Archive for Reynolds, Julie

Think It’s Cold Outside? How Do Insects Survive the Winter?

Julie's research subjects, southern ground crickets (Allonemobius socius)

For most of her life, Julie Reynolds has been fascinated by insects, and when she went off to college, she thought they would make a great subject of study.  Julie majored in biological sciences at the University of Alabama-Huntsville and focused on ecology.  Her undergraduate research examined the effects of microgravity stressors on crustaceans, and through these studies she became fascinated with the ability of animals to adapt to extreme environments.

Excited by these studies, Julie entered a master’s program in entomology at Penn State University.  However, this department was not a good fit.  Most of her colleagues conducted applied research, which basically amounts to pest control.  Though Julie wanted to better understand the lives of insects, her department largely focused on how to kill them!

After completing her master’s degree, Julie searched for a Ph.D. program that emphasized basic research and interdisciplinary studies.  She found her niche in the biological sciences department at Louisiana State University.   Her doctoral research investigated diapause, a form of dormancy that helps insects and other animals “escape” harsh winter temperatures or periods of drought.  Similar in some ways to hibernation patterns in mammals, insect diapause also displays unique characteristics: in particular, it can occur long before insects reach full maturity, even within embryos.

Insects struggle to survive the winter, even in the southern United States

One of Julie’s recent study subjects was Allonemobius socius, better known as the southern ground cricket.  Since these crickets have a short lifespan and only produce one or two generations per year, surviving the winter is a serious obstacle.   The species A. socius has solved this problem by laying a certain percentage of eggs that enter diapause, halting their development until environmental conditions are conducive to survival.  In certain populations, if a female matures during periods of long daylight (late spring and summer), it will primarily lay eggs that develop immediately.  Females reproducing in shorter daylight conditions of autumn will produce more embryos bound for diapause.  Only when days become longer again, when survival conditions improve, will these embryos complete their development.

 

In the past fifteen years, many studies have assessed the environmental triggers and physiological effects of insect dormancy, but Julie’s research is noteworthy in that it analyzes diapause on a molecular level, measuring changes in specific mRNAs and proteins.  Also, studying diapause in embryos (instead of larvae, pupae, or adults) is rare given the difficulty of extracting RNA when so little tissue is present.

A. socius embroys

What did Julie discover through her innovative research?  As is often the case, not what she expected!  Approximately 4-5 days after the eggs are laid, the embryos entering diapause cease their development.  In many vertebrate and invertebrate species, this stage is marked by a dramatic drop in metabolic activities, which conserves resources while the embryo is dormant.  But in the case of A. socius, the metabolic rate remains constant, quite to the surprise of the investigators.  Subsequent investigation revealed that the energy savings actually occur later than expected.  In non-diapause embryos, the metabolic rate increases after the first 5 days, whereas in diapause embryos, it remains the same.  Only over the course of a full 15 days of normal embryonic development do the dormant embryos display a comparatively lower metabolic rate.

Julie has found that insects serve as excellent models for studying biochemical pathways.  One reason, as she pointed out, is that “no one gets upset when my crickets die!”  But her research has also shown that the details of molecular activities are highly species-specific, and that one must be careful not to over-generalize when comparing the biochemistry between species.

Julie Reynolds with her family

Julie joined the American Scientific Affiliation in 2010 after she heard that her friend Steve Hall was elected as an ASA fellow.  She was already a member of InterVarsity’s Emerging Scholars Network and was looking for opportunities to connect with other Christians in her field.  After encountering so few believers in her undergraduate, master’s, and doctoral programs, she was delighted to find several practicing Christians in her department at Ohio State University, where she is completing her post-doc.

If you can identify with Julie’s story, and you are a Christian graduate student or post-doc, the ASA would love to hear from you!   We are a community of those who love God and practice science with integrity.  Fostering these relationships is vital to developing an integrated sense of our personal and professional identities.  Our membership is extensive, so through involvement in the ASA, there is a good chance that you’ll meet others at your university, perhaps even in your own department!