Engaging Undergraduates in the Scientific Process: Exploring Invertebrate Endocrine Disruption

Engaging students in the process of science to increase learning and critical thinking has become a key emphasis in undergraduate education. Introducing environmental topics, such as the effects of endocrine-disrupting chemicals, into undergraduate courses offers a new means to increase student engagement. Daphnia magna can serve as a model organism for endocrine disruption, and its ease of handling, rapid reproduction rate, and clearly defined endpoints make it useful in short-term, student research projects. The concept of endocrine disruption can be tested through a 21-day reproductive study of D. magna exposed to varying concentrations of the pesticide fenoxycarb. Students will observe an altered reproduction rate and increased production of males under conditions that would typically result only in the production of female offspring. This research system allows students to formulate hypotheses, set up experiments, analyze data, and present results, leading to a greater appreciation of and interest in science.

Year-round maturity of the chaetognath Aidanosagitta regularis in the Hauraki Gulf, New Zealand

The reproductive biology of planktonic chaetognaths is poorly known, particularly with regard to the importance of seasonal factors such as daylength, temperature and lunar phase. We undertook semilunar plankton sampling (March 2013–March 2014) in the Hauraki Gulf, New Zealand, to survey sexual maturity of the abundant chaetognath Aidanosagitta regularis (the only chaetognath species present in sufficient numbers for reproductive study). Contrary to our expectations, breeding of A. regularis appeared unconstrained by seasonal factors, as reproductively mature individuals were available year-round. This finding has implications for embryological study of the chaetognaths.

New record of intraspecific nest parasitism by the Silky Starling (Sturnus sericeus)

The Silky Starling (Sturnus sericeus) is endemic to East Asia and little is know about its’ breeding ecology. We found intraspecific nest parasitism (INP) by this species in a reproductive study conducted from March to June 2011. We found three nests were parasitized using the obvious morphological differences or partition of egg-laying. One egg appeared 3 days after the 26th female had finished laying eggs. One egg was different in color from the other five eggs in the 27th nest. The third instance was discovered in the 37th nest after the fledglings had fledged. Our findings confirmed INP by the Silky Starling.