Biology Commons^™

Growth And The Expression Of Alternative Life Cycles In The Salamander Ambystoma Talpoideum (Caudata: Ambystomatidae), Travis Ryan, Raymond Semlitsch

Travis J. Ryan

Complex life cycles (CLCs) contain larval and adult phases that are morphologically and ecologically distinct. Simple life cycles (SLCs) have evolved from CLCs repeatedly in a wide variety of lineages but the processes that may underlie the transition have rarely been identified or investigated experimentally. We examined the influence of larval growth rate on the facultative expression of alternative life cycles (metamorphosis or maturation as gill-bearing adults [= paedomorphosis]) in the salamander Ambystoma talpoideum. We manipulated growth rates by altering the amount of food individuals received throughout larval development. The expression of alternative life cycles in A. talpoideum is influenced …

Plant-Animal Interactions, W. Abrahamson, T. Taylor

Warren G. Abrahamson, II

No abstract provided.

Access To Mutualistic Endosymbiotic Microbes: An Underappreciated Benefit Of Group Living, Michael Lombardo

Michael P Lombardo

"The original publication is available at www.springerlink.com"

A central question in behavioral ecology has been why animals live in groups. Previous theories about the evolution of sociality focused on the potential benefits of decreased risk of predation, increased foraging or feeding efficiency, and mutual aid in defending resources and/or rearing offspring. This paper argues that access to mutualistic endosymbiotic microbes is an underappreciated benefit of group living and sets out to reinvigorate Troyer’s hypothesis that the need to obtain cellulolytic microbes from conspecifics influenced the evolution of social behavior in herbivores and to extend it to nonherbivores. This extension is …

On The Evolution Of Sexually Transmitted Diseases In Birds, Michael Lombardo

Michael P Lombardo

"The definitive version is available at www.blackwell-synergy.com".

Sexually transmitted diseases (STDs) in animals are caused by pathogens that are transmitted during copulation. Birds have played an important role in the development of STD-centered theories of mating behavior. However, it is not known whether STDs exist in wild bird populations. While the avian cloaca with its dual functions of gamete transfer and excretion seemingly predisposes birds for the evolution of STDs, the life history patterns of most birds (i.e., seasonal breeders with relatively brief annual periods of sexual activity) suggest otherwise. The importance of STDs as selective forces that shape host …

Hydroperiod And Metamorphosis In The Small-Mouthed Salamander

Travis J. Ryan

Legacy Of Land Use In Southern Appalachian Forests: Effects On Terrestrial Salamander Abundance Along Edges And Within Abandoned Logging Roads, R. Semlitsch,, Travis Ryan, M. Chatfield, B. Drehman, K. Hamed, N. Pekarek, M. Spath

Travis J. Ryan

Presence And Colonization Of Placobdella On Two Species Of Freshwater Turtles (Graptemys Geographica And Sternotherus Odoratus), Travis Ryan

Travis J. Ryan

It is generally accepted that bottom-dwelling turtles have a higher ectoparasite load than turtles that bask aerially because of effects of desiccation on ectoparasites, especially with regard to leeches. We compared number of leeches (primarily Placobdella parasitica) on field-caught Common Musk Turtles (Stemotherus odoratus) and Common Map Turtles (Graptemys geographica). The bottom-dwelling species S. odoratus had more than 20 times the number of leeches than the aerial-basking species G. geographica. We then exposed cleaned (leech-free) turtles to leeches in mesocosms (cattle tanks) to measure the rate of colonization. In this experiment, S. odoratus had more than four times the number …