Increased Flight Activity Research Articles

Seasonal heavy metal effects on detoxification and antioxidant gene expression in the urban honeybee

AbstractEnvironmental pollutants are associated with honeybee colony losses and may show seasonal concentration variations with respect to the environment and plants. In this study, we examined arsenic (As), lead (Pb), and mercury (Hg) seasonal variations in honey and honeybees in urban areas. Seasonal trends in detoxification (CYP9Q1, CYP9Q2, and CYP9Q3) and antioxidant genes encoding catalase (CAT) and superoxide dismutase (SOD1) were also determined in honeybees. Accordingly, As, Pb, and Hg concentrations were significantly increased in summer in both honey and honeybee samples when compared with other seasons. Similarly, the expression level of CYP9Q1, CYP9Q2, CYP9Q3, SOD1, and CAT showed a significant increase in summer honeybees. This increased expression level particularly in summer honeybees indicating an increased summer honeybee exposure and adaptive oxidative stress responses to environmental pollutants, including heavy metals due to increased flight activity when compared with other seasons. Thus, active season honeybees were subjected to environmental oxidative and detoxification stressors when exposed to environmental pollutants, including heavy metals.

Metabolic stress as a driver of life-history plasticity: flight promotes longevity and antioxidant production in monarch butterflies.

Life-history theory predicts that increased investment in traits related to reproduction will be associated with a reduced ability to invest in survival or longevity. One mechanistic explanation for this trade-off is that metabolic stress generated from current fitness activities (e.g. reproduction or locomotion) will increase somatic damage, leading to reduced longevity. Yet, there has been limited support for this damage-based hypothesis. A possible explanation is that individuals can respond to increases in metabolic stress by plastically inducing cellular maintenance responses, which may increase, rather than decrease, longevity. We tested this possibility by experimentally manipulating investment in flight activity (a metabolic stressor) in the migratory monarch butterfly (Danaus plexippus), a species whose reproductive fitness is dependent on survival through a period of metabolically intensive migratory flight. Consistent with the idea that metabolic stress stimulated investment in self-maintenance, increased flight activity enhanced monarch butterfly longevity and somatic tissue antioxidant capacity, likely at a cost to reproductive investment. Our study implicates a role for metabolic stress as a driver of life-history plasticity and supports a model where current engagement in metabolically stressful activities promotes somatic survival by stimulating investment in self-maintenance processes.

Flight activity and glycogen depletion on a low-carbohydrate diet.

Glycogen is a critical store for locomotion. Depleted glycogen stores are associated with increased fatigue during exercise. The reduced effectiveness of low-carbohydrate diets for weight loss over longer time periods may arise because such diets reduce glycogen stores and thereby energy expenditure via physical activity. To explore the effect of a low-carbohydrate diet on activity and glycogen utilisation, we fed adult Drosophila melanogaster a standard or low-carbohydrate diet for 9days and measured patterns of flight activity and rates of glycogen depletion. We hypothesised that flight activity and rates of glycogen depletion would be reduced on a low-carbohydrate diet. Flight activity was elevated in the low-carbohydrate group but glycogen depletion rates were unchanged. We conclude that increased activity is probably a foraging response to carbohydrate deficiency and speculate that the previously demonstrated metabolic depression that occurs on a low-carbohydrate diet in this species may allow for increased flight activity without increased glycogen depletion.

Effects of Climate and Host Age on Flight Activity, Infestation Percentage, and Intensity by Coptoborus ochromactonus (Coleoptera: Curculionidae: Scolytinae) in Commercial Balsa Plantations of Ecuador.

Coptoborus ochromactonus (Smith and Cognato) is one of the most common and important pests of balsa, Ochroma pyramidale (Cav. Ex Lam. Urb.), an economic pillar of the wood industry in Ecuador. Commercial balsa plantations have been expanded from humid to dry climate areas to limit insect damage, but basic knowledge is still lacking on the interaction of C. ochromactonus activity with variation in climate and plantation age. We investigated the effects of climate and host age on the seasonal flight activity of C. ochromactonus and its infestation rate and intensity, as well as the effect of age and individual infestation intensity on balsa dieback. Experiments were conducted in 1-, 2-, and 3-yr-old commercial balsa plantations located in areas of humid or dry climates. Seasonal flight activity (monitored with baited traps) differed between study sites and seasons. Increased flight activity was significantly correlated with higher relative humidity, higher mean temperature, and reduced precipitation during the dry season in the humid site and with increased mean and minimum temperature and increased precipitation during the rainy season in the dry site. Infestation rates by C. ochromactonus significantly increased with plantation age, especially in the humid site. Intensity of individual infestations (measured as number of successful insect entry holes per tree) was significantly influenced by both climate and plantation age, and it was particularly severe on 3-yr-old trees in the dry site. Percentage of foliage loss significantly increased with infestation intensity. Overall, our results can be relevant for devising preventive measures and suitable management strategies for this emerging pest in Ecuadorian wood plantations.

Tradeoff between triglyceride consumption and ovariole development in Plutella xylostella (L.) released in mixed-host environments

After exposure to mixed environments with multiple hosts, the frequency of flight take-offs for Plutella xylostella (L.) is known to increase with a concomitant decrease in female fecundity. The objective of the present study was to elucidate the physiological mechanism underlying the increased flight activity and decreased fecundity of P. xylostella in mixed-host environments. We measured ovariole length, and triglyceride and vitellogenin (Vg) content in P. xylostella females after they were released into different host environments consisting of either a single host (Brassica campestris, Brassica oleracea or Brassica juncea) or a mixture of all three hosts. Our results indicated that ovariole length varied significantly between female adults from different host environments. Females from the B. campestris environment had the longest ovarioles, whereas those from the mixed environment had the shortest ones. A negative correlation was found between ovariole length and the flight take-off frequency of P. xylostella adults. Additionally, there were significant differences in the triglyceride content of P. xylostella females from different host environments. Our data revealed that more triglyceride was consumed by P. xylostella female adults from B. oleracea and the mixed environments than those from environments containing only B. campestris or B. juncea. In contrast, the relative Vg content in P. xylostella females from the mixed environment was lower than that in females from the B. campestris-, B. juncea- or B. oleracea-only environments. In conclusion, the mixed environment caused increased consumption of available energy resources (triglyceride) at the cost of retarding ovarian development and decreasing the amount of Vg produced.

Migratory bats are attracted by red light but not by warm-white light: Implications for the protection of nocturnal migrants.

The replacement of conventional lighting with energy‐saving light emitting diodes (LED) is a worldwide trend, yet its consequences for animals and ecosystems are poorly understood. Strictly nocturnal animals such as bats are particularly sensitive to artificial light at night (ALAN). Past studies have shown that bats, in general, respond to ALAN according to the emitted light color and that migratory bats, in particular, exhibit phototaxis in response to green light. As red and white light is frequently used in outdoor lighting, we asked how migratory bats respond to these wavelength spectra. At a major migration corridor, we recorded the presence of migrating bats based on ultrasonic recorders during 10‐min light‐on/light‐off intervals to red or warm‐white LED, interspersed with dark controls. When the red LED was switched on, we observed an increase in flight activity for Pipistrellus pygmaeus and a trend for a higher activity for Pipistrellus nathusii. As the higher flight activity of bats was not associated with increased feeding, we rule out the possibility that bats foraged at the red LED light. Instead, bats may have flown toward the red LED light source. When exposed to warm‐white LED, general flight activity at the light source did not increase, yet we observed an increased foraging activity directly at the light source compared to the dark control. Our findings highlight a response of migratory bats toward LED light that was dependent on light color. The most parsimonious explanation for the response to red LED is phototaxis and for the response to warm‐white LED foraging. Our findings call for caution in the application of red aviation lighting, particularly at wind turbines, as this light color might attract bats, leading eventually to an increased collision risk of migratory bats at wind turbines.

What makes Alpine swift ascend at twilight? Novel geolocators reveal year-round flight behaviour

Studying individual flight behaviour throughout the year is indispensable to understand the ecology of a bird species. Recent development in technology allows now to track flight behaviour of small long-distance bird migrants throughout its annual cycle. The specific flight behaviour of twilight ascents in birds has been documented in a few studies, but only during a short period of the year, and never quantified on the individual level. It has been suggested that twilight ascents might be a role in orientation and navigation. Previous studies had reported the behaviour only near the breeding site and during migration. We investigated year-round flight behaviour of 34 individual Alpine swifts (Apus melba) of four different populations in relation to twilight ascents. We recorded twilight ascents all around the year and found a twofold higher frequency in ascents during the non-breeding residence phase in Africa compared to all other phases of the year. Dawn ascents were twice as common as dusk ascents and occurred mainly when atmospheric conditions remained stable over a 24-h period. We found no conclusive support that twilight ascents are essential for recalibration of compass cues and landmarks. Data on the wing flapping intensity revealed that high activity at twilight occurred more regularly than the ascents. We therefore conclude that alpine swift generally increase flight activity—also horizontal flight—during the twilight period and we suppose that this increased flight activity, including ascents, might be part of social interactions between individuals.Significance statementYear-round flight altitude tracking with a light-weight multi-sensor tag reveals that Alpine swifts ascend several hundred meters high at twilight regularly. The reason for this behaviour remains unclear and the low-light conditions at this time of the day preclude foraging as a possibility. The frequency and altitude of twilight ascents were highest during the non-breeding period, intermediate during migration and low for active breeders during the breeding phase. We discuss our findings in the context of existing hypotheses on twilight ascent and we propose an additional hypothesis which links twilight ascent with social interaction between flock members. Our study highlights how flight behaviour of individuals of a migratory bird species can be studied even during the sparsely documented non-breeding period.

Circadian clocks of both plants and pollinators influence flower seeking behavior of the pollinator hawkmoth Manduca sexta

Most plant-pollinator interactions occur during specific periods during the day. To facilitate these interactions, many flowers are known to display their attractive qualities, such as scent emission and petal opening, in a daily rhythmic fashion. However, less is known about how the internal timing mechanisms (the circadian clocks) of plants and animals influence their daily interactions. We examine the role of the circadian clock in modulating the interaction between Petunia and one of its pollinators, the hawkmoth Manduca sexta. We find that desynchronization of the Petunia circadian clock affects moth visitation preference for Petunia flowers. Similarly, moths with circadian time aligned to plants show stronger flower-foraging activities than moths that lack this alignment. Moth locomotor activity is circadian clock-regulated, although it is also strongly repressed by light. Moths show a time-dependent burst increase in flight activity during subjective night. In addition, moth antennal responsiveness to the floral scent compounds exhibits a 24-hour rhythm in both continuous light and dark conditions. This study highlights the importance of the circadian clocks in both plants and animals as a crucial factor in initiating specialized plant-pollinator relationships.

Environmental and genetic influences on the dispersal propensity of spruce budworm (Choristoneura fumiferana)

Abstract For many species, dispersal among populations has profound impacts on local dynamics and the spread of outbreaks. Understanding the environmental and genetic triggers of density‐dependent dispersal is important for improving population models and developing reliable management strategies. We hypothesized that moth dispersal in the spruce budworm (Choristoneura fumiferana Clem.) is triggered by reductions in larval food availability and mediated by the expression of the for gene, which affects movement and dispersal activity in Drosophila and other species. Late‐stage larvae were reared under different food‐limitation treatments. Dispersal of adults was assessed using three measures of flight performance on flight mills: maximum velocity, 1‐h flight distance and maximum sustained flight time. Accumulation of for transcripts was measured by a quantitative polymerase chain reaction on moths from each treatment. Flight activity was positively related to moth size and, although food limitation caused reductions in moth size, it also had an independent and positive effect on maximum velocities, sustained flight times and flight distances. Food limitation had no effect on expression of the for gene. We conclude that reductions in food availability will produce moths that are smaller but exhibit increased flight activity, potentially increasing the population of dispersing individuals. The physiological basis for this effect remains unknown.

Time and travelling costs during chick‐rearing in relation to habitat quality in Little OwlsAthene noctua

In many bird species, parents adjust their home‐ranges during chick‐rearing to the availability and distribution of food resources, balancing the benefits of energy intake against the costs of travelling. Over recent decades, European agricultural landscapes have changed radically, resulting in the degradation of habitats and reductions in food resources for farmland birds. Lower foraging success and longer foraging trip distances that result from these changes are often assumed to reduce the reproductive performance of parents, although the mechanisms are not well understood. We tested the behavioural response of chick‐rearing Little OwlsAthene noctuato variation in habitat diversity in an agricultural landscape. We equipped females withGPSloggers and received adequate range‐use data for 19 individuals (6063–14 439 locations per bird). In habitats dominated by homogeneous cropland habitats, home‐ranges were over 12 ha in size, whereas in highly diverse habitats they were below 2 ha. Large home‐ranges were associated with increased flight activity (117% of that of birds in small home‐ranges) and distances travelled per night (152%), increased duration of foraging trips (169%) covering larger distances (246%), and reduced nest visiting rates (81%). The study therefore provides strong correlative evidence that Little Owls breeding in monotonous farmland habitats expend more time and energy for a lower benefit in terms of feeding rates than do birds in more heterogeneous landscapes. As nestling food supply is the main determinant of chick survival, these results suggest a strong impact of farmland characteristics on local demographic rates. We suggest that preserving and creating islands of high habitat diversity within uniform open agricultural landscapes should be a key target in the conservation of Little Owl populations.

Effects of Light Intensity on the Flight Behaviour of Adult Tirumala limniace (Cramer) (Lepidoptera: Nymphalidae: Danainae)

Light intensity significantly affects insect flight behaviour. Mating of butterflies is significantly associated with flight frequency. However, no research has elucidated the effects of light intensity on butterfly flight. Thus, a clear understanding of the effects of light intensity on flight has significant theoretical implications for the cultivation and utilization of butterflies. We observed the flight behaviour of adult Tirumala limniace (Cramer) exposed to light intensities from 243 to 2240 lx and measured the frequency of flight, take-off rhythm, thoracic temperature excess (△T) when perching and flying, and the tendency for thoracic temperature to increase. Results showed that high-intensity light significantly increased flight activity, and males were more active than females under similar light intensities; strong light (1280–2240 lx) resulted in female and male butterflies taking flight earlier compared with weak light (243–864 lx); and a similar pattern was observed for flight duration, with flights by males being significantly longer than those by females at 864–2240 lx; △T of adults flying in strong light was significantly higher than in weak light, whereas the thoracic temperature of perching adults was similar to the air temperature. Compared with other light intensities, the equilibrium thoracic temperature of adults exposed to 2240 lx was higher, and the time to reach it was shorter; in addition, the △T and rate of thoracic temperature increase were higher and achieved more quickly, respectively. Thus, of the 243–2240 lx range, 2240 lx was the most optimal light intensity for adult T. limniace flight and captive rearing.

Effects of elevation and aspect on the flight activity of two alien pine bark beetles (Coleoptera: Curculionidae, Scolytinae) in recently-harvested pine forests

Climate is an important driver of the establishment and impact of invasive alien species. Species transported to new regions can only invade those with a climate that meets their thermal requirements, but climate change is likely to alter the invasibility of recipient environments. Likewise, species are unlikely to reach pest status where climatic conditions are suboptimal. Here our objectives were to determine the relationship between climatic conditions and flight activity of two alien pine bark beetles (Hylastes ater and Hylurgus ligniperda) and to anticipate how climate change may affect the future distribution of these species. We used elevational gradients and slope aspect (north versus south-facing slopes), which are known to affect microclimates, to assess the effects on beetle flight across 18 locations in pine forests in the South Island, New Zealand. Using panel traps baited with alpha-pinene and ethanol we caught a total of 45,363 H. ligniperda and 6676 H. ater. Catches of both species decreased significantly and substantially with increasing elevation. Significantly more beetles were caught at north-facing than at south-facing sites towards the end of the flight season in autumn, leading to an extended flight period at northerly aspects. These results are important for pest management and the identification of ‘areas of low pest prevalence’ as a measure to reduce post-harvest infestations of logs destined for export. For example, during risk periods, logs could be harvested preferentially from stands with reduced flight activity (i.e., southerly aspects and higher elevations). Furthermore, such sites could be chosen to reduce post-harvest infestation risks during periods of temporary log storage at skid sites in the forest. Our findings are also important because climate change can be an important factor contributing to population expansion of bark beetles, and warmer temperatures could lead to increased flight activity and abundance, as well as enhanced suitability of sites that are currently less favourable.

Volatile semiochemical-conditioned attraction of the male yellow fever mosquito, Aedes aegypti, to human hosts.

We investigated the olfactory responses of male mosquitoes to kairomones of vertebrate hosts in a dual-port olfactometer. The behavioral responses of unmated and mated male and female mosquitoes from one to ten days old to human odors were compared to the odors of different human hosts. To evaluate the relationship between the age of male mosquitoes and their responses, we performed experiments with males at different ages. Unmated Ae. aegypti males, one to two days old, did not fly upwind to human odor, whereas between three and ten days old they exhibited increased flight activity. The results showed that unmated and mated females were attracted by human odor, but those mated were more attracted by human odor than when unmated. Mated males were, in general, attracted by human odor, while the unmated males were not attracted but showed increased flight activity in the presence of human odor, suggesting swarming behavior. Further studies should be carried out in order to determine the role of human odors on male Ae. aegypti behavior.

Habitat utilization in white‐tailed eagles (Haliaeetus albicilla) and the displacement impact of the Smøla wind‐power plant

AbstractOn average, 7.8 white‐tailed eagles (Haliaeetus albicilla) collide with wind turbines annually at the operating wind‐power plant on the island of Smøla off the coast of central Norway. To better understand the impact of this wind‐power plant on white‐tailed eagles, we investigated how habitat utilization affected displacement effects. We collected data on habitat utilization in non‐territorial subadult white‐tailed eagles using global positioning system satellite telemetry (2004–2009). From these data, we estimated utilization distributions using the Brownian bridge movement model and analyzed them using Resource Utilization Functions. Home ranges were circa 10–30% smaller for subadults hatched on skerries and islets farther from the wind‐power plant, and tended to be circa 40% larger during spring. Shallow sea, skerries, and islets were utilized extensively, as was marsh, heathland, and forest on the main island of Smøla. We noted lower selectivity for arable land and higher levels of differentiation in utilization among individuals for forest and islets. Females also had a nearly 4 times higher between‐individual variation, which was likely due to long‐ranging excursions. The within‐ and between‐individual variation among seasons showed an annual pattern, with increasing between‐individual variation toward summer. Displacement (indicated by an overall 40% proportional reduction in utilization) was more pronounced in the birds' second and third calendar year compared with their first calendar year, and during autumn–winter. Reduced displacement during spring coincides with the white‐tailed eagle pre‐breeding period with increased flight activity. This may, in part, explain increased collision risk during spring. Possible displacement effects in white‐tailed eagles may be avoided by siting wind‐power plants farther inland or offshore. © 2013 Wiley Periodicals, Inc.

Flight behavior and pheromone changes associated to Nosema ceranae infection of honey bee workers (Apis mellifera) in field conditions

Parasites are known to cause the loss of individuals in social insects. In honey bee colonies the disappearance of foragers is a common factor of the wide extended colony losses. The emergent parasite of the European honey bee Nosema ceranae has been found to reduce homing and orientation skills and alter metabolism of forager bees. N. ceranae-infected bees also show changes in Ethyl Oleate (EO) levels, which is so far the only primer pheromone identified in workers that is involved in foraging behavior. Thus, we hypothesized that N. ceranae (i) modifies flight activity of honey bees and (ii) induces EO changes that can alter foraging behavior of nestmates. We compared flight activity of infected bees and non-infected bees in small colonies using an electronic optic bee counter during 28days. We measured EO levels by gas chromatography–mass spectrometry and spore-counts. Bee mortality was estimated at the end of the experiment. Infected bees showed precocious and a higher flight activity than healthy bees, which agreed with the more elevated EO titers of infected bees and reduced lifespan. Our results suggest that the higher EO levels of infected bees might delay the behavioral maturation of same age healthy bees, which might explain their lower level of activity. We propose that delayed behavioral maturation of healthy bees might be a protective response to infection, as healthy bees would be performing less risky tasks inside the hive, thus extending their lifespan. We also discuss the potential of increased flight activity of infected bees to reduce pathogen transmission inside the hive. Further research is needed to understand the consequences of host behavioral changes on pathogen transmission. This knowledge may contribute to enhance natural colony defense behaviors through beekeeping practices to reduce probability of colony losses.

Seasonal variation in metabolic rate, flight activity and body size of Anopheles gambiae in the Sahel

Malaria in Africa is vectored primarily by the Anopheles gambiae complex. Although the mechanisms of population persistence during the dry season are not yet known, targeting dry season mosquitoes could provide opportunities for vector control. In the Sahel, it appears likely that M-form A. gambiae survive by aestivation (entering a dormant state). To assess the role of eco-physiological changes associated with dry season survival, we measured body size, flight activity and metabolic rate of wild-caught mosquitoes throughout 1 year in a Sahelian locality, far from permanent water sources, and at a riparian location adjacent to the Niger River. We found significant seasonal variation in body size at both the Sahelian and riparian sites, although the magnitude of the variation was greater in the Sahel. For flight activity, significant seasonality was only observed in the Sahel, with increased flight activity in the wet season when compared with that just prior to and throughout the dry season. Whole-organism metabolic rate was affected by numerous biotic and abiotic factors, and a significant seasonal component was found at both locations. However, assay temperature accounted completely for seasonality at the riparian location, while significant seasonal variation remained after accounting for all measured variables in the Sahel. Interestingly, we did not find that mean metabolic rate was lowest during the dry season at either location, contrary to our expectation that mosquitoes would conserve energy and increase longevity by reducing metabolism during this time. These results indicate that mosquitoes may use mechanisms besides reduced metabolic rate to enable survival during the Sahelian dry season.

Behavioural compensation reduces energy expenditure during migration hyperphagia in a large bird

Summary1. Bird migration is often seen as the summit of animal performance. Because higher foraging effort associated with fuelling and increased flight activity should generate maximum level of energy turnover, we expect the migratory process to be constrained by energy, whether it is energy expenditure or energy intake.2. We used implanted data loggers to continuously monitor foraging effort, flight activity and heart rate (as a proxy for rate of energy expenditure), in a wild migratory sea duck before and after moult migration to test the energy budget limitation hypothesis.3. We show that despite the fact that departing birds forage at three times the level observed during post‐migration, daily energy expenditure (DEE) remains the same when periods before and after migration are compared.4. In an attempt to determine how the birds achieve such a feat, we compared heart rate when active (feeding and flying) for the periods before and after migration and found no significant difference for feeding and flight heart rate. However, heart rate during periods of inactivity was significantly lower during fuelling which together with a reduced time spent flying completely counteracted the observed high energy costs of foraging.5. The time spent active represented a tiny proportion (8–20%) of the 24‐h time budget suggesting that energy minimization and an optimization process may be at work here, confounding any apparent support for the energy budget limitation hypothesis. We thus concluded that similar DEE before and after migration could be owing to the bird’s inability to increase energy expenditure over a certain limit or to the survival costs associated with a certain level of physical exertion. Nevertheless, our results indicate that behavioural, and possibly physiological, compensation may be used as a mechanism to reduce the overall energy cost of fuelling in migrating birds.

Wild geese do not increase flight behaviour prior to migration

Hypertrophy of the flight muscles is regularly observed in birds prior to long-distance migrations. We tested the hypothesis that a large migratory bird would increase flight behaviour prior to migration, in order to cause hypertrophy of the flight muscles, and upregulate key components of the aerobic metabolic pathways. Implantable data loggers were used to record year-round heart rate in six wild barnacle geese (Branta leucopsis), and the amount of time spent in flight each day was identified. Time in flight per day did not significantly increase prior to either the spring or the autumn migration, both between time periods prior to migration (5, 10 and 15 days), or when compared with a control period of low activity during winter. The lack of significant increase in flight prior to migration suggests that approximately 22 min per day is sufficient to maintain the flight muscles in condition for prolonged long-distance flight. This apparent lack of a requirement for increased flight activity prior to migration may be attributable to pre-migratory mass gains in the geese increasing workload during short flights, potentially prompting hypertrophy of the flight muscles.

Enantiomeric selectivity in behavioural and electrophysiological responses of Aedes aegypti and Culex quinquefasciatus mosquitoes

1-Octen-3-ol is a kairomone for many haematophagous insects including mosquitoes. Numerous studies have examined the effects of racemic 1-octen-3-ol; however, few studies have investigated the role of individual enantiomers in relation to mosquito attraction. In the present study, we investigated the behavioural and electrophysiological responses of two mosquito species, Aedes aegypti and Culex quinquefasciatus, to individual enantiomers and mixtures of 1-octen-3-ol, employing a laboratory Y-tube olfactometer and single sensillum recordings. The olfactory receptor neurons of both Ae. aegypti and Cx. quinquefasciatus had a significantly higher response to the (R)-1-octen-3-ol enantiomer compared to the (S)-1-octen-3-ol enantiomer at 10-9 g μl-1 to 10-6 g μl-1. Behaviourally, Ae. aegypti was more responsive to the (R)-1-octen-3-ol enantiomer, showing an increase in flight activity and relative attraction compared to Cx. quinquefasciatus. The (R)-1-octen-3-ol enantiomer caused an increase in activation for Cx. quinquefasciatus. However, the most notable effect was from an (R:S)-1-octen-3-ol mixture (84:16) that caused significantly more mosquitoes to sustain their flight and reach the capture chambers (demonstrated by a reduced non-sustained flight activity), suggesting that it may have a behaviourally excitatory effect. For Cx. quinquefasciatus, a reduced relative attraction response was also observed for all treatments containing the (R)-1-octen-3-ol enantiomer, either on its own or as part of a mixture, but not with the (S)-1-octen-3-ol enantiomer. This is the first time enantiomeric selectivity has been shown for Ae. aegypti using electrophysiology in vivo. The implications of these results for exploitation in mosquito traps are discussed.

GREENHOUSE CLIMATE: AN IMPORTANT CONSIDERATION WHEN DEVELOPING PEST MANAGEMENT PROGRAMS FOR GREENHOUSE CROPS

Greenhouse climate not only has a major impact on plant growth and productivity, but also influences the development, behaviour and interactions among pest and beneficial arthropods present in the greenhouse production system. Studies have demonstrated how temperature and humidity affect the flight activity of pests and their biological control agents. Increased flight activity can increase the dispersal of biocontrol agents and improve the efficacy of pesticide applications. Recent research has shown how seasonal climatic conditions (i.e., temperature, light intensity and photoperiod) affect the parasitism and predation levels of whitefly parasitoids and predatory mites on thrips. In addition, elevated temperatures and low humidity can be used as a control strategy at crop clean up. With the trend to continuous year round production of greenhouse crops, growers in northern temperate climates have started to use supplemental lighting. The effect of continuous or extended lighting on arthropods is not well understood. Also, dynamic temperature regime models are being investigated as an energy conservation method for greenhouse vegetable production. This paper will discuss the current status of our knowledge on how pest dynamics and integrated pest management practices, especially biological control, are influenced by the greenhouse climate. In addition, we will discuss how all year round greenhouse vegetable production under supplemental lighting and how continuous or extended artificial lighting can affect integrated pest management in floriculture and vegetable crops. INTRODUCTION Greenhouse climate (the general spatial above canopy climate and the more specific microclimate within the canopy and around the plant) is a major driving force influencing plant productivity and fruit/flower quality of greenhouse crops (Papadopoulos et al., 1997; van Henten et al., 2006). With the high cost of energy, global warming and the need to protect our environment, energy conservation and energy use efficiency are top priorities of greenhouse growers. Different strategies have been investigated and developed to increase energy conversion, minimize heat loss, and improve energy efficient cooling (Bakker et al., 2008). Growers have also been expanding the production season to essentially year round production where possible to maintain continuity of product supply and increase their competitiveness in the global market share. As a result, this has led to the development of semiand closed-greenhouse systems to improve control of greenhouse climate variables. However, this technology requires substantial a les.shipp@agr.gc.ca Proc. IS on High Technology for Greenhouse Systems GreenSys2009