Flight Capacity Research Articles

Field Trapping and Flight Capacity of Eucosma giganteana (Riley) (Lepidoptera: Tortricidae) in Response to Behaviorally Active Congeneric Semiochemicals in Novel Silflower Agroecosystems.

Simple SummaryRosinweed is a novel perennial crop being developed for oilseed and biofuel in the midwestern US. A primary pest is the Giant Eucosma Moth (GEM). Little is known about the chemical ecology or flight behavior of adults, but many attractants have been identified from other closely related species. The goals of this study were to evaluate whether any of these compounds could improve the capture of GEMs on sticky cards in the field and determine whether the most attractive volatiles might affect flight behavior in the laboratory. We found that there was significant attraction to (E)-8-dodecenyl acetate, which may possibly be a component in the pheromone blend for GEM. Exposure to these compounds in the laboratory reduced flight capacity. Our results suggest these two compounds could be included in monitoring or management programs for the Giant Eucosma moth.Silphium integrifolium is a novel perennial crop being developed for oilseed and biofuel in the midwestern US. One of the primary pests in this system is Eucosma giganteana (Lepidoptera: Tortricidae). Little is known about the chemical ecology or flight behavior of E. giganteana, but many semiochemicals have been identified from other closely related Eucosma species. Some of these compounds include: (Z)- and (E)-8-dodecenyl acetate, (E)-9-dodecenyl acetate, (Z)-8-dodecenol, (E,E)-8,10-dodecadienyl acetate, and (Z,E)-9,12-tetradecadienyl acetate. The goals of this study were to evaluate whether any of these compounds could improve capture of E. giganteana on clear sticky cards in the field, and the most attractive volatiles might affect flight behavior on a computer-automated flight mill assay. We found that there was significant attraction to (E)-8-dodecenyl acetate in two years in the field, which may possibly be a component in the pheromone blend for E. giganteana. On flight mills, E. giganteana flew an average of 23 km in a 24 h period. The presence of attractive stimuli (e.g., (E)-8-dodecenyl acetate) had arresting properties and decreasing flight distance on the mill by 78 to 80%. The longest flight distances were registered in the morning (4:00–12:00) and were 1.8-fold greater than flight distances and durations at night (20:00–4:00). (E)-8-dodecenyl acetate may be useful in behaviorally based monitoring and management strategies for E. giganteana. Overall, our research expands the knowledge on the chemical ecology of adult E. giganteana.

Galliformes exhibit reduced cardiorespiratory morphology yet similar skeletal mass compared with other gamebirds

Flight is one of the most effective yet energetically demanding means of movement. Its energy costs are normally associated with interspecific variation in efficiency, size of organs, and physiological systems that reflect different flight capacities. Adaptive morphological variation may be constrained by physical demands that vary with body size, but work remains to place allometry associated with flight mode in an ecological and evolutionary context. We predicted that heart, lung, and skeletal masses, as well as tracheal diameter, should show a reciprocal positive correlation and have reduced size in species with poor flight capacities. We measured tracheal diameter together with lung, heart, and skeletal mass in 21 species of medium to large body sized game birds. We then compared 7 of these species categorized as short flyers belonging to the order Galliformes with 14 other species capable of sustained flapping flight. Our comparative analyses incorporating phylogeny revealed that once accounting for body mass, Galliformes had smaller heart mass compared to other species, as shown in few previous studies. Additionally, we detected reduced tracheal diameter and lung mass in Galliformes, suggesting the presence of morphological pleiotropy predicted under the concept of symmorphosis. These organs all showed different levels of reciprocal correlations due to their functional connection. Residual skeletal mass was independent of flight capacity and showed no relationship with heart mass, thus indicating that selection for reduced skeletal mass may have already maximized how light a bird skeleton can be, constraining mass-independent variation in this trait. Our results suggest that cardiorespiratory organs have evolved symmorphic variation in size that reflects costs and benefits associated with different flight capacities. However, our observed differences are confounded with phylogenetic history, so additional comparative studies are needed to rigorously test this hypothesis.

Microscopy imaging and modeling study on the mechanical properties of the primary flight feather shaft of the bean goose, Anser fabalis.

Avian flight feathers have the unique advantages of lightweight and high strength, which play a key role in their flight capacity. In this article, the rachis of the bean goose's primary flight feather was used as the research object. Its compressive properties were analyzed and the 3D microscale was observed by 3D microscope system with a super wide depth of field. The distribution of mechanical properties, section variation of fiber and internal microstructure of rachis were obtained by micro-CT technique. Based on these results, a 3D reconstructed model was established for structure mechanical simulation. The simulation results were close basically to the compressive strength of the actual sample. These results show that the synergistic effect of cortex and medulla can improve mechanical resistance of the rachis. Therefore, the best position (N3) of the primary flight feather shaft can be applied to the bionic design of thin wall structures for energy absorption. This research can provide some guidance for the application of lightweight structural design. RESEARCH HIGHLIGHTS: The internal structure of bean goose feather shaft was observed by micro-CT. The experimental method has a deeper understanding of the compressive properties of rachis fiber orientation. Under the synergistic effect of cortex and medulla, the compressive performance of rachis is better.

Bmmp influences wing morphology by regulating anterior-posterior and proximal-distal axes development.

Insect wings are subject to strong selective pressure, resulting in the evolution of remarkably diverse wing morphologies that largely determine flight capacity. However, the genetic basis and regulatory mechanisms underlying wing size and shape development are not well understood. The silkworm Bombyx mori micropterous (mp) mutant exhibits shortened wing length and enlarged vein spacings, albeit without changes in total wing area. Thus, the mp mutant comprises a valuable genetic resource for studying wing development. In this study, we used molecular mapping to identify the gene responsible for the mp phenotype and designated it Bmmp. Phenotype-causing mutations were identified as indels and single nucleotide polymorphisms in noncoding regions. These mutations resulted in decreased Bmmp messenger RNA levels and changes in transcript isoform composition. Bmmp null mutants were generated by clustered regularly interspaced short palindromic repeats (CRISPR) / CRISPR-associated protein 9 and exhibited changed wing shape, similar to mp mutants, and significantly smaller total wing area. By examining the expression of genes critical to wing development in wildtype and Bmmp null mutants, we found that Bmmp exerts its function by coordinately modulating anterior-posterior and proximal-distal axes development. We also studied a Drosophila mp mutant and found that Bmmp is functionally conserved in Drosophila. The Drosophila mp mutant strain exhibits curly wings of reduced size and a complete loss of flight capacity. Our results increase our understanding of the mechanisms underpinning insect wing development and reveal potential targets for pest control.

Carry‐over effects of larval food stress on adult energetics and life history in a nectar‐feeding butterfly

Abstract Stressful juvenile developmental conditions can affect performance and fitness later in life. In holometabolous insects such as butterflies, development under stressful conditions may lead to smaller adult size, lower reproductive output, and shorter lifespan. However, how larval developmental stress affects energy intake and expenditure in adult individuals is poorly understood. We subjected last‐instar larvae of Speyeria mormonia Edwards (Lepidoptera: Nymphalidae) to periodic dietary restriction (DR) to examine the allocation of energy and nutrients among different life history processes. We measured adult food intake, resting metabolic rate (RMR), metabolic flight capacity, lifespan, and reproductive output. Consistent with pressure to disperse from a poor environment while maintaining offspring number, we predicted that stressed individuals would have increased adult food intake and higher flight capacity. Adult body size was strongly reduced. Contrary to predictions, we found no compensatory adult feeding. Mass‐adjusted flight metabolic rate was reduced, suggesting poor dispersal capacity. Larval DR did not affect adult lifespan, nor did the rate of metabolic senescence change. Larval DR did affect RMR, as stressed females had a steeper slope between RMR and body mass, which may reflect differences in physiological activity due to condition. Fecundity decreased less than predicted based on body mass. Instead of investing in flight capacity, females increased relative allocation to reproduction, which may partly buffer against poor environmental conditions. Understanding the interplay of energy acquisition and allocation to life history traits across the life cycle is vital for predicting responses to environmental change.

Evaluating the effects of water and food limitation on the life history of an insect using a multiple-stressor framework.

Many environmental stressors naturally covary, and the frequency and duration of stressors such as heat waves and droughts are increasing globally with climate change. Multiple stressors may have additive or non-additive effects on fitness-related traits, such as locomotion, reproduction, and somatic growth. Despite its importance to terrestrial animals, water availability is rarely incorporated into multiple-stressor frameworks. Water limitation often occurs concurrently with food limitation (e.g., droughts can trigger famines), and the acquisition of water and food can be linked because water is necessaryfor digestion and metabolism. Thus, we investigated the independent and interactive effects of water and food limitation on life-history traits using female crickets (Gryllus firmus), which exhibit a wing dimorphism mediating a life-history trade-off between flight and fecundity. Our results indicate that traits vary in their sensitivities to environmental factors and factor-factor interactions. For example, neither environmental factor affected flight musculature, only water limitation affected survival, and food and water availability non-additively (i.e., interactively) influenced body and ovary mass. Water availability had a larger effect on traits than food availability, affected more traits than food availability, and mediated the effects of food availability. Further, life-history strategy influenced the costs of multiple stressors because females investing in flight capacity exhibited greater reductions in body and ovary mass during stress relative to females lacking flight capacity. Therefore, water is important in the multiple-stressor framework, and understanding the dynamics of covarying environmental factors and life history may be critical in the context of climate change characterized by concurrent environmental stressors.

Effect of fluctuating temperatures on development, reproduction and energy of oriental armyworm populations, Mythimna separata

AbstractMythimna separata (Walker) is a destructive grain crop pest in China and other Asian countries. However, the effects of fluctuating environmental conditions on M. separata populations remain poorly understood. Here, we investigated how fluctuating temperatures affect the development, reproduction, flight capacity and energy reserves of both migrant and resident populations of M. separata. Our experiments demonstrated that fluctuating temperatures (20–30°C) significantly accelerated development but inhibited adult reproduction and reduced triglyceride reserves in both migrant and resident populations compared with a constant temperature of 25°C, because the larval period, pupal period, lifetime fecundity, mating frequency, ovarian development and triglyceride content significantly decreased, while the preoviposition period obviously increased. A relative decreased tendency of flight capacity was observed for migrants and residents under fluctuating temperatures. We also confirmed that populations and sexes differed in their responses to temperature variations. Mythimna separata residents showed slower development, weaker flight capacity and lower triglyceride content but greater reproductive performance than the migrants under both fluctuating and constant temperatures. Furthermore, female migrants had greater flight potential and triglyceride levels than those of males at both constant temperature and fluctuating temperatures. These findings expand our knowledge of the relationships between fluctuating temperatures and armyworm development, reproduction, energy reserves and adaptive strategies in a complex ambient environment.

Low temperature triggers physiological and behavioral shifts in adult oriental armyworm, Mythimna separata

Migratory insects display diverse behavioral strategies in response to external environmental shifts, via energy allocation of migration-reproduction trade-offs. However, how migratory insects distribute energy between migration and reproduction as an adaptive strategy to confront temporary low temperatures remains unclear. Here, we used Mythimna separata, a migratory cereal crop pest, to explore the effects of low temperature on reproductive performance, behavior, and energy allocation. We found that the influence of low temperatures on reproduction was not absolutely negative, but instead depended on the intensity, duration, and age of exposure to low temperature. Exposure to 6°C for 24 h significantly accelerated the onset of oviposition and ovarian development, and increased the synchrony of egg-laying and lifetime fecundity in 1-day-old adults compared to the control, while female's flight capacity decreased significantly on the first and second day after moths were exposed to 6°C. Furthermore, the abdominal and total triglycerides levels of females decreased significantly from exposure to low temperature, but their thoracic triglyceride content was significantly higher than the control on the third and fourth day. These results indicated that low temperatures induced M. separata to reduce energy investment for the development of flight system. This resulted in the shifting of moths from being migrants to residents during the environmental sensitive period (first day post-emergence). This expands our understanding of the adaptive strategy employed by migratory insects to deal with low temperatures and aids in the management of this pest species in China.

Myoglobin as a conservation‐relevant predictor of short‐distance flight capacity in Neotropical forest birds

AbstractSome forest‐dwelling tropical bird species are unable or unwilling to fly even a few hundred meters across habitat discontinuities, restricting connectivity of isolated populations in fragmented landscapes. Experimental evidence for flight limitation has reliably predicted occurrence across archipelagoes of habitat fragments varying in their distance from potential source populations. Mechanistic explanations for large differences in flight capacity of tropical birds, even over remarkably short distances, have not been tested. We evaluated myoglobin concentration in pectoralis muscles and hearts of eight Neotropical species for which experimental evidence revealing a wide range of flight abilities exists. We found a strong positive relationship between myoglobin concentration in the pectoralis muscles, but not hearts, and average overwater flight distance during dispersal‐challenge experiments. The approximately 2.5‐fold difference in pectoralis myoglobin concentration is directly associated with flight capacity and allows predictions of species or species groups most likely to be impeded by habitat discontinuities and therefore at conservation risk in fragmented landscapes.

Evolutionary Relationships and Flight Capacity of Late Cretaceous Pterosaurs Elucidated by New Azhdarchoid Pterosaur Remains From Afro-Arabia

Evolutionary Relationships and Flight Capacity of Late Cretaceous Pterosaurs Elucidated by New Azhdarchoid Pterosaur Remains From Afro-Arabia

Variability and Genetic Structure of the Montezuma Quail Cyrtonyx montezumae in the Northern Limit of its Distribution

A species’ geographic distribution of genetic variability is influenced by different factors including size of geographic distribution, dispersal capability, mating system, and migration. For instance, a low migration rate among populations may cause a decrease in genetic variation. Such is the case of the Montezuma quail (Cyrtonyx montezumae), a popular game bird with a limited flight capacity that prevents long-distance dispersal. In the northern limit of the species’ distribution in Arizona, New Mexico, and Texas in the United States, the species inhabits oak forests that are separated from one another by deserts. Consequently, Montezuma quail populations are distributed in patches or islands. Knowledge of the species’ genetic structure is likely to help inform habitat management decisions. The objective of this study was to determine patterns of genetic variation in populations of the Montezuma quail using 9 microsatellite DNA loci. We genotyped 119 individuals harvested from 4 populations: Arizona (AZ), western New Mexico (WNM), eastern New Mexico (ENM), and west Texas (WTX). Montezuma quail populations had low observed heterozygosity (Ho = 0.22 ± 0.04) and a low number of alleles per locus (A = 2.41 ± 0.27) compared to other quail species. A global population genetic differentiation index (RST) of 0.045 suggests a weak genetic structure. Max(RST) occurred among pairwise comparisons AZ-WTX, AZ-ENM, and WNM-WTX. A Bayesian allocation analysis indicates that individuals were separated into 3 groups (K = 3), placing the populations of Arizona and Texas in distinct groups apart from the 2 populations of New Mexico, which are in the same group. Despite this differentiation, the Bayesian allocation analysis suggests admixture among populations, which may be an indicator of migration between them, especially between the populations in New Mexico and Arizona. An isolation-by-distance analysis indicates that there is a strong correlation (R2 = 0.84) and suggestive evidence (P = 0.08) of non-independence between geographical and genetic distances, though Montezuma quail populations in the southwestern United States may not be isolated. Climate change projections indicate an increase in aridity conditions in this region, especially in temperate ecosystems where the species occurs. In this scenario, corridors between the populations may disappear, thus causing their complete isolation.

Locust density shapes energy metabolism and oxidative stress resulting in divergence of flight traits

Flight ability is essential for the enormous diversity and evolutionary success of insects. The migratory locusts exhibit flight capacity plasticity in gregarious and solitary individuals closely linked with different density experiences. However, the differential mechanisms underlying flight traits of locusts are largely unexplored. Here, we investigated the variation of flight capacity by using behavioral, physiological, and multiomics approaches. Behavioral assays showed that solitary locusts possess high initial flight speeds and short-term flight, whereas gregarious locusts can fly for a longer distance at a relatively lower speed. Metabolome-transcriptome analysis revealed that solitary locusts have more active flight muscle energy metabolism than gregarious locusts, whereas gregarious locusts show less evidence of reactive oxygen species production during flight. The repression of metabolic activity by RNA interference markedly reduced the initial flight speed of solitary locusts. Elevating the oxidative stress by paraquat injection remarkably inhibited the long-distance flight of gregarious locusts. In respective crowding and isolation treatments, energy metabolic profiles and flight traits of solitary and gregarious locusts were reversed, indicating that the differentiation of flight capacity depended on density and can be reshaped rapidly. The density-dependent flight traits of locusts were attributed to the plasticity of energy metabolism and degree of oxidative stress production but not energy storage. The findings provided insights into the mechanism underlying the trade-off between velocity and sustainability in animal locomotion and movement.

Area, isolation and climate explain the diversity of mammals on islands worldwide.

Insular biodiversity is expected to be regulated differently than continental biota, but their determinants remain to be quantified at a global scale. We evaluated the importance of physical, environmental and historical factors on mammal richness and endemism across 5592 islands worldwide. We fitted generalized linear and mixed models to accommodate variation among biogeographic realms and performed analyses separately for bats and non-volants. Richness on islands ranged from one to 234 species, with up to 177 single island endemics. Diversity patterns were most consistently influenced by the islands’ physical characteristics. Area positively affected mammal diversity, in particular the number of non-volant endemics. Island isolation, both current and past, was associated with lower richness but greater endemism. Flight capacity modified the relative importance of past versus current isolation, with bats responding more strongly to current and non-volant mammals to past isolation. Biodiversity relationships with environmental factors were idiosyncratic, with a tendency for greater effects sizes with endemism than richness. The historical climatic change was positively associated with endemism. In line with theory, we found that area and isolation were among the strongest drivers of mammalian biodiversity. Our results support the importance of past conditions on current patterns, particularly of non-volant species.

Flight and Reproduction Variations of Rice Leaf Roller, Cnaphalocrocis medinalis in Response to Different Rearing Temperatures

Simple SummaryTemperature directly affects the development, adult reproduction, and flight capacity in migratory insects. However, the adaptive strategies applied by some migratory insects to cope with stressful temperatures throughout their life cycles are not well understood. In this study, we evaluated the effects of rearing temperatures in the immature stage (from egg to pupae stage) on the immature development, adult reproduction flight ability, and migratory behavior of Cnaphalocrocis medinalis, one major facultative long-distance migratory pest feeding on rice. Our data suggest that immature C. medinalis that experienced different rearing temperatures had different developmental, reproductive, and migration patterns. Cnaphalocrocis medinalis reared under high temperatures had weaker reproductive capacity and stronger flight potentiality, which might be more likely to trigger the migration. However, those reared at low temperatures in the immature stage had an accelerated reproduction but relative weaker flight ability, which might weaken the migratory motivation of adults.Understanding how species that follow different life-history strategies respond to stressful temperature can be essential for efficient treatments of agricultural pests. Here, we focused on how the development, reproduction, flight, and reproductive consequences of migration of Cnaphalocrocis medinalis were influenced by exposure to different rearing temperatures in the immature stage. We found that the immature rice leaf roller that were reared at low temperatures (18 and 22 °C) developed more slowly than the normal temperature 26 °C, while those reared at high temperatures (34 °C) grew faster. Female adults from low immature stage rearing temperatures showed stronger reproductive ability than those at 26 and 34 °C, such as the preoviposition period (POP) significantly decreased, while the total lifetime fecundity obviously increased. However, 34 °C did not significantly reduce the reproductive performances of females compared to 26 °C. On the contrary, one relative decreased tendency of flight capacity was found in the lower immature temperature treatments. Furthermore, flight is a costly strategy for reproduction output to compete for limited internal resources. In the lower temperature treatments, after d1-tethered flight treatment, negative reproductive consequences were found that flight significantly decreased the lifetime fecundity and mating frequency of females from low rearing temperatures in the immature stage compared to the controls (no tethered-flight). However, in the 26 and 34 °C treatments, the same flight treatment induced a positive influence on reproduction, which significantly reduced the POP and period of first oviposition (PFO). The results suggest that the experience of relative high temperatures in the immature stage is more likely to trigger the onset of migration, but lower temperatures in the immature stage may induce adults to have a greater resident propensity with stronger reproductive ability.

Description and study of the Hippoboscidae Family Samouelle, 1819. (Insecta: Diptera)

Hippoboscidae Samouelle, 1819 is a family of flies (Diptera) consisting of species that are obligatory parasites of several species of mammals and birds. The family includes winged species, with good or reasonable flight capacity, and species with vestigial or even absent wings, incapable of flight and with strong apomorphy. The objective of this collection consists of bibliographical research on the Muscoid dipterans of the Hippoboscidae Family. The research was carried out in studies related to quantitative aspects of the Family, Subfamily and Species (taxonomic groups) and conceptual aspects such as: biology, geographical distribution, methodologies, species, life cycle, damage, economic importance, medicinal importance, biological aspects, monitoring and control and reproduction. A literature search was carried out containing articles published from 1940 to 2021. The mini-review was prepared in Goiânia, Goiás, from September to October 2021, through the. The mini-review was prepared in Goiânia, Goiás, from September to October 2021, through the Online Scientific Library (Scielo), internet, ResearchGate, Academia.edu, Frontiers, Publons, Qeios, Portal of Scientific Journals in Health Sciences, Pubmed, Online Scientific Library (Scielo), internet, ResearchGate, Academia.edu, Frontiers, Biological Abstract, Publons, Qeios, Portal of Scientific Journals in Health Sciences, and Pubmed, Dialnet, World, Wide Science, Springer, RefSeek, Microsoft Academic, Science, ERIC, Science Research.com, SEEK education, Periódicos CAPES, Google Academic, Bioline International, VADLO, Scopus, and Web of Science.

Flight Potential of Western Tarnished Plant Bug (Hemiptera: Miridae).

The western tarnished plant bug, Lygus hesperus Knight, is an economically important pest of several agricultural crops in the western United States. It is an increasing threat to potato, Solanum tuberosum L. (Solanales: Solanaceae), in the diverse landscape of the Columbia Basin of Oregon and Washington. In this study, flight mills were used to investigate the flight capacity of L. hesperus with the aim of better understand its dispersive characteristics in the agricultural landscape. Explicitly, we investigated the effects of biological factors such as generation, gender, and body weight on the flight potential of adult L. hesperus adults collected from field populations during spring and summer of 2019 and 2020. The study flight parameters assessed were distance, activity, velocity, and diel periodicity. In 24-h flight mill assays, a clear dichotomy pattern was found in sum flown distance for adults that travelled 1 km or shorter and adults that travelled greater than 1 km. Individuals from the summer population flew farther and more actively than those from the overwintered population. Female L. hesperus flew farther and were more active compared to males. Adult body weight before the flight was directly proportional to flight distance and number of flights, but not with velocity. Overwintered L. hesperus adults lost a higher percentage of their pre-flight body weight compared to summer adults over the course of the study. To the best of our knowledge, this is the first study that demonstrated that L. hesperus summer adult population has the flight ability to disperse greater distance in the agricultural landscape than overwintered population.

Path Optimization of Joint Delivery Mode of Trucks and UAVs

With the development of e-commerce and information technology, new modes of distribution are emerging. A new type of distribution tool, UAV (unmanned aerial vehicle), has entered into the public’s field of vision. In the background of growing e-commerce, this paper proposes a new delivery mode of joint delivery of trucks and UAVs which particularly has been popular in recent years, with the advantages of prompt delivery, low cost, and independence from terrain restrictions, while traditional transportation tools such as trucks have more advantages in terms of flight distance and load capacity. Therefore, the joint delivery mode of trucks and UAVs proposed in this paper can well realize the complementary advantages of trucks and UAVs in the distribution process and consequently optimize the distribution process. Moreover, the growing e-commerce promotes customers’ higher needs for delivery efficiency and the integrity of the delivered goods which urges companies to pay more attention to customers’ satisfaction. This paper analyzes the joint delivery mode of trucks and UAVs, aims to minimize total delivery cost and maximize customer satisfaction, and builds a multiobjective optimization model for joint delivery. Furthermore, an improved ant colony algorithm is proposed in order to solve the mode in this paper. In order to effectively avoid prematurity of the ant colony algorithm, the limited pheromone concentration and the classification idea of the artificial bee colony algorithm are introduced to improve the ant colony algorithm. Finally, some experiments are simulated by MATLAB software, and the comparison shows that the joint delivery of trucks and UAVs has more advantages, and the improved ant colony algorithm is more efficient than the traditional ant colony.

Size-dependent flight capacity and propensity in a range-expanding invasive insect.

For capital-breeding insects, all resources available for adult metabolic needs are accumulated during larval feeding. Therefore, body size at adult eclosion represents the total energetic capacity of the individual. For female capital breeders, body size is strongly correlated with lifetime fecundity, while in males, body size, which correlates with fitness, is less understood. In capital-breeding species with wingless, flightless, or dispersal-limited females, flight potential for male Lepidoptera has important implications for mate-finding and may be correlated with body size. At low population densities, failure to mate has been identified as an important Allee effect and can drive the success or failure of invasive species at range edges and in species of conservation concern. Th capital-breeding European subspecies of Lymantria dispar (L.), was introduced to North America in 1869 and now ranges across much of eastern North America. In L. dispar, females are flightless and mate-finding is entirely performed by males. We quantified male L. dispar flight capacity and propensity relative to morphological and physiological characteristics using fixed-arm flight mills. A range of male body sizes was produced by varying the protein content of standard artificial diets while holding other dietary components constant. Wing length, a proxy for body size, relative thorax mass, and forewing aspect were all important predictors of total flight distance and maximum speed. These results have important implications for mate-finding and invasion dynamics in L. dispar and may apply broadly to other capital-breeding insects.

Laboratory Evaluation of Flight Capacities of Aedes japonicus (Diptera: Culicidae) Using a Flight Mill Device.

Dispersion expands the distribution of invasive species and as such, it is a key factor of the colonization process. Aedes japonicus japonicus (Theobald, 1901) is an invasive species of mosquito and a vector of various viruses. It was detected in the northeast of France in 2014. The population of this species can expand its distribution by several kilometers per year. However, though flight capacities play an active part in the dispersion of Ae. japonicus, they remain unknown for this species. In this study, we investigated the flight capacities of Ae. japonicus in a laboratory setting using the flight mill technique. We evaluated the influence of age on flight. We recorded videos of individual flights with a camera mounted on Raspberry Pi. We extracted data on distance, duration, and speed of flight using the Toxtrac and Boris software. Our analysis showed a median flight distance of 438 m with a maximum of 11,466 m. Strong flyers, which represented 10% of the females tested, flew more than 6,115 m during 4 h and 28 min at a speed of 1.7 km per h. As suspected, Ae. japonicus is a stronger flyer than the other invasive species Aedes albopictus (Skuse, 1894) (Diptera: Culicidae). To our knowledge, this is the first flight mill study conducted on Ae. japonicus and therefore the first evaluation of its flight capacity. In the future, the flight propensity of Ae. japonicus determined in this study can be included as a parameter to model the colonization process of this invasive vector species.

Identification of genes and gene expression associated with dispersal capacity in the mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae).

Dispersal flights by the mountain pine beetle have allowed range expansion and major damage to pine stands in western Canada. We asked what the genetic and transcriptional basis of mountain pine beetle dispersal capacity is. Using flight mills, RNA-seq and a targeted association study, we compared strong-flying, weak-flying, and non-flying female beetles from the recently colonized northern end of their range. Nearly 3,000 genes were differentially expressed between strong and weak flying beetles, while weak fliers and nonfliers did not significantly differ. The differentially expressed genes were mainly associated with lipid metabolism, muscle maintenance, oxidative stress response, detoxification, endocrine function, and flight behavior. Three variant loci, two in the coding region of genes, were significantly associated with flight capacity but these genes had no known functional link to flight. Several differentially expressed gene systems may be important for sustained flight, while other systems are downregulated during dispersal and likely to conserve energy before host colonization. The candidate genes and SNPs identified here will inform further studies and management of mountain pine beetle, as well as contribute to understanding the mechanisms of insect dispersal flights.