Resource discovery in ant communities: do food type and quantity matter?

1. Omnivorous woodland ant species trade off between the ability to find and behaviourally control food resources. Dominant species can limit the ability of subordinates to harvest certain food items. However, subordinate species, by being faster discoverers, could gain access to such food items by arriving at them first. 2. In this study, we tested the hypothesis that resource‐directed discovery occurs in ant communities and that good discoverers preferentially discover high value resources. We did this by measuring time to discovery and the number of discoveries of high and low levels of two resource types, crickets and honey, for species occurring in Texas and Arizona woodland ant communities. 3. Ants discovered resources roughly 10 times faster in Texas than in Arizona. They discovered crickets more rapidly than honey in both communities, but there was no difference in the discovery of different resource levels. We also found that species were not biased in their discovery of different resource types or levels. 4. These results provide indirect evidence that discovery is directed by resource stimuli but that such directedness does not impact interspecific exploitative competition.     

A Screening Level Mass Balance Model of Sediment Remediation Options

It is suggested that dynamic mass balance models can provide valuable support information when sediment remediation activities, such as dredging, are contemplated. A model with sufficient credibility and accuracy can be used to compare and contrast the results of various remediation actions and the effect of natural remediation processes. A food web model can also be included. The information provided by the model can be summarized in periodic (e.g. annual) “Report Cards” documenting the status of the contaminated system during and after the remediation process. Time plots of relevant properties of the system, such as contaminant masses, concentrations and levels in water, sediment and biota, can convey the essential information required for decision-making. This approach is illustrated by applying it with screening level accuracy to the remediation activities currently being undertaken in the St. Clair River, which flows from Lake Huron to Lake St. Clair near Sarnia, Ontario, Canada. The effects of dredging to reduce concentrations of hexachlorobenzene in sediment, water and biota are explored.     

A new genus and phylogenetic analysis of the Bathyaulacini and Glyptomorphini (Hymenoptera: Braconidae: Braconinae)

A new genus Annectobracon (type species A. eventus sp.n. from China, Thailand, Laos and Vietnam) and A. excavata sp.n. from India and Sri Lanka belonging to the tribe Bathyaulacini are described and illustrated, and an identification key to the species is provided. A phylogenetic analysis of the tribes Bathyaulacini and Glyptomorphini is presented, and the new genus is shown to be the sister group of Ischnobracon Baltazar.     

Terga1 and inter–tergal metasomal glands of male braconine wasps (Insecta, Hymenoptera, Braconidae)

The distribution of cxocrine tergal and inter–tergal glands among males of more than sixty genera of Braconinac has been surveyed. The morphology of the glands and their reservoirs is described. Two gland types were found. Large, sac–like inter–tergal glands, usually most prominent between the 7th and 8th abdominal tergites, were found in all members of the Braconini, Adeshini, Aphrastobraconini, Glyptomorphini and the Atanycolus and Merinotus groups of genera. Inter–tergal glands were generally considerably smaller in members of the Bathyaulacini, Coeloidini. Euurobraconini and Iphiaulacini. Small pore–plate, vase–like or tubular tergal glands opening on the medio–lateral or antero–lateral selerotized parts of the 8th metasomal tergite were found in many genera, but were largely absent from members of the Braconini, Euurobraconini and Iphiaulacini ss. The phylogenetic implications of these findings are discussed.