Lab News

Updated: 03-13-2017

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.:Recent papers

Undergraduates Letitia Clay, Sade Moore, and Taylore Williams co-author a manuscript in Parasitology Research

Here we showed that Echinostoma trivolvis cercariae exhibit active preference for the second intermediate host species that is most susceptible to infection. Specifically, cercariae prefered Physa snails rather than Helisoma snails, the species used as its first intermediate host. Others have suggested avoiding the first intermediate host species might be an advantageous strategy, as individuals infected as first-intermediate hosts have reduced survival - and thus may not make a great new home. . Additionally, we found that Chaetogaster limnaei oligochaete worms that happened to be living commensally in Helisoma snails reduced parasite transmission!

(Wojdak JM, L Clay, S Moore, T Williams, LK Belden. Echinostoma trivolvis (Digenea; Echinostomatidae) second intermediate host preference matches host-suitability. Parasitology Research, in press)

Some important features of the basic biology of Metagonomoides oregonensis revealed in collaborative study

Left figure - A) a salamander infected with MO, B) the same salamander cleared and stained, C) close up - LOOK AT ALL THOSE METACERCARIAE!, D) a single metacercariae in the muscle tissue.

Even with high infection intensities, there was no serious pathology visible in the tissues.


Right figure - A-B) MO cercariae viewed with light microscopy, C) MO cercariae viewed with scanning electron microscopy (SEM). Our microscopy revealed previously undescribed features of MO.

D) many cercariae bursting out of a redia - colored electronically for fun, E-F) a stained redia viewed with light microscopy, F) redia under SEM.

(Belden LK, WE Peterman, SA Smith, LR Brooks, EF Benfield, WP Black, Z Yang, JM Wojdak. 2012.  Metagonimoides oregonensis (Digenea, Heterophyidae) infection in pleurocerid snails and Desmognathus quadramaculatus salamander larvae in southern Appalachian streams.  Journal of Parasitology 98:760-7. )

"Pond acidification may explain differences in corticosterone among salamander populations", in press at Physiological and Biochemical Zoology (D. Chambers, J. Wojdak, P. Du, and L. Belden).

Vertebrates possess several highly conserved physiological mechanisms for coping with environmental stressors, including the hormonal stress response that involves an endocrine cascade resulting in the increased production of glucocorticoids. We examined the function of this endocrine axis by assessing both baseline and acute stress-induced concentrations of corticosterone in larvae from eight natural breeding populations of Jefferson’s salamander, Ambystoma jeffersonianum. Population-level baseline and stressed corticosterone concentrations were negatively related to pH, but responses to stress were greater at low pH. We followed the field survey with an outdoor mesocosm experiment in which we manipulated pH and again observed an increase in the baseline corticosterone concentration of individuals in the lowest pH treatment (pH 5-5.8).  A combined approach of field surveys and experiments can be a powerful tool for trying to unravel the complexities of environmental impacts on species physiology and their ultimate distributions.