Simon K A Robson

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We examine the paraphylectic hypothesis of bat origins, both in the light of previous discussions, and in the light of new evidence from our analyses of neurological traits and wing morphology. Megabats share with primates a variety of complex details in the organization of neural pathways that have not been found in any other mammalian group, particularly(More)
Foragers of the ant Formica schaufussi recruit nestmates to large anthropod prey and cooperatively transport the prey to the nest. The size of the group of ants retrieving prey is significantly correlated with the prey mass at the point at which the retrieval group reaches the nest entrance. To understand the mechanism involved in this “size matching”(More)
Cooperative prey retrieval in the monomorphic ant Formica schaufussi is carried out by workers that perform functionally distinct roles which persist only for the duration of a single retrieval event. A forager (scout) that locates prey too large to retrieve individually organizes cooperative prey transport by recruiting nestmates (recruits) to assist in(More)
Weaver ants (Oecophylla smaragdina) are dominant ants in open forests from India, Australia, China and Southeast Asia, whose leaf nests are held together with larval silk. The species, together with its sole congener O. longinoda, has been important in research on biological control, communication, territoriality and colony integration. Over most of the(More)
Division of labour by worker age is one of the most prominent and widespread features of colony organization in the social insects. Tofts & Franks (1992) and Tofts (1993) proposed through simulations that a simple algorithm (‘foraging for work’) serves as a general model for understanding task allocation in eusocial animals ranging from ants and bees to(More)
Changes in milk composition are described for three species of free-ranging insectivorous bats (Myotis lucifugus, M. velifer, and Tadarida brasiliensis) from early to mid (peak) lactation. Dry matter and energy concentrations in milk increased from early to mid-lactation. In M. lucifugus and T. brasiliensis, but not M. velifer, these increases were due(More)
This research provides the first evidence of dispersal of bryophytes and associated microorganisms through ingestion by a highly mobile vertebrate vector, the spectacled flying fox (Pteropus conspicillatus). Bryophyte fragments were found in faeces collected at four P. conspicillatus’ camps in the Wet Tropics bioregion, northeastern Australia. These(More)
Twelve of 30 species examined in the ant genus Polyrhachis carry single nucleotide insertions at one or two positions within the mitochondrial cytochrome b (cytb) gene. Two of the sites are present in more than one species. Nucleotide substitutions in taxa carrying insertions show the strong codon position bias expected of functional protein coding genes,(More)
Understanding the maintenance and evolution of complex group behavioural systems has broad significance to our understanding of social evolution, yet we have little insight into how these systems have evolved. Nest-weaving, a rare group behaviour considered a pinnacle of cooperative action in social insects, involves the coordination of workers and larvae(More)
The evolution of territorial behavior requires that the benefits of territoriality outweigh the costs. The costs are primarily those of territorial defense against encroaching neighbors or against floaters seeking to establish their own territory. One way to reduce the cost of defense might be to restrict serious conflict to encounters with those posing the(More)