Modelling push-pull management of pest insects using repellents and attractive traps in fruit tree orchards.

Background: Push-pull with semiochemicals in pest management uses repellents to reduce response of pests to food-mate resources (push) and attractive traps to reduce populations (pull). Simulation models of push-pull can aid understanding of plant-insect interactions in nature and suggest hypotheses for field tests that improve management. A previous model indicated advantages of push-pull for controlling ambrosia beetle, Euwallacea fornicatus, pest of avocado trees.

Circadian rhythms of insect pheromone titer, calling, emission, and response: a review.

Many insect species have circadian rhythms of pheromone production/titer, calling, emission, and response that are involved in intraspecific communication and impact pest management practices. Rhythms of pheromone biosynthesis, most studied in moths affecting forestry and agriculture, contribute to a periodicity of pheromone concentration or titer within glands or hemolymph. Calling rhythms by the pheromone-emitting sex are physical movements (pumping, vibrating wings) that aid in release and dispersion of the volatile pheromone components attractive to the opposite conspecific sex or both sexes.

Methyl Salicylate Fails to Enhance Arthropod Predator Abundance or Predator to Pest Ratios in Cotton.

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.

Semiochemicals Affecting Attraction of Ambrosia Beetle Euwallacea fornicatus (Coleoptera: Curculionidae: Scolytinae) to Quercivorol: Developing Push-Pull Control.

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.

Index of host habitat preference explored by movement-based simulations and trap captures.

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.

Inhibitory Effects of Semiochemicals on the Attraction of an Ambrosia Beetle Euwallacea nr. fornicatus to Quercivorol.

The Euwallacea fornicatus (Eichhoff) species complex includes the polyphagous shot hole borer (PSHB), an ambrosia beetle infesting avocado limbs, Persea americana Mill. Synthetic quercivorol, a monoterpene alcohol, is known to attract females (males are flightless) over a range of release rates spanning three orders of magnitude. The upper release dose was extended 10-fold using sticky traps baited with quercivorol released at 1× (0.

An insect anti-antiaphrodisiac.

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 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.

Attraction of the Euwallacea sp. near fornicatus (Coleoptera: Curculionidae) to Quercivorol and to Infestations in Avocado.

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.

Caterpillar-induced plant volatiles attract conspecific adults in nature.

Plants release volatiles in response to caterpillar feeding that attract natural enemies of the herbivores, a tri-trophic interaction which has been considered an indirect plant defence against herbivores. The caterpillar-induced plant volatiles have been reported to repel or attract conspecific adult herbivores. To date however, no volatile signals that either repel or attract conspecific adults under field conditions have been chemically identified.

Pollinator-prey conflicts in carnivorous plants: When flower and trap properties mean life or death.

Insect-pollinated carnivorous plants are expected to have higher fitness if they resolve pollinator-prey conflicts by sparing insects pollinating their flowers while trapping prey insects. We examined whether separation between flowers and traps of the carnivorous sundew species or pollinator preferences for colours of flowers enable these plants to spare pollinators. In addition, we collected odours from flowers and traps of each carnivorous species in order to identify volatile chemicals that are attractive or repellent to pollinators and prey insects.

Earwigs (Labidura riparia) mimic rotting-flesh odor to deceive vertebrate predators.

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.

Sex pheromone component ratios and mating isolation among three Lygus plant bug species of North America.

The plant bugs Lygus hesperus, Lygus lineolaris, and Lygus elisus (Hemiptera: Miridae) are major pests of many agricultural crops in North America. Previous studies suggested that females release a sex pheromone attractive to males. Other studies showed that males and females contain microgram amounts of (E)-4-oxo-2-hexenal, hexyl butyrate, and (E)-2-hexenyl butyrate that are emitted as a defense against predators.

Modeling and regression analysis of semiochemical dose-response curves of insect antennal reception and behavior.

Dose-response curves of the effects of semiochemicals 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.

Estimating insect flight densities from attractive trap catches and flight height distributions.

Methods and equations have not been developed previously to estimate insect flight densities, a key factor in decisions regarding trap and lure deployment in programs of monitoring, mass trapping, and mating disruption with semiochemicals. An equation to estimate densities of flying insects per hectare is presented that uses the standard deviation (SD) of the vertical flight distribution, trapping time, the trap's spherical effective radius (ER), catch at the mean flight height (as estimated from a best-fitting normal distribution with SD), and an estimated average flight speed. Data from previous reports were used to estimate flight densities with the equations.

Genetic versus census estimators of the opportunity for sexual selection in the wild.

Abstract 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)).

Analysis of vertical distributions and effective flight layers of insects: three-dimensional simulation of flying insects and catch at trap heights.

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.

Inbreeding depression in pronghorn (Antilocapra americana) fawns.

Although inbreeding depression affects survival, fitness and population viability, the extent of inbreeding depression in wild populations remains unclear. We examined inbreeding depression in the small, isolated National Bison Range (NBR), MT, pronghorn (Antilocapra americana) population following a bottleneck. We have studied the National Bison Range pronghorn extensively since 1981, and we have detailed birth, survival and mate choice data.

Olfactory and visual responses of the longlegged chafer Hoplia spectabilis Medvedev (Coleoptera: Scarabaeidae) in Qinghai Province, China.

Background: Monitoring traps and control methods are needed for the long-legged chafer, Hoplia spectabilis Medvedev, which has recently reached outbreak numbers in pastureland of Qinghai Province, China.

Results: Field trapping experiments, using cross-pane funnel (barrier) traps, showed that H. spectabilis adults were not significantly attracted to branches of the host plant Dasiphora fructicosa (L.

Photosynthesis and assimilate partitioning between carbohydrates and isoprenoid products in vegetatively active and dormant guayule: physiological and environmental constraints on rubber accumulation in a semiarid shrub.

The stems and roots of the semiarid shrub guayule, Parthenium argentatum, contain a significant amount of natural rubber. Rubber accumulates in guayule when plants are vegetatively and reproductively dormant, complicating the relationship between growth/reproduction and product synthesis. To evaluate the factors regulating the partitioning of carbon to rubber, carbon assimilation and partitioning were measured in guayule plants that were grown under simulated summer- and winter-like conditions and under winter-like conditions with CO(2) enrichment.

Lygus spp. (Heteroptera: Miridae) host-plant interactions with Lesquerella fendleri (Brassicaceae), a new crop in the arid southwest.

Lesquerella fendleri is a new crop being cultivated in the arid Southwest for the hydroxy fatty acids found in its seed oils; however, little is know about the agricultural pests that will affect the seed production of this crop or the role the crop may have as a possible source or sink for current agricultural pests in the Arizona landscape. In the early spring, lygus bugs, some of our most important agricultural pests, are normally found in relatively small numbers on weeds; however, as lesquerella production increases, it may serve as an important early-season host for lygus. Here we present results from olfactometer bioassays that showed a significant attraction by Lygus hesperus females to volatiles associated with flowering lesquerella.

Modeling distributions of flying insects: effective attraction radius of pheromone in two and three dimensions.

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.

Active space of pheromone plume and its relationship to effective attraction radius in applied models.

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.

Simulation of mating disruption and mass trapping with competitive attraction and camouflage.

Simulation models of mass trapping and mating disruption were developed based on correlated random walks (CRW) of flying male moths searching for females. Males encountered pheromone plumes, transformed into a circular probability surface represented as an effective attraction radius (EAR), from females and from dispensers with or without traps. In simulations, parameters of dispenser EAR and density, female EAR and density, female stationary periods, male density, and male orienting times in EAR of dispensers or females were varied, whereas the male CRW parameters (speed, turning angle, and step size) remained constant to evaluate effects on the percentages of females mating.

Good genes sexual selection in nature.

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.