SICB 2014 Annual Meeting Abstracts 50.7 ABBOTT, EM*; AZIZI, E; Univ. of California, Irvine; P2.8 ABBOTT, J.*; VANLEUVEN, A.; SKOPEC, M.; Weber State [email protected] University; [email protected] The effect of muscle relaxation rate on tendon recoil during energy Caching behavior of non−food items in woodrats (Neotoma dissipating tasks albigula) Series elastic elements, such as tendons and aponeuroses, can Woodrats (genus Neotoma) are commonly referred to as packrats due amplify muscle power, minimize energy consumption and limit to their characteristic behavior of caching both food and non−food injury susceptibility. Specifically, during energy dissipating tasks, objects from their surroundings. We conducted a series of muscles initially store energy in tendons before recoil of the tendon experiments to evaluate the caching behavior of non−food items in stretches the fascicles as muscle force declines. This mechanism is Neotoma albigula. Trials were run to see if the woodrats showed a thought to reduce the rate of stretch directly applied to a muscle preference for brilliance, color or scent of a non−food object, jingle fascicle and may function to protect the muscle from stretch−induced bells. The brilliance trial investigated whether woodrats prefer shiny damage. We hypothesized that the rate of muscle relaxation over dull objects, as anecdotal evidence suggests that woodrats prefer determines the rate of tendon recoil. Previous studies have shown shiny objects and sometimes will even trade dull objects for shinier that the rate of muscle relaxation can vary as a function of ones. Woodrats were placed in cages that had two external temperature as well as muscle fiber type composition. Here, we used compartments where jingle bells were offered. Jingle bells were a temperature manipulation protocol in an in vitro muscle−tendon painted with either a shiny or matte finish of the same color. The preparation to examine how relaxation rate alters the rate at which woodrats showed no preference for bells exhibiting more brilliance tendons recoil and subsequently stretch the muscle fascicles. We which indicates that woodrats do not necessarily prefer shiny objects. measured muscle fascicle lengths by instrumenting the plantaris In the color trials, the woodrats were given access to gold or blue muscles of Rana catesbeiana (bullfrog) with sonomicrometry jingle bells. The blue color resembled the juniper berries that crystals. MTU force and length were measured by a servomotor. To woodrats consume, and preference for the blue−colored bells may be determine the twitch kinetics, we characterized the rate of force evidence that they cache non−food items that are similar in color to development and relaxation during twitches at 10, 20 and 30ºC. The food items. The woodrats, however, showed no preference for color MTU was also actively lengthened at the various temperatures with a and cached blue and gold bells at an equal rate. Scent trials were 50ms tetanic stimulation and a simultaneous 100ms stretch. As conducted to determine if woodrats potentially raid conspecific's expected, the rate of force development and relaxation increased with caches. The woodrats were given access to jingle bells scented by a increasing temperature. We also observed that the rate of tendon same or opposite sex woodrat or unscented jingle bells. The woodrats recoil correlated positively with rising temperature during eccentric showed no preference between the scented and unscented bells, contractions. These data imply that factors that alter relaxation rate however, woodrats in the scent trials cached significantly fewer bells can influence the rate of fascicle stretch in a muscle tendon unit and overall than those in the brilliance or color trials suggesting that thus alter the likelihood of muscle damage. Supported by NSF grant woodrats may not be raiding conspecific's caches. 1051691. 125.1 ABOLINS−ABOLS, M*; KETTERSON, E D; Indiana 123.7 ABRAMYAN, J*; CHENG, J; RICHMAN, JM; University of University, Bloomington; [email protected] British Columbia, UBC; [email protected] Shift in a life history trade−off linked with change in hormonal Comparative studies on the ontogeny of the primary palate and cross−talk nasal cavities in birds and mammals Perhaps the most fundamental life history trade−off is that between A critical period in craniofacial ontogeny involves the proper reproduction and self−maintenance. This trade−off is mediated by the development of the primary palate and nasal cavities. Nasal cavities interaction of two major endocrine systems, the initiate as external nasal pits which grow dorsally and connect with hypothalamic−pituitary−gonadal (HPG) axis, which regulates the oral cavity via paired choanae. However, this developmental reproduction, and the hypothalamic−pituitary−adrenal (HPA) axis, process has diverged between mammalian and reptilian (including which regulates metabolism and the stress response. Environmental birds) embryos. A key characteristic of choana development in change may alter optimal allocation of resources to reproduction and mammals is the presence of a transient oronasal membrane which self−maintenance, shifting the trade−off, thus giving rise to selection initially separates oral and nasal cavities and subsequently ruptures on the interaction of the HPA and HPG axes. Recent independent during developmental progression. The breakdown of this membrane colonization events of an urban environment by the typically is essential for respiration and ultimate survival. Interestingly, the mountain−breeding Oregon junco (Junco hyemalis thurberi) in presence of this membrane in non−mammalian amniotes is still a California has dramatically altered timing of breeding and stress contentious subject in the literature. This is compounded by the ecology, resulting in increased allocation to reproduction and reduced scarcity studies of primary palate formation in reptiles. In this study, response to stressors. We investigated the direction and strength of we used optical projection tomography and histology to obtain 3D the interaction between the HPA and HPG axes in two locations of reconstructions of the nasal cavities and associated choanae in recent independent montane−urban colonization events. We injected chicken and mouse embryos. We found that avian embryos do not wild birds with corticotropin releasing hormone (CRH), a major form an oronasal membrane. Instead, the outgrowing frontonasal and activator of the HPA axis, and measured corticosterone. We then maxillary processes leave a groove between them which connect the injected birds with of gonadotropin releasing hormone (GnRH), a oral and nasal cavities. Furthermore, we measured relatively lower major activator of the HPG axis, and measured testosterone. We will cellular proliferation in the mesenchyme at the base of invaginating compare and contrast findings from the two city−mountain groove and higher proliferation within the outgrowing processes. The comparisons and show that in at least one colonization event, CRH groove remains while the facial processes outgrow and subsequently negatively affects the ability of birds to release testosterone in the fuse, leaving a choanal tube connecting the external nares to the oral mountain population but not in the city population, indicating greater cavity. These results, along with a similar choanal development sensitivity to stressors on reproduction in the mountain population. described in amphibians, suggest that the formation of a groove is the Interestingly, corticosterone and testosterone are positively, not basal condition in vertebrates and that mammals have derived a negatively, correlated in both populations. We conclude that divergent ontogenetic process for the development of the primary hormonal interactions are plastic, complex, and reflective of palate and connection of external nares to the oral cavity. environmentally induced changes in life−history trade−offs. January 3−7, 2014, Austin, TX 1 SICB 2014 Annual Meeting Abstracts 23.7 ACKERLY, KL*; WARD, AB; McGill University, Adelphi S4.2−2 ADAMO, Shelley A; Dalhousie Univ., Halifax; University ; [email protected] [email protected] The role of vertebral morphology in a fish eat fish world Stress/immune interactions: A pathological relationship or an Many selective factors work together to determine the optimal body adaptive response to adverse conditions? morphology to maximize swimming performance in fishes. The Both the stress response and immune response defend animals vertebral column is one of the most important morphological against organisms that can cause catastrophic declines in fitness. elements in determining maximum swimming performance. When resources are abundant, having these two systems work Variation in vertebral morphology has been shown to significantly synergistically with each other would seem adaptive. However, impact escape swimming performance, leaving individuals more negative interactions between the stress and immune responses are susceptible to predation. Our previous work in zebrafish (Danio common and phylogenetically widespread even under ad lib rerio) has shown that individuals with fewer vertebrae and a higher conditions. It seems unlikely that these negative interactions are vertebral ratio have decreased escape response performance. This simply pathological as they are partly driven by stress hormone performance variation is a result of a decreased number of effects on immune cells. In crickets (Gryllus