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Conservation biological control is a fundamental tactic in integrated pest management (IPM). Greater biological control services can be achieved by enhancing agroecosystems to be more favorable to the presence, survival, and growth of natural enemy populations. One approach that has been tested in numerous agricultural systems is the deployment of synthetic chemicals that mimic those produced by the plant when under attack by pests. These signals may attract arthropod natural enemies to crop habitats and thus potentially improve biological control activity locally. A 2-yr field study was conducted in the cotton agroecosystem to evaluate the potential of synthetic methyl salicylate (MeSA) to attract native arthropod natural enemies and to enhance biological control services on two key pests. Slow-release packets of MeSA were deployed in replicated cotton plots season long. The abundance of multiple taxa of natural enemies and two major pests were monitored weekly by several sampling methods. The deployment of MeSA failed to increase natural enemy abundance and pest densities did not decline. Predator to prey ratios, used as a proxy to estimate biological control function, also largely failed to increase with MeSA deployment. One exception was a season-long increase in the ratio of Orius tristicolor (White) (Hemiptera: Anthocoridae) to Bemisia argentifolii Bellows and Perring (= Bemisia tabaci MEAM1) (Hemiptera: Aleyrodidae) adults within the context of biological control informed action thresholds. Overall results suggest that MeSA would not likely enhance conservation biological control by the natural enemy community typical of U.S. western cotton production systems.

Euwallacea fornicatus (Eichhoff), the polyphagous shot hole borer (PSHB), is an ambrosia beetle infesting avocado Persea americana Mill. limbs in North America and Israel. We conducted field experiments with sticky traps in avocado orchards to develop push–pull semiochemical methods of managing PSHB. Traps baited with 10-fold increasing doses (0.01 to 100× or 1.26 µg to 12.6 mg/d) of attractant quercivorol were previously shown to increasingly capture female PSHB (males flightless). We converted trap catch of this relationship to a standardized effective attraction radius (EAR) that predicts capture power of baited-traps regardless of insect flight density. Earlier, piperitone and verbenone were shown to strongly inhibit attraction of PSHB to quercivorol-traps. We tested increasing numbers of 1× piperitone dispensers at 0.75-m distance surrounding a quercivorol-trap and found PSHB catch to decline exponentially. Increasing decadic doses (0.01 to 10×) of either verbenone or piperitone released at 1× quercivorol-traps caused a sigmoidal first-order kinetic-decay in catch. Verbenone (1×) placed at increasing distances (0, 0.25, 0.5, 1, and 2 m) from a 1× quercivorol-trap became increasingly ineffective in reducing catch of PSHB. We found no evidence that ethanol released from 7.5 to 480 mg/d affected attraction of PSHB, but Scobicia chevrieri (Villa and Villa) (Coleoptera: Bostrichidae) was increasingly attracted. Due to their relatively short-range (

We characterized the seasonal composition and quality of migrant and non-migrant Pronghorn (Antilocapra Americana) diets in Yellowstone National Park during 2006–2007. During winter (January–April), when migrants and non-migrants occupied the same winter range, the overall percent relative density for each forage class in Pronghorn diets (n = 51 composite fecal samples) was 67 + 6% (standard error) shrubs, 17 + 3% forbs, 13 + 3% grasses, and 3 + 1% other. However, spring and summer diets differed for migrants and non-migrants. Diets of migrants (n = 34) to higher-elevation ranges with higher precipitation and forage quality during May–August were dominated by 68 + 2% forbs, whereas summer diets of non-migrants (n = 21) remaining on the winter range were co-dominated by 48 + 2% forbs and 42 + 1% shrubs. Diet quality for migrant Pronghorn, as indexed by fecal nitrogen and DAPA, was also generally higher than for non-migrants during a period when the demands of late gestation and lactation were high...

The Euwallacea sp. near fornicatus (Euwallacea sp. 1 hereafter) feeds on many woody shrubs and trees and is a pest of avocado, Persea americana Mill., in several countries including Israel and the United States. Quercivorol baits are commercially available for Euwallacea sp. 1 females (males do not fly), but their attractive strength compared to other pheromones and potential for mass trapping are unknown. We used sticky traps baited with quercivorol released at 0.126 mg/d (1×) and at 0.01×, 0.1×, and 10× relative rates to obtain a dose-response curve of Euwallacea sp. 1 attraction. The curve fitted well a kinetic formation function of first order. Naturally infested limbs of living avocado trees had attraction rates equivalent to 1× quercivorol. An effective attraction radius (EAR) was calculated according to previous equations for each of the various baits (1× EAR = 1.18 m; 10× EAR = 2.00 m). A pole with six sticky traps spaced from 0.25-5.75 m in height had captures of Euwallacea sp. 1 yielding a mean flight height of 1.24 m with vertical flight distribution SD of 0.88 m (0.82-0.96 m, 95% CI). The SD with specific EAR was used to calculate EARc, two-dimensional EAR (1× EARc = 0.99 m; 10× EARc = 2.86 m), for comparison with other insect pheromone traps and for use in simulations. The simulation methods described previously were performed with combinations of 1-16 traps with 1-50 aggregations per 9-ha plot. The simulations indicate mass trapping with quercivorol could be effective if begun in spring before Euwallacea sp. 1 establishes competing sources of attraction.

After a bottleneck in a closed population of pronghorn (Antilocapra americana), some inbred matings occurred, and we detected significant inbreeding depression. But inbred matings occurred less frequently than would be expected by chance. Pronghorn females chose mates after a sampling period and had complete control of the mating decision. Therefore, to discover the behavioral mechanism by which females avoided mating with close kin, we studied female movements and courtship sequences. When females moved from one harem to another in the sampling process, they did not shift to harem males of lower coancestry as they approached estrus. Rather, females progressed more slowly through the later courtship stages when the harem male was related vs. unrelated. Also, the rates of male courtship acts were higher within unrelated vs. related pairs. Some females appeared to use multiple mating as an inbreeding avoidance strategy. Our results suggested that inbreeding avoidance by female pronghorn occurred primarily by reactions to the late stages of male courtship, rather than by spatial avoidance of related males.

Animal species likely have different strengths of host habitat preference (HHP) that might be characterized by a standardized index ranging from 0 (no preference) to 1 (maximum preference). We hypothesized that in some species, HHP may result from individuals dispersing out of the host habitat having a probability of turning back at the boundary, or after entering host habitat by reducing speed or increasing size of turning angles. Computer simulations of individuals moving between various sized patches of host and nonhost habitat were conducted based on these three behaviours hypothesized to affect HHP. In the rebounding model, simulations resulted in equilibria of animal numbers inside and outside of host habitat that depend on sizes of these areas, initial number and the rebounding probability. Curvilinear regression of simulation results suggested an equation that predicted numbers in the host habitat and was solved for rebounding probability. A modified equation that sampled population densities (e.g., insect pheromone trap catches) inside and outside host habitat areas gave the rebounding probability, an index of HHP, without requiring the sizes of the areas. Simulations with traps and moving animals verified that the modified equation could predict the index correctly. The modified equation also estimates an index of HHP from sampled densities due to speed reductions and a combination of this and rebounding. Changes in angular turning size upon entering host habitat, however, did not affect habitat preference. Using pheromone trap captures, we found that the lesser date moth Batrachedra amydraula has a HHP for date Phoenix dactylifera plantations of 0.96. Host habitat preference indexes also were calculated from sampled insect densities reported in the literature. The new index of HHP is useful to characterize habitat patches of many organisms and aid understanding of animal spatial distributions and speciation processes. In addition, the index can be applied in studies of invasive species, trap crops of pest insects and conservation management.

The Trivers–Willard hypothesis (TWH) predicts that in a polygynous mating system, when fitness of male offspring is more variable than fitness of female offspring, mothers should invest more heavily in the sex with the highest marginal fitness returns. Females in good condition or high social rank should benefit by investing in sons, and females in poor condition or low social rank should benefit by investing in daughters. Many empirical studies have tested different aspects of the TWH, but no study has tested the assumptions and predictions in a single polygynous species using measures of maternal condition and maternal social rank, while accounting for random effects that can also influence offspring growth and survival. Here, we followed individuals in an isolated population of pronghorn on the National Bison Range, Montana, over multiple generations and tested the assumptions and predictions of the TWH. Pronghorn females who were in good condition or were socially dominant weaned larger fawns that were in better condition, but this advantage did not increase male fawn survival or reproductive success. We detected a slight bias in birth sex ratios according to maternal social rank, but overall we did not detect any adaptive benefit to mothers adopting a sex-biased investment strategy.

Passive mechanisms of mate guarding are used by males to promote sperm precedence with little cost, but these tactics can be disadvantageous for their mates and other males. Mated females of the plant bug Lygus hesperus are rendered temporarily unattractive by seminal fluids containing myristyl acetate and geranylgeranyl acetate. These antiaphrodisiac pheromones are gradually released from the female’s gonopore, declining until they no longer suppress male courtship. Because starting quantities of these compounds can vary widely, the repellant signal becomes less reliable over time. Evidence was found of a complimentary mechanism that more accurately conveys female mating status. Once inside the female, geranylgeranyl acetate is progressively converted to geranylgeraniol then externalized. Geranylgeraniol counteracts the antiaphrodisiac effect despite having no inherent attractant properties of its own. This is the first evidence for such an anti-antiaphrodisiac pheromone, adding a new element to the communication mechanisms regulating reproductive behaviors. DOI: http://dx.doi.org/10.7554/eLife.24063.001, eLife digest In many animal species, males guard females to prevent rivals from mating so that they can be sure that they fathered the female’s offspring. Some guarding methods work even when the male is not present. For example, the semen of some male insects contains chemicals known as antiaphrodisiacs that repel other males from females who have recently mated. Over the course of several days or weeks, the females expel or degrade the antiaphrodisiacs, making themselves attractive to other mates again. How long it takes to eliminate the antiaphrodisiacs depends on how much of the chemicals were deposited in the first place. Therefore, males could gain an advantage in fertilizing more eggs by depositing excess antiaphrodisiac to make the females unattractive to other mates for a long time. The Western tarnished plant bug (Lygus hesperus) is an agricultural pest that targets cotton, strawberries and other crops. One antiaphrodisac had already been identified in the semen of male Lygus bugs. To investigate whether the males produced any others, Brent et al. tested the molecules emitted by recently mated females. This search identified another potential antiaphrodisiac. However, females are able to convert this second chemical into a third one that neither attracts nor repels males. This “anti-antiaphrodisiac” acts against the males’ two antiaphrodisiacs, and allows the females to more accurately signal when they are ready to mate again, giving them more control over their reproduction. Anti-antiaphrodisiacs were not previously known to exist, but now that scientists know where to look, more are likely to be found in other species. A better understanding of how different chemicals interact to influence the mating behavior of insects could also lead to new methods of targeting pests of crops, which are safer for the environment than existing chemical pesticides. DOI: http://dx.doi.org/10.7554/eLife.24063.002

Phenotypic plasticity in reproductive traits is of theoretical and applied interest as one avenue by which organisms might maintain an optimal annual reproductive routine in the face of cyclic and/or directional change in environmental conditions. We used long‐term, individual‐based data from parapatric populations of bighorn sheep (Ovis canadensis canadensis) and pronghorn (Antilocapra americana) to evaluate plasticity in breeding date, gestation duration, birth date, birth mass, and fetal growth rate in response to inter‐annual (cyclic) variation in indices of maternal energy income and expense. Traits in both species responded plastically to variation in maternal energy balance. However, despite nearly identical climate and similar vegetative habitat, plasticity was expressed in fundamentally different ways in the study species. Variation in bighorn birth date was primarily due to plasticity in breeding date, whereas variation in pronghorn birth date was primarily due to variation in gestation duration. Across traits, bighorn plastic responses were more consistent with explanations that invoked periodic energy surplus as the basis for plasticity, whereas pronghorn plastic responses were more consistent with explanations that invoked periodic energy deficiency. Later birth date was associated with increased fetal growth rate in bighorn but decreased fetal growth rate in pronghorn. Finally, we detected strong directional selection for early birth among bighorn mothers but found no evidence of selection on pronghorn birth date. Collectively, our results indicate markedly different maternal tactics for timing birth. Bighorn mothers appeared to use stored energy to subsidize the cost of birth prior to the local environmental optimum in an energy‐mediated competition with other females to minimize birth order rank. Pronghorn mothers, committed to high levels of energy allocation to offspring and subject therefore to frequent energy deficiency, timed birth conservatively to more closely match peak reproductive expenditure with peak energy income at the local environmental optimum.

Summary 1. The pink bollworm moth Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) is one of the most destructive pests in agriculture. An ongoing eradication program using a combination of sex pheromone monitoring and mating disruption, irradiated sterile moth releases, genetically modified Bt cotton and local insecticide applications have all but exterminated the pink bollworm from the south-western USA and portions of northern Mexico. However, the continued threat of reinvasion from Mexico reinforces the need to improve pheromone-based monitoring. Invasions from other parts of the world such as India, where resistance to single-gene transgenic Bt cotton has evolved, further heightens the need for better monitoring strategies. 2. The mean flight height and standard deviation (SD) of the vertical flight distribution of pink bollworm males were estimated from catches on transparent sticky cylinder traps baited with synthetic pheromone at several heights above-ground. An effective attraction radius (EAR) of a standard pheromone lure was estimated from male moth catches on the pheromone-baited sticky traps and many similar blank traps. The circular EARc was estimated from the spherical EAR and SD. 3. The EAR of a pheromone lure for pink bollworm was 1� 03 m, and the EARc was 2� 61 m. The mean flight height of males was 0� 82 m, and the vertical flight distribution SD was 0� 26 m. 4. A computer program simulated male moth movement and capture on various numbers of traps of EARc distributed over areas of 1–100 km 2 . The simulated catch results were comparable to predictions using the EARc with modified encounter rate equations of Royama and Rogers. The encounter rate equations were solved for initial populations of male moths in the regions, and Poisson statistics were used to calculate population confidence limits. 5. Synthesis and applications. Encounter rate models and Poisson methods can be used to determine levels of pheromone trap densities that are likely to detect and estimate low population levels of resident or invasive pink bollworms and many other pest insect species.

Individual behavior promotes genetic structure within many mammalian populations, yet few studies have explored coarse- and fine-scale structure associated with migration. Fewer still have considered the conservation implications of such structure in at-risk populations. Pronghorn ( Antilocapra americana ) inhabiting Yellowstone National Park are partially migratory, and strong adult fidelity to migratory strategy and breeding areas may promote social and genetic structure within this population. We used 18 nuclear DNA microsatellite loci and fecal samples from 47 individuals to quantify group divergence and pairwise relatedness of Yellowstone pronghorn. The genetics of this population are characterized by individual isolation by distance ( P = 0.009). Evidence for fine-scale social and genetic structure was strong, with mean relatedness between individuals declining rapidly with geographic distance (0–3 km) within areas selected by both migrants and non-migrants. On average, females sampled within social groups were related at the level of first cousins (mean R = 0.105 ± 0.192 SD). We found low differentiation of the population by migratory strategy ( F ST = 0.019), moderate differentiation among some summer use areas ( F ST ⩾ 0.033), and an excess of heterozygotes within all migrant groups ( F IS ⩽ −0.017). Weak and inconsistent substructure was detected using spatial and aspatial Bayesian clustering methods. Our results are the first to document fine-scale social and genetic structure in pronghorn, most likely organized along matrilines. Access to a majority of the total summer range available to this population is maintained by social inheritance and individual fidelity to areas of use. The maintenance and reestablishment of migratory routes may therefore hinge on the retention of experienced individuals, the strength of natal and adult philopatry, and the accessibility of seasonal habitat to pioneering females.

Dose-response curves of the effects of semioche- micals on neurophysiology and behavior are reported in many articles in insect chemical ecology. Most curves are shown in figures representing points connected by straight lines, in which the x-axis has order of magnitude increases in dosage vs. responses on the y-axis. The lack of regression curves indicates that the nature of the dose-response relationship is not well understood. Thus, a computer model was developed tosimulateafluxofvariousnumbersofpheromonemolecules (10 3 to 5×10 6 ) passing by 10 4 receptors distributed among 10 6 positions along an insect antenna. Each receptor was depolarized by at least one strike by a molecule, and subse- quent strikeshad noadditionaleffect.Thesimulationsshowed that with an increase in pheromone release rate, the antennal response would increase in a convex fashion and not in a logarithmic relation as suggested previously. Non-linear re- gression showed that a family of kinetic formation functions fit the simulated data nearly perfectly (R 2 >0.999). This is reasonable because olfactory receptors have proteins that bind to the pheromone molecule and are expected to exhibit en- zyme kinetics. Over 90 dose-response relationships reported in the literature of electroantennographic and behavioral bio- assays in the laboratory and field were analyzed by the loga- rithmic and kinetic formation functions. This analysis showed that in 95 % of the cases, the kinetic functions explained the relationships better than the logarithmic (mean of about 20 % better). The kinetic curves become sigmoid when graphed on a log scale on the x-axis. Dose-catch relationships in the field are similar todose-EAR(effectiveattractionradius,inwhicha spherical radius indicates the trapping effect of a lure) and the circular EARc in two dimensions used in mass trapping models. The use of kinetic formation functions for dose- response curves of attractants, and kinetic decay curves for inhibitors, will allow more accurate predictions of insect catch in monitoring and control programs.

Simulation models of insects encountering sex pheromone with or without mass trapping in which the searching sex is either male (moths and many insect species) or female (some true bugs, beetles, and flies) were developed. The searching sex moved as a correlated random walk, while the opposite sex remained stationary (calling) and released an attractive sex pheromone. The searching sex was caught when encountering a pheromone-baited trap, and females mated when encountering a male. Anencounterwith pheromone was defined by the searcher’s interceptionofa circletermedtheeffective attraction radius (EARc). Parameters of movement (speed and duration), initial numbers of calling sex and searching sex, number of traps, area, and EARc of traps and calling sex were varied individually to evaluate effects on the percentage of females mating. In the natural condition without traps, female mating success in both models was identical. Increasing the EARc of the calling sex caused diminishing increases in female mating success, suggesting that evolution of larger pheromone release and EARc is limited by increasing costs (production/sensitivity) relative to diminishing increases and benefits of mating encounters. With mass trapping, increasing the EARc of traps or density of traps caused similar declines in female mating in both models, but the female-searching modelpredictedslightlylower matingsuccess thanthe male-searching model. Increasingthe EARcof calling insects or the initial density of insects caused similar increases in female mating in both models, but again the female-searching model had slightly lower mating success than the malesearching model. The models have implications for mating lek formation and for understanding the variables affecting the success of mass trapping programs for insect pests with either male or female sex pheromones.

The existence of a direct link between intensity of sexual selection and mating-system type is widely accepted. However, the quantification of sexual selection has proven problematic. Several measures of sexual selection have been proposed, including the operational sex ratio (OSR), the breeding sex ratio (BSR), and the opportunity for sexual selection (I(mates)). For a wild population of pronghorn (Antilocapra americana), we calculated OSR and BSR. We estimated I(mates) from census data on the spatial and temporal distribution of receptive females in rut and from a multigenerational genetic pedigree. OSR and BSR indicated weak sexual selection on males, but census and pedigree I(mates) suggested stronger sexual selection on males than on females. OSR and BSR correlated with census but not pedigree estimates of I(mates), and census I(mates) did not correlate with pedigree estimates. This suggests that the behavioral mating system, as deduced from the spatial and temporal distribution of females, does not predict the genetic mating system of pronghorn. The differences we observed between estimators were primarily due to female mate sampling and choice and to the sex ratio. For most species, behavioral data are not perfectly accurate and therefore will be an insufficient alternative to using multigenerational pedigrees to quantify sexual selection.

The mean height and standard deviation (SD) of flight is estimated for over 100 insect species from their catches on several trap heights reported in the literature. The iterative equations for calculating mean height and SD are presented. The mean flight height for 95% of the studies varied from 0.17 to 5.40 m, and the SD from 0.12 to 3.83 m. The relationship between SD and mean flight height (X) was SD = 0.711X(-0.7849), n = 123, R(2) = 0.63. In addition, the vertical trap catches were fit to normal distributions and analyzed for skew and kurtosis. The SD was used to calculate an effective flight layer used in transforming the spherical effective attraction radius (EAR) of pheromone-baited traps into a circular EAR(c) for use in two-dimensional encounter rate models of mass trapping and mating disruption using semiochemicals. The EAR/EAR(c) also serves to reveal the attractive strength and efficacy of putative pheromone blends. To determine the reliability of mean flight height and SD calculations from field trapping data, simulations of flying insects in three dimensions (3D) were performed. The simulations used an algorithm that caused individuals to roam freely at random but such that the population distributed vertically according to a normal distribution of specified mean and SD. Within this 3D arena, spherical traps were placed at various heights to determine the effects on catch and SD. The results indicate that data from previous field studies, when analyzed by the iterative equations, should provide good estimates of the population mean height and SD of flight.

Spring and summer-autumn nutrition are the prime determinants of reproductive investment in most largeherbivore populations, though winter severity is known to affect reproductive rates in some situations. To evaluate the effects of a long-term decline in winter habitat quality, a diet shift away from sagebrush (Artemisia spp.) during winter, and differential habitat selection during spring-autumn on pronghorn (Antilocapra americana) reproduction, we assessed female and fawn condition, maternal investment, and early fawn survival in migrant and nonmigrant portions of the Yellowstone pronghorn population in Montana and Wyoming during 1999–2001. Mean female mass at capture in late winter (46.81 kg, SE = 0.66), pregnancy rate (0.94, SE = 0.03), date of birthing (median = 1 June), litter size (1.90, SE = 0.07), ratio of litter mass to maternal mass (0.134, SE = 0.005), fawn mass at birth (3.08 kg, SE = 0.07), and fawn survival to August (0.15, SE = 0.04) were within the ranges reported for populatio...

Mitigation of predation risk promotes high-elevation dispersion prior to birthing in many ungulate populations. Coyotes (Canis latrans) account for nearly 80% of pronghorn (Antilocapra americana) fawn mortality in Yellowstone National Park, but reintroduced gray wolves (Canis lupus) and factors associated with mountainous terrain can strongly influence space use by predators during summer and are likely to underlie significant spatial variation in survival rates of pronghorn fawns. We used generalized logit models paneled by maternal identity to assess the relative and interactive influences of summer wolf density, winter snow depth, and terrain slope on survival of pronghorn fawns in Yellowstone during 1999–2001 and 2004–2006. In this partially migratory population only migrant pronghorn accessed areas where wolves were numerous and winter snow depths were high. Survival of migrant fawns was higher in areas that experienced deep winter snow and had steeper slope. The influence of wolves on fawn survival was positive only in areas of low winter snowfall where coyotes were abundant, supporting predictions of a coyote-mediated effect of wolves and winter snowfall on pronghorn reproductive success. Our results suggest that deep winter snow, coupled with constraints on mobility imposed by reproduction in populations of social carnivores, can lead to the formation of highelevation refugia for migrant ungulates. This research offers novel insights into the indirect effects of wolf restoration and climatic factors on the Yellowstone predator–prey complex and a conceptual framework for examining the ecological effects in other mountain communities of restoration of, and seasonal space use by, large carnivores. DOI: 10.1644/09-MAMM-A-057.1.

Yellowstone National Park supports a small population (

The long-term viability of small, isolated populations has been questioned in light of stochasticity and bottlenecks. Following a drought in northwestern Montana in 2003, the pronghorn (Antilocapra americana )o f the National Bison Range experienced a demographic bottleneck. We used information theoretic approaches to examine the influence of sex, age, genetic variation, summer lactation, mate-search effort by females, and mating effort by males on subsequent winter survival and spring fecundity. Survival of males was influenced by age, whereas survival of females was influenced by prior energy expenditure and genetic variation, implicating inbreeding depression as the mechanism. Fecundity of females also was influenced by prior energy expenditure and genetic variation, with heterosis as the apparent mechanism. Our results agree with those of other studies that have emphasized the need to maintain genetic variation and limit inbreeding in small, isolated populations, and to account for stochasticity in population viability assessments and long-term management planning.

The release rate of a semiochemical lure that attracts flying insects has a specific effective attraction radius (EAR) that corresponds to the lure's orientation response strength. EAR is defined as the radius of a passive sphere that intercepts the same number of insects as a semiochemical-baited trap. It is estimated by calculating the ratio of trap catches in the field in baited and unbaited traps and the interception area of the unbaited trap. EAR serves as a standardized method for comparing the attractive strengths of lures that is independent of population density. In two-dimensional encounter rate models that are used to describe insect mass trapping and mating disruption, a circular EAR (EAR(c)) describes a key parameter that affects catch or influence by pheromone in the models. However, the spherical EAR, as measured in the field, should be transformed to an EAR(c) for appropriate predictions in such models. The EAR(c) is calculated as (pi/2EAR(2))/F (L), where F (L) is the effective thickness of the flight layer where the insect searches. F (L) was estimated from catches of insects (42 species in the orders Coleoptera, Lepidoptera, Diptera, Hemiptera, and Thysanoptera) on traps at various heights as reported in the literature. The EAR(c) was proposed further as a simple but equivalent alternative to simulations of highly complex active-space plumes with variable response surfaces that have proven exceedingly difficult to quantify in nature. This hypothesis was explored in simulations where flying insects, represented as coordinate points, moved about in a correlated random walk in an area that contained a pheromone plume, represented as a sector of active space composed of a capture probability surface of variable complexity. In this plume model, catch was monitored at a constant density of flying insects and then compared to simulations in which a circular EAR(c) was enlarged until an equivalent rate was caught. This demonstrated that there is a circular EAR(c), where all insects that enter are caught, which corresponds in catch effect to any plume. Thus, the EAR(c), based on the field-observed EAR, can be used in encounter rate models to develop effective control programs based on mass trapping and/or mating disruption.

Western flower thrips, Frankliniella occidentalis (Pergande), and onion thrips, Thrips tabaci Lindeman, are economic pest insects of head lettuce, Lactuca sativa L, and dehydrator onions, Allium cepa L, in the Imperial Valley, California. Colored sticky traps were evaluated as potential detection and monitoring devices of the two thrip species over a two-month period in 2006. Results showed that blue sticky card traps consistently captured more adult thrips of both species compared to yellow sticky card traps. Numbers of thrips captured on blue sticky traps were positively correlated to numbers captured on yellow sticky traps. Adult thrips were captured in much higher numbers on sticky card traps than recovered from whole plant samples. Significant negative correlations between F. occidentalis numbers on plant samples and colored sticky traps suggest that adults left lettuce plants and were attracted to nearby traps In addition, the numbers of thrips caught on traps relative to estimated plant po...

Many insects repel predators with caustic chemicals, while insects mimicking odors of wastes/dead insects to fool predators have not been documented. We found that the shore earwig, Labidura riparia (Dermaptera: Labiduridae) when bitten by anole lizards, Anolis carolinenesus, spits a rotting-flesh odor that deceives these insectivores into rejecting prey. Once a lizard attacked and rejected an earwig, the lizard did not attack another earwig during several weeks despite consuming other prey, indicating associative learning after one trial. The fetid odor was found in the head-prothorax containing salivary glands of both male and female earwigs and was comprised of ∼ 100 ng dimethyl disulfide and ∼ 600 ng dimethyl trisulfide. Nymphs had5 ng of either compound. Adults also spit odorous sulfides after prolonged attacks by harvester ants, Pogonomyrmex rugosus, who were only deterred by the earwig's forceps. Sulfides released by the earwig are similar to odors of carrion/feces, which may be innately repulsive to some vertebrate predators. The mean initial discharge percentage (IDP) of sulfides from a cohort of earwigs was 62 %; however, IDPs of individuals were highly variable (3-99 %; mean 57 %). The discharge refill time (DRT) to refill 50 % of the earwig's allomone reservoir was estimated at 13 h. A positive relationship in sulfide amounts with body weight was found only in females in 2009, suggesting metabolic cost tradeoffs were revealed when sulfide content was half that in 2010. This is the first report of insects releasing sulfur-containing compounds that may mimic carrion-fecal odors as a deceptive defense against vertebrate predators.

Although a variety of species exhibit birth-site fidelity, examples from ungulate species are rare. We recorded birth-site locations of pronghorns (Antilocapra americana) at the National Bison Range in northwestern Montana during 2000–2004 and found that 82% of females changed locations from the previous year. Females that exhibited birth-site fidelity had successfully weaned more fawns and were less likely to have experienced a fawn mortality event in the previous year than females that changed birth sites. Females that weaned a single fawn or weaned 0 fawns were equally likely to change birth sites. There was a year effect on distribution of birth sites as well as on birth-site fidelity. Dry range conditions in 2003 after multiple years of low precipitation may have caused more females to move their birth sites to areas of greater forage availability. The low observed frequency of birth-site fidelity may be a result of high fawn mortality rates at the National Bison Range. Success in the previo...

Although multiple paternity has been observed in various groups of mammals with litter sizes >1, it has not been documented in wild ungulate populations. With the use of DNA microsatellites, we investigated multiple paternity in pronghorn (Antilocapra americana) at the National Bison Range. Females in this population twin every year, and we were able to assign paternity to 25 sets of twins sired in 1999 and 2000, eleven (44%) of which were fathered by different males. Complex female mate choice is the most likely explanation for the observed pattern; however, sperm competition might contribute if a female has mated multiple times. This study represents the 1st reported example of multiple paternity in a natural ungulate population and indicates that some aspects of mammalian mating systems still are not fully understood.

Sexual Versus Natural Selection In a 1948 experiment with Drosophila , Angus Bateman showed that sexual selection is strongest in males (versus females) because the number of mates they obtain is correlated with the number of offspring they produce. This relationship between mate number and offspring number has since become known as the Bateman slope, but there has been much debate concerning whether such a relationship can be expected in nature. Using a 30-year data set collected from a closed population of pronghorn antelope in Montana, Byers and Dunn (p. 802 ; see the Perspective by Wade ) show that the relationship between mate number and offspring number indeed provides an opportunity for strong sexual selection in this polygynous and dimorphic species—however, environmental effects can make such selection null. In years when coyote predation on newborn fawns was high, sexual selection could not operate and reproductive success was instead determined by natural selection.

Animal movement and dispersal can be described as a correlated random walk dependent on three parameters: number of steps, step size, and distribution of random turning angles. Equations of Kareiva and Shigesada use the parameters to predict the mean square displacement distance (MSDD), but this is less meaningful than the mean dispersal distance (MDD) about which the population would be distributed. I found that the MDD can be estimated by multiplying the square root of the MSDD by a three-dimensional surface correction factor obtained from simulations. The correction factors ranged from 0.89 to 1 depending on the number of steps and the variation in random turns, expressed as the standard deviation of the turning angles (SDA) about 0° (straight ahead). Corrected equations were used to predict MDDs for bark beetles, butterflies, ants, and beetles (based on parameters from the literature) and the nematode Steinernema carpocapsae (Weiser). Another equation from the literature finds the MDD directly, and this agreed with the MDD obtained by simulation at some combinations of SDA and numbers of steps. However, the equation has an error that increases as a power function when the standard deviation of turning angles becomes smaller (e.g.

Larger bark beetles such as Ips typographus (Coleoptera: Scolytidae) fly at abou t2ms 1 for up to several hours. Computer simulations in two dimensions showed that bark beetles are capable of dispersing from a brood tree over wide areas while drifting with the wind. For example, if beetles take an angle of maximum turn (AMT) at random up to 10° either left or right each second, about 90% of the beetles become distributed over a 31.9 km 2 area after 1 h of flight. Larger maximum turning angles by beetles decrease the area of dispersal in proportion to the reciprocal of the square of the AMT. An increase in the dispersal time causes a linear increase in dispersal area and downwind drift distance, while increases in wind speed have no affect on the ultimate dispersal area but do increase the drift distance. Dispersal of bark beetles in a 1010 km forest of 5 million trees of 0.15 m trunk radius, corresponding to the natural density and trunk size of a 70-year-old Norway spruce forest (Picea abies), was simulated by spacing trees at appropriate density in a 50 m radial area centred on a beetle. A new area with trees was constructed similarly whenever the beetle left the former area. These simulations showed trees reduced the size of the dispersal area by 11% and downwind drift by 18% afte r1ho fflight due to the effect of turning some beetles back toward the release point, similar to the effects of increasing the AMT. The average dispersal distance and downwind distance decreased as linear functions of trunk density. Given step size, number of steps, and AMT, the correlated random walk equation of Kareiva and Shigesada [1983, Oecologia 56, 234‐238] predicts mean squared dispersal distance. This can be transformed to the more meaningful average dispersal distance by taking the square root and multiplying by a proportion obtained from a three dimensional surface equation fitted from simulation results. © 2000 Elsevier Science B.V. All rights reserved.

Results were analyzed from six previous studies in which marked bark and ambrosia beetles, Ips typographus, I. paraconfusus, and Trypodendron lineatum (Coleoptera: Scolytidae), were released at the center of concentric rings of pheromone traps. Assuming nearly straight flight paths, a “filtering” equation model predicts recapture percentages on several trap rings of specified radii, trap numbers, and effective attraction radius (EAR) of a pheromone trap. Equations were used to calculate recapture percentages on concentric trap rings as a function of increasing EAR and gave polynomial relationships for each ring with terms equal to the number of inner rings plus one. Results were confirmed by computer simulations. Filtering equations were iterated with increasing EAR values to find one that gave a recapture percentage for the innermost trap ring that matched the field results. The estimated EAR for a synthetic pheromone bait of I. typographus was similar in five tests (range 1.39–1.78 m), but in two other tests was larger (3.27 and 15.9 m). The EAR for pheromone of 75 male I. paraconfusus in ponderosa pine logs ranged from 0.35 to 34.5 m (mean of 4.7 m) and was generally larger for previously pheromone-responding beetles than for freshly emerged ones. For T. lineatum, the EAR of lineatin-baited traps at 100-m radius was 2.43 m. Recaptures of I. typographus were reasonably predicted by the estimated EARs in the filtering model. To obtain perfect fits, another model assumed the EAR could vary with ring radius (dispersal distance) and found that the EAR for I. typographus decreased with dispersal distance in four experiments, but increased or was variable in two others. However, in I. paraconfusus and T. lineatum, the EAR increased with dispersal distance. Simulations that varied combinations of the EAR and random angles of maximum turning (AMT) of beetles stepwise showed that a nearly straight flight path for I. typographus explained observed catches on trap rings best, while a higher AMT of 36° was better to explain catches of T. lineatum. Simulations show that catch per trap ring in relation to radial distance can be influenced by the beetle's AMT (still unobserved in the field). A conceptual model of dispersal and host selection in “aggressive” bark beetles with regard to pioneer and joiner colonization strategies is presented.

Whether the mate sampling and choice performed by females in nature influences offspring performance is a controversial issue in theory and an open empirical question. Pronghorn ( Antilocapra americana ) females engage in an obvious and energetically expensive mate sampling process to identify vigorous males. Although individual females sample independently, their choices converge on a small proportion of males that sire most young. Offspring of attractive males were more likely to survive to weaning and to age classes as late as 5 years, resulting in a selection differential, calculated by expected differences in lifetime number of offspring weaned, of 0.32 against random mating. Enhanced survival to weaning appeared to be accomplished by faster growth rates. Females compensated for matings with a less attractive mate by elevating rates of milk delivery to their young. Because pronghorn males do not have costly ornaments, we conclude that female choice for good genes can exist in the absence of ornaments. Furthermore, female choice may be important and unrecognized as a force that can lower population genetic load.

Because of scientific, management, and ethical considerations, it is important to know if capture and handling of neonatal ungulates increases their mortality risk. At the National Bison Range in northwestern Montana, where coyotes annually kill many young, I captured and marked young pronghorns (Antilocapra americana) in most years from 1981 to 1996 and recorded the number that were born and the number that survived to weaning each year. Mortality of young was ≥56% in all years, and the number of coyotes removed from the range of pronghorns in May and June was significantly correlated with the percentage of young that survived. Capture effort varied from none to intense among years, and not all young were captured in any year. I found no evidence that mortality risk was increased due to handling. With proper precautions, one may handle young pronghorns without exposing them to additional risk.

The sequence of arrival of the bark beetlesIps typographus andPityogenes chalcographus (Coleoptera: Scolytidae) at traps baited with their synthetic pheromones was monitored with a portable fraction collector. Histograms of the natural arrival patterns of both species were nonrandom and clumped at shorter time scales (1-, 2-, 4-, 5-, or 6-min cells) but appeared random at larger time scales (10, 20 or 30 min). Monte Carlo generation of similar histograms showed them to be random at all of these time scales. A stochastic computer model could graphically simulate insect orientation to odor sources based on present theories of odor-modulated anemotaxis and casting. Although this model was used throughout, since it assumes only that insects cast perpendicular to the current wind direction, a second model could slightly improve orientation success. However, the second model requires that the insect remember its ground path (upwind) prior to losing the plume (after an abrupt wind direction change). The effects of casting and flight parameters on orientation success and randomness of arrival sequence within various plumes were determined by simulation. Similarly, the effects of random walks in plume direction, plume width, and wind speed were explored. The results showed that dynamic random variations in plume direction and especially wind speed could cause an otherwise random arrival sequence (e.g., under constant wind) to become clumped and nonrandom. Therefore, the clumped arrival patterns of bark beetles and other insects, includingSpodoptera litura, at pheromone sources could result from random-walk fluctuations in wind speed and wind direction.

Iterative equations were developed that predict the encounter rate between a population of moving animals and a population of stationary objects, where the animals cease to search upon finding an object. The encounter rate through time depends on the number of searching animals (bark beetles), number of stationary objects (host trees), average speed of the animals, average radius of the object, and area of the search arena. The iterative equations were used in a computer program to vary these parameters with regard to flight dispersal of the bark beetle Ips ~pographus (Coleoptera: Scolytidae) during their search for susceptible host trees of Norway spruce (Pica abies). Realistic parameters of flight speed, numbers of beetles and susceptible host trees, tree diameters, density of healthy trees, search area, and time searching were held constant while certain of these parameters were varied in computer model runs. In most cases, significant proportions of the modeled bark beetle population (of which individuals fly forward with a random component) found the relatively few susceptible host trees suitable for colonization. Only at very low effective flight speeds (due to longer stays on trees) or with widely distributed hosts of smaller diameter, did relatively few beetles find suitable hosts. Once the 'pioneer' beetles find susceptible hosts, release of aggregation pheromone would greatly increase the effective radius of the host and allow rapid concentration of the population on these trees. The model suggests that primary attraction to host tree volatiles is not mandatory for host finding and selection in many species of bark beetle. Evolution of an olfactory response to host volatiles is more probable in species with low population densities or widely dispersed host plants, or both. Also, there would be little selection pressure on a bark beetle species to evolve aggregation pheromones if they can respond over some meters to plant volatiles that reveal the location of a susceptible host.

Abstract. At the National Bison Range (western Montana, U.S.A.) mate choice by female pronghorn, Antilocapra americana , is clearly observable. Females move independently, and copulate once per oestrus. Males cannot force copulation, only temporarily block female movement, and do not monopolize resources critical to females. Females practice three distinct strategies of mate choice. 'Sampling' females visit several harem-holding males, remain with each male a short time, and switch between males at an increased rate as oestrus approaches. Switches often appear to be energetically expensive. The actual mating visit is brief, about 1·5 days. Sampling females always leave males that fail to defend an adequate zone of tranquillity around the harem, but also leave males when there is no apparent cause. The majority (71%) of exits from males are of the latter type. Most sampling females return to and mate with a male that they visited within the week before oestrus. 'Inciting' females behave as samplers until oestrus; then they move away from the harem male, inciting fights and other aggressive competitition. Inciting females watch the competition, and they always mate immediately with the winning male. Finally, a small proportion of females each year practise a 'quiet' strategy. More than a month before oestrus, they move to an isolated, peripheral location occupied by a single male, and remain with that male throughout oestrus. Some evidence suggests that the quiet strategy may be used when females have low energy reserves. Among samplers, there is no evidence that females copy mating decisions of others. Mating success of males was not correlated with body size, horn size, age, rate of display, or with activity budgets of females in harems they controlled. Male mating success was strongly correlated with haremdays, the sum of each day's harem size across the rut. Because harem defence demands sustained, often strenuous activity by males, the behaviour of females is a direct assay of male vigour, and therefore a likely case of mate selection by a good genes criterion.

Bark beetles (Coleoptera: Scolytidae), especially pests in the genera Dendroctonus, Ips, Scolytus, Trypodendron, Tomicus, and Pityogenes of the Northern hemisphere are reviewed regarding aspects of their chemical ecology during host finding and selection. Most of the species covered here feed on conifers, primarily pines (Pinus) in the Northern hemisphere and Norway spruce (Picea abies) of Europe and Asia. Bark beetles use a variety of olfactory strategies to discriminate suitable host trees from among less suitable, overcolonized, or decaying hosts as well as nonhosts. Bark beetles also use olfactory strategies to find mates and select attack sites. These strategies have implications for coevolution of trees and bark beetles. Knowledge of the chemical ecology of insect-insect and insect-plant relationships is necessary to develop improved methods for monitoring and controlling bark beetles that are predators of trees.

A spatial-temporal model for personal computers is developed that simulates trapping of an insect population based on trap and population parameters that can be varied independently. The model allows individual "insects" to move forward at any step size with right or left turns within any specified angle taken at random. Thex andy axes of the area within which insects move can be varied as well as the number of insects, their flight speed, and the duration of the control period. In addition, the number of pheromonebaited traps, their placement in a grid or at random (with a variable degree of spacing), and their effective catch radius (proportional to pheromone release rate) can also be varied. Simulations showed that catch was similar regardless of whether traps were placed in a grid or practically at random (random placement but no traps were allowed to overlap in their effective catch radii). Iterative equations were developed for computer that can rapidly obtain values that correspond to the mean results from the slower simulation model. Based on a set of input parameters, the equations determine the percentage of the population that should be caught during a specified time, the time required to catch a specified proportion of the insects, and the number of traps necessary to catch the population proportion in the time period. The effects of varying the number of insects, flight speed, trap radius, and number of traps on the percent control or time to catch all insects are presented. Population control of the bark beetleIps typographus was simulated using realistic pheromone trap and population parameters. A discussion of insect and bark beetle (Coleoptera: Scolytidae) population control using pheromone traps is presented.

"Lure and kill" technology has been used for several decades in pest management and eradication of invasive species. In lure and kill, the insect pest attracted by a semiochemical lure is not "entrapped" at the source of the attractant as in mass trapping, but instead the insect is subjected to a killing agent, which eliminates affected individuals from the population after a short period. In past decades, a growing scientific literature has been published on this concept. This article provides the first review on the potential of lure and kill in long-term pest management and eradication of invasive species. We present a summary of lure and kill, either when used as a stand-alone control method or in combination with other methods. We discuss its efficacy in comparison with other control methods. Several case studies in which lure and kill has been used with the aims of long-term pest management (e.g., pink bollworm, Egyptian cotton leafworm, codling moth, apple maggot, biting flies, and bark beetles) or the eradication of invasive species (e.g., tephritid fruit flies and boll weevils) are provided. Subsequently, we identify essential knowledge required for successful lure and kill programs that include lure competitiveness with natural odor source; lure density; lure formulation and release rate; pest population density and risk of immigration; and biology and ecology of the target species. The risks associated with lure and kill, especially when used in the eradication programs, are highlighted. We comment on the cost-effectiveness of this technology and its strengths and weaknesses, and list key reasons for success and failure. We conclude that lure and kill can be highly effective in controlling small, low-density, isolated populations, and thus it has the potential to add value to long-term pest management. In the eradication of invasive species, lure and kill offers a major advantage in effectiveness by its being inverse density dependent and it provides some improvements in efficacy over related control methods. However, the inclusion of insecticides or sterilants in lure and kill formulations presents a major obstacle to public acceptance.

Summary Modern studies of chemical ecology and behaviour of the locusts Schistocerca gregaria and Locusta migratoria in the laboratory need to be more closely coupled with field experiments and observations. The life history relating to oviposition, transformation to gregarious phases, and adult maturation mediated by pheromones is reviewed. The principles of pheromone isolation and identification are discussed. The long-term effects of the gregarization pheromone on the physiology are presented, with discussion of morphological changes, chiasma frequency increases, and synchronization of moulting induced by the pheromone. Isolation of the purported gregarization pheromone, locustol, from faeces is discussed in regard to inconsistent effects. Other more immediate effects of the pheromone on the social (gregarious) behaviour and the isolation of possible pheromone components different from but related to locustol are presented. It is stressed that more rigorous isolation studies should be undertaken to resolve conflicting reports and methodological problems. The possibility of an anti-gregarization pheromone or solitarizing pheromone is discounted. The source and biosynthesis of locustol (or gregarization pheromone) from degradation of lignin by symbiotic bacteria is discussed. Theories of reception of the gregarization pheromone such as inhalation through the spiracles or sensory perception by the antennae are presented. Also an internal mechanism involving cAMP and/or corpora allata may be induced by gregarization pheromone to effect the physiological phase changes. The advantages to an individual of reception of the gregarization pheromone from a group of gregarious and pre-migrating locusts is discussed. Also the possible benefits of gregarious behaviour, phase polymorphism and migration are dealt with. An adult (sexual) maturation pheromone has long-term effects on reducing the period of maturation, and immediate effects on the behavioural vibration response. The epidermal source of the pheromone and glandular cells responsible for the production of the pheromone are discussed. The reception and internal mechanisms of response via the corpora allata are mentioned. The benefits to individuals of synchronized and rapid adult maturation in a gregarious group are considered. An oviposition-stimulating pheromone produced by the male accessory reproductive glands appears to be a proteinaceous substance of large molecular weight. On the other hand, an oviposition-aggregating pheromone volatilizes from epidermal areas of either sex and causes higher oviposition rates in the area of release. The behavioural and ecological aspects of this pheromone are discussed. Several other possible pheromones and semiochemicals are discussed, such as a long-range sex pheromone, sex-recognition pheromone, grass odours and feeding stimulants and deterrents. Several possible control strategies using locust pheromones are considered. The general conclusion is that the chemical isolation of the various pheromones is necessary before further progress can be achieved on the source and biosynthesis of pheromone, reception of pheromone, behavioural effects of pheromone, and control measures.

An algorithm for animal searching behaviour was constructed that allows independent variation at random of movement parameters such as speed, duration, step size, and maximum right or left turn angle. The area, radius of the object searched for, and number of objects and searchers can also be varied. A capture algorithm is presented that can determine whether a searching animal intercepts a circle (object) irrespective of the step size. These two algorithms were incorporated into a computer simulation model of mate finding for walking male bark beetles, Tomicus piniperda, in search of females that remained stationary when boring into the bark of Scots pine, Pinus sylvestris. The model showed that, for realistically chosen parameters, males were able to find ‘females’ at apparently natural rates without the need to enlarge the radius of the ‘female’ beyond the size of an actual female. This indicates that there may be little, if any, advantage in the evolution of a long-range pheromone, for which no chemical and behavioural evidence has yet been found.

The effective attraction radius (EAR) of an attractive pheromone-baited trap was defined as the radius of a passive "sticky" sphere that would intercept the same number of flying insects as the attractant. The EAR for a particular attractant and insect species in nature is easily determined by a catch ratio on attractive and passive (unbaited) traps, and the interception area of the passive trap. The spherical EAR can be transformed into a circular EAR(c) that is convenient to use in two-dimensional encounter rate models of mass trapping and mating disruption with semiochemicals to control insects. The EAR(c) equation requires an estimate of the effective thickness of the layer where the insect flies in search of mates and food/habitat. The standard deviation (SD) of flight height of several insect species was determined from their catches on traps of increasing heights reported in the literature. The thickness of the effective flight layer (F(L)) was assumed to be SD x square root of 2pi, because the probability area equal to the height of the normal distribution,1/(SD x square root of 2pi), times the F(L) is equal to the area under the normal curve. To test this assumption, 2000 simulated insects were allowed to fly in a three-dimensional correlated random walk in a 10-m thick layer where an algorithm caused them to redistribute according to a normal distribution with specified SD and mean at the midpoint of this layer. Under the same conditions, a spherical EAR was placed at the center of the 10-m layer and intercepted flying insects distributed normally for a set period. The number caught was equivalent to that caught in another simulation with a uniform flight density in a narrower layer equal to F(L), thus verifying the equation to calculate F(L). The EAR and F(L) were used to obtain a smaller EAR(c) for use in a two-dimensional model that caught an equivalent number of insects as that with EAR in three dimensions. This verifies that the F(L) estimation equation and EAR to EAR(c) conversion methods are appropriate.

We measured the energy cost of mate sampling by female pronghorn (Antilocapra americana), a species for which there are no apparent direct benefits of mate choice and for which the sampling tactic most closely resembles best‐of‐n or comparative Bayes. We used Global Positioning System collars to record the position of individuals at 10‐min intervals during the 2 weeks preceding estrus in females that actively sampled and in females that did not sample. The difference in the 2‐week energy costs of these two classes of females was 8,200 (±2,300) kJ, or roughly one‐half of the energy cost of a single day. This value, expressed as the fraction of total yearly energy expenditure, is 59 times the value reported for a lekking bird. Our finding calls into question the common assumption in models of mate search that the cost of search is negligible as well as the common assumption that the cost of sampling must be small when there are only indirect benefits of female choice.

Bark beetles (order Coleoptera: family Scolytidae) comprise a taxonomic group of species that look similar although they differ widely in their ecology and biochemical adaptations to host trees. This diversity of bark beetle biology, in which each species is adapted to only one or a few host-tree species, has probably resulted from natural selection due to the great variety of trees and their biochemicals. It also is likely that each species of tree has coevolved various chemicals to defend against the herbivorous selection pressures of bark beetles and other insects (Erlich and Raven, 1965; Feeny, 1975; Cates, 1981; Berryman et al., 1985). Host-plant chemicals can be attractive, repellent, toxic, or nutritious to bark beetles and have effects on: (1) finding and accepting the host tree (host selection and suitability); (2) feeding stimulation and deterrence; (3) host resistance; (4) pheromone/allomone biosynthesis and communication; and (5) attraction of predators, parasites, and competitors of bark beetles.

We developed a set of eight polymorphic microsatellite loci for pronghorn, Antilocapra americana. We screened 233 individuals from the National Bison Range in Moiese, MT, and found allele numbers from three to 11 and heterozygosity levels ranging from 0.142 to 0.807. These results suggest that these loci will be useful in paternity analysis and basic population genetics applications.

A puddle trap was designed that is simple to build and efficient in catching bark beetles (Coleoptera: Scolytidae). The trap is insensitive to wind and should be much easier to manufacture than the more complicated perforated pipe and barrier traps commercially available. A 7 × 7 grid of 49 puddle traps baited with aggregation pheromone components ofPityogenes chalcographus (chalcogran and methyl decadienoate) was placed at either 1.5-, 3-, 6-, or 12-m spacing between traps in the field for two or more replicates of one day length (June 1989, Torsby, Sweden). The resulting catches showed that beetles were trapped as they flew into the grid since the inner square-ring of 24 traps caught less beetles per trap than the outer square-ring trap average (36 traps) in most experiments.Ips typographus also landed in puddle traps primarily on the periphery of the grid (6-m spacing only) when traps were baited with its pheromone components, (S)-cis-verbenol and methyl butenol. Computer simulation of flying bark beetles in grids of traps of various spacings and catch radii estimated that the experimental pheromone traps had an effective catch radius of 1.3 m or less forP. chalcographus, depending on the spacing between traps. An effective catch radius of 2 m forI. typographus was found for the 6-m grid spacing.P. chalcographus beetles were increasingly disrupted in their orientation to pheromone at the closer trap spacings since the effective catch radius declined linearly with closer trap spacing. However, landing was still precise since unbaited puddle traps within the grid did not catch any bark beetles.