SRYGLEY, R.B.: Locomotor Mimicry among Passion-vine Butterflies Heliconius With regard to prey motion, the evolution of mimicry has been investigated in three areas: 1) locomotor mimicry, 2) anti-apostatic selection, and 3) escape mimicry. Locomotor mimicry is the similarity in motion of two distantly-related prey species. Because of evolutionary convergence in key morphological features that are […]

KIRKTON, S.D.*; HARRISON, J.F.: Effects of Allometric Growth on Oxygen Sensitivity and Jumping Performance in the American Locust Body size changes within instars and across the lives of insects could have significant respiratory and locomotory consequences because of possible problems with oxygen delivery in larger insects. We investigated the effect of across and within instar […]

Jindrich, D. L.*; Full, R. J.: Dynamic Stabilization of Rapid Hexapodal Locomotion Mechanical properties of muscles, connective tissues, and skeletal elements contribute to reducing energy costs, but can also simplify the control of rapid locomotion in animals. Passive mechanical behavior of the musculo-skeletal system may play a role in stability. Rapidly acting, musculo-skeletal ‘preflexes’ have […]

ANDERSON, B.D.*; FULL, R.J.; GARCIA, M.: A Spring-Mass Model of Centipede Locomotion The laterally undulating Arizona centipede, Scolopendra heros, uses a metachronal gait in which all legs on the concave side of the bent body touch the ground at a single point. Each leg of the wave of legs traveling through this point is not […]

OWEN-ASHLEY, N.T.*; BUTLER, L.K.; ROHWER, S.; WINGFIELD, J.C.: The Role of Testosterone in a Moving Avian Hybrid Zone Three narrow hybrid zones exist between hermit (Dendroica occidentalis) and Townsend’s (D. townsendi) warblers in Oregon and Washington. Asymmetries in character transition curves suggest that these zones are moving, with Townsend�s warblers replacing hermit warblers. Previous work […]

PLACE, N.J.; DREA, C.M.; HOLEKAMP, K.E.; WELDELE, M.L.; COSCIA, E.M.; GLICKMAN, S.E.: Sex differences and effects of prenatal anti-androgens on LH secretion in spotted hyenas Sex differences in the secretion of luteinizing hormone (LH) have been attributed to the hormonal milieu to which mammals are exposed during gestation. Additionally, prenatal treatment with androgens can alter […]

LYNN, S.E*; WINGFIELD, J.C.: Sensitivity to supplementary testosterone during the parental phase in a high arctic breeding passerine In avian species that show paternal care, males� testosterone (T) levels peak early in the breeding season, and then decline through the parental phase. This may be related to a trade-off between T and paternal care: T […]

PERFITO, N; TRAMONTIN, A.D.; MEDDLE, S.L.; WINGFIELD, J.C.: Environmental and endocrine regulation of reproduction in song sparrows along an altitudinal gradient. While the direct effects of daylength on seasonal reproduction are well understood, less is known about how supplementary cues (e.g. temperature, rainfall) influence this process. We compared seasonal gonadal growth among non-migratory populations of […]

ELF, P.K.*; LANG, J.W.; FIVIZZANI, A.J.: Dynamics of Exogenous 3H Estradiol Uptake in Turtle Eggs During Development. Sex steroids in the egg yolks of reptiles with TSD (temperature-dependent sex determination) likely affect sex determination and differentiation in some lizards, turtles and crocodilians. In order to determine yolk estradiol (E) dynamics during embryonic development, 3H-estradiol (3H-E) […]

SKALS, N.*; Lund University, Sweden: Sex or Death: The Sensory Conflict Between Mate Attraction and Predator Avoidance in Moths In many situations animals will receive simultaneously information from different sensory modalities. Moths are distinguished for their abilities to evade echolocating insectivorous bats and for their skilled mate location by pheromone detection. The relatively simple system […]