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MEDIA ADVISORY April issue of Ecology Brown-headed cowbirds skew host offspring sex ratios It's long been known that Brown-headed cowbirds, birds that – like cuckoos – lay eggs in the nests of other birds, reduce the number of offspring from a nest they parasitize. Now a recent report shows they also affect the sex of the host's offspring. Liana Zanette, Elizabeth MacDougall-Shakelton, (University of Western Ontario), Micheal Clinchy (University of Toronto at Scarborough) and James Smith (University of British Colombia, Vancouver) found the presence of cowbird chicks increase competition in the nests of Song Sparrows, with the sparrow's female chicks loosing out. Shifts in open-ocean fish communities coinciding with the commencement of commercial fishing Comparing data from a 1950's scientific survey with observations collected on longline fishing vessels, Peter Ward and Ransom Myers ( Dalhousie University , Canada ) found a major shift in the size and diversity of fish in areas of the tropical Pacific Ocean since the introduction of industrial fishing. Large predators such as sharks and large tuna declined in abundance an average of 21 percent, while the overall size of these animals also grew smaller. Smaller species, such as pelagic stingrays, increased in numbers. See http://www.pewoceanscience.org/press/press-article.php?ID=28 . Plant defense theory provides insight into interactions involving inbred plants and insect herbivores Inbreeding is generally seen as detrimental, even for some self-fertilizing plants. Helen Hull-Sanders* and Micky Eubanks ( University of Auburn ) compared the reactions of inbred and non-inbred entire-leaf morning glory plants to various insects. The outbred, or cross-pollinated plants, were more resistant to generalized insect herbivores such as aphids while the self-fertilizing inbred plants fared better against leaf-chewing herbivores. This study is the first attempt to use plant defense theory to predict interactions between several different herbivores and inbred plants. *(currently at University of Wisconsin , Milwaukee Field Station) |
The Ecological Society of America is the world's largest professional organization of ecologists, representing 10,000 scientists in the United States and around the globe. Since its founding in 1915, ESA has promoted the responsible application of ecological principles to the solution of environmental problems through ESA reports, journals, research, and expert testimony to Congress. For more information about the Society and its activities, visit the ESA website at www.esa.org. |
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