Biology Projects 2009
Natural History of the pirate spider, Mimetus hesperus, in Kern County.
Faculty Mentor - Carl Kloock
Pirate Spiders (Family Mimetidae) are little-studied spiders best known for their dietary specialty: they specialize on eating other spiders, and are sometimes also called Cannibal Spiders because of this trait. Pirate spiders are able to successfully prey upon other spiders, including some species larger then they are (and potentially including Black Widows), by using a specialized tactic known as aggressive mimicry. Specifically, pirate spiders invade the web of their prey and use vibratory signals to draw their intended target away from the relative safety of the web's center, then attack with a lightning-fast lunge, biting the victim with a spider-specific venom that typically paralyzes it within seconds.
The Pirate spider Mimetus hesperus occurs throughout California, and has been located at several sites in Kern county, but virtually nothing is known about its habitat, prey species, or behavior. This summer's REVS-UP project will focus on learning this basic natural history, and will include field surveys documenting prey species, habitat types and vegetation preferences. We will also bring individuals into the lab and stage predation events, measuring the vibrations used by the spider and comparing those vibrations to other signals in prey webs, in an attempt to determine the signal(s) used by M. hesperus to lure prey.
Please note: Pirate spiders are nocturnal organisms. This means that this project will require extensive night work in the field, as all surveys and experiments will, by necessity, occur at times the animals are active. Because the main focus is on learning the basic natural history of the spider, I expect that most of the work (3-4 days/week, with the exception of the first week) will begin in the early evening and extend into the morning hours. It also extremely likely that we will collect some scorpions in support of other research that is ongoing in my lab.
The evolution of peg-like setae in species of Anervina: a molecular genetic perspective.
Faculty Mentor - Paul Smith
The genus Anevrina is a group of relatively large phorid flies whose distribution is restricted to the northern hemisphere. All species are scavengers, and some are collected frequently from small mammal burrows. Some species possess unusual peg-like structures on the inner face of the hind femur (Figure 1.). These structures are present on male specimens only and are believed to be sensory structures that aid the male during copulation. At present there are 15 known species of Anevrina and about 1/3 of these possess these peg-like structures.
Figure 1. Scanning electron micrograph of the inner face of the hind leg showing the peg-like sensory structures.
Summer 2009 Revs-Up project participants will learn and utilize the techniques of molecular biology (e.g., PCR, gel electrophoresis) and phylogenetic analysis to study the relationships of Anevrina species and the evolution of the peg-like setae. Specifically, we will determine whether the peg-like setae evolved once from a common ancestor or independently multiple times among species in the genus.
Investigation of Cutaneous Bacteria Inhabitants of the North American Bullfrog, Rana catesbeiana
Faculty Mentors - Antje Lauer, Kathleen Szick-Miranda
Invasive species such as the North American Bull frog are successful breeders in a variety of environments. They are outcompeting native amphibian species due to various reasons. One reason that explains their success is the immunity to a variety of amphibian diseases including Chydridiomycosis. Chydridiomycosis in amphibians is caused by a fungus. This disease is responsible for major amphibian declines worldwide, in areas where habitat destruction and pesticides play a major role. The reason why the North American Bull frog is not succumbing to fungal infections is not known. The objectives of the summer research project is to isolate bacteria from the skin of bull frogs from different populations and test them for antibiotic production in challenge assays against a known fungus and an unknown fungus that was isolated from the skin of one amphibia. We have discovered and swabbed 32 individual bull frogs at five different locations in Bakersfield and also in the foothills of the Sierra Nevada. This project will contribute to the global search for a plausible solution to combat Chydridiomycosis that can be applied in nature without concern.
Vascular Transport of California Native Shrubs
Faculty Mentors - R. Brandon Pratt
Wood, referred to as xylem by scientists, is a globally important commodity that has been important to humans for building material, shelter, and fuel for millennia. In plants, wood makes up the water transport tissue that is crucial for moving water and chemicals throughout the plant body to maintain healthy functioning. Understanding how wood functions not only enables more efficient use of this important resource, but it also helps us understand how plants are adapted to the environment, how ecosystems function, and plant evolution.
Although wood is commercially and physiologically important, many aspects of wood function remain a mystery. Summer research will focus on the physiology of water transport in wood in a ecological context. Sampled species will include some of California's beautiful and rare woody shrubs.
Dr. Pratt's laboratory includes a vibrant and fun loving group that includes undergraduates, Master's students, and post-doctoral scholars.