Saint Anselm College

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Brian K. Penney, Ph.D.
Research

Associate Professor, Biology

Saint Anselm College; 100 Saint Anselm Dr., Manchester, N.H. 03102

bpenney@anselm.edu; Ph: 603 641-7149; FAX 603 222-4012

http://www.anselm.edu/homepage/bpenney/main.html
http://www.anselm.edu/internet/bio/penneypage.htm

Lower rocky intertidal community, Rye, New Hampshire

General Research Interests

I am generally interested in the link between an organism's physiology and behavior and the roles it takes in an ecological community. A major theme is the role of acquired defenses in determining feeding specialization, and antipredator defense. My current focus is on nudibranchs— shell-less, colorful marine snails that often steal defenses from their prey. However, I have previously worked on insects and I also entertain student projects based on other invertebrates.

I also have a side interest in the use of technology as a learning aid in biology and health, and pursue small projects on the topic as time and opportunity permit.

Several ongoing projects are listed below.


The role of kleptocnidae in defense of aeolid nudibranchs


Kleptocnidae exploding from the cnidosac of Flabellina verrucosa (J.R. Friedman photo)

Although stinging cells stolen from cnidarian prey (kleptocnidae) are often cited as a defense for aeolid nudibranchs, there is actually very little concrete evidence for their effectiveness. We are testing the role of kleptocnidae against fish and other local predators, in conjunction with Dr. Lori LaPlante, and colleagues at the REU program at Shoals Marine Lab.


Mechanisms used to maintain kleptocnidae in functional states

Aeolids appear to prevent some nematocysts from firing as they are consumed, keep these organelles intact as they are transported through the gut, and maintain them in special structures called cnidosacs in the tips of their cerata. Maintaining and controlling and organelle from a different organism— from a different phylum!— is a pretty remarkable ability. However, we poorly understand how this is accomplished, and whether this ability varies with prey type or among aeolid nudibranch species. We are currently investigating the ability of nudibranchs to keep one particular firing mechanism intact (the "coulomb explosion" of Berking and Hermann 2006) and whether nudibranchs alter the tendency of nematocysts to fire in response to certain stimuli.


Spicule networks in dorid nudibranchs


Spicule network of Phyllidiopsis cardinalis

Many dorid nudibranchs have calcareous spicules as a large component of their dry weight, and these are often described as an additional (or alternate) defense against predators. However, the biological roles of these structures are poorly understood, and at least one study (Penney, 2006) indicates they may not be an effective defense.

We use histological, behavioral and comparative approaches to understand the importance of spicules to this group. One of the more intriguing findings is that muscles appear to insert into this network


Putative muscle insertion into spicule network, Cadlina luteomarginata mantle

Updated 2/12/09

All written material and all photos (c) Brian K. Penney, unless otherwise noted

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