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Poster Abstracts

Posted on: Monday, 28 February 2005, 15:00 CST

PZ104

ADDIS, E, WACKER, D, CLARK, A, COVERDILL, A, MEDDLE, S, WALKER, B, LANDYS, M, RENEERKENS, J, WINGFIELD JC; addise@u.washington.edu. University of Washington, University of Edinburgh, NIOZ

INFLUENCE OF HABITAT CONDITION ON BREEDING IN PLECTROPHENAX NIVALIS AND CALCARIUS LAPPONICUS

Arctic songbirds face unpredictable environmental conditions upon arrival at their breeding grounds. Mutable food supply, temperature, and precipitation may shorten an already brief breeding season. Thus, breeding in these areas requires early arrival and quick nesting. One major determinant of breeding commencement appears to be habitat condition. Snow cover, wind, temperature, vegetation, and moisture all influence the state of the habitat. Thule, Greenland (N 76 32, W68 50) is near the northern range limit of two Arctic breeding passerines: Snow bunting (SNBU), Plectrophenax nivalis, and Lapland longspur (LALO), Calcarius lapponicus. We hypothesized that the above variables influence choice of territory, nest site, and subsequently, date of first egg. We predicted that SNBUs would prefer different habitats from LALOs because the former are cavity nesters while the latter build nests in grass. While much of egg laying and nest building is controlled hormonalIy, timing is also influenced by the presence of suitable nest sites and food abundance. We plotted nest sites on GIS vegetation maps, and found that SNBUs prefer rocky areas and LALOs prefer moist, heavily vegetated areas. We also discovered for both SNBUs and LALOs, date of first egg corresponds with reduced snow cover; nests were established later in areas with lingering snow. In addition, while LALOs arrive later than SNBUs, their date of first egg ranges from earlier than (2004) to concurrent with (2001 ) SNBUs. In future work, we hope to quantitatively measure snow cover reduction and food availability, correlate them with nest initiation, and further assess the role microhabitat conditions play in nest location.

P3.12

AJEMIAN, MJ, SANFORD, CP; majemil@pride.hofstra.edu. Hofstra University

KINEMATICS OF PREY CAPTURE IN THE CHAIN CATSHARK SCYLIORHINUS RETIFER

Modulation of prey capture has been observed in several aquatic vertebrates and may represent a fitness advantage when resources are scarce and varied. However, the presence of modulation in feeding among the elasmobranchs (sharks, skates, and rays) has not been extensively studied. The chain catshark (Scyliorhinus retifer) is a member of one of the most well researched groups of elasmobranchs (order: Carcharhiniformes), but this particular species inhabits a deep-sea environment (the Atlantic continental shelf) and its biology is virtually unknown. To understand the feeding biology of the chain catshark we utilized high-speed videography to document the kinematic events during prey capture. Chain catsharks were filmed feeding on two differently sized fish pieces of Atlantic silversides Menidia menidia. A preliminary analysis of feeding events indicates that the chain catshark primarily utilizes suction to capture its prey. Additionally, this shark does not seem to modulate suction based on prey size as no significant differences were found in ram-suction variables. In contrast, statistical analysis of kinematics revealed that neurocranial movements were significantly different based on prey size. We are currently investigating the functional consequence of these differences.

P 1.96

AGUILAR-ROCA, N, LONG, T, BENNETT, A; nmaguila@uci.edu. University of California, Irvine

GENOMIC CHANGES DURING ADAPTATION TO VARIABLE TEMPERATURES IN ESCHERICHIA COLI

Most organisms live in thermally variable environments and understanding the genetic basis of adaptation to variable temperatures has been made is now becoming possible by high-density arrays and sequenced genomes. DNA high-density arrays were used to examine insertion and deletion events in six independently derived lines of Escherichia coli that evolved for 2000 generations in a fluctuating temperature environment (daily oscillations between 32 and 42C). Genomic DNA from these derived lines that had evolved for 2000 generations in oscillating temperatures was radiolabelled and hybridized to Sigma-Genosys nylon membrane arrays. Spot intensity differences between the derived lines and a corresponding ancestor were used to identify the insertions and deletions of major segments of DNA in the bacterial chromosome. A deletion event occurred in each of two lines in different regions of the genome. All of the lines had a significant increase in fitness at both 32 and 42C relative to the ancestor, but the deletion event does not appear to be an important factor in changes in fitness at either 32 or 42C. The deletions included genes involved in iron transport and glycolate metabolism. Although the deletions were neither beneficial or detrimental under the culture conditions used, under different culture conditions fitness may be compromised. These results suggest that deletions arc one mechanism of trade-offs during evolutionary adaptation to a specific environmental condition. Supported by NSF Grant IBN9905980 and NASA Grant 632731.

P1.91

ALAMILLO, H; hap4f@umr.edu. University of Missouri-Rolla THE VALIDITY OF PHRYNOHYAS VENULOSA (LAURENTI, 1768)

Hylid frogs of the species Phrynohyas venulosa (Laurenti, 1768) occur from the northeastern Mexican state of Tamaulipas to the eastern Argentinian province of Entre Rios. The large and diverse geographic range of this taxon has caused many researchers to suspect that it comprises more than one species. In 1956, Duellman elevated seven species, although the validity of some of these species has been questioned. To determine if the name P. venulosa refers to a single valid taxon, and/or if Dulllman elevated groups that are valid, we examined the entire holdings of P. venulosa in the herpetological collections of the University of Kansas Natural History Museum, California Academy of Sciences, and the Museum of Vertebrate Zoology at the University of California-Berkeley. My sample included specimens from all countries in the species range. I collected measurements for sixteen morphometric characters, ran a preliminarily Principal Components Analysis, and implemented a Discriminant Function Analysis to identify clusters that partition the species into distinct groups. The results of my analyses and consequences for the taxonomy of the species group will be discussed.

P3.10

ALEXANDER, JK, TYTELL, ED; jalexand@fas.harvard.edu. Harvard University

SYNCHRONIZATION OF RESPIRATION AND LOCOMOTION IN THE BLUEGILL SUNFISH LEPOMIS MACROCHIRUS

To determine if fish synchronize their locomotion and respiration, we filmed blucgill sunfish (Lepomis macrochirus) using high-speed video and calculated the time differences between locomotory and respiratory events. It is well known that many tetrapods, from lizards to humans, synchronize their respiration and locomotion in such a way as to improve their respiratory efficiency. We hypothesize that fish also synchronize their locomotion and respiration. Due to the close proximity of the operculum and the pectoral fins, water jetting out of the operculum could affect flow over the pectoral fins, possibly changing locomotory efficiency. Using a Photron high-speed video system, we filmed three bluegill sunfish swimming at speeds ranging from 0.5 to 1.5 body lengths per second. We then determined phase differences between pectoral fin beating (locomotion) and opercular jetting (respiration). Data show that the bluegill and do indeed synchronize locomotion and respiration, and that this is constant across all three individuals and all swimming speeds. The operculum is open during fin abduction and closed during fin adduction, suggesting several mechanistic models, such as decreasing the time necessary for developing lift forces to act or avoiding interaction with the propulsion phase.

P2.84

ANDERSON-STYGLES, JP, BIESIOT, PM, CURRY, KJ; janderson5112@comcast.net. University of Southern Mississippi, Hattiesburg

A HISTOLOGICAL STUDY OF REPRODUCTION IN LEITOSCOLOPLOS FOLIOSUS (POLYCHAETA, ORBINIIDAE) FROM THE NORTHERN GULF OF MEXICO

Leitoscoloplos foliosus is an infaunal orbiniid polychaete reported from sandy beaches of Mississippi and Florida and from mud flats of Mississippi and Texas. Few records of L. foliosus exist, and much of its biology is unknown. Reproductive biology within the Orbiniidac varies among the few species for which such information is known. The objectives of the present study are to determine the spawning period and the mode of oviposition of L. foliosus from the Mississippi Gulf Coast and to document the reproductive systems of this species at the tissue level. Monthly collections were made at East Beach in Ocean Springs, MS; L. foliosus seems to be both larger and more abundant in warmer months. Oviposition has been reported for 13 other orbiniid species and includes deposition into cylindrical or pear-shaped cocoons or jelly masses as well as spawning freely into water. Although spawning and oviposition were not observed in the field or the laboratory, one female L. foliosus was collected with developing embryos in a cylindrical jelly cocoon surrounding the middle portion of the body. Worms were fixed in Allen-Bouins fixative, dehydrated in alcohol, embedded in paraffin, and sectioned. sections were stained for light microscopy and photography with either hematoxylin and eosin or a tri\chrome stain and used to describe the reproductive anatomy of male and female L. foliosus.

P2.16

ALLMAN, P, ROOSENBURG, W; pa508701@ohio.edu. Ohio University

INTRASPECIFIC VARIATION IN REPRODUCTIVE STRATEGIES OF A WIDE RANGING TURTLE

Understanding the importance of intraspecific phenotypic differentiation among wide ranging populations remains at the core of life history research. Phenotypic variation in life history traits such as offspring size, growth, and survivorship are the target of studies attempting to understand the coevolution of these traits. Species with a wide geographic range have long been used for these studies because adaptation to local environmental conditions is expected. We collected diamondback terrapin, Malaclemys terrapin, eggs from multiple sights within its range to quantify variation in egg size and the amount of stored energy reserves provided within the eggs. Females in southern populations produce significantly larger eggs than females in northern populations. The larger eggs contain a larger yolk and have higher lipid stores. Eggs from three populations were incubated at three temperatures to compare the thermal influence of lipid utilization and development rates among the populations. The variation in incubation period was explained by the incubation temperature and the source population. We will present preliminary results on hatchling energetics and metabolic rates resulting from different incubation temperatures.

P1.120

ARNOLD, E, SHUSTER, S; emarnold@berkeley.edu. Northern Arizona University, University of California Berkeley

USE OF CHEMICAL CUES BY MARINES ISOPODS (PARACERCEIS SCULPTA) IN THE LOCATION AND SELECTION OF MATES

Chemical cues are used by many animals to locate breeding habitats and mates. Semelparous species face time and energy constraints that require rapid location of suitable breeding habitats, and in aquatic habitats, individuals in such species may use chemical cues to . locate their breeding habitat from a distance. We used 3 Y-maze exper- . iments to test for sensitivity to chemical cues in a population of the marine isopod Paracerceis sculpta. This population contains three distinct male morphs, the dominant of which forms breeding aggregations in an intertidal sponge. Females in this population are semelparous and face extremely short receptivity times. In choice tests, females showed no sensitivity to chemical cues from breeding aggregations and no preference between cues from two different male morphs. . However, males were attracted to chemical cues from sponges (F=14.81, P<0.0001). Our results indicate that males locate breeding sites using chemical cues from sponges, and that chemical cues from males and from breeding aggregations may be unimportant in female mate choice.

P2.92

BABCOCK, SK, HURNEY, CA, VAGLIA, JL, TURNER, SD, COGBILL, S; babcocsk@jmu.edu. James Madison University, DePauw University

EMBRYONIC DEVELOPMENT IN THE FOUR-TOED SALAMANDER, HEMIDACTYLIUM SCUTATUM

We present a staging table of normal development for Hemidactylium scutatum (Plethodontidae: Hemidactyliini), from fertilization to hatching. Terrestrial egg clutches from naturally ovipositing females (n=6) were collected in May 2002 and April 2004. Embryos were maintained at 15C on moistened filter paper; embryos that were removed from the vitelline membrane were kept in artificial pond water. Observations and photographs of 21 embryos were taken at 12 and 24 hour intervals throughout the 40-45 day embryonic period. Average diameter of single-cell embryos in H. scutatum is 2.41 mm (n=6; range 2.31mm-2.49mm). Development through neurula stages closely resembles development of other salamanders. Thus, we assign early embryonic stage numbers using criteria described hi Ambystoma, Eurycea and Gyrinophilus. Stage descriptions are based primarily on external morphology. Consistent with many Amphibia, cleavage in H. scutatum is holoblastic and mesolecithal, with formation of the initial cleavage plane meridional to the animal and vegetal poles. The first sign of gastrulation occurs 3.5 days after oviposition with the appearance of cellular blebbing on the animal surface along with a darkened area of cells at the putative site of invagination. About 1 day later, a crescent-shaped blastopore lip is visible. Consistent with gastrulation in Eurycea, the crescent-shaped lip appears to regress and deepen to form a U- shaped lip that ultimately becomes a slit. Neural groove and folds emerge about 7 to 8 days after oviposition. As neurulation progresses, the neural folds fuse medially with fusion proceeding anteriorly and posteriorly to form the neural tube. Eye, gill, limb, pigmentation, and tail fin development will be presented with discussion of ancestral developmental patterns in Hemidactyliines.

P1.63

BANTA, MR, KATZMANN, JM, MACKESSY, SP; marilyn.banta@unco.edu. University of Northern Colorado, Greeley

EVAPORATIVE WATER LOSS DURING ECDYSIS IN SNAKES FROM A BROAD RANGE OF HABITATS

Snakes are found in a variety of habitats ranging from tropical rainforests to hot deserts. Due to their elongate shape, snakes have a large surface area relative to their volume (mass) and evaporative water loss from the skin may be a concern for snakes living in arid climates. In addition, snakes periodically shed their entire skin and evaporative water loss (EWL) during ecdysis is typically elevated. This study examined whole-animal evaporative water loss (respiratory and cutaneous) in 14 species of snakes from a variety of habitats ranging from very arid to tropical. Evaporative water loss rates (mg water/hr) were calculated gravimetrically by passing dry air through an air-tight chamber holding the snake and then measuring the weight gain in tubes of anhydrous calcium sulfate located downstream from the chamber. Measurements were taken daily for 3-5 days before and 3-5 days after shedding as well as during a non-shedding period. The surface area of each snake was calculated geometrically and these values were used to control for body size in whole-animal EWL. For most species, EWL was higher in the days preceding and following ecdysis than during the non-shedding period. EWL was typically higher in the days just after ecdysis than in the days just before. As expected, EWL was elevated in species from more mesic environments. Evaporative water loss is a significant source of water loss to snakes and this loss is exacerbated during ecdysis. This water loss could be stressful and may affect the behavior of snakes from arid environments, but probably has a lesser impact on tropical or semitropical species.

P3.18

BAGLEY, JC, SECOR, SM; bagle004@bama.ua.edu. University of Alabama, Tuscaloosa

THE ALLOMETRY OF METABOLIC AND INTESTINAL PERFORMANCE FOR THE MARINE TOAD AND DIAMONDBACK WATER SNAKE

To investigate the potential interactions between the allometry of metabolic rates and intestinal performance, we assess the effects of body mass on standard metabolic rates, intestinal mass, intestinal nutrient uptake rates, and total intestinal nutrient uptake capacities of the marine toad (Bufo marinus) and diamondback water snake (Nerodia rhombifer). Standard metabolic rates of marine toads (2.4-950 g) and water snakes (7-1800 g) scaled (log-log) with body mass with mass exponents of 0.70 and 0.90, respectively. For both species, wet mass of the small intestine scaled with a mass exponent of 0.81. Mass-specific intestinal uptake rates of the amino acid L-leucine and L-proline and of the sugar D-glucose, measured using the everted sleeve technique, tended to decline with body mass. Total intestinal capacity for nutrient uptake, a function of intestinal mass and mass-specific rates of uptake, scaled with exponents between 0.55 and 0.74 for marine toads and between 0.60 and 0.83 for the water snakes. A potential relationship between the allometry of metabolic rate and intestinal performance is suggestive for the toads, but appears less likely for water snakes.

P1.60

BARBIERI, MM, MCLELLAN, WA, WELLS, RS, HOFMANN, S, PABST, DA; mmb2460@uncw.edu. University of North Carolina, Wilmington, Mote Marine Lab

SEASONAL PATTERNS IN DORSAL FIN SURFACE TEMPERATURES OF FREE- RANGING BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) IN SARASOTA, FL

The dolphin dorsal fin is a thermoregulatory control surface containing vascular structures that function in both heat conservation and dissipation. The goal of this study was to measure the response of this thermal window to seasonal changes in environmental temperature in wild, free-ranging bottlenose dolphins (Tursiops truncatus) in Sarasota, FL. These resident dolphins can experience yearly water temperatures ranging from 11 to 33C. The temperature differential between the skin surface and ambient environment (ΔT) strongly influences heat loss. We hypothesized that dolphins would need to conserve body heat in winter and would exhibit a smaller ΔT during this season. We used non-invasive, infrared thermography (FLIR Agema 570, ThermaCam Researcher 2001) to measure dorsal fin surface temperatures of dolphins (n=551 images) encountered during synoptic surveys in the summer, fall, and winter from 2002-2004. Water temperatures were independently measured during each sighting (Aquacal(c) ClineFinder). There was a positive, linear relationship between dorsal fin surface temperature and water temperature (r^sup 2^=0.978; p<0.001), as mean ΔT across all seasons (0.9C) was similar. Thus, a much larger temperature gradient between the dolphin core and the dorsal fin surface existed in winter than in summer. Dorsal fin surface temperatures appear to be modulated in response to environmental temperature to maintain a steady ΔT at the dorsal fin skin surface across seasons. In winter, increases in insulation, both integumentary (i.e. blubber) and vascular (via reduced perfusion and utilization of heat exchangers) must account for the protection of \core temperature and stability of ΔT.

P1.9

BARREIRO, W, LUXAMA, J, SARINSKY, G, CARROLL, MA, NDUKA, E, CATAPANE, EJ; catapane@mcc.cuny.edu. Medgar Evers College, Brooklyn, Kingsborough Community College, Brooklyn

GROWTH AND SURVIVAL OF THE AMERICAN OYSTER CRASSOSTREA VIRGINICA IN JAMAICA BAY, NY

Jamaica Bay (JB) was abundant with oysters until early 1900 s when they began to disappear. Our earlier work found oysters placed in Jamaica Bay at two sites (Kingsborough Marina and Gateway National Park Marina) grew well when suspended in protective containers 1 foot below the water surface. We found growth was influenced by placement near the sediment as compared to the surface. Oysters were placed in protective container 1 foot above the sediment or suspended 1 foot below the surface and growth determined by measuring shell lengths on the anterior-posterior axis (height) as well as on the transverse axis (width). After 1 year, bottom dwelling oysters were 23% and 12% larger at the Kingsborough and Gateway sites, respectively, as compared to the top oysters. Animal width showed similar increases. Survival was good at all sites. Water temperature, pH, turbidity, salinity, conductivity, chlorophyl-a and dissolved O2 were taken to monitor and compare water quality at both depths at each site. To study growth and survival in a more natural condition, oyster seed and adults were placed just off the bottom in unprotective containers and photographed. After 4 weeks they are growing and surviving well, but are being fouled by growth of sea squirts and algae. Thus far there are no serious signs of predation by crabs or starfish. The study continues to show that JB water quality is suitable for oyster growth under the various conditions of our experiments. The work was supported by grants 1R25GM62003 of NIGMS, 0516041071 of NYSDOE, the CUNY Groundworks Program, and 66273-0035 and 66288-0035 of PSC- CUNY. We thank Frank M. Flower & Sons, Inc., Oyster Bay, NY for supplying oysters.

P1.101

BECKER, BA, DARGIS-ROBINSON, VR, DAHLHOFF, EP; edahlhoff@scu.edu. Santa Clara University

EFFECTS OF TEMPERATURE ON PERFORMANCE AND FITNESS OF TWO SPECIES OF CALIFORNIA WILLOW BEETLE

We compared effects of temperature stress on running speed, fecundity and mating frequency for two species of California leaf beetle, Chrysomela schaefferi and C. confluens. C. confluens prefers warmer, inland locales and typically has higher body temperatures than C. schaefferi in nature. Differences in thermal tolerance between these species may explain differences in habitat use. To test this idea, we collected adults from sites in Sonoma, Santa Cruz and Santa Clara counties shortly after emergence from winter diapause. Individuals were sorted randomly into mating pairs and held in the laboratory at 20C d, 4C n. Each afternoon for 17 d, mating pairs were exposed to 20, 28 or 36C for 4 h. Running speed, number of eggs laid (females) and mating activity (males) was assessed daily. We also quantified expression of a 70-kD heat shock protein (Hsp70) in beetles of known running speed. Fecundity was higher for C. confluens than C. schaefferi, especially at higher treatment temperatures. Male mating frequency did not differ between species, yet C. schaefferi males ran faster than C. confluens males after acute exposure to moderate temperatures (20C), and slower after chronic exposure to elevated temperatures (28, 36C). Running speed was correlated with fecundity and mating success and was fastest in beetles with lowest Hsp70 expression, implying beetles with better performance have better reproductive success, perhaps due to lower cost of Hsp expression. These results suggest a mechanism for temperature affecting habitat selection: C. schaefferi males may be more active in mild microclimates, resulting in higher mating success, but C. confluens females may have higher fecundity than their C. schaefferi counterparts in warmer microclimates.

P2.79

BATTIPROLU, PK, RODNICK, KJ; battpava@isu.edu. Idaho State University

GENDER AND MATURITY DIFFERENCES IN CARDIAC PERFORMANCE UNDER GLUCOSE AND GLUCOSE-FREE CONDITIONS IN RAINBOWTROUT (ONCORHYNCHUS MYKISS)

The heart of teleost fish is omnivorous in its preference for metabolic fuels. However, the importance of glucose to contractile performance and the possibility that gender-related differences in cardiac metabolism exist have not been established. Our objective was to determine the inotropic effects of extracellular glucose in rainbow trout. Ventricles from 10-12 month old mature (n=12) and immature males (n=13), and immature females (n=16) were excised; four strips were cut and were attached to isometric force transducers, incubated in glucose-free Ringers for 1 h at 14C, and electrically-stimulated to contract at 0.5 Hz. Strips were then treated with 1, 2, 5, or 10 mM glucose for 1 h. Basal tension, contraction force and post rest potentiation (PRP) after 5 min were measured. Results: In the absence of glucose basal tension decreased in mature males and increased in immature males and females. With the addition of a physiological concentration (5 mM) of glucose, basal tension was maintained in all fish and yet force productions was significantly higher in mature males (49%) when compared to immature males (25%) and females (23%). At 10 mM glucose, basal tension decreased in mature males and increased in immature males and females. PRPs were higher in strips that received glucose (5 mM) when compared to glucose-free strips. Conclusion: Depending on sex and maturity of the fish, a specific concentration of glucose was required to maintain basal tension. Glucose promoted 1) more contractility in mature males than in immature fish and 2) calcium storage in the SR. These results highlight the importance of available substrate, gender and maturity differences to studies of trout cardiac performance.

P1.40

BELANGER, JH, DEWELL, RB, MILLET, L, VIDAL-GADEA, AG; jimb@lsu.edu. Louisiana State University, Baton Rouge, Centenary College of Louisiana

COMPARATIVE STUDIES OF WALKING IN CRABS: FROM NEUROANATOMY TO BEHAVIOR

Spider crabs (Libinia emarginata) and shore crabs (Carcinus maenas) are two brachyuran crabs with different walking strategies and environmental niches. L. emarginata walks preferentially forwards and is strictly aquatic. C. maenas preferentially walks sideways and is amphibious. Furthermore, C. maenas is capable of locomotion on land with limb kinematics that closely resemble those seen while it walks underwater. Libinia does not appear to be capable of walking on land, or when carrying an added load of more than 25% of its body weight. Are there differences in physiology and/ or morphology that reflect these differences? We are using a combined approach of neuroanatomy, neuromuscular physiology, and EMG combined with kinematics in freely-behaving animals, to answer this question. While the neuromuscular anatomy of the distal limb segments is similar in the two species, there is a more anterior placement of Libinias fused thoracic ganglia, and a reduction in proximal leg musculature, compared to Carcinus. The latter difference may reflect the reduced ability of spider crabs to walk when laden. Furthermore, in isolated preparations, limb muscles in Libinia show much lower rates of facilitation than do similar muscles in Carcinus. Both species show similar alterations in limb kinematics as a response to increased load. In addition to increasing the duration and within-burst frequency of power stroke muscles, Carcinus responds to added load by altering the timing of muscle activity relative to limb kinematics. We are currently investigating whether Libinia show similar changes in the timing of muscle activation.

P2.114

BELDEN, LK, WINGFIELD, JC, KIESECKER, JM; belden@vt.edu. Virginia Polytechnic Institute and State University, University of Washington, Pennsylvania State University

CORTICOSTERONE AND GROWTH IN LARVAL AMPHIBIANS (RANA SYLVATICA, AMBYSTOMA JEFFERSONIANUM AND SCAPHIOPUS HOLBROOKI)

In amphibians, corticosterone (the main glucocorticosteroid) has a role in both responses to environmental perturbations and in regulating larval growth and development preceding metamorphosis. As such, corticosterone may be mediating some of the well-documented effects that environmental Stressors have on larval amphibian growth and development. In a series of studies, we began to explore this potential link for several species of amphibians native to the Eastern U.S. We completed confinement stress series on larvae of four species of amphibians in natural/semi-natural conditions: Wood frogs (Rana sylvatica), Spring peepers (Pseudacris crudfer), Jeffersons salamanders (Ambystoma. jeffersonianum) and Eastern spadefoot toads (Scaphiopus holbrooki). Three of the species had a typical vertebrate response of increasing corticosterone with increased time of confinement. However, Eastern spadefoot toads, which have a very short developmental period prior to metamorphosis, did not show any increase in corticosterone over an hour of confinement. In addition, we treated 3 of the species (R. sylvatica, A. jeffersonianum, S. holbrooki) with low doses (0.001 M and 0.01 M) of corticosterone in the laboratory and examined effects on growth. While we were successful in raising baseline corticosterone levels with our high dose of corticosterone, this did not translate into changes in mean larval growth for any of the three species.

P2.18

BERNICK, EP, MOFFETT, SB, MOFFETT, DF; ambulocetus@earthlink.net. Washington State University

A VISCERAL MUSCLE NETWORK IN LARVAL AEDES AEGYPTI

Intrinsic gut muscle plays a vital role in digestive processes, and is under control of both neurons and enteroendocrine secretions. The structure of this muscle is especially interesting in some insects, where it is arranged in a grid-like manner (as opposed to continuous layers). Visceral muscle associated with the larvalstomach of the yellow fever mosquito Andes aegypti was identified by O'Brien in 1966. This larval tissue, however, remains poorly characterized in this species. In these studies, stomachs from 4th instar A. aegypti larvae were examined using both transmission and scanning electron microscopy. Over most of the gut surface, individual circular muscle fibers intersect with longitudinal fibers at right angles. Bilaterally, some circular fibers bifurcate to interlock with adjacent fibers; this interlocking zone is associated with longitudinally-running serotonergic axons. While the spacing between the circular fibers of the anterior and posterior stomach is similar (21.91.3 and 25.20.7 respectively, means SEM), there is disparity in their diameter. Circular fibers had a diameter of 2.30.3 in the anterior stomach and 4.00.8 in the posterior (means SEM). In contrast, the distance between the posterior longitudinal fibers was 25.41.3 while that of the anterior stomach was 14.5+0.9 (means SEM). The diameter of posterior longitudinal fibers was 4.60.4 while that of the anterior fibers was 1.70.2 . Extensive innervation of the muscle is visible, particularly flanking the gastric caeca and in the posterior stomach. Parallel studies of contractile responses to serotonin and neuropeptides are underway in our laboratory. (Supported by NSF Grant #IBN-0091208).

P1.10

BENO, C, GILCHRIST, SL; gilchrist@ncf.edu. New College of Florida

CONTRIBUTIONS TO THE CARBONATE BUDGET OF REEF BUILDING CORALS: DISSOLVED ORGANIC MATTER AND CO2

Ecological interaction between corals and the oceanic environment have been suggested to be fundamental in global climate change. Carbon dioxide levels have been associated with global warming and the greenhouse effect. This greenhouse gas is naturally stored in calcium carbonate formations and released with the death of coral reef communities but excess CO2 and lowered pH inhibits coral growth. Corals and other calcifying reef organisms metabolize carbon in two ways: organic carbon production and consumption, or CaCO^sub 3^ deposition. The role of dissolved organic matter (DOM) in coral nutrition has not been extensively considered heretofore regarding the oceanic carbon cycle. We decided to investigate whether DOM would influence CaCO^sub 3^ deposition and therefore supplement the endosymbiotic contribution to the coral energy budget and promote skeletal structure. Because CO2 is produced by deposition of CaCO^suB 3^, we used this as a measure of growth. Measured carbon flux on the reefs of Roatan, Bay Islands, Honduras revealed significant contribution of DOM in the metabolism of Massive Starlet Coral (Siderastrea siderea) and Boulder Brain Coral (Colpophyllia natans) and greater coral growth was associated with elevated DOM usage. Results suggest that organic carbon flux, calcification and gas exchange can provide valid measures of coral growth and that higher DOM levels could contribute significantly to CaCO^sub 3^ deposition and metabolism. Further work in this area may facilitate improvement of oceanic-atmospheric interaction models.

P1.32

BERNSTEIN, P; peter.bernstein@uni-tuebingen.de. University of Tuebingen

THE INNER EAR ANATOMY OF THE COELACANTH REVEALED BY HIGH- RESOLUTION X-RAY CT

High resolution computed tomography (CT) was used to investigate the otical region of an adult specimen of Latimeria chalumnae. In earlier studies a complicated composition of the coelacanths inner ear has been described, with a confusing arrangement of endo- and perilymphatic ducts, partly combining both inner cars and the labyrinths with the endocranial cavity. The CT data were used in combination with 3-D-software to create a three-dimensional digital reconstruction of the otical region. For this study an industrial CT scanner was used allowing for much higher resolution than conventional medical CT devices. Thus it was possible to show even very small structures otherwise only accessible by histological or dissection methods. Because the CT method is noninvasive (using x- ray technology) the material was not destroyed during the procedure. Computed tomography gives information on different densities of the organisms tissues and is particularly useful with respect to hard tissues i.e. bone and cartilage. Since the inner ear ducts are embedded in skeletal tissue the CT method was the most suitable noninvasive method. The results show the course of the duct between the inner ears (canalis communicans) and the tiny ducts leading from this canal to the endocranial cavity in great detail. The data confirm earlier results and make visible the threedimensional course of these ducts for the first time.

P2.25

BEULIG, A, FOWLER, J; beulig@ncf.edu. New College of Florida

SEROTONIN AND AVOIDANCE LEARNING IN GOLDFISH

Serotonin (5-HT) has been implicated in clinical phenomena such as depression, and stress as well as general activity. The development of specific serotonin re-uptake inhibitors (SSRIs)such as fluoxctine (Prozac)effective in the treatment of clinical depression was a significant achievement. However, diversity of serotonergic function remains to be completely characterised and phylogenetic history of serotonergic mechanisms is not yet well- understood. Studies on rats have shown a negative relationship between serotonergic activity and active avoidance learning suggesting a role in cognition. We sought to investigate this in a phylogenctically lower group, the fish. We assigned groups of 15 goldfish (Carassius aumtus) to each of three treatments: fluoxetine; a 5HT-1^sub A^ receptor antagonist (WAY 100,635); and a sham control. Drugs were added to aquarium water and levels of fluoxetine were maintained at 81/L and WAY 100,635 at 16/L during the experiment. Subjects were trained in a two-way shuttle-box avoidance task, 15 trials per day for 13 days. A two-way ANOVA showed that WAY- treated subjects performed significantly more avoidance responses (p=.0079) than Prozac-treated or control subjects. It is suggested that normal or cxogenously elevated serotonin levels have an inhibitory effect on spontaneous activity in fish in concordance with results in rats. This may have had a negative effect on the rate of acquisition of avoidance responding of control groups and fluoxetine-treated groups compared with 5HT-1^sub A^ receptor blocker-treated group. The latter may, therefore, have been more susceptible to the acquisition of the shuttling response. It is also suggested that serotonergic mechanisms may be highly conserved in the vertebrates and that fish may be useful model systems for the study of these mechanisms.

P2.8

BIARDI, JE; jebiardi@ucdavis.edu. University of California, Davis, San Francisco State University

ECOLOGICAL AND EVOLUTIONARY CONTEXT OF MAMMALIAN RESISTANCE TO SNAKE VENOMS

Snake venoms are a complex mixture of proteins, polypeptides, biogenic amines, and other components that may have neurotoxic, hemostatic, and/or hemorrhagic effects on prey. Their primary functions are to immobilize prey and initiate the process of digestion. For example, most viper venoms contain metalloproteases that break down the lining of blood vessels and other components of the extracellular matrix, leading to hemorrhage and tissue necrosis. However, some mammals are able to neutralize the toxins in of snake venoms. While clinical treatment of snakebite in humans relies on antibodies raised in domestic animals, resistance in prey appears to be an innate, not an immune, response to predation. The hemostatic and hemorrhagic effects of venoms pose a significant threat apart from death, since they can reduce fitness due to tissue destruction and necrosis. In some mammals, this threat has been met by the modification of endogenous serum protease inhibitors in ways that make them effective against snake venom proteases. This paper examines the current state of knowledge about mammalian factors that neutralize snake venom proteases and prevent extensive tissue damage. This work shows that five marsupials, two hedgehogs, a shrew, a mole, four mongoose, a raccoon, two mtistelids, and 15 rodents (including three sciurid and eight murid rodents) have some form of resistance to venom toxins. An examination of new and existing data using an evolutionary and ecological perspective reveals previously unexplored patterns in venom resistance. There are significant gaps in our knowledge of innate defenses against venomous snakes, and a comparative approach can lead to new insights into the arms race between these predators and their prey.

P1.6

BEULIG, A, GANGE, J*; bculig@ncf.edu. New College of Florida

CORAL REEF AND MANGROVE INTERACTIONS IN BOCAS DELTORO, PANAMA

Results from studies in the Caribbean and Indo-Pacific have differed on the importance of mangrove-derived biomass in the economy of reefs. We studied reciprocal influences of coral reef and mangrove forest in Bocas delToro, Panama. We focused on movement and degradation of mangrove leaf litter, distribution of holothurian detritivores, and character of the fouling community on mangrove root systems as well as water quality in three different sites. Site A: sandy beach (no mangroves) with nearshore coral reef; Sire B: coastal mangrove forest with no adjacent coral reef; Site C: mangrove shoreline with adjacent coral reef. Transects 150 m long with 2xlOm quadrats every 10m were established and organisms/leaves counted. When a coral reef was adjacent, there was significantly less settled mangrove leaf litter within the first 30 m from shore. There was significantly greater population density of holothurians when a coral reef was adjacent to the mangroves (Site C) than a shoreline with coral reef alone (Site A) or mangroves alone (Site B). Species diversity of the fouling community on mangrove root systems was greater on mangroves with adjacent coral reef. There were no significant differences among sites in water quali\ty except for significantly greater silica concentration in Site A. It is suggested that mangrove-derived detritus (as well as some from reef) supported a larger population of sea cucumbers at Site C than at the other sites. Further, mature holothurians may cany out reproductive activities in the reef areas and when pelagic larvae settle, they may select mangroves and sea grasses as substrate. Survival and recruitment would be enhanced because of shelter and nutrients obtainable in the mangroves. It is also suggested that the reef may be a source of pelagic larvae of sessile organisms that may settle on mangrove roots for greater diversity. Corals were found growing on some mangrove roots.

P1.84

BILEWITCH, JB, COATES, KA*; jaret@bbsr.edu. University of Toronto, Bermuda Biological Station for Research

A MORPHOMETRIC REANALYSIS OF GORGONIAN SCLERITES: OLD MICROSCOPY SHEDS NEW LIGHT ON OCTOCORAL PHYLOGENY

Historically, taxonomic classifications of octocorals were based on morphology of sclerites without testing character homology in a phylogenetic framework. Recently, some inter- and intra- generic relationships have been elucidated with cladistic methods but the majority of octocoral relationships have not been examined in this way, despite the vast amount of sclerite descriptions and measurements accumulated over past decades. We have thus analyzed the shape and size distributions of sclerites in a number of holaxonian octocoral species from Bermuda and the Bahamas using discrete and morphometric distinctions of character states. Using digital images captured from a compound light microscope, we were able to reconstruct a cladogram that allows evaluation of common taxonomic indicators as well as the evolutionary relationships of octocorals, themselves. We found our morphology-based phylogeny inconsistent with historical taxonomy and identified several sclerites types and sizes useful in identification of species, genera, and families. Furthermore, we examined the variation in our continuous variables as an indicator of phylogeography by comparing mean sizes in Bahamian and Bermudian populations. Finally, we compared and combined our morphological characters to recent molecular data in both consensus and total evidence phylogenetic trees. Analyses combining both types of data appear more robust and implicate more useful characters for distinguishing the studied taxa. They also suggest a continuing need for morphological characters in an ever-increasing world of molecular phylogenetics.

P3.43

BLACKBURN, DG, JOHNSON, AR, PETZOLD, JL; daniel.blackburn@trincoll.edu. Trinity College, Hartford

FETAL MEMBRANE ULTRASTRUCTURE IN THE CORN SNAKE, PANTHERINA GUT7ATUS

In amniotes, fetal (extraembryonic) membranes are responsible for all physiological exchange between eggs and their environments. The anatomical basis for such exchange is largely unknown in reptiles, and has not previously been studied in oviparous snakes. "We used transmission EM and thin-section histology to examine fetal membranes in oviparous corn snakes. During development, the chorioallantois shows an increase in vascularity and a decrease in thickness of the chorionic epithelium. These features enhance respiratory exchange across the eggshell. As in viviparous snakes, the allantois invades the yolk cleft, vascularizing the abembryonic pole of the egg and forming an omphalallantoic membrane. As development proceeds, the isolated yolk mass is digested by the omphalopleure, converting the omphalallantoic membrane into a secondary chorioallantois; thus the entire egg becomes surrounded by vascularized membrane. Both the chorioallantois and the omphalopleure show evidence of phagocytosis of eggshell material. Coupled with recent studies of eggshell morphology and calcium mobilization, these findings offer evidence for the uptake of eggshell material by the fetal membranes. In viviparous squamates, placental transfer of organic and inorganic nutrients is widespread, if not universal. The capacity for uptake by the fetal membranes may well be a primitive sauropsid feature that long predates the evolution of viviparity.

P2.35

BOCK, NL, WYETH, RC, CAIN, SD; crabboy@u.washington.edu. Friday Harbor Labs, University of Washington

THE TEMPORAL STRUCTURE OF MULTIPLE GUIDANCE CUES DURING PREY- FINDING BEHAVIOR OF THE MARINE MOLLUSC TRITONIA DIOMEDEA

Motile animals often use multiple sensory cues while navigating through their environment. The relative importance of these cues is typically structured both hierarchically and temporally. In this study, we investigated three distinct sensory modalitities (chemoreception, rheosensation, and magnetoreception) used by the marine mollusc Tritonia diomedea when orienting and navigating toward prey. Even over small spatial scales, the benthic habitat of these animals presents a challenge for rheotactic navigation, due to local currents that can vary rapidly in amplitude and direction. To investigate how T. diomedea localizes its prey effectively within an ever-shifting environment, we characterized the orientation and prey localization of T. diomedea in a flow tank, surrounded by a circular magnetic coil system (that reverses the horizontal component of the ambient magnetic field), with both sea pen odotant and current flows. Using time-lapse video, we recorded the behavior of individual slugs exposed to different temporal combinations of chemical, water current, and magnetic cues navigating towards prey. Preliminary results indicate prey odors act as a gate to initiate positive rheotaxis, correctly aligning the slug in the proper direction, after which current cues are not necessary for continued successful navigation. Attempts to determine if this later portion of navigation is dependent on magnetic cues have been unsuccessful. The results of this study, combined with ongoing investigations of the neural pathways underlying these sensory modalities, will allow us to examine the neuroethological questions of how multiple sensory cues drive a given behavior.

P1.51

BLAKE, MA, ANGILLETTA, MJ; mblakel@indstatc.edu. Indiana State University

GROWTH OF THE GERMAN COCKROACH AT CONSTANT AND FLUCTUATING TEMPERATURES

Growth rate is temperature sensitive in all ectotherms, but most of our estimates of sensitivity are based on measurements of the growth of animals at constant temperatures. Fluctuating temperatures, which arc similar to those experienced in nature, have seldom been used in comparisons of growth rate. To determine whether there is any significant difference in growth rate at constant and fluctuating temperatures, we incubated German cockroaches (Blatella germanicd) for 28 days in one of four thermal treatments. Fluctuating thermal treatments (27 5 C and 22 5 C) were designed such that the mean temperature equaled constant temperature treatments (27 C and 22 C). Virgin parents were mated and the offspring were divided randomly among the four treatments. Each nymph was weighed at hatching and again after 28 days. We compared growth at high and low mean temperatures to quantify the thermal sensitivity of growth. Individuals at higher mean temperatures grew faster regardless of thermal fluctuation. We compared growth in fluctuating temperatures to growth in constant temperatures to show the effect of thermal fluctuation on growth rate. Fluctuating temperatures decreased the growth rate for roaches in the first 28 days of life. Recently published theories cannot be used to predict the outcome of a comparison of growth in constant versus fluctuating temperatures. Our study, combined with previous ones, indicate that the effects of thermal fluctuations on organismal performance can be complex. The thermal factor that primarily determines growth rate may be maximal temperature, minimal temperature, the relative duration of thermal exposures, the rate of temperature change, or a combination of all of these.

P2.130

BONIER, F, MARTIN, PR, RAMENOFSKY, M, WINGFIELD, JC; fb2@u.washington.edu. University of Washington

DEPARTURE BIOLOGY OF AN ARCTIC-BREEDING PASSERINE

In the fall, migratory birds prepare to depart the Arctic for southerly clines to overwinter. Whereas a great deal is known of the preparatory stages for spring (northward) migration, relatively little is known about fall migration, particularly for populations breeding in the most northern range of their distribution. Wc explored fall migratory life history stage in Gambels White-crowned Sparrows at Toolik Lake, Alaska (longitude W149.6, latitude N68.6). The spring migratory life history stage is initiated by the prealternate molt and fattening both of which are induced by spring photoperiods. The molt is restricted to replacing feathers on the head and body. In fall, the daylength is decreasing and molt is a much more extensive involving replacement of feathers as well a components of skin, blood, and bones. These differences provide a unique comparison of the two migratory life history stages. We document changes in fat scores, mass, molt, and plasma levels of corticostcrone from the conclusion of breeding through the prebasic molt and migratory fattening in preparation for departure. In the field, birds did not fatten until molt was nearing completion. Our results provide new insight into the preparation for fall migration in a population located at the extreme northern edge of its geographic range.

Pl .48

BOTTON, M, POGORZELSKA, M, SMORAL, L, SHEHATA, A, HAMILTON, M; botton@fordham.edu. Fordham University

THERMAL BIOLOGY OF HORSESHOE CRAB EMBRYOS AND LARVAE: A ROLE FOR HEAT SHOCK PROTEINS

The sandy intertidal beaches where horseshoe crab (Limtduspolyphemus) embryos and trilobite larvae live are thermally stressful habitats. Heat shock proteins (Hsp's) arc known to help protect a wide variety of organisms against temperature and other stresses by protecting proteins from denaturation, thereby preserving their physiological int\egrity. To study the potential importance of Hsp's in the thermal biology of horseshoe crabs, stage 20 embryos and trilobite larvae were acclimated to 13 or 22C and then heat shocked at 35C for 3 hr, and the quantity of Hsp70 was assayed after O, 2, 4, and 6 hr recovery times at 22C. The temperature shocks were sublethal; 98% to 100% of the animals that were heat shocked under these conditions successfully molted. Embryos and trilobites were homogenized in tissue PELB buffer with DTT (reducing agent) and protease inhibitors. We then detected Hsp70 in tissue extracts using SDS-PAGE electrophoresis followed by Western blotting (using monoclonal mouse antibody against bovine Hsp70). We found high levels of constitutive Hsp70 in control crabs that were maintained at constant temperatures of 13 and 220C. By using 2-D electrophoresis, which combines isoelectric focusing and SDS-PAGE, we found qualitative differences between the embryos and trilobites in their Hsp70 isoforms. However, levels of Hsp70 in control crabs were similar to those found in all heat shock treatments, regardless of the acclimation temperature or the duration of the recovery period. Temperature stress did not induce additional synthesis of Hsp70; rather, by maintaining a high constitutive level of Hsp's, horseshoe crabs may be adapted to the cyclical tidal/diurnal temperature fluctuations that typify estuarine beaches.

P3.8

BRANSTETTER, MG; greaser6l6@aol.com. The Evergreen State College

oil-COLLECTING STRUCTURES OF THE SOUTH AFRICAN BEE GENUS REDIVIVA (HYMENOPTERA, MELLITIDAE): AN INVESTIGATION USING SCANNING ELECTRON MICROSCOPY

Bees have been coevolving with flowering plants for millions of years and have as a result a wide range of adaptations for collecting many different types of floral rewards. In addition to being adapted to collecting nectar and pollen, many bees have specially modified structures for the extraction of floral lipids, which are produced by special secretory glands called elaiophores. Rediviva (Hymenoptera, Mellitidae) is an oil-collecting genus of bees occurring in southern Africa. It has undergone diffuse coevolution with oil-producing flowers in the family Scrophulariaceae, primarily with species in the genus Diascia, and some Orchidaceae. Modifications in both plant and pollinator are evident: many Diascia species have long elaiophore containing spurs and many female Rediviva species have disproportionately long forelegs with specially adapted oil-collecting setae. Using scanning electron microscopy, I have been able to document the diversity in oil-collecting structures of 23 Rediviva species and compare it with Rediviva males and several non oil-collecting species in closely related genera. As hypothesized, only the oil-collecting Rediviva bees have specialized setae, which can be found on the foretarsus of all species and both the fore- and midtarsus of several. Setae type range from being thin and highly branched, forming dense tomenta, to being broad and spatulate. Like several investigations into the oil- collecting structures of Neotropical and Holarctic bees, this new research combined with other data about Rediviva species systematics, distributions, and host plants should bring new understanding to this unique mutualistic plant-pollinator relationship.

P2.131

BOYD, EH*, BUSCH, DS*, WINGFIELD, J*; Ellen@boydvet.com. University of Washington

AFFECTS OF INTERMITTENT INCREASES IN CORTICOSTERONE IN THE WHITE- CROWNED SPARROW ZONOTRICHIA LEUCOPHRYS GAMBELII-. AN EXPERIMENTAL PARADIGM FOR REPEATED ACUTE STRESSORS

When vertebrates experience perturbations, the hypothalamo- pituitary-adrenal axis is activated causing glucocorticoid secretion to increase followed by a cascade of physiological events. These include suppression of reproduction and regulation of the immune system. While these events promote survival in response to acure perturbations, they can be deleterious in the long term. One important question in basic biology and conservation is when do repeated acute Stressors become chronic stress? We tested whether frequent intermittent increases in corticosterone can have effects similar to chronic stress. White-Crowned Sparrows were exposed to 20 hours of light and 4 dark per day with food and water ad lib. Birds were treated 3 times daily for 3 weeks with a topical solution of 10 Ug corticosterone in 20 ul DMSO or 20 ul DMSO as a control. A separate group was undisturbed. There was no affect of treatment on gonad size, as determined by laparotomy, but there was a decline in health compared with the control and undisturbed groups. Four of eight corticosterone treated birds developed bacterial infections including three with a mild anemia consistent with anemia of chronic disease and two had leukocyte counts outside the normal range. Of these birds only one showed an increased leukocyte count in response to infection. This decline in health is consistent with chronic immune suppression. These results show that intermittent increases of corticosterone simulating acute stress responses id frequent can cause deleterious effects associated with chronic stress.

Pl.112

BRIAN, BK, SCHILL, RO, TUNNACLIFFE, A; atl0004@biotech.cam.ac.uk. University of Cambridge, UK, University of Tbingen, Germany

HYDROPHILIC PROTEINS IN INVERTEBRATE ANHYDROBIOSIS

Over the last 30 years, much attention has been focused on the role of trehalose in anhydrobiosis. However, desiccation tolerant bdelloid rotifers Philodina roseola and Adineta vaga lack trehalose or other disaccharides, suggesting that other biostabilisers are used. Candidates include hydrophilic proteins like the late embryogenesis abundant (LEA) proteins associated with desiccation tolerance in plant seeds. Given the recent discovery of LEA proteins in nematodes, we tested for their presence in other anhydrobiotic and dehydration-tolerant invertebrates, including rotifers. A polyclonal antiserum against the AavLEAl protein from anhydrobiotic nematode Aphelenchus avenae was used in Western blots of protein extracts from other organisms. Clear signals were observed in R roseola, tardigrade Macrobiotus hufelandi, stress resistant gemmules of sponge Spongilla lacustris, larvae of the beetle Tenebrio molitar, and in cysts and larvae of brine shrimp Anemia franciscana. The regulation of putative A. franciscana LEA proteins is consistent with a role in desiccation tolerance: they are present at high levels in dry anhydrobiotic cysts, but after rehydration the level declines; no signal is seen in the non-anhydrobiotic adult. Expression of LEA protein in P. roseola is also linked to desiccation tolerance, since it is upregulated by dehydration. Proof of the identity of these proteins will require sequencing, but the data suggest that LEA proteins are widespread in invertebrates and are associated with resistance to water stress.

P3.108

BROWN, KR, WALTERS, LJ, GLARDON, CG, BLACK, MW, SACKS, PE, BEACH, KS, STAM, WT, OLSEN, JL; ljwalter@pegasus.cc.ucf.edu. University of Central Florida, Orlando, Winter Springs High School, University of Tampa, Tampa, University of Groningcn, The Netherlands

IS THE "KILLER ALGA" IN FLORIDA? FIELD COLLECTIONS, RETAIL AND E- COMMERCE AVAILABILITY OF CAULERPA IN THE SUNSHINE STATE

Since 1984, aquarium releases of Caulerpa taxifolia Mediterranean strain have led to this killer alga becoming established in coastal waters in Europe, California and Australia. In all cases, ecological and economic costs have been astronomical. Because Floridas climate, surface water temperatures and biodiversity are similar to previous invasion locations, we are presently collecting all native/non- native species of Caulerpa: 1) in Floridas coastal waters, and 2) from retail and e-commerce distributors. DNA from all collected individuals is being scquenced to determine its origin. To date, Caulerpa has been collected from 36 field locations in central and south Florida. We have collected 11 species of Caulerpa, with C. racemosa and C. prolifera most frequently encountered. We have visited 28 local aquarium shops; 50% sold at least one species of Caulerpa either loose or attached to live rock. We have purchased Caulerpa via e-commerce from 33 sources: 56% of the purchases were from E-Bay, 19% were from commercial distributors in Florida, and 25% were from distributors from other states, most notable being California and Ohio. In summary, we have presently completed approximately 50% of our search grid. So far, no Caulerpa taxifolia (native or invasive) has been field-collected, purchased, or shipped to addresses within state boundaries.

P3.27

CALSBEEK, R, MILES, DB, SINERVO, B; dmiles@ohio.edu. University of California, Los Angeles, Ohio University, University of California, Santa Cruz

CORTICOSTERONE, LOCOMOTOR PERFORMANCE, AND METABOLISM IN SIDE- BLOTCHED LIZARDS (UTA STANSBURIANA)

Elevated levels of circulating corticosterone commonly occur in response to stress in wild vertebrates. A rise in corticosterone, usually in animals of subordinate rank, results in a variety of effects on behavior and physiology. Behavioral and physiological responses to short term increases in corticosterone are well studied. In contrast, the effects of chronic elevated levels of corticosterone are poorly understood, particularly in lizards. Here, we examined the long term effects of exogenous corticosterone on Iocomotor performance, resting and active metabolic rate, and hematocrit in male side-blotched lizards Ufa stansburiana. Corticosterone implantation resulted in higher levels of stamina relative to sham-surgery controls in both the field and laboratory. In addition, lizards with elevated corticosterone exhibited lower resting metabolic rates relative to controls. Corticosterone had no effect on peak activity metabolism, but did result in faster recovery times following exhaustive exercise. We suggest that elevated levels of corticosterone in response to do\minance interactions promote enhanced Iocomotor abilities, perhaps as a flight response to avoid agonistic interactions. Furthermore, stressed lizards are characterized by lower resting metabolic rates, which may serve as strategy to conserve energy stores.

P3.46

BROWNE, WE, PATEL, NH, MARTINDALE, MQ; wbrowne@hawaii.edu. Kcwalo Marine Lab, University of Hawaii, HHMI, University of California, Berkeley

DEVELOPMENTAL EXPRESSION OF LAB AND EMS IN THE HEAD AND CNS OF PARHYALEHAWAIENSIS

The arthropod head is a complex multimeric structure. At the level of molecular patterning in Drosophila it appears that a relatively small number of transcription factors play a major role in specification of the supraesophageal ganglion. From anterior to posterior in the crustacean, Parhyale, the supraesophageal ganglion can be subdivided into protocerebral, deutocerebral, and tritocerebral neuromeres. Here we present expression patterns associated with Parhyale orthologs of labial (lab) and emptyspirades (ems). The Hox gene lab is expressed in the IC segment during insect development. In Parhyale, Ph lab is expressed pregastrulation in a single row of cells corresponding to the primordium of the second antennal (AN2) segment (homologous to the insect intercalary (IC) segment). During formation of the Parhyale germband, Ph lab expression includes all ectodermal cells contributing to the AN2 segment. Later expression of Ph Lib is restricted medially to the tritocerebrum and to lateral and posterior regions of the stomodeum. In Drosophila the head gap gene ems is expressed in an early broad domain in both the AN and IC segments and plays a role in specifying structures on these segments. In Parhyale there is no analogous broad ems domain in the head. Parhyale ems is first detected in small, bilateral, domains after germband formation. Once the germband is complete and appendage buds begin to appear anteriorly, Ph ems is detected in bilateral reiterated sets of ventral ectodermal cells along the A-P axis. Early expression of Ph ems is inconsistent with a role as a head gap gene as Ph ems expression in the anterior head occurs after the head lobes appear. Current experiments seek to explore the function of lab and ems genes in Parhyale.

Pl.113

CAPRIOLI, M, RICCI, C, SANTO, N; manuela.caprioli@unimi.it. University di Milano, Milano

CHANGES IN A BDELLOID ROTIFER ENTERING DESICCATION

Fine morphology (Scanning Electron Microscope, Confocal Laser Scanning Microscope) and metabolism (calorimeter) of a bdelloid rotifer, Macwtrachela quadricornifera, were studied to illustrate the morphological and metabolic changes that seem to be responsible for successful recovery after anhydrobiosis. In response to desiccation, bdelloids withdraw head and foot, sealing them into the trunk, and attain the tun shape. At the end of this process the rotifer reduces its body volume and loses about 75% of its weight. It is likely that the weight loss is mainly due to water loss, possibly from the main body cavity (pseudocoel). Attainment of the tun shape implies contraction of the longitudinal muscles, which appear tied in the hydrated rotifer but loose in the dormant rotifer. We hypothesize that the body cavity of the dormant bdelloid loses its internal fluids, and that this hampers its role as hydroskeleton and prevents movements. In other words, the tun shape of the anhydrobiotic rotifer is not maintained by musculature contraction, but by the reversible absence of hydroskeleton. Metabolism of a hydrated active bdelloid is about 0.01 W by an isotherm calorimeter; no metabolic activity is detectable in the anhydrobiotic rotifer. Unlike most anhydrobiotic animals, bdelloids lack trehalose as a protective chemical: no trehalose was found in M. quadricornifera. What molecules are involved in the protection of the bdelloids biological structures from the injuries due to desiccation is still an open question.

Pl.130

CARSIA, RV, COX, RM, MCILROY, PJ, JOHN-ALDER, HB; heniy@aesop.rutgers.edu. UMDNJ-School of Osteopathie Medicine, Rutgers University, New Brunswick, Rutgers University, Carnden

OVARIAN INFLULNCE ON ADRENOCORTICAL CELL FUNCTION IN SCELOPORUS VIRGATUS (STRIPED PLATEAU LIZARD)

Adrenal steroidogenic (adrenocordcaJ) cells from male Sceloporus undulatvs undergo changes in steroidogenic function and sensitivity to ACTH in response to orchiectomy and testosterone maintenance (JohnAlder and Carsia, 2004). Here we report the influence of ovariectomy on adrcnocortical cell function from S. virgatus. Pre- maturational females were captured and surgically ovariectomized (OVX) or sham-operated (CON) at 7.5-8 months of age. Dispersed adrenocortical cells were prepared and evaluated for progesterone (P- i), corticosterone (B), and aldosterone (ALDO) production in response to ACTH 6 months after treatment. With the exception of a 40% reduction in basal P/, by OVX cells, basal and maximal rates of steroidogenesis did not differ between treatments. Steroidogenic responses to ACTH were polyphasic (P < 0.05), having 2-4 response components. A simplified biphasic fit showed high ACTH-sensitive (- 300 fM30 pM) and low ACTH-sensitive (-80 pM3 nM) components comprising the maximal responses. Compared to CON cells, OVX cells tended to show reduced sensitivity to ACTH for both components, dramatically so for ALDO (by 1 /30 to 1 /80). In addition, ovariectomy tended to shift the proportional contribution of each ACTH-sensitive component in the maximal response of the steroids. Collectively, the present work with ovariectomized S. virgatus and previous work with orchiectomized S. undulatus show a dynamic but complex role of the gonad in the modulation of liz

Source: Integrative and Comparative Biology

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