Energetics and foraging behaviour of the European seed harvesting ant Messor capitatus: I. Respiratory metabolism and energy consumption of unloaded and loaded workers during locomotion

Abstract The respiratory metabolism of workers of Messor capitatus (Latreille) was measured using standard micro-Warburg techniques on single individuals. The experiments were carried out at 10, 20, 25, 30 and 40^oC, and the respiratory quotient (RQ), measured for the same individuals at 30^oC, was found to be 0.77. The specific respiratory rate (y , in μl O₂/mg dry weight/h) could be described by the following equation: Iny = -2.24 + 0.098r -0.258 In W; where T is temperature and W is the dry weight in mg. The Q₁₀ for M. capitatus in the temperature interval 20–30^oC was 3.4, a higher value than for other ants.
The energy costs of movement and carrying were determined by using the RQ to convert the continuous measurement of CO₂ produced at 30^oC by Enfiuran anaesthetized workers ('resting metabolism'), by running workers and by workers loaded with a 20 mg weight to units of energy. The resting metabolism was 10.0±1.0 mJ/mg fresh weight/h. The cost of running ( Y in joule per km) could be described by: Y = 3.865 + 0.363 Wf , where Wf is fresh weight in mg. The cost of transport for all experiments could be expressed as 0.64 × the cost of running.     

The distribution pattern of herbivory in a beech canopy

Abstract. (1) The spatial distribution pattern of herbivory by phyllophagous canopy arthropods in a 90-year-old beech stand was analysed.
(2) Two main patterns of spatial distribution were recorded. The leaf mining moths Phyllonorycter maestingella and Stigmella hemargyrella and the adult weevils Rhynchaenus fagi and Phyllobius argentatus mainly attacked the under-story and the latter species especially the low canopy in the central part of the stand. Mines of R. fagi chiefly occurred in the top of the overstory canopy or at the fringe of the stand. However, comparable distribution patterns are only expected in mature beech stands composed of distinct overstory and understory layers.
(3) The effect of the actual spatial distribution pattern of herbivory on photosynthesis, productivity, and transpiration of beech in the research stand is discussed. It is suggested that in some cases the shade leaves of the understory canopy may cushion the effect of herbivory in the beech stand.     

The peculiar Asian ghost moth genus Bipectilus Chu & Wang: taxonomy and systematic position (Lepidoptera: Hepialidae s.str.)

Abstract Bipectilus Chu & Wang, 1985, from China, Nepal, Thailand and Vietnam is redescribed. Eight species are recognized in the genus; two were described previously ( Gorgopis unimacula Daniel and Bipectilus yunnanensis Chu & Wang) and six new species are named. A key to the males is provided and all species and their genitalia are described and illustrated. One new combination is established and one lectotype is designated. Observations on the cuticular anatomy of Bipectilus are presented. The monophyly of Bipectilus is supported by several autapomorphies but the genus also possesses many plesiomorphic traits including spurs on the hind tibia in some species. Bipectilus is placed in the Hepialidae s.str. and the autapomorphies of that taxon are summarized. It is concluded that Bipectilus represents an early lineage within the family, and possibly represents the sister-group of all other Hepialidae s.str. All Asian species originally placed in Gorgopis Hübner are removed from this endemic Afrotropical hepialid genus.     

Cellular responses of developing Fucus serratus embryos exposed to elevated concentrations of Cu2+

Elevated concentrations of Cu²⁺ can have inhibitory effects on early development in plants and algae by targeting specific cellular processes. In the present study the effects of elevated Cu²⁺ on developmental processes in embryos of the brown algae Fucus serratus (Phaeophyceae) were investigated. Elevated Cu²⁺ was shown to inhibit fixation of the zygotic polar axis but not its formation. Actin localization was unaffected by elevated Cu²⁺ but polarized secretion, which occurs downstream, was inhibited. Significant differences in tolerance to Cu²⁺ were observed for polarization and rhizoid elongation of embryos derived from adults from Cu²⁺‐contaminated and uncontaminated locations. Moderate Cu²⁺ exposure inhibited the generation of cytosolic Ca²⁺ signals in response to hypo‐osmotic shocks. In contrast, cytosolic Ca²⁺ was elevated by treatments with high [Cu²⁺] and this coincided with production of reactive oxygen species. The results indicate that direct effects on signalling processes involved in polarization and growth may in part explain complex, concentration‐dependent effects of Cu²⁺ on early development.