Gustatory receptor neuron responds to DEET and other insect repellents in the yellow-fever mosquito, Aedes aegypti

Three gustatory receptor neurons were characterized for contact chemoreceptive sensilla on the labella of female yellow-fever mosquitoes, Aedes aegypti. The neuron with the smallest amplitude spike responded to the feeding deterrent, quinine, as well as N,N-diethyl-3-methylbenzamide and other insect repellents. Two other neurons with differing spikes responded to salt (NaCl) and sucrose. This is the first report of a gustatory receptor neuron specific for insect repellents in mosquitoes and may provide a tool for screening chemicals to discover novel or improved feeding deterrents and repellents for use in the management of arthropod disease vectors.     

Are men better negotiators everywhere? A meta‐analysis of how gender differences in negotiation performance vary across cultures

Prior research has found that each culture and gender influences negotiation strategies and outcomes, but less is known about their interplay. We integrate these two research streams by providing a meta‐analytic review of the interactive impact of gender and culture on negotiation performance. We reviewed 185 studies that reported gender differences in intracultural negotiation performance across 30 societies that varied across seven cultural dimensions. Results showed that Hofstede's individualism–collectivism, GLOBE's in‐group collectivism and assertiveness practices, and Schwartz's harmony moderated the gender effect on negotiation performance. We found that in cultures lower in individualism, higher in in‐group collectivism practices, lower in assertiveness practices, and higher in harmony, women more likely outperformed men in negotiations. Implications for the role of gender and culture in negotiations and organizations more broadly are discussed.     

Mole rats (<Emphasis Type="Italic">Spalax ehrenbergi</Emphasis>) select bypass burrowing strategies in accordance with obstacle size

Mole rats inhabit extensive individual tunnel systems. Since the energetic cost of burrowing far exceeds that of surface locomotion, excellent orientation ability is crucial. Here we examined whether mole rats can bypass an obstacle (ditch) intersecting an existing tunnel in order to rejoin the two tunnel sections. The mole rats dug two bypass types, depending on the size of the obstacle confronting them: a bypass around the small ditches, parallel and close to the ditch walls; or a bypass beneath the floor of the large ditches. These results demonstrate that the mole rat has the ability to avoid obstacles by digging accurate and energy-conserving bypass tunnels. In order to utilize such a capacity, the mole rat must possess both the means to evaluate the size of the obstacle as well as the ability to perceive its exact position relative to the original tunnel that it will rejoin. Possible mechanisms of orientation that could explain such ability are briefly discussed.     

Prenatal diagnosis of thrombocytopenia absent radius syndrome using ultrasound and fetoscopy

The prenatal diagnosis of thrombocytopenia absent radius syndrome in both dizygotic twins utilizing ultrasound, radiography and fetoscopy is described.     

An individual-based numerical model of medusa swimming behavior

Scyphomedusae are ubiquitous in marine and estuarine systems, where they frequently play an important role in trophodynamics. Many scyphomedusae are cruising predators, and feeding rates depend, in part, on swimming behavior. Yet, no model of medusa swimming exists. An individual-based correlated random walk (CRW) model of medusa swimming behavior in three dimensions was developed. The model was validated using a previously published dataset of the swimming of 19 Chrysaora quinquecirrha (Desor, 1848) medusae that were observed in the presence or absence of zooplankton prey in laboratory mesocosms in August–October 1998 (Matanoski et al. in Mar Biol 139:191–200, 2001). In the presence of prey, medusae swam at a constant moderate rate in looping trajectories. In the absence of prey, medusae alternated periods of slow and fast swimming in more linear trajectories. In the model, looping trajectories were reproduced only when changes in movement by a medusa were oriented to its current position and orientation; more linear trajectories were reproduced by movement oriented to a fixed framework. This suggests that medusae change from swimming behavior oriented to local stimuli (e.g., contact with prey) to long-range stimuli (e.g., gravity) depending on the availability of prey. The model reproduced cyclical changes in swimming speeds by medusae in the absence of prey by simulating switching in the behavior controlling the strength of swimming bell pulsations using a probabilistic function. Model results also demonstrated that medusae tend to swim toward the surface, avoid contact with the bottom, increase time spent in prey patches if they alter swimming patterns in the presence of prey, and exhibit significant periodicities in swimming patterns that are the result of deterministic behavior. The model will permit the simulation of the complex behavior of medusae.     

Variation among populations of the sailfin molly in the rate of concurrent multiple paternity and its implications for mating-system evolution

We examined patterns of concurrent multiple mating in a live-bearing poeciliid fish, the sailfin molly (Poecilia latipinna). We tested whether the probability of multiple paternity was related to female body size or fertility and whether the rate of multiple paternity varied among four populations that differed in their distributions of female body size and fertility. We analyzed data on mother and offspring genotypes for three polymorphic allozymes by three techniques, including a maximum-likelihood estimator that accounts for sampling error in both parental and offspring allele frequencies. The estimated rate of multiple paternity varied between 0.09 and 0.85, and the rate in one population varied seasonally between 0.33 (spring) and 0.85 (autumn). The variation in these rates was not associated with variation in body-size distributions among populations but was closely associated with variation in size-specific fertility: populations with greater variation in female fertility had higher multiple-paternity rates. Within two populations, logistic regression revealed that individual females of larger body size and greater size-specific fertility were more likely to carry multiply sired broods. This result is consistent with observations made in one of the populations 5 years earlier. In general, the results strongly suggest that the mating system varies markedly among conspecific populations of sailfin mollies and that larger, more fertile females are the objects of intermale competition. Received: 6 May 1996 / Accepted in revised form: 5 December 1996     

Housing values,census estimates,disequilibrium, and the environmental cost of airport noise: A case study of Atlanta

Two unresolved issues about airport noise-property value studies are addressed. The first issue concerns the comparability of empirical results from aggregate census data vs individual sales values, and the second issue concerns the homogeneity and stability of results from housing price studies over time and across markets. Hedonic price models from two sets of data for a residential area near the Atlanta International Airport are estimated at two points in time 1979–1980 and 1970–1972. The available data yield similar estimates of the noise discount over time, and from the prices of individual house sales vs owner-appraised census block aggregates.     

Threat-sensitive foraging by larval threespine sticklebacks (Gasterosteus aculeatus)

Summary The threat-sensitive predator avoidance hypothesis predicts that prey can assess the relative threat posed by a predator and adjust their behaviour to reflect the magnitude of the threat. We tested the ability of larval threespine sticklebacks to adjust their foraging in the presence of predators by exposing them to conspecific predators of various sizes and recording their foraging and predator avoidance behaviours. Larvae (<30 days post-hatch) displayed predator escape behaviours only towards attacking predators. At 3 weeks post-hatch larvae approached the predator after fleeing, a behaviour which may be the precursor to predator inspection. Larvae reduced foraging and spent less time in the proximity of large and medium-sized predators compared to small predators. The reduction in foraging was negatively correlated to the predator/larva size ratio, indicating that larvae increased their foraging as they increased in size relative to the predator. We conclude that larval sticklebacks can assess the threat of predation early in their ontogeny and adjust their behaviour accordingly.Correspondence to: J.A. Brown     

Prenatal ultrasound diagnosis of rhizomelic chondrodysplasia punctata in a primigravida

Rhizomelic chondrodysplasia punctata (RCDP) is a sublethal autosomal recessive disorder characterized by skeletal dysplasia, microcephaly, mental retardation, congenital cataracts, joint contractures, skin changes, and failure to thrive. Prenatal ultrasound diagnosis has been reported during the second trimester of pregnancy. Prenatal diagnosis is also possible from the first trimester onwards by demonstration of peroxisomal dysfunction in cultured chorionic villous or amniotic fluid cells. In all cases reported hitherto, the prenatal diagnosis was established after the birth of a previous affected child. In contrast to these studies in pregnant multiparous women at risk for RCDP, we report on the first case of prenatal ultrasound diagnosis of RCDP at 19 weeks' gestation in a primigravida. In addition, a complex cardiac malformation associated with hypoplasia of the thymus (DiGeorge anomaly) is described.