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.

Species-specific metabolic responses of songbird, shorebird, and murine cultured myotubes to n-3 polyunsaturated fatty acids.

Migratory birds may benefit from diets rich in polyunsaturated fatty acids (PUFAs) that could improve exercise performance. Previous investigations suggest that different types of birds may respond differently to PUFA. We established muscle myocyte cell culture models from muscle satellite cells of a migratory passerine songbird (yellow-rumped warbler, Setophaga coronata coronata) and a nonpasserine shorebird (sanderling, Calidris alba). We differentiated and treated avian myotubes and immortalized murine C2C12 myotubes with n-3 PUFA docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), and with monounsaturated oleic acid (OA) to compare effects on aerobic performance, metabolic enzyme activities, key fatty acid (FA) transporters, and expression of peroxisome proliferator-activated receptors (PPARs). Sanderling and C2C12 myotubes increased expression of PPARs with n-3 PUFA treatments, whereas expression was unchanged in yellow-rumped warblers. Both sanderlings and yellow-rumped warblers increased expression of fatty acid transporters, whereas C2C12 cells decreased expression following n-3 PUFA treatments. Only yellow-rumped warbler myotubes increased expression of some metabolic enzymes, whereas the sanderling and C2C12 cells were unchanged. PUFA supplementation in C2C12 myotubes increased mitochondrial respiratory chain efficiency, whereas sanderlings increased proton leak-associated respiration and maximal respiration (measurements were not made in warblers). This research indicates that songbirds and shorebirds respond differently to n-3 PUFA and provides support for the hypothesis that n-3 PUFA increase the aerobic capacity of migrant shorebird muscle, which may improve overall endurance flight performance.

Honeybee colonies provide foragers with costly fuel to promote pollen collection.

Honeybee pollen foragers departing the hive carry concentrated nectar to use as fuel for flight and glue for forming pollen loads. Since nectar is concentrated by in-hive bees at the cost of time and energy, using concentrated nectar increases the cost of foraging at the colony level. This experimental study explored the potential benefit to honeybees of using concentrated nectar for pollen collection by diluting nectar carried by pollen foragers from the hive. Mass feeding with 30% sugar solution successfully reduced the crop-load-sugar concentration in putative pollen foragers departing the hive, but while those bees tended to increase the crop-load volume, such increase did not fully compensate for the decreased amount of dissolved sugars in the crop load. Feeding 30% sugar solution reduced the pollen load dry weight by approx. 10-20% compared to the unfed control and to another test group fed 60% sugar solution. In addition, the pollen load size and sugar concentration of crop load remaining in returning pollen foragers was positively correlated. These results clearly show the advantage to honeybees of using concentrated nectar for pollen foraging.

Adjustment of fuel loads in stingless bees (Melipona subnitida).

Eusocial bee foragers leave their nest with nectar as flight fuel, therewith reducing the risk of starvation during a foraging trip. Yet, the extra mass results in an increase of energetic expenditure for flight. Thus, bees should tune their fuel loads to the respective foraging situation. In the present study, we investigated the fuel adjustment in the Brazilian stingless bee Melipona subnitida (Apidae, Meliponini). Specifically, we examined whether foragers of this species increase their fuel loads when they have low expectation for nectar collection during a foraging trip. Crop load measurements revealed that nectar foragers carried significantly less fuel on departing the nest than foragers collecting either pollen, clay, or resin. Surprisingly, 75% of nectar foragers left the nest without any detectable amount of nectar, which suggests that the majority of bees collected at nearby nectar sources and avoided an increase in foraging costs. Moreover, foragers increased their fuel loading when repeatedly experiencing empty food sources that had previously been rewarding. These results support our hypothesis and demonstrate that the capability of fuel adjustment is not restricted to honey bees.

Honey bees increase their foraging performance and frequency of pollen trips through experience.

Honey bee foragers must supply their colony with a balance of pollen and nectar to sustain optimal colony development. Inter-individual behavioural variability among foragers is observed in terms of activity levels and nectar vs. pollen collection, however the causes of such variation are still open questions. Here we explored the relationship between foraging activity and foraging performance in honey bees (Apis mellifera) by using an automated behaviour monitoring system to record mass on departing the hive, trip duration, presence of pollen on the hind legs and mass upon return to the hive, during the lifelong foraging career of individual bees. In our colonies, only a subset of foragers collected pollen, and no bee exclusively foraged for pollen. A minority of very active bees (19% of the foragers) performed 50% of the colony's total foraging trips, contributing to both pollen and nectar collection. Foraging performance (amount and rate of food collection) depended on bees' individual experience (amount of foraging trips completed). We argue that this reveals an important vulnerability for these social bees since environmental stressors that alter the activity and reduce the lifespan of foragers may prevent bees ever achieving maximal performance, thereby seriously compromising the effectiveness of the colony foraging force.

Archaeorhynchus preserving significant soft tissue including probable fossilized lungs.

We describe a specimen of the basal ornithuromorph Archaeorhynchus spathula from the Lower Cretaceous Jiufotang Formation with extensive soft tissue preservation. Although it is the fifth specimen to be described, unlike the others it preserves significant traces of the plumage, revealing a pintail morphology previously unrecognized among Mesozoic birds, but common in extant neornithines. In addition, this specimen preserves the probable remnants of the paired lungs, an identification supported by topographical and macro- and microscopic anatomical observations. The preserved morphology reveals a lung very similar to that of living birds. It indicates that pulmonary specializations such as exceedingly subdivided parenchyma that allow birds to achieve the oxygen acquisition capacity necessary to support powered flight were present in ornithuromorph birds 120 Mya. Among extant air breathing vertebrates, birds have structurally the most complex and functionally the most efficient respiratory system, which facilitates their highly energetically demanding form of locomotion, even in extremely oxygen-poor environments. Archaeorhynchus is commonly resolved as the most basal known ornithuromorph bird, capturing a stage of avian evolution in which skeletal indicators of respiration remain primitive yet the lung microstructure appears modern. This adds to growing evidence that many physiological modifications of soft tissue systems (e.g., digestive system and respiratory system) that characterize living birds and are key to their current success may have preceded the evolution of obvious skeletal adaptations traditionally tracked through the fossil record.

The effects of iprodione fungicide on survival, behavior, and brood development of honeybees (Apis mellifera L.) after one foliar application during flowering on mustard.

A semifield study to assess the effects of iprodione on honeybees at label use rates was conducted on a bloom mustard crop. The present study followed the Organisation for Economic Co-operation and Development guideline 75 tunnel test and consisted of 3 groups: the iprodione-treated group, the untreated control group, and the toxic reference item group. In addition to the tunnels used for biological assessments, a tunnel was set up in the treatment and control groups to determine the level of residues in flowers, nectar, and pollen. The major endpoints to assess the effects of the application of iprodione were mortality, flight intensity, behavior, condition of the colonies, and development of the brood. Residue analysis showed that honeybees were exposed to significant residues of iprodione. However, no adverse effects were observed on overall mortality, flight intensity, behavior, or brood development of honeybees compared to control. It is concluded that iprodione does not adversely affect the health of honeybees when applied in agriculture at commercially relevant rates in a worst-case exposure scenario. Environ Toxicol Chem 2018;37:3086-3094. © 2018 SETAC.

Effects of Wheat Germ Oil Concentration in Gel Larval Diets on Production and Quality of Queensland Fruit Fly, Bactrocera tryoni (Diptera: Tephritidae).

Queensland fruit fly ('Q-fly'), Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), is the most destructive insect pest of horticultural crops in Australia. The sterile insect technique (SIT) has attracted significant interest for sustainable management of Q-fly through the mass rearing and release of sterile flies. Cost-effective diets are required to rear Q-flies for SIT. Wheat germ oil (WGO) is the main source of fatty acids and vitamins in gel larval diets that are used to rear Q-fly but is an expensive ingredient. With the aim of reducing WGO cost in gel larval diet, we assessed performance of Q-flies reared on diets that varied in WGO content. Q-fly larvae were reared on two diets that differed mainly in yeast composition ('gel diet 2006' and 'gel diet 2009') and contained 0, 0.03, 0.07, 0.11, 0.15, or 1% WGO to identify reduced concentrations of WGO (and hence cost) without compromising productivity or quality. Diets containing WGO outperformed diets without WGO in development rate, pupal number, adult emergence, percentage of fliers, rate of fliers, and fecundity. Concentrations of 0.11% and above provided full benefit in gel diet 2006 (original formulation 0.15%), and concentrations of 0.15% (original formulation 1.0%) and above provided full benefit in gel diet 2009, and for both diets, a concentration-dependent decline in fly performance resulted from lower doses. Savings can be made in gel diets for mass rearing of Q-fly without compromising productivity by reducing WGO concentration.

Obese super athletes: fat-fueled migration in birds and bats.

Migratory birds are physiologically specialized to accumulate massive fat stores (up to 50-60% of body mass), and to transport and oxidize fatty acids at very high rates to sustain flight for many hours or days. Target gene, protein and enzyme analyses and recent -omic studies of bird flight muscles confirm that high capacities for fatty acid uptake, cytosolic transport, and oxidation are consistent features that make fat-fueled migration possible. Augmented circulatory transport by lipoproteins is suggested by field data but has not been experimentally verified. Migratory bats have high aerobic capacity and fatty acid oxidation potential; however, endurance flight fueled by adipose-stored fat has not been demonstrated. Patterns of fattening and expression of muscle fatty acid transporters are inconsistent, and bats may partially fuel migratory flight with ingested nutrients. Changes in energy intake, digestive capacity, liver lipid metabolism and body temperature regulation may contribute to migratory fattening. Although control of appetite is similar in birds and mammals, neuroendocrine mechanisms regulating seasonal changes in fuel store set-points in migrants remain poorly understood. Triacylglycerol of birds and bats contains mostly 16 and 18 carbon fatty acids with variable amounts of 18:2n-6 and 18:3n-3 depending on diet. Unsaturation of fat converges near 70% during migration, and unsaturated fatty acids are preferentially mobilized and oxidized, making them good fuel. Twenty and 22 carbon n-3 and n-6 polyunsaturated fatty acids (PUFA) may affect membrane function and peroxisome proliferator-activated receptor signaling. However, evidence for dietary PUFA as doping agents in migratory birds is equivocal and requires further study.

Tiny insects against the weather-flight and foraging patterns of Frankliniella schultzei (Thripidae) not altered by onset of rainfall.

To survive in nature, organisms may need to take direct action to mitigate specific dangers from their environmental surroundings. Tiny flying insects are thought to be at particular risk from rainfall that would be of negligible concern to larger animals. The study species Frankliniella schultzei is a thrips that inhabits flowers and feeds mostly on petal tissue and pollen. While found to respond in the laboratory to decreases in atmospheric pressure associated with cyclonic conditions (rather than merely heavy rainfall), their responses to conditions preceding rainfall have not been tested in the field. Initial field sampling investigated the relationship between floral development and sites at which male, female, and larval thrips were generally present on sunny days. We then designed a sampling strategy to test if these thrips can anticipate imminent rainfall or storms and so seek shelter deep within flowers, by sampling host flowers (in sections) on multiple days with different weather conditions. Sticky traps were used to intercept thrips in flight, thus providing a measure of flight behavior across different days. The initial sampling found adult thrips primarily at the petal apex of anthesis-stage flowers where pollen is distributed. We subsequently found that rainfall, atmospheric pressure change, temperature, humidity and wind had no effect on flight behavior of F. schultzei, or on their positions within flowers. These findings suggest rainfall is not a serious hazard for them. Perhaps thrips can survive raindrop collisions during flight, as impacts with water droplets are not expected to break the surface tension.

Frequency shifting reduces but does not eliminate acoustic interference between echolocating bats: A theoretical analysis.

Bats have been observed to shift the frequency of their echolocation calls in the presence of other echolocating bats, ostensibly as a way to reduce acoustic interference. Few studies, however, have examined the theoretical efficacy of such jamming avoidance responses. The present study uses the wideband ambiguity function to analyze the effects of acoustic interference from conspecifics and congeneric heterospecifics on the target acquisition ability of Myotis californicus and Myotis yumanensis, specifically whether unilateral or bilateral frequency shifts reduce the effects of such interference. Model results suggest that in conspecific interactions, M. yumanensis recovers its target acquisition ability more completely and with less absolute frequency shift than does M. californicus, but that alternative methods of jamming avoidance may be easier to implement. The optimal strategy for reducing heterospecific interference is for M. californicus to downshift its call and M. yumanensis to upshift its call, which exaggerates a preexisting difference in mean frequency between the calls of the two species. Further empirical research would elucidate whether these species do in practice actively employ frequency shifting or other means for jamming avoidance, as well as illuminate the role of acoustic interference in niche partitioning.

Homing pigeons externally exposed to Deepwater Horizon crude oil change flight performance and behavior.

The Deepwater Horizon oil spill was the largest in U.S. history, contaminating thousands of miles of coastal habitat and affecting the lives of many avian species. The Gulf of Mexico is a critical bird migration route area and migrants that were oiled but did not suffer mortality as a direct result of the spill faced unpredictable fates. This study utilized homing pigeons as a surrogate species for migratory birds to investigate the effects a single low level external oiling event has on the flight performance and behavior of birds flying repeated 161 km flights. Data from GPS data loggers showed that lightly oiled pigeons changed their flight paths, increased their flight durations by 2.6 fold, increased their flight distances by 28 km and subsequently decreased their route efficiencies. Oiled birds also exhibited reduced rate of weight gain between flights. Our data suggest that contaminated birds surviving the oil spill may have experienced flight impairment and reduced refueling abilities, likely reducing overall migration speed. Our findings contribute new information on how oil spills affect avian species, as the effects of oil on the flight behavior of long distance free-flying birds have not been previously described.

Light oiling of feathers increases flight energy expenditure in a migratory shorebird.

Flying birds depend on their feathers to undertake most activities, and maintain them in peak condition through periodic molt and frequent preening. Even small exposures to crude oil reduce the integrity of feathers, and could impair flight performance. We trained wild western sandpipers (Calidris mauri) to perform endurance flights in a wind tunnel, and used magnetic resonance body composition analysis to measure energy expenditure after birds were exposed to weathered MC252 crude oil from the Deepwater Horizon oil spill. The cost of transport was 0.26±0.04 kJ km-1 in controls, and increased by 22% when the trailing edges of the wing and tail were oiled (<20% of body surface; considered light oiling). Additional crude oil on breast and back feathers (∼30% total surface; moderate oiling) increased the cost of transport by 45% above controls. Oiling tended to decrease flight control, and only half of moderately oiled birds completed the flight test. We then flew birds at a range of speeds to estimate basic kinematic parameters. At low speeds, light and moderately oiled birds had larger wingbeat amplitudes than controls, while moderately oiled birds showed greater wingbeat frequencies across all speeds, and a shift in optimal flight speed towards higher wind speeds. We suggest these changes reflect poorer lift production and increased drag on the wings and body. Oiling will increase the difficulty and energy costs of locomotion for daily and seasonal activities such as foraging, predator evasion, territory defense, courtship, chick provisioning, commuting and long-distance migration. These sub-lethal effects must be considered in oil spill impact assessments.

Low level exposure to crude oil impacts avian flight performance: The Deepwater Horizon oil spill effect on migratory birds.

In 2010, the Deepwater Horizon oil spill released 134 million gallons of crude oil into the Gulf of Mexico making it the largest oil spill in US history. The three month oil spill left tens of thousands of birds dead; however, the fate of tens of thousands of other migratory birds that were affected but did not immediately die is unknown. We used the homing pigeon as a surrogate species for migratory birds to investigate the effects of a single external oiling event on the flight performance of birds. Data from GPS data loggers revealed that lightly oiled pigeons took significantly longer to return home and spent more time stopped en route than unoiled birds. This suggests that migratory birds affected by the oil spill could have experienced long term flight impairment and delayed arrival to breeding, wintering, or crucial stopover sites and subsequently suffered reductions in survival and reproductive success.

Mosaic evolution in an asymmetrically feathered troodontid dinosaur with transitional features.

Asymmetrical feathers have been associated with flight capability but are also found in species that do not fly, and their appearance was a major event in feather evolution. Among non-avialan theropods, they are only known in microraptorine dromaeosaurids. Here we report a new troodontid, Jianianhualong tengi gen. et sp. nov., from the Lower Cretaceous Jehol Group of China, that has anatomical features that are transitional between long-armed basal troodontids and derived short-armed ones, shedding new light on troodontid character evolution. It indicates that troodontid feathering is similar to Archaeopteryx in having large arm and leg feathers as well as frond-like tail feathering, confirming that these feathering characteristics were widely present among basal paravians. Most significantly, the taxon has the earliest known asymmetrical troodontid feathers, suggesting that feather asymmetry was ancestral to Paraves. This taxon also displays a mosaic distribution of characters like Sinusonasus, another troodontid with transitional anatomical features.

Body mass change in flying homing pigeons externally exposed to Deepwater Horizon crude oil.

The Deepwater Horizon oil spill contaminated thousands of miles of habitat valuable to hundreds of species of migratory and resident birds of the Gulf of Mexico. Many birds died as a direct result of the oil spill; however, the indirect effects of oil exposure on the flight ability and body condition of birds are difficult to assess in situ. This study utilizes the homing pigeon as a surrogate species for migratory birds to investigate the effect of multiple external oil exposures on the flight performance and body mass change of birds over a series of repeated flights from 136.8km flight distance. Oiled pigeons took significantly longer to return home, lost more weight during flight, and were unable to recover their weight, resulting in reduction of body weight overtime. Based on our data, migratory birds that were oiled, even partially, by the Deepwater Horizon oil spill likely took longer to complete migration and were likely in poor body condition, increasing their risk of mortality and reproductive failure.

Trouble on takeoff: Crude oil on feathers reduces escape performance of shorebirds.

The ability to takeoff quickly and accelerate away from predators is crucial to bird survival. Crude oil can disrupt the fine structure and function of feathers, and here we tested for the first time how small amounts of oil on the trailing edges of the wings and tail of Western sandpipers (Calidris mauri) affected takeoff flight performance. In oiled birds, the distance travelled during the first 0.4s after takeoff was reduced by 29%, and takeoff angle was decreased by 10° compared to unoiled birds. Three-axis accelerometry indicated that oiled sandpipers produced less mechanical power output per wingbeat during the initial phase of flight. Slower and lower takeoff would make oiled birds more likely to be targeted and captured by predators, reducing survival and facilitating the exposure of predators to oil. Whereas the direct mortality of heavily-oiled birds is often obvious and can be quantified, our results show that there are significant sub-lethal effects of small amounts crude oil on feathers, which must be considered in natural resource injury assessments for birds.

Season and landscape composition affect pollen foraging distances and habitat use of honey bees.

Honey bees (Apis mellifera L.) show a large variation in foraging distances and use a broad range of plant species as pollen resources, even in regions with intensive agriculture. However, it is unknown how increasing areas of mass-flowering crops like oilseed rape (Brassica napus; OSR) or a decrease of seminatural habitats (SNH) change the temporal and spatial availability of pollen resources for honey bee colonies, and thus foraging distances and frequency in different habitat types. We studied pollen foraging of honey bee colonies in 16 agricultural landscapes with independent gradients of OSR and SNH area within 2 km and used waggle dances and digital geographic maps with major land cover types to reveal the distance and visited habitat type on a landscape level. Mean pollen foraging distance of 1347 decoded bee dances was 1015 m (± 26 m; SEM). In spring, increasing area of flowering OSR within 2 km reduced mean pollen foraging distances from 1324 m to only 435 m. In summer, increasing cover of SNH areas close to the colonies (within 200 m radius) reduced mean pollen foraging distances from 846 to 469 m. Frequency of pollen foragers per habitat type, measured as the number of dances per hour and hectare, was equally high for SNH, grassland, and OSR fields, but lower for other crops and forests. In landscapes with a small proportion of SNH a significantly higher density of pollen foragers on SNH was observed, indicating that pollen resources in such simple agricultural landscapes are more limited. Overall, we conclude that SNH and mass-flowering crops can reduce foraging distances of honey bee colonies at different scales and seasons with possible benefits for the performance of honey bee colonies. Further, mixed agricultural landscapes with a high proportion of SNH reduce foraging densities of honey bees in SNH and thus possible competition for pollen resources.

Dietary antioxidants and flight exercise in female birds affect allocation of nutrients to eggs: how carry-over effects work.

Physiological challenges during one part of the annual cycle can carry over and affect performance at a subsequent phase, and antioxidants could be one mediator of trade-offs between phases. We performed a controlled experiment with zebra finches to examine how songbirds use nutrition to manage trade-offs in antioxidant allocation between endurance flight and subsequent reproduction. Our treatment groups included (1) a non-supplemented, non-exercised group (control group) fed a standard diet with no exercise beyond that experienced during normal activity in an aviary; (2) a supplemented non-exercised group fed a water- and lipid-soluble antioxidant-supplemented diet with no exercise; (3) a non-supplemented exercised group fed a standard diet and trained to perform daily endurance flight for 6 weeks; and (4) a supplemented exercised group fed an antioxidant-supplemented diet and trained to perform daily flight for 6 weeks. After flight training, birds were paired within treatment groups for breeding. We analyzed eggs for lutein and vitamin E concentrations and the plasma of parents throughout the experiment for non-enzymatic antioxidant capacity and oxidative damage. Exercised birds had higher oxidative damage levels than non-exercised birds after flight training, despite supplementation with dietary antioxidants. Supplementation with water-soluble antioxidants decreased the deposition of lipid-soluble antioxidants into eggs and decreased yolk size. Flight exercise also lowered deposition of lutein, but not vitamin E, to eggs. These findings have important implications for future studies of wild birds during migration and other oxidative challenges.