal extracellular matrix deposition. Aged hepatocytes were characterized by hypertrophy, cytoplasmic vacuolization and a significant increase in the volume densities of the nuclei, mitochondria and dense bodies. Lipofuscin accumulation and decreased microvilli in bile canaliculi and space of Disse also were observed. The adverse alterations were ameliorated significantly by both ginger and ALA supplementation; ALA was more effective than ginger. Ginger and ALA appear to be promising anti-aging agents based on their amelioration of ultrastructural alterations in livers of old rats.     

Simultaneous Collection of Body Temperature and Activity Data in Burrowing Mammals: a New Technique

Abstract: Integrating physiological and behavioral observations into ecological field studies of animals can provide novel insights into relationships among animal behavior, physiology, and ecology. We describe and evaluate a new technique for simultaneously collecting body temperature (T_b) and burrow use data for semi-fossorial mammals by combining light-sensitive radiotransmitters and implanted temperature-sensitive dataloggers. We used this approach to collect core T_b and activity data for 9 free-ranging arctic ground squirrels (Spermophilus parryii) in northern Alaska, USA, at approximately 5-minute intervals for 30–90 days each to address questions related to thermoregulation, energetics, foraging, sociality, and timing of activity in natural environments.     

ANATOMY OF PSEUDOTRITONIA THIELE, 1912 AND NOTAEOLIDIA ELIOT, 1905 (GASTROPODA: OPISTHOBRANCHIA: NUDIBRANCHIA) FROM SIGNY ISLAND, ANTARCTICA

Several species of nudibranch molluscs are abundant amongstthe rich benthic hard substratum communities found close tothe British Antarctic Survey base at Signy Island, in the Atlanticsector of the Antarctic. Over the austral summer 1992/1993,two of the authors (LWB and DKAB) were able to collect someof the lesser known species of Nudibranchia at depths between3 and 40 metres, using SCUBA. New information on morphologyand anatomy of two of these species, Pseudotritonia gracilidensOdhner, 1944 (Charcotiidae, Arminoidea) and Notaeolidia gigasEliot, 1905(Notaeolidiidae, Aeolidoidea) are presented in thispaper. The validity of the species Notaeolidia gigas is strengthened. (Received 9 February 1994; accepted 18 September 1994)