LUCAS LAB - MEMBERS
Kerry Fanson | Ken Henry | Mark Nolen | Megan Gall | Lauren Brierley
STATUS: Ph.D (started in 2003)
CONTACTS: Email: kfanson@purdue.edu; Office Phone: 765-494-9654
RESEARCH INTERESTS
In this perpetually dynamic world, animals must find a way to prevent environmental changes from altering important physiological processes. The hypothalamic-pituitary-adrenal (HPA) axis is fundamental to achieving this. The hormones released from the HPA axis trigger a cascade of physiological changes that help the body maintain proper functions in the face of adversity. While this physiological response has been well studied in regards to short term stressors, the effect of long-term, or even permanent environmental perturbations remains unclear.
Reintroductions, although a valuable conservation tool, often create drastic, permanent changes in an individual's environment. In order to gain a clearer understanding of how an individual's response to these changes may influence the success of the reintroduction effort, we must take a closer look at how reintroductions affect organisms.
I hope to address this question by looking at hormonal changes in Canada lynx ( Lynx canadensis ) following their reintroduction to Colorado . By quantifying reproductive and stress hormone metabolites in an individual's feces over several years, we can monitor how the endocrine system responds to long term changes. This will help us begin to understand the phenotypic plasticity of the endocrine system, and may also help improve success rates of reintroductions.
STATUS: Ph.D (started in 2004)
CONTACTS: Email: kshenry@purdue.edu; Office Phone: 765-494-9654
RESEARCH INTERESTS
Vocal communication is used for a variety of important functions in birds including mate attraction, territory defense, predator avoidance, and mediation of social interactions in groups. Across species there is extensive diversity in vocal communication, but the impact of this diversity on the auditory system is not clear.
My research focuses on two broad questions about communication and hearing. First, do species with complex vocalizations also have specialized auditory systems with broader frequency sensitivity and finer temporal resolution? Second, do characteristics of the auditory system change seasonally to optimize the efficiency of vocal communication during courtship?
To answer these questions, I am monitoring the auditory characteristics of four bird species across seasons. The study species, white-breasted nuthatches, tufted titmice, Carolina chickadees, and house sparrows, differ in vocal complexity and the timing of courtship. To monitor hearing, I record auditory evoked potentials from the auditory system in response to sound. Different types of acoustic stimuli can be used to study different aspects of hearing. For example, I use tone bursts to measure frequency sensitivity and amplitude modulated sounds to measure temporal resolution. Because this technique is non-lethal, subjects can be tested multiple times in different seasons.
Example responses:
STATUS: Ph.D (started in 2003)
CONTACTS: Email: mtnolen@purdue.edu; Office Phone: 765-494-9654
RESEARCH INTERESTS
I am broadly interesting in gaining a better understanding of the mechanisms governing the evolution of sociality and cooperation. In particular, I am interested in the role of signals in mediating interactions between individuals. Of special interest are signals directed towards other species in interspecific communication. Such signals are known to mediate a variety of mutualistic (both sender and receiver benefit) and manipulative (sender benefits) interactions. But perhaps more widespread is the use of information from a heterospecific signal that is not intended for heterospecific receivers (eavesdropping - in which the sender may benefit, be harmed, or not affected at all). Mixed-species forest bird flocks offer an interesting opportunity to investigate if and how individuals pay attention to vocal information provided by other species.
Foraging flocks of birds containing individuals of different species and stable membership can be found in forests worldwide. Individuals in such groups, as in single species groups, are thought to receive some combination of benefits from higher foraging rates and lower predation risk. However, the costs and benefits in a mixed-species flock are likely to differ among species owing to their different anti-predatory behaviors, foraging strategies, and roles in flock formation.
Mixed-species flocks in the eastern temperate woodlands of North America consist of Carolina or Black-capped chickadees (Poecile carolinensis), Tufted titmice (Baeolophus bicolor, pictured to left wearing a radio-transmitter), White-breasted nuthatches (Sitta carolinensis), and Downy woodpeckers (Picoides pubescens), among a few others. All of these species, except for the woodpecker, are highly vocal. White-breasted nuthatches and Downy woodpeckers often follow chickadees and/or titmice for variable periods of time during the non-breeding season (mid-June through March or April). Flock formation and cohesion seems to be facilitated by chickadee and titmouse vocalizations, but we know very little about vocal information exchange within flocks and prior to mixed-species flock formation. A more detailed understanding of individual behavior in mixed-species flocks will allow us to make further inferences about the importance of flocking for the species involved and about the nature of information flow across species through vocal signaling.
STATUS: Ph.D (started in 2008)
CONTACTS: Email: mgall@purdue.edu; Office Phone: 765-494-9654
RESEARCH INTERESTS
Broadly I am interested in the interplay among behavioral, sensory and cognitive ecology. Sensory physiology affects the quality and quantity of sensory information available to an animal, how an animal interprets sensory information and how that information affects the decisions the animal makes about foraging and reproduction. I'm particularly interested in 
animals that parasitize the communication of other species - eavesdrop on conversations that they are not intended to be a part of. For instance, a coyote could eavesdrop on scent communication between male and female mammals (sexual signals that are intended for potential mates) in order to obtain information about the location of prey items, while a bird could not due to difference in sensory physiology between the taxa. My previous research focused on visual perception and foraging tactics in the Black Phoebe (Sayornis nigricans), a passerine flycatcher.
I am currently interested in auditory perception and reproductive tactics. The brown-head cowbird ( Molothrus ater ) is a brood parasite that does not rear its own young. Instead, female cowbirds deposit eggs in the nest of host species. The host will incubate the egg and 
rear the cowbird chick along with her own offspring. Nearly 150 species of birds have been identified as hosts for the brown-headed cowbird. Cowbirds, therefore, are in a unique position to exploit the signals used by host species in social and sexual communication. These signals could be used both to locate potential hosts and determine the quality of the host species. I will be using auditory evoked potentials to characterize the auditory system of the cowbirds in concert with semi-natural and field experiments to determine whether cowbirds can use host signals, what aspects of host signals may be the most salient for location and quality assessment, and whether cowbirds select host based on the quality of their vocal signals.
STATUS: Ph.D (started in 2008)
CONTACTS: Email: lbrierle@purdue.edu; Office Phone: 765-494-9654
RESEARCH INTERESTS