Jon Allen

Professional Preparation

Bates College. 1994-1998.
B.S. Biology. 1998.Jon Allen: Bowdoin College: Biology

University of North Carolina at Chapel Hill. 1998-2005.
Ph.D. Biology. 2005.
Advisor: Dr. Robert D. Podolsky

Bowdoin College. 2005-2008.
Doherty Marine Biology Postdoctoral Scholar

Randolph-Macon College.  2008-2009
Assistant Professor 

College of William and Mary.  2009-present
Assistant Professor

Teaching Area

Ecology and Evolution

Research Interests

My research interests lie at the intersection of ecology and evolution. Primarily, I study the evolution of life histories and the larval ecology of marine invertebrate animals. Invertebrates comprise more than 98% of all known animal species and exhibit a wide variety of reproductive modes and strategies. Most marine invertebrate species possess a complex life cycle that is made up of a benthic adult stage and a planktonic larval stage. There is wide variation in both the form and function of the adult and larval stages of marine invertebrates and often the two stages of the life cycle are extraordinarily dissimilar in their morphology (Fig. 1). My research is focused on explaining the diversity of strategies that organisms use as they switch between habitats and morphologies during their life cycle. In particular, I am interested in investigating how changes in maternal investment affect larval and juvenile development, survival and growth.

marine Invertebrates - jon allen - bowdoin college biology Figure 1: One example of a complex life cycle in a marine invertebrate. In this case, a benthic adult brittlestar releases its gametes into the water column where fertilization occurs and development takes place over a period of days to weeks. During this period a planktonic larval stage develops which is morphologically dissimilar from the adult. Eventually the larva settles as a benthic juvenile and the cycle repeats itself in the next generation. This pattern is common among marine invertebrates and the size of the egg is positively correlated with parental investment and predicts the length of the developmental period. Note that the images are not to scale. The adult is many times larger than the egg, larval and juvenile stages.

Peer-Reviewed Publications * indicates undergraduate coauthor

Allen, J.D., C. Zakas* and R.D. Podolsky. 2006. Effects of egg size reduction and larval feeding on juvenile quality for a species with facultative-feeding development. Journal of Experimental Marine Biology and Ecology. 331(2): 186-197.
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Allen, J.D. and R.D. Podolsky. 2007. Uncommon diversity in developmental mode and larval form in Macrophiothrix. Marine Biology. 151(1): 85-97.
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Moran, A.L. and J.D. Allen. 2007. How does metabolic rate scale with egg size? An experimental test with sea urchin embryos. Biological Bulletin. 212:143-150.
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Allen, J.D. and J.S. McAlister. 2007. Testing rates of planktonic versus benthic predation in the field. Journal of Experimental Marine Biology and Ecology. 347 (1-2): 77-87.
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Allen, J.D. and B. Pernet. 2007. Intermediate modes of larval development: bridging the gap between planktotrophy and lecithotrophy. Evolution and Development. 9: 643-653.

Allen, J.D. 2008. Size-specific predation on marine invertebrate larvae. Biological Bulletin. 214: 42-49. 
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Manuscripts in Preparation

Allen, J.D. Effects of egg size reductions on development time and juvenile size in three species of echinoid echinoderms (In preparation for American Naturalist).

Allen, J.D. and E. Robinson*. Planktonic predation on embryos of three common marine invertebrates (In preparation for Marine Ecology Progress Series).

Podolsky, R.D. and J.D. Allen. Egg size, larval form, and the evolutionary transition to non-feeding development in Macrophiothrix. (In preparation for Evolution).

Student Research

Nick Alcorn, '08

Nick Alcorn, '08 - Eric Robinson '07 - Bowdoin BiologyDuring the summer of 2006 I studied the larval development of Echinarachnius parma, the most common species of sand dollar on the northern Atlantic coast.  This work was interesting because it combined multiple fields of biology including embryology, larval ecology, and marine invertebrate biology.  The goal of the project was to determine the effects of decreasing egg size and food availability on E. parma development.  Understanding marine invertebrate development is important for gaining knowledge about the evolutionary compromise between parental investment and offspring number.  Results demonstrated that food availability and egg size both had significant effects on larval development, but that food availability had a greater effect than egg size.

Eric Robinson, '07

The larvae of many benthic invertebrates undergo vertical migrations within the water column, possibly to avoid predation.  While many studies have focused on larval vertical migrations in decapods including lobsters and crabs, little research has been done on non-decapod, benthic invertebrates.  In addition, few studies have investigated how rates of predation on invertebrate larvae differ over the range of water depths encompassed by vertical migrations.  To address these topics, I spent the summer of 2006 at Bowdoin College's Coastal Studies Center, where I tested the rates of predation on non-decapod larvae at various heights off the benthos.  In order to observe rates of predation on larvae, I made agarose baits flavored with homogenates from clam, mussel, and sea urchin eggs and unflavored agarose pellets, all of which I tethered to monofilament lines and set in the field at multiple heights above the sea floor.  I deployed the baits for 2 hour intervals during daytime high tides, after which they were recollected and I assessed the baits for predation.  I found the highest rates of larval predation to be on the benthos, followed by another, smaller peak at 3.0 m and 6.0 m above the ocean floor.  In addition, I noticed predation on mussel flavored baits appears to be more pronounced than that on clam and sea urchin flavored baits.  This latter finding suggests that mussel larvae may lack survival mechanisms such as chemical defenses, which clams and sea urchins could possess.  From the results, I determined that larval predation is a significant force acting on marine larvae that may in part explain the evolution of vertical migrations and complex life cycles of many benthic invertebrates.

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