Research

Gray treefrogs (Hyla versicolor) have amazing color change ability, and can range from dark brown to bright green. Yet, nothing is known about the distribution of body color in nature, or whether frogs choose their resting perches based on their body color, or adjust body color as a function of ambient color or temperature. Here, we examine the behavioral ecology of color change in gray treefrogs. Color change can function to hide the individual from predators (crypsis), or to make the individual obvious for conspecifics (conspicuousness). In addition, in ectotherms (cold blooded animals), body color may help with thermoregulation (darker colors heat up better, brighter colors increase reflection and stay cooler).

Humans perceive several sounds in close temporal succession as a single event originating from the location of the leading sound, a trick played by the auditory system to improve sound localization. Surprisingly, a visual cue associated with the leading sound enhances sound localization, while a visual cue associated with the lagging sound inhibits it, suggesting that auditory spatial perception in humans is a fundamentally multisensory process.

Signal production and reception often encompass various modalities of communication. For example, a calling frog cannot but produce a visual component as it inflates and deflates its vocal sac to emit an acoustic signal. A frog calling in a pond also creates water surface waves, and calling on a branch he creates vibrational signals. Thus, a simple “acoustic signal” actually encompasses three modalities (acoustic, visual and surface wave / vibrational).

Elaborate ornaments are hypothesized to honestly signal individual quality, including the ability of an individual to combat parasitic infection. Although there have been many studies of this hypothesis, the results of these studies have been mixed. One explanation for these varying results is that measures of ornaments and parasitic infection intensity are typically obtained only once for each individual. Therefore, correlations between ornamentation and parasitic infection intensity do not consider within-individual relationships, which may differ from between-individual relationships.

Changes in the local pollinator community may shape the dynamics of plant-pollinator interactions. Since the quality of pollination services often varies markedly among pollinator species, the consequences of pollinator declines for plant reproductive success may be unpredictable. Therefore, changes in the composition of visiting pollinators, in terms of their pollination efficiency and visitation rates, may play a significant role in determining the effect of pollinator loss on plant reproductive success.

The pitcher plant Sarracenia purpurea grows in nutrient-deficient wetlands such as Cedarburg Bog and supplements mineral nutrition by carnivory. Newly formed pitchers are sterile, but fill with rainwater, in which insect prey drown. Within the pitcher detrital food web, invertebrates begin macroscopic breakdown of prey while microbial hydrolytic enzymes (chitinases, phosphatases, proteases) digest and release nutrients, prior to absorption by the plant.

A local-scale groundwater-flow model of the Cedar Creek Watershed and Cedarburg Bog area was constructed to determine the effects of future changes in temperature and precipitation on water resources. The Cedar Creek Watershed is a 330 km² subbasin of the Milwaukee River Watershed located about 30 km north of Milwaukee. The importance of this watershed lies in its location at the sub-continental divide separating the Mississippi River Basin from the Great Lakes Basin.

Over the summer of 2015 we completed range-wide genetic sampling of Platanthera leucophaea. Claire Ellwanger and Cathy Pollack collected leaf tissue samples from 18 populations and received leaf samples from 14 populations thanks to collaborators like Jim Reinartz (UWM Field Station) across the range of the species.

Understanding the mechanisms influencing the timing of reproduction has taken on new urgency as climate change is altering environmental conditions during reproduction, and there is concern that species will not be able to synchronize their reproduction with changing food supplies. One of our main goals is to determine how environmental factors, particularly temperature and food abundance, influence the timing of breeding and reproductive success.

Decomposition of prey in the leaves of the carnivorous pitcher plant Sarracenia purpurea provides energy that supports an inquiline community consisting of bacteria, protozoans, rotifers, mites, and dipteran larvae. By demonstrating that midges consume both rotifers and ciliates, we now have reason to redraw the pitcher plant inquilines food web. We suggest that both W. smithii and M. knabi together form a guild of keystone predators.