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Fruit flies in the genus Bactrocera are among the most destructive insect pests of fruits and vegetables throughout the world. A number of studies have identified volatiles from fruit flies, but few reports have demonstrated behavioral effects or sensitivities of fly antennae to these compounds. We applied a recently developed method of automated headspace analysis using SPME (Solid Phase Microextraction) fibers and GC–MS (gas chromatography mass spectrometry), termed SSGA, to reveal volatiles specific to each sex of B. zonata that are emitted in a diel periodicity. The volatiles released primarily at dusk were identified by GC–MS and chemical syntheses as several spiroacetals, pyrazines, and ethyl esters. Solvent extraction of male rectal glands or airborne collections from each sex, followed by GC–MS, showed that certain of the volatiles increase or decrease in quantity sex-specifically with age of the flies. Electroantennographic (EAG) analysis of dose-response indicates differences in sensitivities of male and female antenna to the various volatiles. Our study provides a comprehensive analysis of the volatile chemicals produced and released by B. zonata and their antennal responses. The possible pheromone and semiochemical roles of the various volatiles released by each sex and the difficulties of establishing behavioral functions are discussed.

Amazon’s Free App of the Day program, aimed at improving app visibility using daily free promotions, is a compelling experiment in the ‘economics of free’. In this study, we investigate the longer-term consequences of free app promotions on the performance of apps on Amazon Appstore. In particular, we quantify the causal impact of such promotions on apps’ future download volumes, star ratings, and sales rank using a multi-level model. On average, apps see a surge in download volumes during such promotions, albeit accompanied by a short-term negative effect on its star ratings. On average, sales rank briefly improves but falls to pre-promotion levels within a few months. Interestingly, our findings suggest that lower ranked apps are the biggest beneficiaries of these promotions, as they witness the most significant sales impact. In addition, we show the presence of a cross-market spillover effect of such promotions on the performance of the same apps on Google Playstore. Our results underscore a nuanced set of trade-offs for an app developer: do the benefits of running a promotion and boosting ones’ sales rank warrant the lost revenue and risk of lower user ratings in the long run?

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.

A series of field experiments was conducted in cranberry bogs in 2006e2010 to determine adult attraction of the two most economically important leafhopper pests of cultivated Vaccinium spp. in the northeast USA, the blunt-nosed leafhopper, Limotettix vaccinii (Van Duzee), and the sharp-nosed leafhopper, Scaphytopius magdalensis (Provancher), to colored (yellow, green, red, blue, white, and clear) sticky traps. We also determined the effects of trap height on insect captures, evaluated trap color characteristics (i.e., reflectance spectra, and red, green, and blue RGB values) for maximizing leafhopper capture while minimizing beneficial arthropod capture, and correlated within-season adult leafhopper captures from traps with nymphal captures from sweep nets. Leafhopper species exhibited distinct preferences to particular colors differing in intensities along a spectrum of wavelengths and RGB values: green was the most attractive color to blunt-nosed leafhoppers, followed by red and yellow; while yellow was most attractive to sharp-nosed leafhoppers, followed by green and red. Attraction of leafhoppers to other colors was similar to clear. Most insect predators (e.g. lady beetles, hoverflies, and minute pirate bugs), parasitic wasps, and honey bees also exhibited preferences to particular trap color characteristics, whereas green lacewings and spiders did not. An effective attraction radius was calculated for each color

Males of the plant bug Lygus hesperus prefer to court virgins over recently mated females. Because a male delivers a large spermatophore mass to the female during copulation that contains more than just sperm, we investigated whether males transferred an odorant molecule rendering females less attractive. We found that topical application of homogenates of the spermatophore, or of the male accessory glands (AG) from which this mass is derived, made virgin females less acceptable as potential mates. Additionally, we found that the fatty molecule myristyl acetate is present in male accessory glands and in the seminal receptacles of recently mated females, but is absent in virgin females. The same distribution of myristyl acetate was also found in Lygus elisus and Lygus lineolaris. We hypothesized that myristyl acetate has a repellent effect on L. hesperus males seeking an appropriate mate. Using topically applied synthetic myristyl acetate at biological concentrations, we found that myristyl acetate was as effective as the AG homogenate at reducing the attractiveness of virgin females. Collectively these results indicate that males use myristyl acetate as a seminally transferred antiaphrodisiac for passive mate guarding, and usage of the compound may be widespread among Lygus bug species. The Association for the Study of Animal Behaviour. Published by Elsevier Ltd.

Lygus hesperus and Lygus lineolaris are two of the most economically important plant bugs in North America. Here we present results from field trials that evaluated effective trap characteristics for maximizing Lygus spp. and other herbivorous insect capture, while minimizing beneficial insect capture. The response of lygus bugs, several other key herbivore species and predators to hue (white, clear, black, yellow, orange, blue, purple, green and red) and value (black, white and two neutral grays) was examined in alfalfa over three seasons using traps coated with Pestick adhesive. Lygus spp. exhibited a broad response to trap hue, but showed no response to trap value. Additionally, we showed that time of day, trap height and trap placement influenced the number of Lygus spp. captured. More Lygus spp. were trapped from late afternoon to dusk compared to all other times of the day, and more males than females were captured on sticky traps even though the sexes were at parity in field sweep net samples. In the alfalfa setting, male lygus were more likely to be captured on traps placed 20 cm above the ground; traps placed 50 and 100 cm above the ground caught similar numbers of males and females. The highest number of plant bugs was captured when traps were placed in a cleared area between two alfalfa fields; lower numbers were captured on traps at the edge and in the center of the field. All other herbivores exhibited distinct preferences to trap hue and, in some cases, trap value. Predators were rarely trapped, but did exhibit preferences to trap color (i.e., hue and value) characteristics. The potential of using sticky traps with specific hue and value characteristics to monitor Lygus spp. effectively is discussed.

Content providers often consider the costs of security to be greater than the losses they might incur without it; many view 'casual piracy' as their main concern. Our goal is to provide a low cost defense against such attacks while maintaining rigorous security guarantees. Our defense is integrated with and leverages efficient forward error correcting codes, such as Tornado codes, which are widely used to facilitate reliable delivery of rich content. We tune one such family of codes-while preserving their original desirable properties-to guarantee that none of the original content can be recovered whenever a key subset of encoded packets is missing. Ultimately we encrypt only these key codewords (only 4% of all transmitted packets), making the security overhead minimal.

Heating of chromatographic columns, transfer lines, and other devices is often required in neuroscience research. For example, volatile compounds passing through a capillary column of a gas chromatograph (GC) can be split, with half exiting the instrument through a heated transfer line to an insect antenna or olfactory sensillum for electroantennographic detector (GC-EAD) recordings. The heated transfer line is used to prevent condensation of various chemicals in the capillary that would otherwise occur at room temperature. Construction of such a transfer line heater is described using (80/20%) nickel-chromium heating wire wrapped in a helical coil and powered by a 120/220 V ac rheostat. Algorithms were developed in a computer program to estimate the voltage at which a rheostat should be set to obtain the desired heater temperature for a specific coil. The coil attributes (radius, width, number of loops, or length of each loop) are input by the user, as well as AWG size of heating wire and desired heater temperature. The program calculates total length of wire in the helix, resistance of the wire, amperage used, and the voltage to set the rheostat. A discussion of semiochemical isolation methods using the GC-EAD and bioassays is presented.

The neuropeptide galanin has not been localized previously in the primate uvea, and the neuropeptide somatostatin has not been localized in the uvea of any mammal. Here, the distribution of galanin-like and somatostatin-like immunoreactive axons in the iris, ciliary body and choroid of macaques and baboons using double and triple immunofluorescence labeling techniques and confocal microscopy was reported. In the ciliary body, galanin-like immunoreactive axons innervated blood vessels and the ciliary processes, particularly at their bases. In the iris, the majority of these axons was associated with the loose connective tissue in the stroma. Somatostatin-like immunoreactive axons were found in many of the same areas of the uvea supplied by cholinergic nerves. In the ciliary body, there were labelled axons within the ciliary processes and ciliary muscle. They were also found alongside blood vessels in the ciliary stroma. In the iris, somatostatin-like immunoreactive axons were abundant in the sphincter muscle and less so in the dilator muscle. A unilateral sympathectomy had no effect on the distribution of somatostatin-like or galanin-like immunoreactive axons, and these axons did not contain the sympathetic marker tyrosine hydroxylase. They did not contain the parasympathetic marker choline acetyltransferase, either. The galanin-like immunoreactive axons contained other neuropeptides found in sensory nerves, including calcitonin gene-related peptide, substance P and cholecystokinin. Somatostatin-like immunoreactive axons did not contain any of these sensory neuropeptides or galanin-like immunoreactivity, and they were neither labelled with an antibody to 200kDa neurofilament protein, nor did they bind isolectin-IB(4). Nevertheless, they are likely to be of sensory origin because somatostatin-like immunoreactive perikarya have previously been localized in the trigeminal ganglion of primates. Taken together, these findings indicate galanin and somatostatin are present in two different subsets of sensory axons in primate uvea.

We propose a new web server architecture optimized for delivery of large, popular files. Delivery of such files currently pose a scalability problem for conventional content providers, which must devote server-side resources in direct proportion to the high multiprogramming level induced by a set of these connections. While use of scalable multicast may remedy this problem some day, multicast is rarely supported in today's wide-area infrastructure. Our approach alleviates many of the most serious scalability problems by developing new server-side mechanisms capable of managing a large set of TCP connections transporting the same content. The strategy we employ relies on the use of fast forward error correcting (FEC) codes to generate encodings of popular content, of which only a small sliding window is cached in memory at any time instant. The concurrent TCP connections then access the content only from this shared window, which is globally useful to all clients. Our method hinges on eliminating unscalable TCP retransmission buffers, as we can ''retransmit'' fresh encoding packets in lieu of the originals with no performance degradation and with no modifications to client TCP stacks. Ultimately, our Cyclone server capitalizes on concurrency to maximize sharing of state across different request threads while minimizing context switching, disk I/O, thrashing under high load and the cache memory footprint. In this paper, we describe the design and prototype implementation of our approach as a Linux kernel subsystem.

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.

Peer-to-peer markets, collectively known as the sharing economy, have emerged as alternative suppliers of goods and services traditionally provided by long-established industries. A central question regards the impact of these sharing economy platforms on incumbent firms. We study the case of Airbnb, specifically analyzing Airbnb’s entry into the short-term accommodation market in Texas and its impact on the incumbent hotel industry. We first explore Airbnb’s impact on hotel revenue, by using a difference- in-differences empirical strategy that exploits the significant spatiotemporal variation in the patterns of Airbnb adoption across city-level markets. We estimate that in Austin, where Airbnb supply is highest, the causal impact on hotel revenue is in the 8-10% range; moreover, the impact is non-uniformly distributed, with lower-priced hotels and those hotels not catering to business travelers being the most affected. We find that this impact materializes through less aggressive hotel room pricing, an impact that benefits all consumers, not just participants in the sharing economy. The impact on hotel prices is especially pronounced during periods of peak demand, such as SXSW. We find that by enabling supply to scale – a differentiating feature of peer-to-peer platforms – Airbnb has significantly crimped hotels’ ability to raise prices during periods of peak demand. Our work provides empirical evidence that the sharing economy is making inroads by successfully competing with, differentiating from, and acquiring market share from incumbent firms.

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.

Seven BASIC programs are presented that use algorithms for selection of treatments and samples in spatial and temporal contexts. Program (1) takes a natural sequence of samples (such as logs cut from a tree trunk) and divides them into groups (equal to the number of samples divided by treatments), and then selects non-redundantly from each group a sample at random for each treatment. Program (2) matches items from different categories equally to any number of treatments in proportion to the numbers of items of each category. Program (3) selects sampling times or segment lengths of specified interval and number from within a time period or perimeter distance. These samples can be spaced apart by at least a specified amount of time or distance but otherwise are chosen at random. In program (4), a series of sample coordinates ( x , y ) are chosen at random from a rectangular area so that no points are closer than a specified minimum distance to any other. For each of the sample points, the Cartesian and polar coordinates are given. Program (5) generates any possible Latin square, while program (6) generates Latin cubes, and program (7) makes Graeco-Latin cubes. Examples of program use and output are presented for experiments with bark beetles (Coleoptera: Scolytidae) responding to pheromone blends and colonizing host trees.

Daily deals sites such as Groupon offer deeply discounted goods and services to tens of millions of customers through geographically targeted daily e-mail marketing campaigns. In our prior work we observed that a negative side effect for merchants using Groupons is that, on average, their Yelp ratings decline significantly. However, this previous work was essentially observational, rather than explanatory. In this work, we rigorously consider and evaluate various hypotheses about underlying consumer and merchant behavior in order to understand this phenomenon, which we dub the Groupon effect. We use statistical analysis and mathematical modeling, leveraging a dataset we collected spanning tens of thousands of daily deals and over 7 million Yelp reviews. In particular, we investigate hypotheses such as whether Groupon subscribers are more critical than their peers, or whether some fraction of Groupon merchants provide significantly worse service to customers using Groupons. We suggest an additional novel hypothesis: reviews from Groupon subscribers are lower on average because such reviews correspond to real, unbiased customers, while the body of reviews on Yelp contain some fraction of reviews from biased or even potentially fake sources. Although we focus on a specific question, our work provides broad insights into both consumer and merchant behavior within the daily deals marketplace., Comment: Submitted to ACM EC 2012

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.

To test the hypothesis that rate of play can be modified by natural selection, rates of locomotor play in the inbred BALB/c and DBA/2 strains of house mice and in F1 and F2 crosses of these strains were quantified. Rate of play was low in BALB/c and in the maternal DBA/2 F1, intermediate in the maternal BALB/c F1, and highest in the DBA/2 and F2. Estimated broad sense heritability was 0·55±0·40, so selection can probably modify rate of play. Epistasis appeared to affect rate of play in the F2 litters, and a maternal effect was evident in the F1 litters.

The ability of an animal to discriminate between kin and non-kin (kin recognition) has been the subject of numerous recent investigations. Grafen ( Anim. Behav. , 1990, 39 , 42–54) recently reported that the evidence in support of kin recognition is weak and the data illustrating a preference for kin to associate in the laboratory may be more consistently explained as species recognition. It is suggested here, however, that in many cases it may be impossible to distinguish between species recognition and kin recognition, but in some cases, kin recognition seems apparent. It is also emphasized that very little is known about the adaptive value of kin recognition.

Play behaviour was studied in pronghorn, Antilocapra americana, at the National Bison Range (Moiese, Montana, U.S.A.). The aim of the study was to make field measurements of the energetic costs of play running. Total daily energy expenditures of fawn were estimated in two different ways: (1) time budget analysis and (2) field metabolic rates based on body weight calculated using a regression equation for herbivorous eutherians. The two methods gave similar estimates. Play occupied 1–2% of total time. Running play constituted on average 2% of total daily energy expenditure and 20% of the daily energy expenditure in excess of resting metabolic rate and growth. A pronghorn fawn that eschewed play and shifted the energy savings into growth could expect to weigh 7% more than a playing fawn by post-natal week 12.

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.

Capillary gas chromatography and mass spectrometry were used to quantify the amounts of E- and Z- chalcogran and methyl (E,Z)-2,4-decadienoate (E,Z-MD), pheromone synergists of the bark beetle Pitygenes chalcographys (Coleoptera: Scolytidae). Males were exposed or not to vapours of host (Norway spruce, Picea abies) oleoresin or allowed to feed in host logs prior to extraction of body parts and hindguts for pheromone synergists. E,Z-MD and chalcogran were produced sex-specifically in males, and only after feeding on host-plant tissue. The pheromone synergists were not produced during exposure to oleoresin vapours. Several oxygenated monoterpenes (including trans-verbenol, myrtenol, and trans-myrtanoy) were found in feeding males. The amounts of the pheromone synergists in unmated feeding males remained relatively constant over a 3.5 day period. In contrast to many other pheromone components of bark beetles, including chalcogran, E,Z-MD was found primarily in the male's body (head and thorax) with less in the hindgut (abdomen). The probable acetogenic origins of both pheromone components indicate that the species has evolved control over production and is thus not dependent on host precursors as expected in many other bark beetles.

In 1981, Robert Fagen published the first general review and conceptual evolutionary treatment of animal play [1]. Portraying a field that was beset with ambiguity and uncertainty, Fagen championed the rigorous application of evolutionary hypothesis testing, a zeitgeist that launched the field of behavioral ecology, creating a general conceptual advance. However, the quarter of a century since the publication of Fagen's book has not revealed a similar advance in our understanding of play behavior, a state of affairs reported in and illustrated by Burghardt in his 2005 publication.

The pheromonal components, ipsenol and ipsdienol were found in increasing quantities in hindguts of only the male sex of Ips paraconfusus following exposure of both sexes to a series of increasing concentrations of myrcene vapour. Hindguts of female and male beetles contained similar quantities of myrcene and other volatile compounds associated with myrcene exposure. Unexposed beetles of both sexes did not contain detectable amounts of any volatile compound. This indicates that myrcene induces or is a precursor for sex-specific pheromone biosynthesis.

A dominance hierarchy, in which one individual was dominant over all other individuals but in which the relationships among the subordinates were unclear, was observed in male groups of the cockroach, Byrsotria fumigata (Guerin), over a wide range of population densities. There was no tendency towards territoriality, even in low density populations. The rate of interindividual interactions remained nearly constant at all densities, but the number of contests in which one animal was a clear winner decreased significantly as density decreased. Certain behavioral acts, including submission, decreased with decreasing density, while others, such as fleeing, increased. The social repertoire seems to be relatively plastic, depending upon the density at which animals are kept. Usually hierarchies were maintained when groups of animals were transferred from one density to another, but in some cases a previously subordinate animal became dominant.

Pheromones and metabolites of host (ponderosa pine) compounds were found in association with the hindgut of both naturally fed and of non-fed, host vapour-exposed bark beetles, Ips paraconfusus and Dendroctonus brevicomis . Much smaller amounts were found in the corresponding heads and mid guts. Sex-specific differences in content of pheromones were observed as in earlier studies. Exposure of I. paraconfusus to vapours of a pheromone component, ipsenol and other monoterpene alcohols resulted in their accumulation in the hindgut but relatively very low amounts in the head. The possible sites of pheromone biosynthesis are discussed. Exposure of male I. paraconfusus to vapours of host compounds, myrcene and α-pinene, revealed that immature adults do not produce the pheromone components, ipsenol and ipsdienol, as mature adults do while both immature and mature sexes produced another pheromone component, cis -verbenol, as well as trans -verbenol and myrtenol. Immature D. brevicomis adults did not contain pheromones until their exposure to vapours of (−)-α-pinene which caused production of trans -verbenol but only about 10% that of mature adults treated similarly. Verbenone, a male-produced inhibitory pheromone of D. brevicomis , apparently was not synthesized from (−)-α-pinene in females nor was its synthesis in males enhanced by exposure to this host compound.

Courtship behaviour of two species of periodical cicadas, Magicicada septendecim and M. cassini , was studied in the field during the 1970, 1973, and 1974 emergences of these insects. In areas where both species were courting there were differences in both male and female courtship patterns, both in acoustic and behavioural components. Experiments with models showed that male M. septendecim were more likely to court crude models of females than were M. cassini males. When females were ‘courted’ with models that could imitate some of male courtship, they were more receptive when the models' ‘songs’ were those of conspecific males. Acoustic differences between species are probably used by females in mate selection, maintaining species separation even in areas where the two species overlap in both space and time.