Paul E. Blom

Chemical secretions of two sympatric harvester ants,Pogonomyrmex salinus andMessor lobognathus

Messor lobognathus, an apparent mimic ofPogonomyrmex salinus, shows little chemical resemblance to its exemplar. The mandibular glands ofM. lobognathus gave no volatile compounds. Those ofP. salinus contain chiefly 4-methyl-3-heptanone. Both species contain a mixture of straight-chain alkanes, alkenes, and methyl-branched alkanes in their Dufour glands. Tridecane (64%) is the major substance inM. lobognathus and dodecane (25%) and pentadecane (24%) are the major compounds ofP. salinus. No secretion induced trail-following in either species. A mixture of 9-, 11-, and 13-methylheptacosane formed the largest peak in the chromatograms obtained from the postpharyngeal glands of both species, but otherwise the hydrocarbon mixtures in this gland too were distinct.

Observations of Ants (Hymenoptera: Formicidae: Myrmicinae, Formicinae, Dolichoderinae) Utilizing Carrion

vida, consistiendo esta bisicamente de atropodos. En forma general la especie se alimenta de arafias, orugas, caracoles, is6podos, escarabajos, bayas, frutos de cactaceas y nectar (Ehrlich et al., 1988). En particular, en nuestro ejemplar (UANL 1672), el contenido estomacal presentaba arafias de la familia Solifugidae y restos de cole6pteros y lepid6pteros no identificables; ademAs las ufias presentaron un desarrollo normal por lo que descartamos la posibilidad de que hubiera sido un ejemplar domesticado. Lo anterior lo remarcamos dado que en la radiografia se presentan centros de recalcificaci6n, lo que indica una dieta alta en componentes como el f6sforo que ayuda a fijar este elemento y que solo pudo ser obtenido por tener una dieta muy selectiva.

Concentrations of 137 Cs and 60 Co in Nests of the Harvester Ant, Pogonomyrmex salinus, and Associated Soils near Nuclear Reactor Waste Water Disposal Ponds

-Waste water from light-water-moderated and cooled nuclear reactors of the Test Reactor Area on the Idaho National Engineering Laboratory was discharged into three ponds to leach into the soil. Soils of Pogonomyrmex salinus nests near these ponds contained concentrations of 137Cs and 60Co greater than those observed in adjacent reference soils. The mound contained the highest concentrations of 137Cs and 60Co with levels at least two times greater than any other nest-associated or reference soil. The concentrations in the mound may have resulted from aggregation of surface particles and/or through vertical exhumation of deeper soils during nest construction. Considerations from Pogonomyrmex biology and the observation that radionuclide concentrations 5-10 cm below the mound were significantly greater than soils of the same depth not influenced by ants lend strength to the latter hypothesis. No significant erosion of 137Cs and 60Co from the mound to the surrounding clearing was detected.

Chemotaxonomic study of undescribed species ofMyrmica ant from Idaho

An undescribed species ofMyrmica collected in Idaho has been shown to have the same substances in its mandibular glands (3-octanol and 3-octanone and related 3-alkanols and 3-alkanones) and in its Dufour gland (linear alkanes, alkenes, and farnesene isomers and homologs) as previously examined European species ofMyrmica. The poison gland contains the trail pheromone 3-ethyl-2,5-dimethylpyrazine, common to allMyrmica species studied so far. The Dufour gland contains large amounts of bishomofarnesene, which easily distinguishes it from some 13 otherMyrmica already known.

MODELING SEASONAL WINE GRAPE DEVELOPMENT USING A MIXTURE TECHNIQUE

Biological growth data typically display an increasing sigmoidal pattern over time. Grape development is no exception and shows a similar general trend. A detailed examination of the growth process in grapes, however, reveals a few systematic deviations from this pattern. Specifically, grape development is often characterized by localized areas of growth plateaus leading to an overall growth pattern referred to as a double sigmoidal curve. Capturing and characterizing these local changes in growth is important as they represent important phases in grape development such as veraison. This paper utilizes a model adapted from the technique of mixture models to estimate the growth curve of grapes. The resulting model provides a more accurate description of the growth process and has parameter estimates directly related to the various phases of grape development. The model is demonstrated using data collected from an experimental trellis tension monitoring system in the Chardonnay grape varietie.