The addiction Stroop task: examining the fast and slow effects of smoking and marijuana-related cues.

Research has shown that attentional bias toward smoking-related stimuli is related to the maintenance of smoking behaviour and the chance of a relapse during a quit attempt. Effects of smoking attentional bias can occur both during smoking stimulus presentation (fast effect) and on stimuli that immediately follow smoking stimuli (slow effect). The current research builds on these findings by closely examining the temporal aspects of these fast and slow effects across groups of different smoking status. In Experiment 1 (n = 64), smokers, smokers attempting to quit (SATQ) and non-smokers completed an addiction Stroop task using smoking related, negative emotion and neutral stimuli. In Experiment 2 (n = 32), marijuana smokers and non-marijuana smokers completed an addiction Stroop task using marijuana and neutral stimuli. Results showed fast effects across all smoking groups (except non-smokers) and slow effects in SATQ and marijuana smokers. Furthermore, marijuana smokers showed slow effects over extended periods of time. Results also show a relationship between anxiety, nicotine dependence and attentional bias in SATQ. The implications of these findings are discussed.

Cloning of a yolk protein gene family from Caenorhabditis elegans.

We have cloned a family of five genes which encode the 170,000 Mr yolk proteins in the nematode Caenorhabditis elegans. The genes and their messenger RNAs are about 5 X 10(3) base-pairs in length. Thus most of the length of each gene is exon, although a few small introns have been discovered. Based on hybridization and restriction mapping experiments, the genes can be subdivided into two subfamilies: YP1-YP2 and YP3-YP4-YP5. Within a subfamily the genes are nearly identical. While most of the genes are not clustered, YP3 and YP4 are tandemly linked. Hybrid-arrest translation experiments demonstrate that the YP3-YP4-YP5 subfamily encodes the yp170A yolk protein, while the YP1-YP2 subfamily encodes the yp170B yolk protein. RNAs homologous to these genes are abundant in the adult hermaphrodite, but missing from larvae and males. Furthermore, RNA isolated from dissected intestines is highly enriched for sequences that hybridize to the genes, whereas RNA from gonad or body wall is nearly devoid of these sequences. Thus, this gene family is apparently expressed only in the intestine of the adult hermaphrodite.

Origins and ecological consequences of pollen specialization among desert bees.

An understanding of the evolutionary origins of insect foraging specialization is often hindered by a poor biogeographical and palaeoecological record. The historical biogeography (20,000 years before present to the present) of the desert-limited plant, creosote bush (Larrea tridentata), is remarkably complete. This history coupled with the distribution pattern of its bee fauna suggests pollen specialization for creosote bush pollen has evolved repeatedly among bees in the Lower Sonoran and Mojave deserts. In these highly xeric, floristically depauperate environments, species of specialist bees surpass generalist bees in diversity, biomass and abundance. The ability of specialist bees to facultatively remain in diapause through resource-poor years and to emerge synchronously with host plant bloom in resource-rich years probably explains their ecological dominance and persistence in these areas. Repeated origins of pollen specialization to one host plant where bloom occurs least predictably is a counter-example to prevailing theories that postulate such traits originate where the plant grows best and blooms most reliably Host-plant synchronization, a paucity of alternative floral hosts, or flowering attributes of creosote bush alone or in concert may account for the diversity of bee specialists that depend on this plant instead of nutritional factors or chemical coevolution between floral rewards and the pollinators they have evolved to attract.

Pollination efficiencies of three bee (Hymenoptera: Apoidea) species visiting rabbiteye blueberry.

Inadequate bee pollination limits rabbiteye blueberry, Vaccinium ashei Reade, production in the some areas of the southeastern United States. Honey bees, Apis mellifera L., are currently the only manageable pollinators available for pollinating V. ashei. However, a new adaptable pollinator for rabbiteye blueberry, Osmia ribifloris Cockerell, was successfully reared and flown in captivity. The bee nested successfully in wooden shelters and conferred superior fruit set to 2-yr-old potted, rabbiteye blueberry bushes. Pollination efficiency or the percentage of blueberry flowers to set fruit after being visited once by a female O. ribifloris was comparable to that of the female blueberry bee Habropoda laboriosa (F.) and worker honey bees. Interestingly, honey bees once thought to be inefficient pollinators of rabbiteye blueberry were found to be very efficient, especially for 'Climax' and 'Premier' flowers.

Management systems response to improving immunization coverage in developing countries: a case study from Cambodia.

INTRODUCTION: In contrast to the initial success following the establishment of the National Immunization Program (NIP) in Cambodia in 1986, infant vaccination coverage rates against the six expanded program immunization diseases have not improved since 1995. In response, the NIP of the Ministry of Health has undertaken a series of institutional initiatives to address the problem of static or declining rates of coverage. The aim of this paper is to describe and assess management strategies undertaken by the NIP in Cambodia in support of improved immunization coverage. METHODS: Sources of information used in preparing this report include international literature, national coverage and surveillance data, government policy documentation, information generated by national strategic planning and health centre microplanning processes, a functional analysis of human resources, and data quality audits. RESULTS: The NIP has implemented planning, organizational development and human resource development responses to the problem of low coverage. These have included: integration of the nip strategic and operational plans into the health sector plan; strengthening of needs-based microplanning; establishment of a national monitoring and management support strategy; and the introduction of performance-based agreements between levels of government for improved immunization coverage. CONCLUSIONS: Our analysis of these findings, in particular of the international literature, suggests that NIP's responses have been appropriate, and that the development of NIP management systems and capacity will increase the likelihood for sustained immunization coverage gains within a reform environment of health system decentralization. In 2003, there are early signs that the reform processes undertaken by the NIP have resulted in improved immunization coverage in targeted areas, and this should place the national program in a stronger position to lift immunization coverage in 2004.

Dufour's gland secretion in the cell linings of bees (Hymenoptera: Apoidea).

The volatile chemicals, detectable by coupled capillary gas chromatography-mass spectrometry, in the nest cell linings of four species in the bee generaColletes, Andrena, andLasioglossum are identical with, and limited to, the volatile components present in the Dufour's gland of females, suggesting this source for some of their cell-lining constituents. The extractable material that lines the cells ofTrachusa byssina, in contrast, is derived fromPinus resin, to which it can be chemically traced.

Predator deterrence by mandibular gland secretions of bees (Hymenoptera: Apoidea).

Volatile lipids from the mandibular gland secretions of bees (Hymenoptera: Apoidea) are potent olfactory repellents of foraging ants (Formica, Crematogaster) in biologically relevant contexts and quantities. In contrast, differential success in capture of bee and fly prey by predatory asilid flies (Efferia), reduviid bugs (Apiomerus), and arachnids (Agelenopsis, Argiope) is better explained by prey size than by chemical repellence, aposematism, or possession of a sting. Supernormal doses of some allomones, applied to worker honeybees (Apis mellifera) that were fed toArgiope aurantia spiders, elicted more frequent preenvenomation pauses following ensnarement but did not significantly increase other prey-handling times. These pauses merely delayed the bee's demise. Mandibular gland secretions of solitary bees augment their other secondary defenses in at least two contexts: (1) during intranest encounters when repelling intruding ants, and (2) retaliation delivered to their arthropodan predators which, if the bee is nearly too large for the predator to handle, may allow the bee to escape.

Dufour's gland triglycerides from Anthophora, emphoropsis (Anthophoridae) and Megachile (Megachilidae) bees (Hymenoptera: Apoidea).

Lipids secreted from the Dufour's glands of the bees Anthophora centriformis, Anthophora californica tarsata, Emphoropsis miserabilis, Megachile (Delomegachile) gemula, M. (Phaenosarus) fortis, M. (Argyropile) parallela, and M. (Melanosarus) xylocopoides primarily consist of short chain (C2-C20) fatty acid triglycerides. Nearly 95% of the triglycerides from Anthophora and Emphoropsis have one palmitoyl-, stearoyl- or arachidoyl moiety, plus two shorter acids (C2-C16). Virtually all triglycerides (98%) from the four Megachile species possess only short-chain fatty acids (C2-C16), often with one like pair of acids.

Floral resource utilization by solitary bees (Hymenoptera: Apoidea) and exploitation of their stored foods by natural enemies.

Bees are phytophagous insects that exhibit recurrent ecological specializations related to factors generally different from those discussed for other phytophagous insects. Pollen specialists have undergone extensive radiations, and specialization is not always a derived state. Floral host associations are conserved in some bee lineages. In others, various species specialize on different host plants that are phenotypically similar in presenting predictably abundant floral resources. The nesting of solitary bees in localized areas influences the intensity of interactions with enemies and competitors. Abiotic factors do not always explain the intraspecific variation in the spatial distribution of solitary bees. Foods stored by bees attract many natural enemies, which may shape diverse facets of nesting and foraging behavior. Parasitism has evolved repeatedly in some, but not all, bee lineages. Available evidence suggests that cleptoparasitic lineages are most speciose in temperate zones. Female parasites frequently have a suite of characters that can be described as a masculinized feminine form. The evolution of resource specialization (including parasitism) in bees presents excellent opportunities to investigate phenotypic mechanisms responsible for evolutionary change.

Pheromonal cues direct mate-seeking behavior of maleColletes cunicularius (Hymenoptera: Colletidae).

Males of the vernal ground nesting bee,Colletes cunicularius, actively search their nesting aggregations for emerging virgin females. Males often detect and unearth preemergent virgin males and females which have not yet dug up to the soil surface. Field experiments indicate that the odors from one unmated individual are sufficient to both excite males and direct their excavation of the virgin bee. A volatile component of this species' mandibular gland secretion, linalool, increases flight activity and directs local search behavior in aerially patrolling males. Linalool is detectable by coupled gas chromatography-mass spectrometry in association with the digging activities of either sex.

Field method for sampling chemicals released by active insects.

An inexpensive, silent, maintenance-free suction/adsorption system is described for efficiently collecting submicrogram quantities of odors over a wide range of volatilities under field conditions. The samples can later be submitted to gas chromatographic-mass spectrometric analyses. An example is given with odors sampled from solitary bees engaged in digging and defensive behaviors at their nesting sites. Gas chromatograms of odor samples collected from known concentrations of synthetic chemicals are provided for standardization.

Chemistry and function of mandibular gland products of bees of the genusExoneura (Hymenoptera, Anthophoridae).

FemaleExoneura richardsoni, E. bicolor, andE. bicincta (Hymenoptera: Anthophoridae) release a pungent, staining liquid from their mandibular glands upon disturbance. This secretion is primarily composed of ethyl dodecanoate, with lesser amounts of homologous ethyl and methyl esters, salicylaldehyde, and 1,4-benzoquinone. The secretion elicits vigorous grooming when topically applied to antennae ofFormica ants. The shared, unique combination of mandibular gland lipids of these threeExoneura species supports their monophyletic classification, while the presence of salicylaldehyde may associateExoneura (Allodapini) withPithitis (Ceratinini).

Impact of enhanced ultraviolet-B radiation on flower, pollen, and nectar production.

Intensified ultraviolet-B radiation or UV-B (wavelengths between 280 and 320 nm) can delay flowering and diminish lifetime flower production in a few plants. Here we studied the effects of enhanced UV-B on floral traits crucial to pollination and pollinator reproduction. We observed simultaneous flowering responses of a new crop plant, Limnanthes alba (Limnathaceae), and a wildflower, Phacelia campanularia (Hydrophyllaceae), to five lifetime UV-B dosages ranging between 2.74 and 15.93 kJ·m·d. Floral traits known to link plant pollination with bee host preference, host fidelity and larval development were measured. Intensified UV-B had no overall effect on nectar and pollen production of L. alba and P. campanularia flowers. A quadratic relationship between UV-B and nectar sugar production occurred in P. campanularia and showed that even subambient UV-B dosages can be deleterious for a floral trait. Other floral responses to UV-B were more dramatic and idiosyncratic. As UV-B dosage increased, L. alba plants were less likely to flower, but suffered no delays in flowering or reductions to lifetime flower production for those that did flower. Conversely, an equal proportion of P. campanularia plants flowered under all UV-B treatments, but these same plants experienced delayed onset to bloom and produced fewer flowers at greater UV-B intensities. Therefore, intensified UV-B elicits idiosyncratic responses in flowering phenology and flower production from these two annual plants. Diurnal patterns in nectar and pollen production strongly coincided with fluctuating humidity and only weakly with UV-B dosage. Overall, our results indicated that intensified UV-B can alter some flowering traits that impinge upon plant competition for pollinator services, as well as plant and pollinator reproductive success.

Attraction of pinyon pine bark beetle,Ips hoppingi, to conspecific andI. confusus pheromones (Coleoptera: Scolytidae).

Females of a pinyon pine bark beetle,Ips hoppingi Lanier, were less attracted by the aggregation pheromone produced by conspecific males than by the pheromone produced by the neighboring sibling species,I. confusus (LeConte). Cross-attraction was elicited by males infesting the regional pinyon pine hosts (P. discolor andP. edulis) of eitherIps species in south-eastern Arizona. Pheromonal specificity has not accompanied speciation in this species pair.

Ancestral semiochemical attraction persists for adjoining populations of siblingIps bark beetles (Coleoptera: Scolytidae).

Three species ofIps pine bark beetles in Hopping's group IX (S.L. Wood'sgrandicollis group),Ips confusus, I. lecontei, andI. paraconfusus, are parapatrically distributed in the American Southwest. They share post-Pleistocene altitudinal ecotones with their host pines. Adjacent to these areas of host overlap, we tested the hypothesis that aggregation pheromones produced by male beetles and/or host volatiles are sufficient to elicit the speciesspecific colonization behaviors typical of these threeIps species in nature. A more distantly related species,I. pini (Hopping's group IV, S.L. Wood'spini group) was used for outgroup comparison. Under the influence of pheromone, males ofI. confusus andI. paraconfusus do not discern among unin-fested log bolts of host and nonhost pine prior to bark contact. Males responding to pheromones emanating from infested bolts are similarly undiscriminating. Females ofI. confusus andI. lecontei olfactorily discern the combination of conspecific males in host pine from other possible beetlepine combinations; females ofI. paraconfusus do not. FemaleI. pini discerned conspecific pheromone from that ofI. lecontei. The bark beetle predator,Enoclerus lecontei, is attracted by, but does not discriminate among, the male-produced volatiles of these Group IXIps species. These results support a hypothesis that divergence in pheromonal responses by these group IXIps species has evolved following their speciation, having been manifested first in the female sex. Evolutionarily, the derived pheromonal messages have preceded their behavioral discrimination by these beetles. Additional speciesspecific cues may operate between the sexes in the field that may preclude heterospecific pairings.

Interspecific pairing between two siblingIps species (Coleoptera: Scolytidae).

Host and conspecific discrimination were tested as reproductive isolating mechanisms betweenIps paraconfusus Lanier infestingPinus coulteri (Torrey) andI. confusus (Le Conte) infestingP. monophylla (Fremont). In two areas (one area largely Coulter pine and the other largely pinyon pine) where these bark beetles and hosts cooccur in southern California, we induced pheromone production in host and nonhost logs using males of each species.Ips paraconfusus females joined both heterospecific and conspecific males tunneling in both tree species in each area.Ips confusus females failed to joinI. paraconfusus males in Coulter pine, but joinedI. paraconfusus in pinyon pine. Sympatry was demonstrated when females of both sibling species joined conspecific males in their respective hosts. Males attacked all four beetlehost treatment combinations in both areas. Laboratory tests confirmed these results. Males did not displace heterospecific males from nuptial chambers in hosts, and they did not occupy a gallery in which heterospecific males produced frass. Females that left conspecific males in a host were readily accepted by heterospecific males and oviposited in a nonhost.

A comparative study of the exocrine products of cleptoparasitic bees (Holcopasites) and their hosts (Calliopsis) (Hymenoptera: Anthophoridae, Andrenidae).

The cephalic secretion of females of the cleptoparasitic beeHolcopasites calliopsidis contains two main volatiles, 6-methyl-5-hepten-2-one and geranyl acetone. The mandibular gland secretion of its host,Calliopsis andreniformis, on the other hand, contains the two isomeric forms of citral (neral and geranial). Neral and geranial are also produced by mandibular glands of two other species ofCalliopsis and one species in the related genusNomadopsis. The Dufour's gland ofC. andreniformis contains an oily secretion composed of hydrocarbons that are deposited on the brood cell walls and pollen balls providing a waterproof lining for both.

Exocrine secretions of bees : IV. Macrocyclic lactones and isopentenyl esters in Dufour's gland secretions ofNomia bees (Hymenoptera: Halictidae).

The volatile components of Dufour's gland extracts were analyzed in four species of NearcticNomia bees;Nomia (Dieunomia)heteropoda, N. (Tetrazonata)tetrazonata, N. (Epinomia)nevadensis, andN. (Epinomia)triangulifera. A homologous series of five saturated macrocyclic lactones ranging from C18 to C26 was identified. A series of esters (branched C5-alkenols and fatty acids) was also identified in all species investigated. Two of these esters are new natural products reported for bees. A discussion of the significance of the Dufour's gland secretion for halictid systematics and its function in the Halictidae is also presented.

The C. elegans vitellogenin genes: short sequence repeats in the promoter regions and homology to the vertebrate genes.

The nematode Caenorhabditis elegans contains a small family of vitellogenin genes which is expressed abundantly, but only in the intestine of the adult hermaphrodite worm. In order to identify possible regulatory elements, we have sequenced the DNA surrounding the 5' ends of five of the six genes. Contained within regions which have largely diverged from one another, two different heptameric sequences are found repeated within the first 200 bp upstream of each of the genes. The first sequence, TGTCAAT, is present as a perfect heptamer at least once upstream of each gene. It is repeated in both orientations four to six times in each 5' flanking region, allowing a one-base mismatch. The second sequence, CTGATAA, is also present as a perfect heptamer in a restricted region upstream of each gene. These two sequence elements may be involved in regulation of the vitellogenin genes. Remarkably, the CTGATAA sequence is present in a similar location in the promoter regions of vertebrate vitellogenin genes. In fact, our data reveal a surprising degree of similarity between the nematode and vertebrate vitellogenins.